HON INTR ATMOSPHERE
HON INTR ATMOSPHERE MET 1010
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Date Created: 09/17/15
Recommended Key Terms to Know From Ahrens Meteorology Today 8th edition All key terms in Ahrens list of Key Terms at the end of each chapter are highlighted in the text the rst time they occur and are also de ned in the glossary at the end of the book Words in brackets are words I have added to the list They are defined in the text but are not always defined in the glossary at the end of the book Chap 1 p 24 atmosphere nitrogen oxygen water vapor carbon dioxide ozone ozone hole acid rain outgassing density air pressure lapse rate temperature inversion r r39 J39 J r r 39 stratopause mesosphere mesopause thermosphere ionosphere weather climate meteorology middle latitudes middle latitude cyclonic storm hurricane thunderstorm tornado wind wind direction front Chap 2 p 51 energy potential energy kinetic energy temperature heat absolute zero Fahrenheit scale Celsius scale latent heat conduction convection thermals advection radiant energy radiation 39 quot waves 39 photons longwave radiation shortwave radiation visible region ultraviolet UV radiation infrared IR radiation selective absorbers greenhouse effect atmospheric window scattering re ected light solar wind aurora borealis aurora australis Chap 3 p 82 summer solstice autumnal equinox Indian summer winter solstice vernal equinox radiational cooling radiation inversion nocturnal inversion thermal belts orchard heaters wind machines to protect plants from inversions freeze controls of temperature what are the controls of temperature isotherms daily diurnal range of temperature mean average daily temperature annual range of temperature heating degreeday cooling degreeday growing degreedays windchill index frostbite hypothermia liquidinglass thermometers maximum thermometer minimum thermometer electrical thermometers radiometers bimetallic thermometer instrument shelter Chap 4 p 103 sublimation J r quot39 r quot water J 39 water saturation precipitation hydrologic cycle humidity actual vapor pressure saturation vapor pressure boiling p 92 relative humidity supersaturation dewpoint temperature dew point frost point heat index HI apparent temperature hygrometer hair hygrometer Chap 5 p 135 136 dew frost condensation nuclei hygroscopic nuclei hydrophobic nuclei haze dry and wet fog acid fog radiation ground fog advection fog advectionradiation fog evaporation mixing fog steam fog winter chilling of trees cirrus clouds cirrocumulus clouds cirrostratus clouds altocumulus clouds altostratus clouds nimbostratus clouds stratocumulus clouds stratus clouds cumulus clouds cumulonimbus clouds lenticular clouds pileus cap clouds mammatus clouds contrails geostationary satellites polarorbiting satellites Chap 6 p 159 parcel of air stable and unstable equilibriums p 140 neutrally stable equilibrium class notes lapse rate p 141 Chap 7 p 188 precipitation equilibrium vapor pressure curvature effect solute effect collision and coalescence process terminal velocity coalescence icecrystal process supercooled water droplets ice nuclei cloud seeding rain drizzle virga shower snow urries blizzard sleet ice pellets freezing rain hailstones standard rain gauge trace of precipitation tipping bucket rain gauge water equivalent Doppler radar Chap 8 p 216 air pressure barometer millibar hectopascal mercury barometer aneroid barometer station pressure sealevel pressure isobars ridges troughs anticyclones pressure gradient pressure gradient force Coriolis force geostrophic wind friction layer Chap 9 p 251 scales of motion microscale mesoscale synoptic scale planetary global scale viscosity mechanical turbulence planetary boundary layer thermal turbulence wind shear clear air turbulence CAT snow rollers windsculptured trees windbreaks wind waves in water onshoreoffshore wind prevailing wind wind vane anemometer aerovane wind profiler thermal circulations thermal highs thermal lows sealake breeze land breeze sea breeze front monsoon wind system chinook wind Santa Ana wind haboob dust devil Chap 10 pp 281 282 general circulation of the atmosphere Hadley cell doldrums subtropical highs horse latitudes trade winds intertropical convergence zone ITCZ westerlies polar front polar easterlies semipermanent highs and lows Bermuda high Pacific high Icelandic low Aleutian low Siberian high jet streams subtropical jet streams polar front jet stream oceanic front Ekman spiral Ekman transport upwelling El Ni o Southern Oscillation ENSO La Ni a teleconnections Chap 11 p 306 air mass source regions for air masses continental polar air mass continental arctic air mass lakeeffect snows maritime polar air mass maritime tropical air mass continental tropical air mass front stationary front cold front back door cold front warm front overrunning frontal inversion dryline occluded front occlusion cold occlusion warm occlusion Chap 12 p 332 polar front theory wave cyclone frontal cyclone warm sector northeaster convergence divergence cold advection warm advection conveyor belt model dry slot comma cloud polar low Chap 13 p 363 weather watch weather warning analysis numerical weather prediction atmospheric models chaos ensemble forecasting persistence forecast trend forecast analogue forecasting method statistical forecast probability forecast climatological forecast very shortrange forecast nowcast teleconnections Jon Ahlquist 1052006 PreCIpltatlon p 164 column 1 ChaEter PreciEitation Is it evertoo cold to snovin 39 but lime snow when it is very cold for 2 reasons The sin of cloud dI39OPletS and indmps QCapaclty torwatervaporis small at low temperatures Increased saturation vapor pressure around a curved 30 even saturated air can condense little moisture 5 91 curvature We oColgest temperatures occur when Skies are clear Terminal velocity ofdroplets of various sizes Cioudg are igreenmugei bianketg 5mm 39 de39e S 395 mt by 39 5i quot39 Is it ever too warm to snow Snow akes possible coalescence 39 a With surface temperature at 50 F See p 177 Formation orice in the atmosphere GIth once crystals viathe iceqysm process a Preclpltatlon any form ofwater solid or llguld that Rainfmm ice falls from a cloud and reaches the ground lnc dlng Ice differth shapes at different temperatures raln drlzzle sleet snow snow gralns snow pellets Measuring precipitation ice pellets and hail Precip types on pp 174184 How Do Cloud Droplets Grow p 164 Formation of raindrops from cloud droplets is complex Saturation around a cloud droplet Curvature effe ct Water evaporates more easi v from a I I ensauon n I S 0 2 mlcro tiny droplet than from a flat Surface c use rnolecul Twical cloud dropler 20 microme er t e surace of a dropl as fewer neighboring Water Typical rain droplet 2000 micrometers 2 mm mo ecu eg m the mm to W S n M 5 399 g 71Vp 164 u uration vaporpressure is higheraround tiny Rain drople radius is abom 100 quotms grea erman clotid droplets than over pan otWater Note tn larger cloud droplet radius so volume is about quotum eromatermo ecu eg 5 ed a the 100x100x100 1 million quotmes grea er d oplet than above the at Water surface The difference H n cloud droplets become raindrops with a 5 exaggerated 39 quotquot39Pquotquot quotlquotquot million times the volume in a fewtens ofminutes 39 39 I We39ll seet ey grow not by continued condensation but Flatwlrsumca m ny small droplets merging to form a rain drop rig 72p1E5 Red ballslndlcate x First we39ll consider small droplets Watervapurmulecules Mme etisl aiuunu euiveu cluud uiupleiinan Saturation around a cloud droplet Curnpare tne numberufnelghbunng muleculesfura mulecule an a flat surface versus the number at nElganrS when tlie surface is curved Saturation around a droplet p 165 Saturation vapor pressure is largest for smallest droplets HEW Wm M m WWW Droplets 1 um 01 larger penave almost like flat sunace Fig 7 3 n 165 Light blue eirele represents water mniewiE m 5mm Extra nelghburs reir 1003 Cloud droplels grow rial Surface 39 relative humidity is above 85 saturation vapor pressure line Light blue reetangle 1002 300 represents Water 3939 Wee With a flat sunaee Cloud 3 09 Tm 1001 39 droplets 39Urbpgbol spneneal mm 2 9 Water if refative humidity i be uruplet l s 1mm saturaton vapor pressure line 1 2 4 1o MET1010 Intro to the Atmosphere Jon Ahlquist 1052006 Wettable vsunwettable Therefore hydrophobic condensation nuclei Condensation on a large diameter wettable Imagine wettable and unwettable condensation nucleus evaporates less easilyman from a tiny nuclei side by side Suppose incl roughly llle Seine droplet on an unwettable hydrophobic nucleus amount ofwater condenses on each one because ones cupmum Analogy to cultured pearls Cultured pearls are condensallon 0quot ngggslzugscgus made by insening a spherical seed made from UllWellable h I shell Into an oyster The seed is almost as big as nucleus has d a the desired pearl The oyster does not have to small diamelel lame er deposit much onto the seed to produce what Condensation drop on unwettable nucleus has small appears to be a large pearl lfwater condenses garnet gt High sat vapor pressure gt more evap onto a large wettable condensation nucleus it Condensation spreads over entire wettable nucleus appears m be a39arge dr Ple l WhiCh d es quotm large diam gt Lower say vapor pressure gt less evap evaporate as easily because its surface is atter Solute Effect p 165 column 1 How fast does a water droplet fall Some substances like salt NaCl are hygroscopic Termmal veloc39ty p 166 ie water can condense on them at less than 100 Terminal velocily maximum Speed offalling body relative humidity Here is why orce of gravity downward balances air resistance up When water condenses onto hygroscopic material the OL V DS fall la let than Smaller d hygroscopic material dissolves forming a solution like QTel mll lal velocity Table 7 saltwater The molecules in the solution like sat cunuensatiun nucleus El 2 urn essentially u rns ions Na and Cl39 bind closely with water inhibiling a Cluud uruplet 2D lirn El ul rns l erns evaporation Known as olu effect email rain druplet mm 4 ms Curvature effect which raises humidity needed for Similar principle for things that rise buoyantly eg condensation and solute effect which lowers humidity a weather balloon rises at its terminal velocity its needed for rnndensation c 0 er 39 39 re i lance Most condensation in the air occurs around 100 so it rises at a steady rate relative humidity Terminal velocity of a person in the troposphere the terrnlnal velocity ora person without a parachute is about loo mph in 1960U8AlrForce Capt Joseph iltittingeriumped out or a balloon at lozooo reet with parachute Because airis so thin at that altitude he reached about 600 mph berore his parachute slowed him See http hypertextboollt cornfactsJlanl luang shtmi ih ism a D09 over Czechoslovakia exploded at 33360 reet from a Croat terrorist bomb Yugoslav ste a dess yesna vuiovic strapped iii herseat survived the plane s rail onto a snowacovered mountainside She was the only survivor She fractured skull broke 3 vertebra amp both legs was in corna ror ternporaniy paralyze om waist down but made ruii recovery mingja rain ropin a c ou Wit out ice Falling roplets co lide pp 166167 Larger uruplets rail raster anu collide with smaller druplets if here is big difference between Size n rig 74b p lEE H I t il thgucluud Q can 39 sirnlhlmplalslJ 1a primalt a m Example oriuu urupietsinthe path ufa biggerurupiet as may it it directly and in are sweptasiue or me in swept asiue4 may euiiiue b 1 lill cir v Wake capture Tutal 84 eullisiuns MET1010 Intro to the Atmosphere Jon Ahlquist 1052006 Coalescence of droplets that collide 166167 Collision of2 droplets does not guarantee that the droplets will merge coalesce Coalescence more likely when droplets have opposite electrical charge Opposites attract The tiniest cloud droplets have so much surface tension that they may bounce apart when they collide Continuing the example from previous slide if 84 out of100 droplets collide with a bigger droplet maybe 63 will coalesce with it So roughly 63 of droplets will collide and coalesce Collision and coalescence can combine cloud droplets to make rain drops The thicker the cloud amp the faster the rising air in the cloud the longer a raindrop spends in a cloud amp the bigger the drop gets Biggest drops are from thunderstorms up to 5 mm smallest from stratus clouds 02 mm 05 mm drizzle Biggest raindrops are torn apart directly by collisions and by oscillations vibrations caused by collisions Forptation8of ice in the atmosphere If water freezes in the atmosphere it needs to freeze onto something to build an ice crystal Ice nucleus particle on which freezing occurs oNot abundant olce is the best ice nucleus oClay dust is most common effective below 15 C Water in air warmer than 10 C 14 F is rarely frozen V thout ice nuclei the temperature must be almost 40 C 40 F for all water to be frozen At temperatures between 10 C and 40 C there is a mix of liquid droplets and ice crystals Types of ice nuclei p 168 Don t memorize all the processes below Just remember that there are various ways to make ice in the atmosphere Deposition nuclei particles on which water vapor can deposit directly as ice no liquid Freezing nuclei particles that will freeze supercooled water ie liquid waterwith temperature below 0 C 32 F Some freezing nuclei cause freezing when they care immersed in liquid water opromote condensation then freezing ocollide with supercooled liquid water contact freezing Saturation vapor pressure over rce rs less than over quurd water p 169 Ice is a crystal Liquid water is more disorganized Molecules are bound more tightly in ice than in liquid So it takes more energyforwater to evaporate from ice than from liquid Therefore the saturation vapor pressure is lower above ice than above liquid water Fig 77 p 169 Water evaporates more easily from liquid than from ice so greater saturation vapor pressure around liquid than ice This figure exaggerates the difference Difference between saturation vapor pressure over quurd and rce 739Sl39emp eratureEPC 0 e e r 7 6 K diff r39enbe mb Liquid 1 Va po r pressu re nr9r II Q mh a r 2 Satu ratio n Va por Temperature C 1 Fig 78 p 170 Saturation Insert from Fig 410 p 91 vapor pressure over liquid Saturation vapor pressure over water minus saturation liquid water and over ice vapor pressure over ice METlOlO Intro to the Atmosphere cecr stal process in quotcoldquot clouds re c ouds wrth rce p 170 171 Ice crystal process V th both liquid and ice present liquid evaporates amp ice grows Most effective with 100000to 1000000 droplets for each ice crystal If too manyice particles ice crystals are too small to fall and cloud is converted to cirrus without precipitation Tnmnetutmeh c Jon Ahlquist 1052006 History of precipitation theories Falling ice cwstals can Fig 710 p 171 Tneury pr ieererystai prdeess aisu eaiied WegenerrElergerune rindeisen prdeess preeede euiiisiunrcuaieseenee tneury BMW as the s irnp rtant in midriatltudes hitsdpereddied rastney nitutner Snatte drdpietsthatrreeze iee erystais ereating i e nde ei German Airred Wegener prdpdsed ieererystai prueess tneury in iaii budk Tnerrnudynarnies uftneAtrnuspnere but is rnprerarnddsrdr iEliEltneury dredntinentai drift p i7i in i922 Swede TurEier erun reaiized the signirieanee pr this prpeess whiie taking Walks thruugn rug Suielm ofArneriCan m therri aeeretiun rnEIre e s a The euiiisiunreuaieseenee tneurV Was rdpdsed artei piiuts in I Wprid War ii i was repdrted rain frurn trupieai eiuuds With nu iee 4 Explanatory text p 170 Rain from melted ice crystals Ice freezes into different shapes Must rain in rnidiatitudes starts as iee by rneans erthe iee erystai prueess and rneitsas itraiis See rig 7 ii p i73 Water 39eezes into different shapes at i ciudd seeding inieet iee ndeiei intp eiuud tn eneuurage iee different temperatures Look at table 73 rueess First attempts in was used dry iee 778 C p 176 but donit memorize it erystai m initiate freezing in i347 Bernard vdnne dt brutner pr urt unnegutwasrirsttu inieetsiiver indide partieies easiertu handiethan dryieetu funetiun as iee rquiEl pp 171472 in generai rain drdps are nuttearshaped Small rain drdps are ruund Larger drdps are riattened en the butturn byalr resistanee See rdeds semidnp i75 Fig 716 p 176 Common forms ofice crystals Srnaii ta r e Plate CO unln Denniiie Neeoie lt 2 rnrn gt 2grnrn Dendrite 6sided snowflake Neil Why are 6sided snow akes more abundant Sleet amp Freezing Rain pp 178182 than other ice shapes p 176 mil m 4 Z tn 46 C is the range fur Besided snuMiakes dendrites amp rm iwr furtne rnagtlt diff between saturatiun vapur pressure ever iiquid MM 7 WW mm and ice Therefure Besided snuMiakes furrn rnust rapidiy 5 s srin 5quot m 7 M I u irr min 0 m 7 Mnximmrtinuinnm 5 5 Mquot M MW 39mquot 395 s W F WW Ilnin um i A V In It Hit a new lull at I i t t an e A rn iayerabuve a mid surface ean resuitin sieetur freezing rain Fig 7 23 p 782 Sieet iee peiiets rdrrns When iain rreezes perdre reaehing iheg d eddires deepfreezingiayerneargruund 0 ii Freezingrainisrai hatrre safterreaeningtnegruund Requires snaiiuvvfreezing layer near gruund MET1010 Intro to the Atmosphere 4 Jon Ahlquist 1052006 Hail pp 182184 Hail tprrns when MANY elpud drppletstreeze pntp an embryu ufalrnustariy kind at partiele iee ureven an inseet Abuut in pillipn elpud drpplets needed tptpnn hailstpne as big asa gulfball Freezin rain pretty but destructive 39180 Fignipiau Freezing rain n Cumulunlmbus is unly type ptelpud With strung enuugh updrattstp suppprtiee as big as hailtpr the 57m minutes 7 hailstpnns eaeh year causing hundreds uf rnillipns uf dpllars uf darnage Renard size hailstpne lriAurura NE pin a June was p ids butllghterthan lam hailstpne atcptteeVille KS See hllp WWW usatnday cumMeathernews r r l rhall uneix hlrn Terminal veluclty DfCuffeevllle hailstpne estirnated tp pe apput nu rnph l Ices aircraft See quotfocusquot section at top ofp181 Measuring rain pp 184185 Measuring snow p 186 F g 7 29 p 1 Because of drifting snow depth is measured in 3 or magmfyme e mwe ram depth 1 H gimme2e more nearby places and averaged tips 7 29 i 7 an m Then a column of snow is melted to determine the A tipping bucket rain auge rig liquid water equivalent 7 3 has 3 Faquot Bf b JEkE Sma Maswinuim Typically 10 cm of snow melts to 1 cm ofwater a f ite y quot 3 mp ie 101 ratio of snow depth to liquid equivalent Tram gm 5 lt D m mmes 5 So 10 inches of snow would melt to 1 inch of liquid V 3 a Very wet snow may be 61 and very light powder 7 a 70Vnillawcyllnuei Toward winter39s end large compacted snow drifts may be 21 7 Fig 73up lEE l mm l Radar Estimates of Precipitation pp 186187 Radar waves are scattered by rain or snow but not by cloud droplets too small Strength of radar echo is related to rain or snowfall rate so radar can be used to estimate rainfall On TV they almost never show you the Doppler part ofthe display only the echoes that can be seen with a traditional radar In chapter 14 we39ll see how a Doppler radar is different from a nonDoppler radar Satellites are also used to estimate rainfall particularly in the tropics High cold cloud tops are usually tops ofthunderstorms Calibrate by comparing cloud top temperature measured from infrared photo with rainfall measured at ground MET1010 Intro to the Atmosphere Jon Ahlquist Chapter 1The Earth and Its Atmosphere Oyerylew or the Earth s atmosphere oThe sular systern OCumpusnlun brine atrnbsphere Stgreerlhuuse gases oThe early atrnbsphere nVertlEal structure otthe atmosphere oAbrretlbbk at alrpressure and an densly otayers brine atrnbsphere oThe radrbsbnde Weather ballbbn sWeather and ellrnate OMeleurulugyr Abrlelhlsmry oSatellrte syrewbtthe weather oWeather Stellmale rn uur lNes Solar System p 2 gure not to scale lst4 planets are small and rocky Mercury tanks llke Earth s rnoon Venus coyered wrth clouds sunace ls hundreds or degrees hut Earth as mllllurl rnrlesrrorn Sun a rnrnrbr lrghtto trayelto Earth Mars Asterbrd belt nut shown rnrrgure 4 gas glarlts Juplter and Saturn Uranus Neptune ls letters or last 3 spell sun Plutu dwan planet ruckvvaterlcejruzerl rnethane IAsteruld belt between Mars l Juplter Remembering Order of Planets You can use the following sentence to help you remem er the order ofthe nine lanets My very e ucated motherjust showed us nine Each word ofthe preceding sentence begins with the letter ofthe next planet as you go out from the Sun Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune uto As ofAugust 2006 Pluto was reclassi ed as one of several dwarf lanetsquot because a number of other small similar bodies have been identi ed beyond Neptune Atmospheric Composi ion pp 28 Hydrogen pnrnary component otSun amp gas glarlt planets H drogen a certa n rnary rnponent or Earth s early atmosphere but grayrty on Earth as other rnner planets Earth s arr roughly dunn nrtrogen N2 and 2m oxygen oz Next must abundant gases are water yapor and argon type orrnert gas each about We at atmosphere Othergases presentrn rnrnute amounts rnuch less than l n trace gases ume are greenhouse gases whrclr rnrluence the Earth s ternperature Greenhouse gases pp 56 more in chap 2 u The two most lrnpprtantgreenhp about on or atmosphere and ca u D4 n We ll say rnore rn chapte r Anrount or co2 has been steadlly rncreasrng due to burnrng Graph below shows lastsu years Also note annual cycle rn co2 lower rn surnrnerwhen plants absorb rnbre coz hrgher rn wrnter when plants dre and release co2 Flg l 5 p a co2 amount water yapor HZEI use gases rburl droxrde coz about r 2 ye lbs lBBE lB75 lBEE lBBE ZEIEIE Greenhouse gases cont other lrnportant greenhouse gases that are trace gases 9 Methane produced by plants a anrrnals 9 Nltruus pxrde laughrng gas n cnlorolluorocarbons CFCs also destroy ozone rn stratosphere whrch protects lrte trorn ultrayrolet UV lrght Wthout uv absorptlorl rnost plants and anrrnals would the ltstratosphenc ozone were cornpressed to sea leyel pressure lt would be a layerabout l8 rnclr thlck zone rn stratosphere helptul to he byabsororng uv but harmful nearsurtace when breathed mall39l part otsrnog Ozone arnount recoyenng Research pu rshed rn 2006 MW lllmw sr rm el r ux MET1010 Intro to the Atmosphere Jon Ahlquist 9142006 Special Topic Breath of Fresh Air p 4 Pressure pp 910 You are constantly breathing history Pressure forcearea Pick any historical person and key event in his or 39 M53quot 555 leve39 Pressure 0 lb51139 es 30 inches of mercur her fe39 Exampl 1013 millibars mb units used on TVfor hurricanes QAFChimedeS Showing Eureka 1013 hectopascals hPa metric system oJuIius Caesar saying Veni vidi vici If the surface pressure changes by a few percent that is a oCIeopatra talking with Marc Anthony BIG Chang oMartin Luther King Jr saying I have a dream g 39ighs gg ggziug iy 7 above average Each breath you take may contain a molecule Recordiow sumce pressure exhaled by that person at the chosen event 870 mb in Typhoon TIP 1979 14 below average Because of small changes in surface pressure pressure is measured to 5 digits of accuracy to tenth of millibar to follow weather changes Bed of nails This bed has 1nail per sq inch By the calculation in the last graphic this is only 15 lb per nail which is no problem Example of pressure calculation How much pressure does someone exert when lying on a bed Solution Pressure force area so consider someone who weighs about 150 lbs Area lying down e 6 ft x1ft 72x12 e 750 sq inches Therefore pressure in lying on a bed 150750 15lb per square inch which is very little Let s test this Air Pressure Decreases with Increasing Height Dens39ty 9 a Airis heldto the Earth by gravity 7 i v y 39 Dens39ty maSSVOIUme ie it has weight High density means lots of material Pressure at any given height is Im rum 7 mass in small volume due tothe Weight 0fthe air that lies Exponential decrease with height ab Ve that he39ght39 w quot Density amp pressure atop Mount This isiust like ayhuman tower g Everest are about 30 of Sea level Pressure on one s shoulders gm quotW Vaues depends n the We39ght ab Ye39 Air density near surface Person at the bottom experiences about 1 kgms 2 lb cubic yard the greatest pressure quot Air at the surface experiences the in 7 Density liquid water density is 1000 we r 3 greatest pressure and pressure a kgIm Ever 1700 IIIBSSUblc yard decreases as you go up w quot so lqu39 water IS mes M runa4 denserthan air p 10 g 18 MET 1010 Intro to the Atmosphere 2 I on Ahlquist 9142006 Why does density decrease with height Atmospheric layers p 11 fig 110 1 Air like any gas is compressible Layers amp Layers determined by temperature structure That is you can squeae it into a to Squot 7 Hot top oxygen smaller volume making it denser Thermsphere absorbs sunlight At the surface where the pressure is greatest the compression is greatest so the density is greatest As pressure decreases going up compression decreases so density es Mesopause 85km L l 39 g Warm middle i Mesosphere i T i 50 km Stratopause gt ozone absorbs decreas stratosphere 39 ultraviolet Tropopause 10km quot Troposphere quot Warm surface39 L 1 Ground absorbs TEMPEEATURE s quotquot9ht i W tuna p lOtig l8 Radiosonde Weather balloon p 14 fig 4 757 100tor balloon and instruments Launched 1 hour before Radiosonde Equipment quot 39 39 Has a radio transmitter Winds track bailoon sradlo Balloon pops oyer 15 mi up paracnutes down some are 35 ecoyered sonde balloon rernnant 60120 u pei lert paracnute orignt red 39 Weather instrurnents wnite box a losondeln alr Radiosonde launches b NWS at FSU Radiosonde launches by NWS at FSU t Balloon tracked autoniatically by disn antenna inside Wnite spnere on roof or Love Bldg t Alltenna s tilt aii le aZimutn and azimuth CW angle trorn nortn adiusts to a Latex balloon inrlated by tying it to nozzle in upper picture Helium used or sarety iiistead or nydrogen Ceiling opened in inrlation o 3 8 a 3 o e g a 3 Loye Bldg lower picture aXirniZe str Badi n eslaun rec vedSlg 7 amlprn Eastern Standard Tracking tne baiio Time 8 aniprn E n s is tne o l nr noon Wind spee ampdlr c rnidnignt39Coordinated Universal Tlrne cornputed at yar ous eig ts METI 01 0 Intro to the Atmosphere 3 Jon Ahlquist 91 42006 Worldwide Radiosonde Network Rough numbers Weather and Climate pp 16 17 W PJ39IO Radiosonde Reporting Sites ntmmmlm US 108 sites Weather condition of atmosphere at any Medmade 39 luln 17 V13 39 Ethans 53th Canada 34 sites particular time or place MeXiCOI 1 5 Sites Climate weather statistics 39 World 1936 S39tes Climatological norrnals average over last 30 2 39aunCheSday at years current period used is 1971 2000 most places Different colors of dots on p denote different companies that make the radiosonde equipment Western History of Meteorology p 17 Storms Of II Slzes p39 20 fig39 13913 eJ 7 ca 340 BC Aristotle wrote Meteorologica Largest to srnallest meteoros Il39fted up in air Mid latitude storrn 1 597 Gali eo invents thermometer Hurricane 1643 Toricelli student of Galileo Thunderstorm invents barometer 1843 Morse invented telegraph 1940 s Radiosondes amp radar 1 950 1 st cornputer weather forecast 1 960 1 st weather satellite TIROS 1 990 sDoppler radar network NEXRAD Tornado too small to see on satellite picture Galileo s thermometer Barometer looks similar Weather in Our Lives pp 20 24 Approximate deaths per year in the United States due to Heat waves 300 to 1 OOO Cold spells 1 50 Floods 150 p 23 col 1 Weather Watch Lightning 90 Web search NASA site Various winds 90 Tornadoes 7O Tropical cyclones 25 For more information see httpwww dasuwyoedugeerlscwxnoteschapO3nathazardhtrnl The hyphen after www is part of the address For information about severe weather and safety in general in Florida see httpwwwFloridaDisasterorg METI O 1 0 Intro to the Atmosphere 4 Jon Ahlquist 9172006 Chapter 3 Seasonal and Daily Temperature uWhy the Earth has seasons Local seasonal var39 io onaily m ohth and yearly tem peratures oUse oftem perature data ir temperature and human comfort Measuring air temperature Chapter 3 requires 3D thinking Some students have trouble with chapter 3 Von must think three dimensionally to understand relationships between the Sun and Earth If you have trouble with the EarthSun relationships make drawings from different perspectives andor use a ball to represent the Earth The Earth rotates around its axis in the same direction that It revolves around the Sun Dlremoh or thlEIrl aruunu Sun East anh Day nght W351 Earth s axls North PD The Sun rises in the east sets in the west Earth s orbit around Sun nearly Circular 5 orbit is almost a circle around the Sun slightly farther from Sun in July II January Fig 31 p 56 Eart July 147 39 lion km4P 152 million km Avg distance to Sun is 150 million km 93 million miles varying only 2 durin year rtth When a light beam is perpendicular to a surface it illuminates a smaller area so there is more heating When a light beam is not perpendicular to a surface 39 39 rea sothere is less heating Sun most concentrated heating at noon A 17 A I The Earth tilts 235 degrees relative to its orbital plane Because Elt the Earth s tllt Huurs of dayllght yary Wlth lamuoe Alvva s 12 hrs at eouator Approaehes 24 hrsoay asyou gm tuvvaru the pale h the summer hemlsphere Approaehes u hrsoay as you gm tuvvaru the pale m the Wlnter hemlsphere Moreless lntense sunllght h summerWlnterhernlsphere METlOl 0 Intro to the Atmosphere Jon Ahlquist 9172006 Solstice and Equmox fig 33 p 57 Earth s aXlS always paints in same direetien teyyard Nurt ar Because of erpit areund Sun tilt ielatiye te Sun yaries during year Sept March sideways tilt SeptMarch N Hem March Sept N Hem tilts away from Sun tilts toward Sun 1 June N elem has WW ax tilttoward Sun Iquot mum ZN e N Hem has max tilt away from 5 When do seasons star 7 Solstice and Equinox cont u Solstices 21 December 21 June i Equinoxes 20 March 22 September For simplicity think of 21st of month for all ofthem Learn these dates i Winter solstice minimum solar energy input to winter hemisphe 5 Summer solstice maximum solar energy input to summer hemisphere W U to n to S U39 l er 21 the winter solstice really the 1st day of Winter p 62 t Cut the year into four equally long period A Cente m on the warmest 91 winter on the coldest 91 days By that de nition summer starts around 1 June and winter starts around 1 December for inland areas Winter and summer start later in the month for coastal areas Also inland areas cool offfaster than coastal area s in fall and warm up faster in spri Solstice and Equinox cont l2 hrs ptdaylight and night at all latitudes Sun nyerhead at nddn dn eguat r s aXlS rlut tdwardaway rrdm Sun buttu side On all dates ether than e uindx l2 hrs at daylight at eguatdr but not elsewhere More than l2 hrs daylight in summer hemisphere less than l2 hrs daylight in Winter hemisphere Sun dyerhea nddn at same latitude in summer hem sdme tllttuWardavvayfrurn sun in summererlterhern sdlstiee t 24 hrs dayightdark pdleward uf antlaretie eirele in summererlter hemisphere Sun dyerhead at nddn at 23 5 deg latin summer hem t Maxtllttuvvard sun in summerhemisph ere Solstice and Equinox Hrs of daylight FOR NORTHERN HEMlSF HERE uppuslte for Southern Hem Z1 Deeemper Minimum hours at dayight Z1Detembertu Z1Jurle Nu daytu ay June Maximum hours of daylight Z1Jurletu Z1December Nu ufhuurs ufdayllght deereasing rrdmdaytd day h l2 hours at daylight 21 March to 21 September l2 prmdre hours of daylight 21 September l2 hours of daylight 21 September to Z1March l2 urless huurs ufdayllght Examples On lSJarluary lt l2 hrs at daylight Stdays getting lunger On 4Julygt12 huurs drdaylight adays getting shdrter At what latitude is the sun directly overhead at noon Graph not in ook 23 5 N Trdpie ur aneer Equator 23 5 5 A Trdpie pti apnedr 5ep2l DeeZl r21 Jurl21 5ep2l Sun never overhead outside of 235quot N to 235quot Overhead once peryearat235quot N or n s v ead twice peryear between 235quot N and 235quot 5 Example At 15quot N 39 39 MET1010 Intro to the Atmosphere Jon Ahlquist 91 72006 Where is the sun at noon at other latitudes fig 36 p 58 Take N Hem latitudes as positive 8 Hem as negative If Sun is overhead at noon at latitude Lsun then at noon at latitude L sun is LSun L degrees down from vertical toward N if positive toward 8 if negative Examples At noon on June solstice the Sun is overhead at LSun 235 N Use the figure above to visualize Therefore At equator the sun is 235 O 235 2350 north of vertical At 47 N the sun is 235 47 235 2350 south of vertical 1 At QOON the sun is 235 90 665 6650 south of vertical H v gt7 H H H Sun at various latitudes fig 38 p 61 a 1 Energ received on 21 June fig 35p 58 Ener y received on 21 Dec from 7 ed Almos constant across Northern Hemisphere Roug ly constant In Southern Hemisphere Decreasmg to 0 In Northern Hem latitudes Top of atmosphere Error in graph This graph should go to 0 at latitude 90 235 665 N Insulation gt Lam39s surface 5 ie at Arctic Circle a not south of 60 N 7 C I I I I I I I I I I I I I I I I o 15 30 45 an 75 9c 90 75 60 45 3O 15 O 15 3O 45 60 75 90 Equator Latitude deg N North Pole Latitude OS Equator Latitude 0N Heating Difference between Annual avera e energy in ut vs energy output Summer and Winter 7th ed VISIb e light inpu max in tropics min at poles Infrared output roughly same at all lats Temperature difference between equator and pole small in summer large in winter Fig 36 p58 I Dallcll Balance Balance Radiation is more spread out at northerly latitudes Dericl 7 Infrared outpu I I 1 2 but more hours of a l 39 I 5 I l39lea eat daylight compensate 395 5 transfer lransler I A roaching 8 Pole E lt73 39 pp g g Heat moved by advection in atlnos and ocean radiation is more g E I I n plus transport of latent heat I ggnpgg mgnur spread out and I n I l I I fewer hours of daylight 90 so 30 0 30 50 SI 39i NDrll i l Fililutle Z SDLJEH METl O 1 0 Intro to the Atmosphere 3 Jon Ahlquist 9172006 Temperature near surface in daytime figs 311 amp 312 p 65 Temperature enange Witn neignt reuueeu it Wian peeause utturpuient lelrig M agtlt uaytime temp at surface Anna i9 u u i iit i n 39i Temperature near surface at night figs 314 amp 315 p67 Minimum nighttim Temperature enange Witn temperature at su d neigntreuueeu itWin y e ace peeause ufturbulentmixing Summary of last two slides e mp ratu between a and nignt ueeur atsurtaee uue tu surtaee heating by VlSlblE rauiauun during day and euuiing by infrared emissiun at mg t be several degrees differentthan uttieiaiiy temperature nearsunaee an a calm nignt is nine stups during nignt tem erature Wlll probably urup even turtner uue tu euntinueu rauiatiunai euuiing and lack ut vertical mixing tnat Wuuld mix in Warmer air Temperature throughout the day to 13 p em perature increases whe 39c 39ngenerg w en inc ming energy eguais outgoing energy Netcooiing er e or sunrise net warming in ernoon METlOl 0 Intro to the Atmosphere Controls of Temperature p 7176 u Read pp 7176 on your own Then explain to yourself why the author Donald Ahrens lists each ofthe following as a control of temperature on 71 Latitude Land and water distribution Ocean currents Elevation Jon Ahlquist Wind Chill Temperature pp 7778 Wind Chill temperature or wind Chill index 39 temperature under calm conditions at which your face would cool at the current rate of cooling given the existing temperature and wind speed a A thermometer even if exposed to the wind measures regular temperature not wind chill temperature Wind chill temperature is computed using a formula See footnote p 77 Results are presented as a table for simplicity because formula complicated If air temperature is higher than skin temperature wind would not cool rather heat blastquot Evaporation important for cooling at high temperatures heat index chap 4 pp 99100 9172006 Wind Chill table p 77 Exam fT 0 ampiiiiin 20m hWC4 F Green reulon frostbite In 30 min es ia its OCU ermometers S OH read In the shade p 81 Thermometer actually measures the temperature of thermometer To measure air temperature thermometer must be at airtemperature Air is clear absorbing little sunlight so thermometer should not be allowed to absorb sunlight either Hence it must be in shade Max amp min temferature thermometers fig 27 8t 3 pp 7 0 Max thermometerllke m w39lm m old fever thermometer iiiliwiamiartiu Mll l thermometer has run owlmoron slide index marker i that is pushed back by iniiil u no4 iLiit i tutu ireJr rim Min amp max thermometers locally t Thermometers are in w ite of Tallahassee METlOl 0 Intro to the Atmosphere Electronic thermometer Surne components like resistors capaclturs can be made so thattheir properties change With temperature Thlsvarlable response can be calibrated to give temperature Uriit ih piotuie is rrom WalMart ihthe ease75 l F lNarldlrl External temperature sensor at end of 10 foot wire Jon Ahlquist 9172006 Bimetallic thermometer thermostat ranu he mseunneeung WEI etecmcat eumaets tnstde the war turmng g cm ur err heaung Dr atr undmumn Hume thermus tat vwm cuver remuved EtmetaHtE thermumeters MET1010 Intro to the Atmosphere Automated Surface Observing System A303 flg 3 0 p81 A505 effun by Nauunatvveamer Semee va5 FAA e Dept of D 1292006 Jon Ahlquist Cha ter 11 Air Masses Defn and Formation p 286 Air asses and Fronts Air massLarge body ofairthat has similar 7 horizontal temperature and moisture characteristics Air mass classification Air mass 50m r99i ns Air mass formation Air must remain over a surface with nearly uniform conditions for days Air masses can form ooyer ocean or fairly flat landllght Wll ldS needed orarely over rnldalatltudes too changeab e Warm r0quot 5 onot over mountains not un OWN quotW s Usually marked by regions of high pressure where winds are weak but may be a heat lowquot Air mass modi cation Fro s n Cold Fronts Back door cold fronts a ryline Air Mass Source Re ions and Their Paths f39 11 287 Types of Air Masses Table 111 p 287 Source Polar P Tropical T 39 Region Cool or cold Warm or hot surface surface Continental cP cT Hot dry stable aloft unstabl c Dry e surface air Maritime mP m Moist Cool moist arm moist unstable usually unstable Coldest and hottest air m has greater temperature extremes than Extremely cold cP air is called continental Arctic cA sses are continental land water What kind of air mass is this Flig 111 What kind ofair mass is this gig 1111 p 295 p 286 Temp from 15 to 27 deg Map for 29 June 1990 Temp from 9 39510108 deg F i 39 r 1 Upper no ur new iquot 1 eaen palrls markslet temperature stream luvver nu l H marks d pulnt 1n pusltlun er degrees F upperrle subtruplcal Answer At W9 W least Eurith Cuntlnentai 39 nentzlppelar mma started as CT 1 untlnental arctic ex MET1010 Intro to the Atmosphere Jon Ahlquist 1292006 Air Mass Modi cation 287 290291 Example of air mass modi cation mP air Pp becomes continental polar g 117 p 291 asses in uence areas into which they move Read chime opening p 235 Maritime bbiar rnF39 air biuvvs bnsnbre at NW US was Muisture rains nut as air basses river rnuuritairi ranges 235572 Z5th27gyrxglgfgadgzggg beturnirig cuntinentai Cary bbiar cuui Nut as Enid as air place that raac es s rrbrn ariada Recall that chiriuuks uccur W Err Warming br air by rain is signiricant QFor exampie a 001d airrnass that reaches Fiorida is Warrrierthari Wheri it rst carne south from Cariada QWheri 001d air moves over a Warmer surface it becomes Liristabie at ieast riearthe surface QWheri airmoves overa 001d surface it is stabiiiZed Vaciiic Oiymni Gasman Romy wESr om Maduraii Muwinir Mnuhtai sasr Example of air mass modification Fig 2 p 289 Purple shading marks Lake effect snow f 1 289 areas With heavy lakeeffect snows Why are shaded areas Lake always on th 7 east and not the w 39 NV west side ofthe WI Ml lakes PA Answer Midlatitudes OH experience westerly r 39 i IL IN winds Lake effect snow occurs in narrow band from a few miles up to 30 miles wide on the east ie leeward downwind side of each Great Lake Exam le of air mass modi cation cP air becomes maritiine over ocean g 115 p 290 Fronts pp39 296 306 Front transition zone between two air rnasses Frontsoccuriri areas or low pressure troughs Witn w nigner pressure on eit erside cP air moves over warm GulfampAtlantic and picks up nd rain 3 ii 0 E 2 9 m 1 lt m 2 L0 All rronts have shallow slopes Witn cold airbeiow arid arm all above Frontal concept pubiisiied in 1919 due to Norwegian tearn btnor Jacob Bierkries iater pioneered El Nino researcn in 1957 METlOl 0 Intro to the Atmosphere Jon Ahlquist 1292006 WeatherMa with Fronts c IdF t f39 1115 299 fig1112 p297 0 mn lg p A steep 001d front has a stope nsrng r unrt up r0150 unrts back a Warm arrabove Passage of cold front table 112 p 300 Back door cold front p 329 at NE W Regurar cutdfrunts usuatty e muvetuvvard 5 5E urE berng pushed by Westerty Wrnds Gus1y sn trng Wm NW Warm Sudden dmp Steadytatt Mrnrrnuranen Steadynse sharp use u Bank duur u1dfrunts Ltuuds rnereasmgcr Tenter rnuvetuvvards 5W berng usn Cs Tau Br Ch snuwers snuwsnuwers en I Occursumeumes arcing haze byrmpruvrng harp drup Dew purnt CrZErrms eserrmsrrams TEUZtDWenng cumutuscurnu1us rm m r Hrrtmutu r tratnrumutu Frg rr 11p sun Warm Front fig 1119 p 301 passa mfrom Typrcat warm front stapes even tess than a cotd front Dunng Usuatty stower movrng than a cotd front Pressure Usuattyfattrng Levetrng err Strgnt use r Unwed bytatt Ctuuds ems k Ns Stratustype Cteanngwrtn S e Maybe 01 1n summer Preerpttatrun Dnzzteurnune Msrbrtrty Fan 1n haze Fem but rrnpruvrng Dew purnt Steady use Steady nrse than s1eaey errms Cserrrus1ratus Cbeumurummbus Cueumurus METlOl 0 Intro to the Atmosphere 3 Jon Ahlquist Coldoccluded front fig 1120 p 304 Transition zone between cP air to west amp mP to east Coldoccluded fronts impact the eastern US 1292006 Ccld type C5 A5 Ns Warmoccluded front fig 1121 p 304 Transition zone between cool mP air to west amp cold cP to east Coldoccluded fronts impact the west coast of the US 11 Wm39n ml 11mm E Dryline p 303 Dryline dewpoint front moisture boundary with continental tropical cT dry hot air to west amp maritime tropical mT moist warm air to east Occurs in spring or early summer in western half of TX OK and KS Hot dry air from desert Southwest to west moist warm from Gulf of Mexico to south Severe thunderstorms can occur along drylines Fig 4 p 303 on next slide shows contrast in temperature dew point and wind direction across a dryline We ll say more in chapter 14 about dryline thunderstorms pp 375376 Fig 4 p 303 Dryline In red Hot dry cT air westerly winds warm m0l5tm0aif I 93 l southerly amp93W winds 32 35 V 91 Ga 99 691 101 quot37quot 25 KO 3 as 33 58 W 0 70K 97 35 550 g 59 6 a 723 West of dryline 70 Very hot and dry 3 East of dryline j Warm and humid MET1010 Intro to the Atmosphere HET 1mm FaH emperature an water In w in v 39 s r tty cool sometimes cold in mama EM Ew Pacific wat r HET 1mm F3 9 NET 1mm F3 9 g 91339 aw Mm av warm mm mma war a a y mm u Hg i E W vim mam npe a urzz Data 15 Coastal town W aim we m4th am he mm k HWQ al a e wawtwmuta e er a Jon Ahlquist 10182006 Chapter 8 Air pressure Atmospheri Pressure PP 192193 Forces and 9183325i liri39ihn t Airigressure is due to the ht ofthe air above a oint Pressure at upper levels p h wwarm Cause of pressure and how it varies with height Mercury and aneroid barome ers Surface pressure ie station pressure M M Adjusting surface pressure readings to sea level i Surface and upperleiiel weathermaps Newton s laws of motion ssure gradient force Coriolis force Example Foucault pendulurn Geostrophic and cuniedwin s Flow near surface and effect of friction Vertical rnotion the air is because that determines ho expanded the column is oUpper level low if column is cold oUpper level high if column is warm 5 39ii 2 i iiwiii his Example Hurricane has up erlevel 53 Mercu barometer high pressure due to warm h in eye wall HEEL PP 19 39196 invented by TDrlEEiil student Dr Gallleu ln iB43 Air pressure pushes mercury up glasstupe Heightcifrnercuiyis Ma39alw prupurtlunal El pressure Mercury used instead cifvvater because lt ls su rnuen denser Height cif mercury ccilurnn an in eight cif er ccilurnn an ft rd maid hi Fig 158 All Latentneat release ivesahurricane a Sarne principle furdrlnklng stravv W s i a lcivver pressure in stravv sci fluid pushed up tupe Mercury parcirneterncitsci pcipular WW pecause mercury is a hazardcius quot W material sci the vveig e pressure decreases atthe surface H rneans high ccirnpared tci sarne level ncit highei than surface Aneroid barometer pp 195196 FFligm ll espofg pssure at sea level luezl rnb nF39a 32 Ell in highest recurded sea level r la A d b pressure Slberla Deeernbe BE W i an I Wss 39 quotelm aroimeerd luaa rnp highestieccirded sealevelpressurelrlUSMlles p HE A w l eta seae can anerol ls CW MT DEEEWber 1983 5 39 quot9 firmfreek w39mmquot 1013 nib AVERAGE SEA LEVEL PRESSURE 5 f 139 i BEU rnp Deep rnldrlatltude lcivvpressure system 5 U59 39quot1 925 rnh Luvvest sea level pressure in HurricaneAndrevv Levarsyxllma l ohome barometers Mlaml AugusLiBBZ Anlrndnnll weamer balloons est reccirded sea level ressure civerthe Atlantic EEZrn p Ocean Hurricane Wlirna Oetuber m5 au 9ma ed Wea her B7B rnp Luvvestreeurded sea level pressure anvvvhere stations 3 o E T Horizontally pressure changes only a few A MET1010 Intro to the Atmosphere Jon Ahlquist 10182006 Adjusting surface pressure readings to sea level pp 1 6198 Pressure changes much more verticallythan horizontally Near the surface going up 100 meters decreases pressure by 10 mb 1 Ears are an aneroid barometer our ears are uncomfortable in elevator or plane takeoff Horizontally a pressure difference of 10 mb may occur over 1000 km 600 miles Difference in surface pressure between 2 cities is mainly due to difference in elevation To see horizontal pressure differences pressure readings are adjusted to common altitude sea level Adjusting surface pressure readings to sea level pp1 6198 Rem effects on a Air pressure reported on radio or TV is always reduced to sea levelquot oving altitude effect leaves weather air pressure Surface weather map p 198 are reduced to se Trough or ridge elongated region of low or high pressure ldenlify a ridge and 2 i ii Pig Happiae Upperlevel chartsog he material below replaces pp 1992 Get info mainly from weather balloons satellites amp commercial aircraft carrying automate equipment Weather maps drawn for levels throughout troposphere u Fastest wind jet stream is in upper troposphere maximum at 3000040000 feet 300200 mb Middle troposphere 18000 feet 500 mb Most moisture is moved in lower troposphere maximum at 5000 10000 feet 850700 mb Water vaporsatellite image shown on TV depicts UPPER tropospheric moisture Also helps show Newton s Laws of Motion pp 202203 i 151 law Object at rest will stay at rest and an object in motion will stay in motion as long as no force is exert d on ob39ect 2quot law Force exerted on object will produce an acceleration given by a Fm where aacceleration Fforce and mmass of object Acceleration involves change of speed and or direction Let39s explore the forces responsible for the wind Pressure Gradient Force p 203204 Pressure gradient pressure girrereneewuistariee iseipar iirie pr constant pressure Ori maps m sea level pressure iseipars are drawn every Amp Pressure gradientlarge Where iseipars are eieise Pressure gradientrurce pushes uh air EauSngWlftd El bluvv 9 Prupuniuriai tn pressure gradlem QPCIlfitS mm lghtulm pressure pg 813 I a Onwesisiueerpigp 3 m4 quot WT pressure gradient mm i AirhbZEIEIkaZm MEIka We u rEast Oneastsideuf igp l V ess egradient MET1010 Intro to the Atmosphere Jon Ahlquist 10182006 Coriolis Force pp 204206 Coriolis Force continued ii Coriolis force apparent force pseudoforcequot we As we ride with rotating Earth Coriolis force appears observe because we are riding on a rotating Earth to push wind toward right of direction of motion in Appears to push an object to the side without Northern Hemispherei toward left in Southern changing its speed Ham39s here Fig 8 in p we T p e push sideways is greater otlie fasterthe object rhoves otlie closerto the North or South Pole the object is Ball moves straight on a non rotating platform Ball appears to Coriolis force due to Earth39s rotation is very weak curve 0 S39de 0quot Only important when all other forces are weak mmm magmaquot I Two slides ago we looked at a 4 mb pressure evequot oug ac 3 difference across 2004 0 km hori path is ralght 0 zontally That is a weak force so Coriolis force matters Coriolis Force continued i Coriolis force is too weak to matter in daytoday life Coriolis example Foucault pendulum Foucault pendulum seen at science museums Very fast pitcher can throw baseball at 10 h 9 P quotdulum SW39quot95 ha and f 391h mm high 45 ms for Stance of 60 5 fee 134 m from ceiling Earth rotates but pendulum s plane of pitcher39s mo me late This takes SW39quot9 e quot 04 seconds The ball is de ected to right only about Eanh39 quot 395 Seems m S that wevare taquot quotaryquotd DA mm by Coriolis area that the plane ofthe pendulum s swmg is rotating i Puzzle lfyou are locked below deck in a ship that SIOWI 39 sails mroughom ocean how can u 9 wha Foucault pendulum knocks down domlnos or little here you are in Supposed answer of seeing bowling pins placed in circle around pendulum whether water spirals down drain in clockwise or 0quot more informationi do a WSb seamh 0quot counterclockwise direction is WRONG Coriolis Foucauu Pendmumquot For examplei 5991 force is abom 10000 quotmes mo weak m accoum for http www calacademy urgpruductspendulumlrldex htrnl acceleration of water rotating around a drai Coriolis example Foucault pendulum Geostrophlc Wind pp 206208 cunni srmE greatest at eeostropnic Wll ld VWld i which Coriolis force is equal pales suturthe rim Brit d o oslte to pressure gradl r eostrophlc Wlhd blows straight arid is PARALLEL re than a iew loo rn ab rlearlygeostrophlc Near In Nort Application We surface the actual Wlhd is surface there is also frlctloh astre Suhurha edu eeple mlspherei W press re to left of wind sIuderltsballterSuuthF39ul Lookat rnovlrlg clouds At cloud level low Epuucaultmml pressure lies to let ofcloud motion eenuitiensrer L rig amp 2m Air ushed experiment raw trein high tuvvard lew pressure liuuu rtelevatien i red arrews eerielisreree paaurnp parallel te isepars lnwpressure te lert geustruphll Wind MET1010 Intro to the Atmosphere Jon Ahlquist 11132006 Chapter 12 De nition xamples from history Polar from theory Life cycle Typical paths oflows and highs MiddleLatitude Cyclones Midlatitude Cyclones Cyclone low pressure area hundreds ofmiles in size with yclonicquot circulation ie counterclockwise C W in the Northern Hemisphere clockwise CW circulation in the Southern Hemisphere Synonym storm OElthel39 lllldrlatlttlde ol39troplcal OTHlS chapter focuses on midrlatltude cyclones Older meaning of cyclone is tornado as in Iowa ate Cyclones named in 1895 We are not using this sense here Anticyclone high pressure area with anticyclonicquot circulation CWCCW in MS Hem Examples of lmportantMidlatitude Storms in History not in book i 1588 Spanish Armada defeated partly by English navy with superior armaments and tactics and later by bad storm 150 Spanish ships started only 65 returned March 1776 Storm caused British to cancel assault on US troops under Washington t 6 June 1944 DDay invasion of France in WWII Allied forecasters correctly forecasted break in storm allowing invasion when Germans thought storm would continue Development of concept of a front Basic concepts developed byNorwegian team published in 1919 amp 1922 Team members oyilnelrn Bierknes leader physics professor odakob Jacob Jack Bierknes son of yilhelrn and chief author 22 years old in 919 30 years later he id fundamental El Nll lO research at UCLA eHalyor Solberg oTorBergeron Swedish pioneer ofice crystal process of rain forrnation p 93 ofAnrens Don39t memorize their names but these guys had od ideas in several areas of meteorology Example of 8020 rule 80 of ide s productivity come from 20 of workers Polar Front Theory pp 310312 Midlatitude storms develop where there is strong horizon al temperature contrast s st in winter when northsouth temperature contrasts are greatest Initial source of ener temperature contrast wi h warm air risin and cold air sinkin precipitation and air being pushed from high towar low pressure Cyclogenesis development or strengthening of a midlatitude cyclone Life Cycle of Cyclone fig 121 p 311 am Culd frurlt moves fasterthan warm frunt Lqu starts at kink in K D Separated frurn Warm muls t air luvydies E w e Headytu ego e Mustlrlterlse ni unwedquot W Slur 39 a furrn atquotlriple paint MET1010 Intro to the Atmosphere Jon Ahlquist Chain of C clones at Various Stages of Life Cycle fig 122 p 312 M Mature cyclune uver At arm Triple point F39lace wnere e new Cyclune I here See starting in lee culurnnl u Ruckletns 311 39 Cycluiie un Eastceiast stilldeveluping 11132006 Typical Winter Path of Lows Toward NE fig 125a p 313 L Ed39s as N179 R L Clippar L L 39 Hatteras Low Colorado L Low a 7 L Gull Low Typical Winter Path of Hi hs Toward SE fig 125b p 13 H H Where and Why Storms Start p 313 Alung East 3an and Gulf Coast in winter stron temperature cuntras t between culd land and warrn water On east side DfRDEklES Culurnns or airare stretened vertically as they descend tne mountains Like a Spinning rigure skatervvhu extends ner arrns upward tne coiurnn or air will spin raster Fig 1219 32B Vertical Structure of Midlatitude Cydon s surface pressure decreases so air 30000 must be leaving column mg For surface pressure to m quotm drop air must be diverging anquot divergenceupper level convergence a Lowlills NW toward cold hiqh lills SW toward warm Upper level disturbances Long amp S on Waves fig 129 p 318 Lo ngewave disturbances in upperelevel conditions are nearly stationary ortewave disturbances move eastward inore quicklyal iiearlylhe speed ofthe Wind often tnggenng precipitation s MET1010 Intro to the Atmosphere Jon Ahlquist 11132006 Simplifications for this course The preceding slide is all you need to know about the section on pp 316318 titled Upperlevel Waves and Surface Stormsquot The Necessary Ingredients for a Developing Wave Cyclonequot pp 318321 You can skip the special topic on p 321 Jet Streaks and Stormsquot Resume on p322 onve or ets in eation to eatures in Sate lite Picture Fig 12 14 p 323 Conveyor Belt Model pp 322323 Air rises as sinks in midriatitude storms on a siant eonyeyor peit Warm eonyeyor e a in Warm seetor glides up Warm tront produces stratus eiouos turns toyyaro NE or E Coio eonyeyorpeit Wnd bluwsrrum eastbeluwnunhem part oi ann on i risesamprnoyes towaro NE Witn iet Dry eonyeyor oeit upperrlevel dry air to W or storrn sinks as it approaenes eoio tront ereating dry slut penino ooio frunt rig 1213 p 323 Northeasters Nor easters p 314 Midrlatitude cyclones tnat eyeiop or intensify aiongtne i 39quot mi east coast in a Name refers to Winds from the NE north of the warm tront along tne coast The nor easterin tnis rnap 11 Dec 1992 caused liundreds of millions of dollars or damage Sometimes nave hurricane Characteristics sucri as an Example of Nor easter Su erstorm of March 1993 The Storm of e Century References Meteors09y Today uur textbook pp 323 e 325 VWWV Emmet uear eduresuurcescasesmj1mar93 irnpaet on Tallahassee on Saturday i3 Mar 1993 Snuvvl Aiso luvvest pressure eyer reeoroeo at Tallahassee Nationai irnpaet 0 27B killed 3 tirnes oornpineo oeatn toii or 73 due to Hunieanes Hugu and Andrew e aanevvs noaa goystoriess334e ntrn 0 Many reeoros fur iuvv ternperature ano snuMall o Eyery airporton east eoast eioseo Oniytirne one storrn nas yer oone tnat Maps of Superstorm of March 1993 Fig 1216 p 324 Fig 1218 p325 ArrJows denote MET1010 Intro to the Atmosphere Jon Ahlquist 11 132006 Colorenhanced infrared photo of The Perfect Storm not in book Storm of the Century fig 1215 p 324 For more info search Web gr Perfect Stomquot Compare to sur ce 1 weather map g 1216 p324 for nearly the Officially called the Halloween Nor easter of 1991 Strengthened when combined with remnants of same time Hurricane Grace to form an unnamed hurricane 39 Yoarm f quott 395 9le Wave heights peaked at nearly 100 feet Satellite photo of Halloween Nor easter of 1991 after becoming a hurricane Yellow area inland of warm front is light rain amp m nimbostratus Black region crossing Florida indicates high clouds along cold front thunderstorms amp intense precipitation center ofthe storm Polar Lows Arctic hurricanes pp 355356 Polar Lows Arctic hurricanes pp 331332 Like hurricanes polar lows oHave diameter of 300 600 miles smaller than midlatitude storms oAre heated by warm ocean oHave intense precipitation oMay have an eye and spiral cloud bands oDissipate rapidly when they move over land Differences between polar lows and hurricanes oPolar lowshurricanes form in the arctictropics oPolar lowshurricanes form during Nov March winterJune November summer and fall oPolar lowshurricanes produce snowrain Develop during winter Fig1223 P 331 NovMarch overwater poleward of polar front at arctic frontquot where frigid airfrom land meets much warmer but still cold air overwater Some have comma shaped cloud band like midlatitude storms Others as in this photo have eye like a hurricane amp spiral cloud bands METlOlO Intro to the Atmosphere 4 Jon Ahlquist 1232006 Chap 14 Thunderstorms Thunderstorms p 368 amp i As the name indicates all thunderstorms produce thunder and hence lightning hey are quotconvectivequot storms associ ted With r buo ant rising air Ordinary thunderstorms u H quot Atmosphere is often conditionally unstable p 145 Severethunderstorms Microburs meaning that air isntwarm enough to rise on its wn Initial rise to condensation level and instability ccurs because cUneqtiai surface heating creates warrn bubble andor cAir iiows over upwardaslopirig topographv andor cAir is iifted pv converging cooier air perhaps frorn an tlierthunderstorm which Wedg Lll l ieath a T39storms most common in summer but can occur in on when cold air aloft creates very unstable Mesoscaie convective systems 2 Squaii iine Mesoscaie convective comp ex Muiticeii thunderstorms move 0 right ofwind Dryline thunderstorms Thunderstorms and Han Lightning and iightning safety cool seas Tornadoes and water spouts situation Florida can have winter thunderstorms Thunderstorm Structure Ordinary Thunderstorms pp 368371 Anvthunderstonn contains rising airupdraft and Sinking i Ordinarythuridersturm urpuprup Dr airrmassthundersturm air downgrart fcirrns within an air rnass having iittie verticai shear i e change updraft Warm a msmg m doud n 000R by work of cfwind speed aridDr directidnwith increasing height expanmn reacheg dew pom amp form CUWMS Crow Cumulus orgrowth stage the updraft fiiis the ciciud That s whv there is a ciciud As cdndensaticin fcirrns iatent heat is Dow irsinwng in cioud Drierairfrorn around the m the Emma my Upmnmngemgh cloud is entrained mixed in at the clouds s de r ase rna g tci prevent srnaii drdpiets frcirn raining nut m Mature stage cioud becomes taii enoughthatdropiets entrained airis cooied as rain evaporates into it and become arge and heavy enough to ram out ome C Oud cooied i inks Also faiiing rain rags own air DO n m We Stage W W 1 0 m a Cell updraft and downdraft pair Thunderstorm rnav Up a a M w mm m m 5mm fa 00mm one 0W0 09 s dnce he du ndraft gets guing itirnpedes e Supercell thunderstorrn with singie verv strong ceii uitirnateiv wiis the updraft in an erdinarvthundersterrn Dissipating stage updraft weakens downdraft dorninates duwndraft Cell f arnpie ll Etlm urnuius cdngestus Mature curnuicin mbus Cumulus stage vvarrn air rises e Rain staRss crr art insg Dciwndraft cciciis bv expansiun ddwndraftfrdrn dcirninates vapdrcdndenses cciciiing hv evapdratidn sci air cant i curnuius fdrrns i drag frcirn faiiing rise Stthufidefr rain Gustfrdntsfdrrn stdrrndiesi Fig 14 iii 369 at urface METlOl 0 Intro to the Atmosphere 1 Jon Ahlquist Severe Thunderstorm pp 371373 Defn any thunderstorm that produces hail andor surface wind gusts of 50 knots 58 mph or more andor a tornado The longer a thunderstorm lives the stronger it can get Few ordinary thunderstorms live long enough to become severe Long lived severe thunderstorms usually form in regions with vertical shear wind speed ampor direction change rapidly with height which separates updraft amp downdraft Shelf amp Roll Clouds Photos by Bill Boutwell httplwwwcrhnoaagovdlhlalbum2htm Shelf Cloud Mesoscale Convective Systems MCS pp 373375 MCS Ensemble of convective thunderstorms producing precipitation over a wide area Two types of MCS s have names GSquall lines u Line or are or bow of thunderstorms along or ahead of cold front z Longest and most intense squall lines usually form ahead of fronts 50 200 miles ahead pre frontal o Mesoscale convective complex 9Very large round collection of thunderstorms Collection of thunderstorms that is not a squall line or mesoscale convective complex is given the generic term mesoscale convective system More details on following slides MET 10 10 Intro to the Atmosphere 1232006 Thunderstorm with separated updraft amp downdraft Fig 1413 p 376 Tmpupausc Drler air Shellcloud 3 FCUS Cloud Sl ble air Triggering a PreFrontal Squall Line Pre fontal squall lines can be triggered by ascending part of upper level waves generated at cold front Fi 149 374 g p Ascending part q of wave Cold front 3 Cold air 1 Jon Ahlquist 1232006 Squall line on radar VEllDW and red in this radar unage rndreate rntense rainfall assuclateu With a sddau line This squall lrne rs an arc and ab nce un radar rs respunslble fur a bew eend beedr attne leadrng edge err rntense luwrlevel wrnds wnren push the gustfrunt anead rapidly tnereby lifting tn 1r1nfruntuf1t rs called a dereehu brbnddneed duhrRAVrshu Mesoscale Convective Complex MCC pp 374375 Verylarge area at urganlzed thuliuersturms in summer can be 1nnntrrnes bigger than a single ndnderstunn identified in satellite pictures by huge were at cirrus eludds frum thunderst rms Fig 141m 375 Often exrst uyemlght mm mm urmDrE Prwlue significant arnudnt err rarn fuerdwest Term MCC nutas pupular nuw because 1tls unly based run he satellite yrew wnren dues nuttell ybd wnat rs gulnu u n underneath the cirrus deck u trce t un erstorms move to right of Wind direction individual ndnderstunn cells rnuye rudgnly at speed and directan Dlenu at lEIDEIEIft 3 km abuve surface Snutherly Winds frum Gulf Dr MEXlEEI feed Warm mulst air tn the suuth nght srde er a multlcell tndnderstunn New cells grbw an the sudtn nght srde Cells an nurth left side Elf are shut Elf frum buuyant air and die Microburst pp 376 amp fig 1418 Microburst intense downdraft from cloud base concentrated into a small area Can knock over structures homes trees etc Public confuses this damage with that of a tornado but microburst knocks everything in one d39 39o w n gure below at a Pilot throttles back at b loses lift with tailwind at c amp plane falls HQ 1418 a Brquot p 378 Dryline Thunderstorms pp 375376 uzeaua buundary between marltlmetruplcal WT and cuntlnentaltruplalc l arr Mu edrnrndnly DEEur in western Texas owahdrna 1 Kansas in sprlhg and early summer when seen 4m uftlrne e thundersturrns rnay furrn an drrdst east ed a dryllne Cold dry air Dryline CP L thunderstorm dry air 7 er my Warm Uri quot3 mursl Fig 1412 arr P 375 W K 0t understorms appear so right or so dark The multicell photo g 141 p 371 shows that a thunderstor c ppear quite bright The shelf and roll cloud pictures show that a thunderstorm can appear quite dark How can a thunderstorm appear both bright and dark Answer It depends on which side ofthe cloud you are If you are on the same s39de e sun is the cloud appears quite bright because almost all the light that enters the cloud is scattered back in the general direction ofthe sun Very little light is transmitted through the cloud so the back side ofthe cloud is quite dark METlOl 0 Intro to the Atmosphere Jon Ahlquist 1232006 Days er ear Wlt I storms E al What ha ens to sunll ht In a cloud PP 9 p 3 1 3 gs 1422 at 1423 lfacluud lsthlEkEr Fla la 3 p 519 Flurlda etstne mustthurldere tnan 1 km Wnlon l Sturms ln oontlnental Us l TWWEVSWW Enalrlly tr ora munM n Re med gt75 daysyrfurvvhule state e W WWW tnun erst quot gtBEI days fur oentral FL l 1 x 1 or less or llgntls Tnunderstorm domaln extends 1 transmltted tnrougn frnm FL NWtu oentral Mldvvest the oloud also max ln Culuradu e Flg 15 2D Abuut5 o otllgntls sun y Veryfevvthurldersturms along apsorped ln tne a a Paolno ooast Hag oloud W3 5 quot Ed Maxlmum number or nall days days peryear Abuut 95 otllgnt ls n DEEurslnCuluradulustNEof rorleeted1seattered WWW a reglonal tnunderstorm back out Elme oloud XlS 5m L T El 1 in 7 Cloud tn39le39kness Lightning amp Thunder pp 383388 Light travels at 186000 milessecond so we see lightning almost instantaneously Sound travels at 1000 feetsecond so count seconds from ash of lightning until rst sound of nds is the number of 1000 o s ested processes I volve lce which corre ates with cumulonimbus clouds which have ice tops being thunderstorm clouds Lightning does strike twice Lightning Down amp up several times ngntnlng strlke oeglns Wltn duvvrlvvard stepped leaders W stepped leader nearstne surtaoearetum stroke comes up frum ground The man rlow or current goes up to tne cloud and ls tne ongnt part or a llgntnlng flash Typlcally leaderand return st ukes lesstnan a second along tne r are repeated 34 tlmes ln same patn tnrougn tne alr Flg 14 26 p 386 Lightrllrlgl u n more llkelytu nlt tall ooleots so repeat nlts to tall ooleots are llKEly rneretore do not take snelterundertre l Ben Frankllrl lrlverlted ne llgntnlng rod ln 1752 He rerused to patent lt oeoause ne dld rlutwarlt to make muney on sometnlng so lmportant tor puollo sate Flg 3 p 389 e l7EIEI s 5 me s g e nttp MNWW evulveflsh cumfreewrlte franklgt ntm tor detalls METlOl 0 Intro to the Atmosphere A fulgurlte as large astne one oelowm can post nundreds or dollars at a tuck g14 shup Jon Ahlquist 1232006 Li htning flows in the metal body Lightning safety ane 0 a car or air p Lightning kills average of 7090year in US a You are safer inside a car than outside riot Floods km about me same number because ofthe rubber tires lf 39 39 Spats miles through the air to reach the car the 6 inches be ween the bottom ofthe car and the ground are recemlnd39V39dualdeams39mml Florida has far more lightning deaths and injuries You are safer because if lightning hits it will ow quot 3quot aquoty her S F S D 39iquot9 19593920 1vfw4 Had amp through the metal car body around you rather 1979 Irll red by llghmlng Iquot Florldai quot 05 Iquot me than through you en39 sula which has more lightning and more people Same thing for airplanes It is not uncommon for quot13quotth 6 quot COaSl 39 i an airplane to be hit bylg ri rig lfyou can hear thunder you can be hit by lightning Governor Jeb Bush39s plane was hit by lightning in February 2003 Lightning safety Summer Lightning in Florida Most lighting deaths occur where it is not raining Lightning strkes per eople are in oors when it is raining Golfers 5 kilometerper farmers and construction workers are particularly vulnerable because they are outside Go inside if you here thunder lfyou are c u ht outside and feel your hair stand up or your skin tingle 39 he http fuelberg met fsu eduresearchf plilightning html Many strkes at Tampa ow through your body 3030 rule lfyou hear thunder less than 30 seconds away 30000 feet stay inside for 30 minutes after the last thunder 39 Fewer strikes over a See ViMM oridadisasterorg for more information water ll iC udii ig Lake Okeechobee is 55 iii a db Lightning above thunderstorms p 384 mammawim circulation that reaches the ground g 1432 p 390 Funnelcloud like a tornado but the circulation does not reach the ground Photo from nan WVWV srh nuaa guvbria suNeysssDBDlDl htm MET1010 Intro to the Atmosphere 5 Jon Ahlquist 1232006 Tornadoes Tornadoes occur in all 50 states Upper it Tornadoes In years Typ39ca39 d39a39 e e 10 39 600 yards39 hm can be as Lower it Tornadoes per year per 10000 sq miles large as 1 mile across a Wind speeds characterized by Fujita scale 1 ovveak F04077 mp F 7110 mp 21 3 25 QStrong Hmoriso mph F31607200 mph W I39li oVroient F42007260 mphF52607320 mph Most tornadoes are F0 or F1 1 l l mu v u Only a few percent are F4 or stronger mm 5 u Forward speed 2040 mph but can exceed 70 mph quotWWW Most move with upperlevel winds from sw to NE quotM rquot V Take shelter in sturdy building awayfrom glass and cover your head eg bike or football helmet mummy Tornado Formation Supercell pp 394398 V Associated with strong multicell thunderstorms Enormous thunderstorm 510 miles in diameter often with mesocyclones embedded in supercells Updra s as strong as 90 Ms 100 mph 3 oftornadoes form in March to July Can travel 300 miles a Most common between 400 and 600 m but can can produce hail as big as grapefruit occur at any hour so NOAA weather radio with an Can Spawn large S rong mmadoes alarm is a good idea 39 fr Can form isolated or at the southern end ofa squall R d d d line where it39s fed bymoist air wagging 355mm Less than 15 of supercells produce tornadoes lfa supercell contains a rotating thunderstorm a PM quotWquot WP few miles across called a mesocyclone tornado WWW mum b quotBaa gums formation is much more likely nslelZElE htm ornado inside Mesocy one inside Supercell Fig 1441 p 396 Ste 1 Vertical shear Viewfrum suutheast luuking nurthvvestvvith t creates ro a ion u d honzomal a V suuthwestsvv at left and nurtheas N trrght 7 a 39 c t Thunderstorm v g Overshuutmgtup AM updraft tilts this 099 I I 1 rotation upright 99 Mammal r a m l 9 air Mesucyciune Reapggnk a 39 uuw raft supercell 39 hive Heavy Light M d ram ram v Turnad W D NE tornadoes spin CW we Hg 5 m p 385 METlOl 0 Intro to the Atmosphere Jon Ahlquist 1232006 Tornado resources on Web Web search will uncover lots of photographs ofwall clouds and Small selection of good sites includes National Geographic httpIMMMnationalgeographiccomforcesofnature lnteractive ndexhtmlsection t Has interactive activities Storm Prediction Center httpMMMspcnoaagov httpMMMharkphotocom One of many sites with storm This chaser is a medical docto information and tornadoes chase pictures r Doppler Radar pp 399400 All US National Weather Service radars have Doppler capability Like regular radars Doppler radars send of radio waves and time how long it takes echoes to return From this the distance to the re ecting object can be determined x This is the only thing you are shown on TV most of the time out pulses for Waterspout pp 400401 Rotating column of air over water typically smaller and weaker than tornadoes Can be tornado that starts over and and moves over ater water but most waterspouts start over w Florida Ke s outsmonth in summer F39hutu ufvvaterspuut rm htt VWWV mm nuaa guvgu vlslturlas4phutusi htrn Doppler Radar pp 399400 Doppler radars do more by comparing the frequency ofthe received radio pulse to that ofthe transmitted pulses 0A higher received frequency means the re ector is approaching a lower received frequency means receding oDoppler radars can determine and speed at which the re ector such precipitation is approaching or receding from the radar but not the part ofthe velocity speed of the re ector that is at right angles to the line of sight to the radar display the as Doppler Radar View of Mesocyclone s a tornado because It is too small but it can see a rotating mesocyclone inside supercell The rotation in a m yclone is identi ed by winds Fig 14 47 p 399 7 ng away from the radar yellow amp red MET1010 Intro to the Atmosphere Jon Ahlquist 11172006 Chapter 13 orecasting is like driving a car down he road where you are only allowed to look outthe back window Source unknown Utility orweatherrorecasts Weather observations and analysis at surface and aloft Weather forecasting methods Accuracy versus Skill ts Numerical ie computer forecasts Ensemble forecasting You can forecast Watches warnings and advisories Weather Forecasting Utility ofWeather Forecasts Meteorologists can39t change the weather but forecasts can help people prepare for it a oTravel driving airlines shipping US Natlunal eather Service is in Dept Dr Cummeree OToul39lsm Good forecasts are based on good observations and a good understanding ofthe underlying science ASOS Automated Surface ObserVIng System Most surface observations come from ASOS Roughly 1000 A808 stations in US operated by National Weather Service FAA and military ASOS automatically and electronically measures temperature relative humidity pressure wind speed and direction rainfall visibility height of cloud ceiling but not cloud t pe rmines whether precipitation is rain or snow and whether there is freezing rain At airports people are contracted to take hourly observations of cloud type and weather that may be 39 39 7 quote in area US Radiosonde Network Roughly 92 stations launching tWice daily overus e uipped With weatherinstruinents Takes opseivations as it is Med b Weatherballool l Released from balloon at preset altitude and glides pack to latinch poll lt Upper air obs info httpMMMuanwsnoaagovl US Radiosonde Stations Other Observing Tools in US 2 geosynchronous satellites for E amp W of US wwwgoesnoaagov 164 Doppler radars covering US see wwnwsnoaagovost88dtechhtml 35 pro lers most in middle third of US measure wind speed and direction as a function of height reporting hourly wwwpro lernoaagov MET1010 Intro to the Atmosphere Jon Ahlquist Other Observing Tools in US Roughly 500 commercial aircraft carry weather sensors amp report 150000 observations per day mostly in the upper troposphere called ACARS MDCRS and AMDAR httpaviationweathergov generalpubsfrontdocsjul03pdf httpacwebfsnoaagov Anchored buoys in Caribbean amp Atlantic also in the Pacific Ocean along amp near the equator to monitor El Nino See httpwwwndbcnoaagov World Meteorological Org WMO World Meteorological Org WMO obranch of the United Nations cover 175 nation members httpwwwwmoch ofacilitates data exchange through World Meteorological Centers in Melbourne Moscow and Washington DC and over 25 regional data centers around the world oeducates meteorologists in developing countries eg workshops at FSU Weather Forecasting Methods p 368 373 Forecasting technique depends on how far into the future ou wantto forecast Short range a few minutes to next day Q Persistence weather will continue as isquot with no change If it is dryraining now it will continue dryraining forever Tomorrow s high and low temperatures will be the same A persistence forecast is olten good in tropics which change little 0 Trend method also called steadystatequot method in textbook present trends will continue eg fronts lines ofthunderstorms hurricanes etc will continue to move bringing in their associated weather Olten used for quotnowcastingquot forecast for next few minutes to at most a few hours MET1010 Intro to the Atmosphere 11172006 Worldwide Weather Network Over 1500 radiosonde observations per day oNorthern Hemisphere land covered fairly well oOceans South America and Africa not well covered Over 10000 landbased stations reporting surface conditions Hundreds of ships help with weather observations Weather Analysis What s the weather like now Wait a few hours after each observation time to collect as many observations as possible before starting the analysis for that time Quality control Discard readings if they are too different from climatology or nearby observations Start analysis using a forecast for the analysis time so every place has weathervalues Blend in the new observations making weighted averages of the forecast with observations to construct a 3D grid of weathervalues Adjust values so that they will work smoothly with the equations in the computerforecasting models Forecasting 1 or more seasons into future Example What would the weather be like for an outdoor wed ding in Jacksonville at 10 am on a day months 39om now Seasonal forecasting methods 0 Forecast the seasonal average ie climatology Eg the Farmer s Almanac seems to be climatological 39r future anomalies ie deviations 39om the mean un on a personal computer or fancy pocket calculator 9 Very complex coupled oceanatmosphere models Requires a supercomputer TL the supercomputer forecasts o Supercomputer forecasts are improving such as advances in ensemble forecas ing by FSU s Dr T N Krishnamurti More about this later in the lecture Jon Ahlquist Forecasting 1 day to 2 weeks into the future Historical ordering of techniques Look at the sky In middle latitudes cirrus clouds are often a sign that a front is coming within 12 to 24 hours See table 133 p 348 and p 351 Study daily weather maps year after year and gain an intuitive understanding how the weathertypically evolves analogue forecasting weathertypes Write a computer program using the equations that describe the atmosphere s motion dynamics and temperature thermodynamics numerical weather prediction This has become the dominant technique supplemented by human and statistica improvements Model Output Statistics 11172006 Accuracy versus Skill Accuracy measures size of forecast error Tropical weather has little variability though so even persistence forecast errors are usually small Midlatitude weather is more variable and forecast errors are larger By definition a forecast has skill if it is better than a persistence or climatology forecast It is easierto have a skillful forecast for midlatitudes than for the tropics even though the errors are larger To verify a forecast one checks what actually took place Many times one assigns a number that measures the size of the overall forecast error such as the magnitude of the average error orthe largest error anywhere in the forecast region Probability Forecasts pp 345346 Probability of precipitation chance of measurable precipitation 001 inches or more at a randomly chosen point in the forecast area during the period covered by the forecast often 12 hours Footnote on p 345 not right With showers chance that a random point is hit equals fraction of area hit Randomly chosen point may as well be where you are Question How can you tell whether a probability forecast say a 10 chance of rain is correc Answer It is impossible to verify one probability forecast by itself Awhole set of forecasts is needed Collect all forecasts with 10 chance of rain Did it rain in 10 of cases Repeat for 20 chance 30 chance etc Numerical Weather Prediction Most National Weather Service forecasts for several hours to 10 days into the future are based on complicated computer programs Forecasting programs calculate what the weather will be Specifically they calculate things like opressure gradient force Coriolis force and friction to compute how the wind speed and direction change with time cheating from sun infrared and condensation minus heat loss by emission of infrared and evaporation to compute temperature changes ocondensation from rising air to compute rain and snow Characteristics of Some Forecasting Models Characteristics of 6 different US numerical models httpllmeteducaredunwppcu2launpcu2htm Subject to change Don t memorize Schedule offorecast runs httpMMNlnconcepnoaagovlpmbnwprodprodstatJ Computer forecasts at httpNvmmnconcepnoaagovlpmbnwprodanalysis Example Global Forecast System GFS global model 0 Horizontal resolution roughly 55 km 34 miles in latitude and longitude o 64 levels in vertical 39om surface into stratosphere o 75 minute time step run out to 16 da s 0 Run four times daily each taking 80 minutes ofcomputer time MET1010 Intro to the Atmosphere Regional models Regional eta Greek letter model over N America oHorizontal resolution 12 km between grid points 060 levels in vertical 0 Run 4 times daily out to 212 days Each run takes 1 14 hrs Rapid Update Cycle RUC model oRun out to 12 hours every hour Takes about 12 hr to do calculations oHorizontal resolution 20 km between grid points 950 levels in ve 39 Regional models need to get conditions on their boundaries from global forecast models That allows weather to enter and exit the limited area covered by a regional model Jon Ahlquist 11172006 Ensemble Forecasting pp 342343 General de nition of ensemble collection ofthings as 39cal ensemble or a clothing ensemble Ensemble forecast 2 or more forecasts that all apply to the same place and time 2 heads are better than 1quot Example You make an ensemble forecast when you compare forecasts from several different TV stations Theory suggests that skillful detailed forecasts of planetaryscale weather is im poss ble beyond about eeks because the atmosphere is chaotic p 2 Smaller scale features can be forecast even less than that Example small thunderstorms have a forecast limit of an hour or so tornadoes less than a An ensemble of forecasts considers some of the possibilities Average of forecast ensemble is usually more accurate than a single high resolution forecast Operational Ensemble Forecasting Example Forecast for DDay invasion of France on 6 June 4 was made by comparing forecasts from 3 separated teams each using different forecast technique Global ensemble forecasts out to at least 10 days since Dec 1992 at ot S amp European forecasting centers In US experimental regional ensemble forecasts since 1995 operational since 2001 Currently US has 15 forecasts in its global ensemble European Centre has 5 i e number isn39t important because it changes but European Centre has more amp better forecasts Ensemble philosophy is similar to mutual funds average over the stock market produces a better return than trying the pick the best performing stock Ensemble Forecasting Breakthrough at FSU Breakthrough improvement in ensemble forecasting by FSU s Prof T N Krishnamurti in spring 1999 o Don tjust average forecasts remove biases 139 quot old quot 39bia so you have to wait months to collect statistics ifmajor changes in model is made oCompute a weighted average forecast where the weighting could be different from place to place and variable to variable oThis work by Dr Krishnamurti has been highlighted on CBS ampABC national evening news ampThe Weather Channel Da b da errors for lobal reci itation Dr l risl s 3uyperensemble gslowestgrror bue line r Individual forecast errors purple lines are muc rge 3 Supzrensemble HMS Errol at Global Pleclpltatlun UDVGBDDEBDDSVBUDNV MlMll 1T at Md l Enkmbl Nun Operational Ensemble Forecasting The Future Ensemble forecasting will become more common o It provides guidance as to forecast reliability You check how well the various forecasts agree o It provides a direct way of estimating probability of an event by considering the fraction of forecasts that have the event Example of application What is the probability ofmore than one inch of rain in 24 hours Because of limited time to compute a forecast there will always be a tradeoff between the number of forecasts in an ensemble and the complexity of each forecast Operational Ensemble Forecasting The Future More people will do what Dr Krishnamurti is doing ie correct biases and allow for a more exible way to combine the forecasts in an ensemble 9 Research topic If forecast model improves can Krish s technique be applied without having to wait months to gather statistics exist More forecasts with probabilities will be produced oChallenge How can we educate the public to understand this extra information More businesses will make use of forecasts to maximize pro ts MET1010 Intro to the Atmosphere Jon Ahlquist 9292006 Chapter 4 Atmospheric Moisture Phase changes of water Hydrologic cycle Evaporation and saturation x Vapor pressure amp saturation vapor pressure x Boiling Relative humidity amp dew point temperature Why is Florida more humid than California Humidity and human comfort Measuring humidity Humidity and musical instruments Phase Changes pp 8688 r Evaporation liquid to vapor densation vapor to H uid r Sublimation ice to vapor without liquid OExarnple rreeze dryin Deposition vapor to ice without liquid QExarnple Frost rorrnrng on ground and Windshields Transpiration plants give up water as vapor to a mos re through small openings on the underside of leaves Circulation of Water in Atmosphere Hydrologic Cycle p 88 In the Earth39s hydrologic cycle water exists in all 3 phases solid liquid and gas ph s t 85 of evaporation occurs over oceans If all vapor in atmosphere were to condense and fall out there would be 1 inch 25 cm of rain or the equivalent in snow about 10quot over the whole Earth 1 Why is it impossible for all the vapor to condense out ofthe atmosphere Given the 1 inch of rain statement above how is it possible to have several inches of rain in a day Saturation or equilibrium a ce between rates of evaporation amp condensation Expressin amount of va or in atmosp ere pp 8990 I will not ask you about absolute humidity speci c humidity and mixing ratio de ned on p 89 If you want to be a meteorology major learn speci c u t t J t 1 water vapor density Vapor pressure pp 9091 Vapor pressure that part of air pressure which is due to water vapor Vapor pressure is lt4 oftotal pressure and that is found only in the most extremely humid tropical air v r r r r exist at equilibrium with at surface ofwater Depends on tem erature only Saturation vapor pressure is normally greater than or equal to vapor pressure You can forget about the rest ofthe air when talking about water vapor Air does not hold water vapor MET1010 Intro to the Atmosphere Jon Ahlquist 9292006 Saturation vapor pressure pp 9091 Triple point temperature and pressure at which all hree phases of water coexist at equilibrium 0 C 6 mb Table of saturation vapor pressure vs temperature For details see p fig 410 p For each 10 C roughly 20 F increase saturation vapor pressure roughly doubles To do all sorts of weather calculations see h In39lvv rh nnaa I html Vapor Pressure and Boiling p 92 Water boils when it is so hot that the saturation vapor pressure pressure in the hot water air pressure small extra pressure due to weight of liquid water Bubbles in boiling waterare 100 watervapor Water is evaporating INSIDE the liquid Higher elevations have lower pressures so water boils at a lower temperature the higher you go Example At Denver the milehigh city the surface pressure is about 850 mb instead of the sea level avera e of m At Denver water boils at 95 C 203 F instead of 100 C 212 F at sea level Because of this lower boiling temperature boiled or steamed foods take longer to cook at high altitudes Relative Humidity pp 91 93 Relative Humidity vapor pressure saturation vapor pressure Examples olf actual vapor pressure and saturation vapor pressure are both 12 mb relative humidity 12 12 100 oAt sunrise relative humidity is often 100 so dew olf actual vapor pressure is 12 mb and saturation vapor pressure is 24 mb relative humidity 12 24 oRelative humidity is often 50 in afternoon at hottest time of day Relative Humidity cont In northern winters the relative humidity indoors is LOW Example OSuppose outdoor temperature is 30 F and air is saturated oSuppose this air comes inside without changing the amount of moisture QWhen air reaches 50 F amount of moisture hasn t changed but capacity has doubled so RH 50 oWhen air reaches 70 F capacity has doubled again so RH 25 People use humidifiers to avoid dry skin and wood cracking furniture amp musical instruments Dew Point Temperature pp 9396 Dew point temperature temperature at which dew forms If amount of moisture stays constant during day dew point is constant can measure dew point by measuring the temperature of the outside of a cold glass when condensation first begins When air is cooled to the dew point vapor pressure saturation vapor pressure so relative humidity 100 MET1010 Intro to the Atmosphere Dew point amp Relative Humidity Relative humidity can be 100 in the morning and 50 in the middle of the day with no change in amount of moisture in air Example Tallahassee during summer oMorning temperature low 70 s Dew point low 705 so dew will form 100 relative humidity oA ernoon high low 90 s Dew point low 70 s 0 Recall that saturation vapor pressure doubles with a roughly 10 C 2 39 rease in tempera ure This is roughlythe change in temperature between morning and a ernoon lf dew point does not change but air temperature increases by 10 C then relative humidity 50 Jon Ahlquist 9292006 Average Dew Point in January p 94 Average Dew Point in July p 94 water vapor content low dew poin s low water vapor contentquot quo e p Relative humidity indicates how close to saturation air is r The air can h ve QHigh relative humidity but low Wateryapor COl itel it QLOW relative humidity but at least moderate Water el lt vaporcon A i 7 V Give examples for these cases Hint Recall that HE Dewimin E Fi 95 Fi DEWFD 5 Fi saturation vapor pressure increases rapidly with RE EWE humidity WWn RE EWE WWW 21 39quotcreasm temperature Culd example has higher relative humidity heeause Tdevv paint but less watervauui Judging relative humidity Whyis the Southeast US more and vapor content humid than California pp 9697 Air bluvvirig rrerh DEEari is nearly saturated in bath eases 39 39 L 39 r 39 1 quot quot u urnrnervvaterternp aiehg eaiirerhia is aheut55 F versus point Tu are close an F fur Buit uast su Gulf Cuast has 2Dquot higher dew imiht a a Large amount ofwatervaporfr high dew point Tu WWW I lt Example Consider these 4 air samples is 55 p I A T 5 F Td20 F 45 F Td43 F C 80 F Td75 F 10 F Td70 F M Which sample has the highest relative humidity 4 Which has the lowest relative humidity2 Which has the highest water vapor content Which has the lowest water vapor content Fig 416 p 97 METlOl 0 Intro to the Atmosphere 3 Jon Ahlquist 9292006 Relative humidity and human discomfort p 99 Text mentions increased number of deaths in hot conditions such as in Chicago in 1995 In summer 2003 Europe suffered catastrophic heat wave About 15000 people died from heat in France in August 2003 Temperatures were as high For more details search Internet for France heat wavequot death toll Any hot day of any year people working outside amp athletes are at risk as are children amp pets in cars Heat index apparent temperature that feels likequot the measured temperature and humidity See g 418 on page Measuring Humidity pp 99 100 102 Dewpoint hygrometer cool something until dew forms measure its temperature dew point temp 5 Ion er at 100 rel humidity than at 0 rel hum Days with high relative humidity are bad hair daysquot Electrical resistance hygrometer measure electrical resistance 0 layer of carbon on a microscope slide Resistance decreases with increase in relative humidity Traditional sensor for weather balloon Humicap humidity affects electrical capacitance of special capacitors Measure their capacitance and convert to relative humidity Newer sensor for weather balloons Measuring humidity Psychrometer pp 99100 Psychrumeter Tvvu ioentieal tnerrnorneters one plain and one thse bulb is EqurEd by 3 Wet Eutturi Air bluvvn pasttnerrnorneters pytan or py Swirling Use taples in Appendix D pp A78 to All uftextbuuk or see litt VWWV srn noaa goyel WgtltialiWgtltiali sntrnl to get dew point is relatiye nurnioity trorn dry is wet pulp ternps Fairly aeeurate rnetnoo useo toroeeaoes Flg419 p 1DEI Measuring weather inSIde the home e mos common indoor weather station has 3 instruments thermometer barometer and hygrometer described below Thermometer bimetallic strip bent into a coil One end ofthe coil is attached to the th the temperature scale The coil winds slightly tighter or looser depending on the temperature Barometer Discussed in chapter 8 lfyou can39t wait I lt tn 3 a a 2 x m E 2 to humidity measurement based on length of a hank of hair or strand of gut inside the hygrometer Humidity and mu3ical instruments Strings tor guitars narps yiolins ete used to pe rnaoe otgut Gutls une at the must cummun humldl sensurs thuugh su Lne piten of gut strings fluctuates notieeaply trorn daytu day requiring retuning Mudern strings are typieally nylon vynien is insensitiye to nurnioity so tney nolo tneirpiteli rnuen petter Alsu nylon is tougher than gut lnstrurnents rnaoe frurri wood string lnstrurnents Clarinets piano souno poaros aeoustie guitars ete ean crack it tney get iiieiii Many rnooern yiolin eases naye bulltrlri nygrorneters Surne yiolin eases made or St rotoarn lightweight insulating air trapped in Styrufuarn puppies proteets trorn irnpaot uust as pieyele nelrnets uften made at Styrufuarn The seasons and music Composers Franz Josef Haydn Austrian a Alexander Glazunov Russian have written pieces titled The Seasonsquot Best known though is Antonio Vivaldi39s The Four Seasonsquot He wrote sonnets about the seasons and set them to music as 4 violin concerlos For more about Vivaldi39s Four Seasonsquot see httplVlmwbaroquecdscomvivaldiseasonshtml METlOl 0 Intro to the Atmosphere Jon Ahlquist 1042006 Chapter 6 Comments on chapter 6 In this chapter hard concepts are mixed in with straightforward concepts nts on chapter Be guided by these notes and my review Delquotmmquot f S abimy questions as to what to lear I don t pect you B CV Te to know too many things from this chapter Just Vemca39 Stab39l39ty 39quot a m spher strengthen the concepts presented in these notes apse rate and stability Stability and I lfyou want to be a meteorology major y ultimately need to understand everything in this chapter so it won t hult to get stalted n Only about 68 exam questions for exam 3 will come 39om this chapter ohanging cloud forms Determining the height of the cloud base Classical Definition of Stability p 140 Stability Psychology Example Something at restis in eguiiioiium Give something at resta small push Then see vvhetherthere is a force on the ooieet Apply the Precedlng Slablllly derlmllons 0 PSYCHOIOQY The equilibrium is fyou experience a small disturbance in life you 1 Stable it aroree pushes it backtuvvard its initial position ould be unstable it a force pushes it runher away rrom its initial position stable if you adj 5 back m me way you were before Neutrally unstable irthere is no push eithertuvvard or avv y me incidem rrom its initial position ball on tlat surraee not pictured A I deal in unstable ifthe small disturbance becomes a big your life quot neutrally stable if you don39t go back to the way you ei milntiiiiiiuni H E 1 were nor do you become more extrem p 9m go with the owquot Buoyancy Force not in book Buoyancy Force continued ntjlglgs ss Iri39l hgi39g 22 gang39sI mmds quotks way If an object is less dense than the uid around it the bu ncyforce will be upward and it will rise If it is Aquot Plea 39quota u39d has 3 lea 3 vemca39 mes denser than its surroundings the buoyancy force will P Sh39quot9 quot quot1 be downward and it will sink l the force of gravity pulling it down 2the pressure in the uid pushing down on its top side and 1 Example Iquot waleri cork risesi 5quot lead Sinks 3the pressure in the uid pushing up on its bottom side Typically an air parcel is less dense than its a The combination ofthese three forces is called the environment if it is warmer than its environment and buoyancyforce denser if it is cooler Hence the saying Warm air lfthe object is moving up or down there is also a drag riSeSi cold air Sinks force which will slow its motion but whether an object goes up or do epends on whether the buoyancy force is up or down MET1010 Intro to the Atmosphere Jon Ahlquist 1042006 Vertical Stability in the Atmosphere Suppose an air parcel blob of air is given a small push up or down The atmosphere 39s stable if the buoyancy force pushes the air parcel back toward its original level before push Usual situation unstable if the buoyancy force pushes the air parcel even further away Happens on hot day near surface and in clouds with warm air rising cool air sinking neutrally unstable if the buoyancy force does not push the air either higher or lower Happens following instability when air is well mixed amp homogeneous Lapse Rate p 141 For an air parcel that starts in equilibrium with its surroundings stability depends on how h temperature of its surroundings decrease with height Lapse rate rate at which temperature decreases with height Expressed as a certain number of degrees per kilometer or per 1000 feet A positive lapse rat means that temperature decreases with height a The atmospheric lapse rate also called the environmental lapse rate is often around 6 7 C per kilometer This means that the temperature of a parcel blob of air one kilometer higher than another parcel is 6 to 7 C colder This is equivalent to a temperature decrease of about 34 F per 1000 feet Large Lapse Rate Unstable The largerthe lapse rate the colderthe environment is as ou go up so the more likely it will be that a rising parcel will be warmerthan its environment and will rise buoyantly That is when the environmental lapse rate is large the atmosphere is unstable Example On a typical summer day in Florida the surface is much warmer than the air aloft so a war bubble of air near the surface will rise easily In other words the lapse rate is large and the atmosphere is vertically unstable You can see the evidence of this in the tall cumulus congestus and cumulonimbus clouds that are common in Florida summer afternoons Small or Negative Lapse Rate Stable If the lapse rate is small the environment does not get much cooler is as you go up so the surrounding environment will be warmerthan a rising parcel The air parcel will sink The atmosphere is stable The extreme case of stability is where the atmospheric temperature is constant or increasing with height negative lapse rate This is called a temperature inversion Examples of Temperature lnversions Example 1 The temperature in the stratosphere is constant or increasing with height That is there is an inversion in the stratosphere so it is always very stable The first part of the word stratosphere comes from the Latin root meaning stratified ie having horizontal layers These layers are a sign of Example 2 Overnight the surface of the Earth cools more than the overlying air does An inversion develops near the surface growing to a depth of roughly 1 km during the night vertical stability ie it is hard for an air parcel to rise MET1010 Intro to the Atmosphere Conditional lnstability pp 145146 Recall that rising air cools by doing expansion work If rising air cools to saturation and rises further condensation will result releasing latent heat This air will still cool as it rises but not as much In some cases this extra warmth is enough to make conditions unstable There is conditional lnstability if q the air is stable ifunsaturated air is rising o the air is unstable if saturated air is rising Conditional instability is common in Earth s atmosphere That is the atmosphere is often not far from vertical instability Jon Ahlquist 1042006 Example of clouds in stable Stability and Clouds atmosphere col 2 of p 154 amp p 155 Unstable conditions result in clouds with vertical A WWW we a mum 5 development such as cumulus congestus shmed u Wm MEN S m mt cumulonimbus Wm saturatlurl a luud Will furrn Stable conditions result in no clouds or stratu stratuslerltllularlsalsu called quotquot E 4m u lentleular lensellke eluud W clouds and its variants le clouds With stratus as When alrls stablE parcels Em artofthe name ecall Istratus Hm I WWW WEWDWW SW D horizontal layer so strati ed air is not moving up the dc W W beluvvthelrurlglrlal level They up is l Changing Cloud Forms pp 15657 Changing Cloud Forms pp 15657 Clouds will change ifthe stability changes To decrease stability increase the lapse rate To increase stability decrease the lapse rate by b 9Cooling air aloft cloud top cools by infrared oWarming air aloft sun heats cloud top andor em39ss39 quot 84 quot 0Cooling air near surface infrared radiation from Warm39w me surface sun hea s surface surface Stability can change without radiation if Temperature inversion ie zero or negative temperamre adVeCtiOquot i5 differem in Upper arid lapse rate is very stabl warm at 39 up I Wertr P 5Phere abov the colder air is near the surface so oLow level warm advection amp upperlevel cold the air stays put advection increase instability oLow level cold advection amp upperlevel warm 39 39 ility Changing stability Example 1 From morning to afternoon the Earth s sur ce Changing stability Example 2 When sun goes down the Earth s surface warms while the temperature 1000m amp above cools while the temperature 1000m amp above does not change much does not change much oLapse rate increases because temperature contrast oLapse rate decreases and stability increas s between surface and 3390 increase ocumulus clouds and thunderstorms often dissipate S abimy decreases Explain how a lowlevel warm win or an OCUMUIUS CIOUdS onequot deVSIOP upperlevel cold wind would decrease vertical ocumulus congestus and cumulonimbus develop stability when atmosphere is more unstable MET1010 Intro to the Atmosphere Jon Ahlquist 1042006 DetermInIn convective cloud base heights p 53 Cumulus clouds are often referred to as convective clouds because convection is rising motion Cumulus cloud base will occur at height at which lifted air parcel reaches saturation Cumulus cloud base may be 91000 m above ground in southeast US where relative humidity is high Because dew point neartemperature air does not have to rise much to cool to dew point 93000 m above ground in desert SW where relative humidity is low Dew point much lower than temperature so air must rise a lot to cool to dew point MET1010 Intro to the Atmosphere 4 Jon Ahlquist Review Chapter 13 Forecasting Name 10 businesses that can benefit from accurate weather forecasts Name all the ways of taking weather observations that we mentioned in class In the US Roughly how many surface weather observing sites are there Roughly how many weather balloon sites How man geosynchronous satellites does the US operate Why does the United States care about weather observations in other coun ries What is done to observations before they can be used as the starting point for a computer weather forecast 11172006 Methods of Forecasting What is a persistence forecast What is a trend forecast How far into the future does it make sense to use a persistence or trend forecast How are forecasts 1 to 10 days into the future usually made Distinguish between skill and accuracy for weather forecasting At what time scale is a climatological forecast generally more skillful than a detailed computer weather forecast What are some approaches to seasonal forecasting Review Chapter 14 Forecasting What is a probability forecast What is ensemble forecasting What did Dr Krishnamurti do at FSU to improve ensemble forecasts What is always the tradeoff involved in ensemble forecasting How can observations of the clouds overhead help you forecast the weather Open your book to page 348 Covertable 133 except for the first column Observations Read an observation and make a forecast Check it by lifting the cover from the other columns Methods of Forecasting What is a climatology forecast Why is persistence a poor way of forecasting tomorrow s weather if a cold front will pass later tonight Describe 3 techniques used to forecast conditions several weeks or more into the future How do meteorologists decide whether a forecasting procedure has skill How is it possible that a fairly accurate forecast may not be a very skillful forecas Can you give an example of this kind of situation for Tallahassee Forecasting and Uncertainty How far into the future is it theoretically possible to forecast the weather What does it mean if there is a 60 chance of rain MET1010 Intro to the Atmosphere Jon Ahlquist 9172006 Energy pp 2829 extra not in book 2 Energy capacity to do work oConcept dates from mid1800 s oCan be converted between various forms u Kinetic energyofm 39 i Gravitational potential eg lifting weights Radiant eg from sunlight Heat random molecular motion 0 Energy is o en conserved p h e o Einstein showed energy is not always conserved Emc2 meaning that energy can be converted to mass and vice versa T e sun s energy comes from fusion which fuses hydrogen into helium Helium has slightly less mass than the hydrogen used to make it The difference goes into energy Recognizmg Heat as Energy Temperature pp 2930 Late 1700 s American Benjamin Thompson who had become Bavarian Count Rumford discovered heat was 39 Temperaturemeasures aVerage random energy 0f not a separate substance previously called caloric Latin mono k39net39c enerQY root calor measured in calories Gas term coined by van Helmont early 1600 s He supervised boring canon which became so hot that from Greekword Chaos EXC em name becagse Water used for cooling would boiL we now know that a gas conSIsts of molecules In random motion Temperature scales freezing boiling 0 Old theory heat stored in metal when it was cast would be released as metal is drilled out as shavings o Rumford observed heat being released even when drill Fahrenhen in US321212 deg F was dull amp metal not ground up The exception probes OCelsius everywhere else 0 100 deg C the rule Absolute zero 459 deg F 273 deg C 0 Lowest approachable temp 0 Minimum motion 0 He realized energy ofdrilling was converted to heat 0 Similar to making re by rubbing two sticks together which had been known for thousands ofyears Fahrenheit ancl Celsius C lOfle IS a Uhlt 0f energy F mm 32 c 59F32 deg F deg C calorie energy needed to warm 1 gram of 40 40 same with both temp scales qu39d water by 1 deg 32 0 cold Food Calorie usually capitalized 50 10 cool 1000 calories 61 16 digits reversed 68 20 warm 86 30 68 and 86 are reversed hot 104 40 04 is 40 reversed 212 100 boiling Similarto fig 22 p 30 MET1010 Intro to the Atmosphere 1 Jon Ahlquist Energy addition amp temperature change First column of p 30 SpeCIfIc heat Table 21 p 30 calories needed to warm 1 g of substance by1 deg C Wet mud 06 Sandy clay 033 Dry air 024 Much energy needed to warm water medium amount to round Little energy is needed to warm a39r Consequently marine amp coastal areas don t have extreme sunlight warms water In winter in m o m a m x 3 Kuroshio in Pacific not so important for mild climate in midlatitiudes but do warm polar areas 9172006 Latent heat pp 3031 Latent means hidden eg latent talent Latent heat is energy that evaporates water Evaporation cools you when you get out of a swimming pool In general evaporation cools environment condensa ion warms environment 600 calories evaporates 1 g ofliquid water Recall It takes 1 calorie to warm 1 g of water 1 C Energy is needed to melt ice 80 caloriesgram energy is released when ice reezes It takes 80600680 calories to evaporate sublimate 1 g of ice During boiling temp stays at 100 C 212 F Energy added goes to evaporate water During freezing temperature stays at 0 C 32 F Energy taken away makes ice Latent heat cont Water evaporating from Earth s surface takes energy from surface When that water condenses as rain the latent heat is released into the atmosphere Latent heat released during a thunderstorm exceeds the energy of small nuclear bomb A similar kind of energy transfer occurs in an air conditioner Warm air inside a car or house is blown past an evaporator looks I ke car radiator in which coolant evaporates changes from liquid to gas using the heat inside the car or house The aseous coolant is piped to the condenser another radiator outside the car or house where the coolant condenses and gives up its heat to the outside air The liquid coolant is then pumped back tothe evaporator and the process repeats p 34 Rising air cools sinking air warms Recall Pressure is due to weight of overlying air so pressure always decreases with increasing height When a bubble of air rises it moves into lower pressure and expands to equalize its internal pressure with the surrounding pressure The same expansion happens to a weather balloon as it rises Because an expanded bubble of air occupies more volume it has to push other air out of the way Pushing back the surrounding air means that the expanding air bubble is doing work The energy for this work comes from the air39s quotinternal energyquot ie random kinetic energy of its molecules so its temperature drops p 34 Rising air cools sinking air warms The opposite occurs when air sinks and moves into higher pressure a In greater pressure the air bubble is compressed meaning that the surrounding air is doing work on it This increases the internal energy of Sinking air the sinking air bubble warming it b bb1 5 compressed Analogies from daily life and olf you pump a bicycle pump you are doing work to compress air heating it 9A can of pressurized air gets cold when it is sprayed as air from the can expands into the surrounding air MET1010 Intro to the Atmosphere Energy transport pp 3235 Conduction of solar energy from ground to air Convection of energy as warm or cold air moves around In meteorology horizontal convection in atmosphere is called advection vertical transport is called convection Example thunderstorms are called convection r Radiation radiative energy such as from sun Advection of water vapor latent heat Heat also convects and advects in ocean Jon Ahlquist 9172006 Conduction pp 3132 Convection pp 3335 A Warm wind or ocean current carries energy Warm molecules bump cooler molecules horizontally called advection in meteorology giving them energy Examples Southerly winds amp Gulf stream in Atlantic Newly warm d molecules bump other Ocean bring advect warmth to polar areas molecules giving them energy Winds and ocean currents from north such as by Energy diffuses through an object Califorma bring com I m gquot n o l a z 2 m u g E m m E m E 3 o m a g m m l a E to Heat rises from Earth39s surface in bubbles ofwarm air called convection in meteorology c ion a a 9 E E m z 3 1 molecules collide with molecules on the surface s QAII rlsmg overasphalt on hot summerday You can see the shlrnrneryappearance caused byl lsll lg hot alr Radiation Radiant ener 3533 Infrared radiation from tress can gy PP now What ls eVIdence that not caused by wmd 3 1 r Examples of radiant energy light ultraviolet visible infrared microwaves TV radio t Anything with temperature above absolute zero emits radiation White hot incandescent light bulb r or sun39s surface I Red hot electric stove e Infrared hot you chair building ground trees etc Radiation consists ofwaves Fig 27 p 35 Wavelength dlstancefrum erestte erest Stefan39BOItzmann Law Of Rad39auon p39ae urtruugh te treugh r StefanBoltzmann law E c T mare ueaevcmmzu where E power emitted per unit area of surface razor mama wavsusunm aznmeoa mmquot weaeuem mm mm wattssq meter e 567 x 108 an mmquot m I l T temperature in kelvins degrees above MN m quotmmquot absolute zero Mums mm m I I 1 u Multiply by surface area to get total power emitted a 0 Increase in temperature means BIG increase in mm W energy radiated quot quotquotquot quot quot w 39 Example 1Your skin temperature is about 300 VIIhlw tlem sX m kelvins amp your surface area is about 1 sq meter uluwv W up You emit 567 x 103983oot1 m2 450 watts xmyl 1o MET1010 Intro to the Atmosphere Jon Ahlquist 9172006 StefanBoltzmann Law of Radiation p36 Example 2 Surface of Eanh is about 300 ketvins Like you it emits about 450 Wmz Example 3 Surface of Sun is 6000 kelvins 2 times hotter than Earth square meter of Sun39s surface emits 20 160000 times as much energy as a square meter of Earth or about 73 megawatts per sq meter Coal red power plant produces about 1000 MW equiv to emission from 14 ms surf ce Surface area of Sun is about 12000 times greater than Earth39s surface area so solar energy emitted is 160000 X 12000 19 billion times that emitted by Earth Wien39 Wavelength ofmax radiatio increase in tem perature ie on temperature Colorofgas flame and au Wien39s Law of Radiation p 36 s law Amy constantT Nudge temperature of pottery klil l by color lnsloe Qnght settlng on TV camera lnooorys outdoor QGlVel l Sun s temperature ltS max output ls m ylslole n decreases with color of glow depends rol39a due to otherfactol39s i0 Kirchoff s Law of Radiation p 40 I Kirchoffs law At any particular wavelength a good absorber is also a good emitter and a poor absorber is a poor emitter In the infrared most things except shinymetals are good absorbers and hence also good emitters Something can be a good absorberemitter at one M w Mum E m w W Hm m r Alrlstransparenttoylslnle ilght so sunllgnt comes ln Opaque atplaces ln lnfrared e lR energy escap plucked Mostll p antapsorpersamp ll re ffect of Infrared so It mmme but atmogpherlc erred absorbs little sunlight but radiates well in the i quotquot b er arne peca se infrared Therefore it stays cold 5 w w greenhouse Works by keeplrlg out cold alr What happens to sunlight Fig 21539p 45 Earth 3 Energy Budget fig 216 p 47 Winn 53mmquot mun We Surface 7595 mm nmllrmhud unrrnunlmmunlt energy as lnfrareu second most by eyaporatlon tnlru by Vquot mquot a 2 s conductlon and convectlo b Surface gem 3mm t m thce as mucn energ quot39quot quotquot quotquot Ywalntmmvbm from at as lnfrared as r cum mmutaa tammm anlklmd amtmum ammo out MET1010 Intro to the Atmosphere m 1512133513 Jon Ahlquist 9172006 Avg no of days per year with aurora Aurora borealisaustralis NorthernSouthern Llhts p 49 9 222 P 50 Magnetic FIQ 2191 P 49 quotquot mm39w eld lines Solar wind hot rora actIVIty 39 7 particles 39om Sun entered iEsgtutioed by t und magnetic a 5 ma ne IC 7 n n eld Partigles 0h P 39e MN enter atmos near l reQUIar North I ll Ie quotNPquot 1 l Fig 220 p 50 Charged 7 particles from solar wind hit Oquot molecules in atmosphere and l l kick electron to higher energy 5 391 level Electron later gives up energy as light ie aurora quotw Culliding charged particlewm kicks electrnn intn higherW Aurora Pictures from GovernmentWeb sites Aurora Pictures from Government Web sites Aurora with Perseid Meteor Streaks MET1010 Intro to the Atmosphere as 39v mdwmwmn dm wmmg i EML W V 7 W39an u 7 J mmm mwm mnnmm ummmaawcmmmlwn m My mum mmm i fmw u m run an r rm 1 2 n a u w 1 a m mum mamtin m mmpwvi m w 12 lt A y 3 arm mmws i W M vEnmuhHr I m M 7 Ianuspnm mini mum Um 2W HUIlowquot Inn Mnowhnl L Slrltosphau a opo umer 5nn a sun 1mm xsn mwmww nmpmm cc umj rmng D u m mm P a S a WW E a MQWM Jame i ente muln k afsim 3E tr 7 vul l39 herlecule which re wrujrnw in mm m o m am am 39 10 a 00 la W I use bann n Ike ffetinth39n HET 1mm FaH a NET 1mm FaH r r Mimi 39 xer I 39 talia when the vorte HET 1mm FaH HET 1mm FaH use vmmm mu
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