Introduction to Meteorology
Introduction to Meteorology GEO 203
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This 78 page Class Notes was uploaded by Lenore West on Saturday September 19, 2015. The Class Notes belongs to GEO 203 at Michigan State University taught by Lifeng Luo in Fall. Since its upload, it has received 42 views. For similar materials see /class/207447/geo-203-michigan-state-university in Geography at Michigan State University.
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Date Created: 09/19/15
4142012 Key Questions I lsist faur re ions in b ortlaAmlerica thelre mid 39 39 39 v 39 atitu e cyc ones ten to eve op or re eve op M D D E C Y C I Explain how net convergence and divergence affects the development of mid latitude cyc ones I How are longwaves in the upperlevel westerlies different from shOrtwaves I How does the polarfront 39et stream in uence the formation of a midlatitu e cyclone I Why do cyclones normally move northeastward but the anticyclones move southeastward I Draw a typical mid latitude cyclone durin its mature stage and identify the fronts weat er in different regions affected by the cyclone I What is a nor easter H mkucoie Cen aia Lalmmi 4142012 39 Polar Front Theow I Polar front is a semi continuous boundary separating cold polar air from more moderate mid latitude air I Mid latitude cyclone wave cyclone forms and moves along polar front in wavelike manner I Life cycle of a wave cyclone I Life cycle of a wave cyclone Q1 d Mature initial occlusion e Advanced occlusion SnacksCola Cengage Learning 1 Cutoff cyclone I Hi Cyclogenesis Lee side lows Hatteras low I I I Nor easters I I v BrooksCola Cengage Learning Northeasters Midlatitude cyclones that develop or intensify off the eastern seaboard of North America then move NE along coast 1020 Ayn v F El BrooksiCole Cengage Learning 1015 c 39 4142012 5 Vertical Structure of Deep Dynamic Lows Gradient Winds I Dynamic 10w intensify with height I Curved winds around lows and highs aloft CYCLONIC FLOW ANTICYCLONIC FLOW I When upperlevel divergence is stronger than surface convergence more air is taken out of the top than the bottom surface pressure drops and low forms or intensifies PGF Cen ripe al force 1 Air parcei a Low pressure area cyclone aloft b High pressure area anticycl one aloft I Subgeostrophic Supergeostrophic 39 39 i D 39 D 39 Cuwed Flow and Divergence An idealized vertical structure of a mid 00 8199 4a 1at1tude cyclone and 39 ceqewea i e Iv ant1cyclone m 295 mb 300mb 300 mb It SEOOm a Pressure quot quot a fy V 500 mb 1 v T 2i 1 0m m i We geostrophic geostrophic quotJ KendaHHunt PLIblIShII39ig Warm air Surface map 4142012 39 i 39 i 7 39iqeliijLjr9 L N Waves In the Westerlles Jetstrea ks 290 mb ow l 295 mb V I Longwaves and shortwaves V Ao rBo gtCo gtoD gtEo I Barotroplc vs bar0c11n1c 300 mb I Cold and warm a1r advectlon 305 mb high pressure Green arrows denote flow of air if the air was in geostrophic balance B N mb Nuance region left exit regiV T 295 mb CONVERGENCE LDIVERGENCE V 300 mb DIVERGENCEquot CONVERGENCE 305 mb right entrance region right exit region Black arrows denote actual flow of air because air is not in geostrophic balance 1 I KendallHunt Publishing 3 DAY 1 b DAY 2 24 hours laer I r Combined Effect of Curvature and Jetstreaks Combined Effect of Curvature and Jetstreaks I J etstream normally contains jetstreaks that I Strongest divergence aloft occurs on the m1grate through curved ow patterns northeast side of the trough north of the j etstream axis in the left exit region of the jetStreak 739 K 9000 m91M240 i t w I I quotquot 9480m V kHz 131ng 39 600m C Convergence 9840 m I v39 Red Curvature v Green Jetstreak 9960 Ln 4142012 Role of Jet stream 1 Jet Stream tropopause con er nce lee 9 69 H surface L N N 39 39 BrooksBole Cengage Learning Akumwlemyc av Sinking 7 Rising arr alr Cirrus clouds Wind speed knots 0 80 100120 4142012 391 FEB 39139 39 a Region of Region of maximum maximum convergence divergence aloft aloft Latent Heat release during cloud upper level flow formation Radiative cooling under clear skies surface J1 39 e Storm Initial Development i Initial Movement of Airmass I A center of low pressure on surface chart I Curvature jetstreak gt divergence aloft I Waves in jetstream KendallHunt Publishing I J etstreak moves to the base of the wave Warm moist air A Uppe rlev AA Front at surface aW 4142012 Weather Pattern East of Cyclone Center Exercise North marica x A A tfquot A A 7 a 39 A We IA I fq w U21 Lin s ower 1 anlor hun ersto s so e ever H 39 I l 39 I 39 Exercise b I Identify the fronts on the map L moves northeaStward H moves southeastward 394 I Identlfy the a1r masses that affects North W39jm l T America 30039 p 1 I Indicate on the map the typical surface wind in l 56mm directions in different parts of the country ll 1393 I Indicate the typical weather you would expect in 0quot 1 different regions around the cyclone 500mb Warm i I Indicate the precipitation types you expect along W the warm front 1 21W 3 W74 I Indicate where the upper level ow would look 05 like for this cyclone to intensify WarnNg Surface mp ATMOSPHERIC HUMIDITY Reading Ch 4 282012 D Key Questions I What is specific humidity what is relative humidity What is mixing ratio What is dew point temperature What does it measure What is wetbulb temperature What does it tell us What is saturation What happens when air is saturated When air is saturated what are the relations between RH Td wet bulb temperature and temperature I What is vapor pressure Saturation vapor pressure What causes vapor pressure and saturation vapor pressure to vary I How does saturation vapor pressure differ over ice and liquid water I Why is cold polar air described as dry when the relative humidity is very high I What is Heat Index How does it relate to temperature and humidity I How much water vapor is there in the atmosphere globally I Is air really heavier when it is more humidy 39 Circulation of Water in the Atmosphere I A general definition of humidity is the amount of water vapor in the air Condensation Evaporation D The Many Phases of Water I Phase is related to molecular motion an increase or decrease in motion creates a phase change I Ice is the coolest slowest phase I Water vapor is the warmest fastest phase I Phase change it Evaporation El Condensation Q Sublimation V 2 L cs NY a E water vapor Liquid water Ice condenses Evaporation Condensation amp Saturation I Saturation is an equilibrium condition in which for each molecule that evaporates one 282012 I Condensation is more likely to occur as air cools l Condensation nuclei Nucleus Nucleus Nucleus a Warm Air Water vapor Nitrogen Oxygen Air parcel 39 I H u m id ity I Any one of a number of ways of specifying the amount of water vapor in the air I Absolute humidity mass of water vapor volume of air Ll Water vapor density Cl Changes with the change of volume iii Not commonly used Parcel Mass of Absolute Size H20 Vapor Humidity I quotin 2 m3 10 g 5 gm3 J 0139 399 1m3 109 10 gm3 282012 39 i 39 Ii l I Specific Humidity mass of water vapor mass I Vapor pressure the pressure exerted by water of air vapor molecules in an air parcel Dalton s Law I Mixing ratio mass of water vapor mass of Of Partlal Pressure dry air 2 Fraction of total vapor pressure 1 or so I Both remain constant as long as water vapor is More Water 1016011165 2 higher Vapor pressure not added to or removed from the parcel I Saturation vapor pressure the pressure that the I water vapor molecules would exert if the air Mass of Mass of SpeleIC Parcel H20 Vapor Humidity were saturated w1th vapor at a g1ven temperature 1 kg 1 g 1 gkg i i Depends primarily on the air temperature 1 kg 1 g 1 gkg 39 C 4 L I 90 DC 3915 40 5 on I Smb ice exist at the same so temperature below freezing the saturation vapor pressure just above the water is greater 1 than the saturation u u a vapor pressure over 20 3 139 It tells us how close the air is to being saturated qu d 39 RHwater vapor content water vapor capacity 70 4mb RHactual vapor pressure saturation vapor Saturation pressure x 100 vapor 50 lt pressure 60 RH can be changed two ways 40 Change vapor content Change saturation Water Vapor Pressure mb 30 the ice C 730 720 710 O 10 2O 3O 4O content C39F 22 4 14 32 50 88 36 104 1 1 remarns rquot the same Temperature RH decreases 282012 39 r 39 r ii I Decreasing temperature causes increasing in I Relative Humidity and Dew Point RH and Vice versa El Dewpoint temperature is the temperature to which air would have to be cooled for saturation to occur without adding more water vapor and changing air pressure IE Cool air parcel to dew point and liquid water condenses 3 IE A good measure of actual water vapor content D I High dew points indicate high water vapor content E f l Low dew points indicate low water vapor content g g3 El Relative humidity indicates how close to saturation i g E dew point indicates the amount of water vapor Relative humi39dg 51 i I I 1 l Midnight 600 AM Noon 600 PM Midnight EmuksICote Cengaga Learning 7 7 V l I Dew point is an important measurement used in predicting the formation of dew frost fog and minimum temperature 1 Outgoing IR energy Outgoing IR energy Water vapor molcicule Expected minimum temperature 729F Expected minimum temperature 559i Dew point temperature 70 F Dewpoint temperature 50 F e vakycnle Cengai e i e a m i n g a a m x m a i a c g n g a g a L e a m m f5 g j 397 a January r IE ankleole Ceng ga Leamin b July a BrooksICola Panama I mminn 282012 55 F 13 C 39 Water temperature K Coo air Bmksfcala Cangage Learning 8 x 52 3 213 g 3 I v 9 6 E 5 5 02 70 E I 0 I 60 0 80 60 40 20 0 20 40 60 80 60 50 40 30 20 10 0 10 20 30 40 50 60 North Latitude south North Latitude South Emakslcme ceugage Learning gamma mm mmmg 1 Computing RH and Td O I RH eeS X 1000 v TA B LE I Saturation Vapor Pressure Over Water for Various Air Temperaturesquot TURATION SATURATION SA All TEMPERATURE VRPOR PRESSURE AIR TEMPERATURE VAPOR PRESSURE 1s 0 15 18 65 210 15 5 19 3921 70 250 12 10 24 24 75 296 9 15 30 27 80 350 7 20 37 29 85 410 4 25 45 32 90 481 1 30 56 35 95 562 2 35 59 38 100 656 4 40 84 41 105 762 7 45 102 43 110 878 10 50 123 46 115 1014 13 55 148 49 120 1153 16 60 77 52 125 1342 E Relative Humidity in the Home II Due to an increase in temperature in a heated home there is a decrease in relative humidity causing more evaporation from body plants etc Humidifier 39 I I39 I Watering plants INSIDE AIFI OUTSIDE AIFI r 20 C 68 F T 15 C 63 F rd 45 C 53 F Ta 15 C 5 F RH gt RH 100 in Heat Index Relative Humidity I D 5 10 15 20 25 30 35 40 45 50 55 60 65 7O 75 80 85 90 95 100 FI Air Temperature BrooksICole Cengage Learning 282012 Cl l Relative humidity and human discomfort Di Main source of body cooling is through evaporation of perspiration DI High relative humidity gt close to saturation gt less evaporation gt less cooling D Wetbulb temperature the lowest temperature that can be reached by evaporating water into air D Heat related health problems Heat exhaustion heatstroke B Heat indeX apparent temperature I Measuring humidity i3 Psychrometer Wetbulb temperature Drybulb temperature Eli Hygrometer I Infrared hygrometer 3192012 Key Questions I Why does air pressure decrease with height more rapidly in cold air than in warm air P R U I algagscczrlisigdered standard sea level atmospheric pressure in millibars In I How does sea level pressure different from station pressure W l I What is the force that initially sets the air in motion I What is Coriolis force What does the Coriolis force do to moving air 1 in the Northern Hemisphere 2 in the Southern Hemisphere I How does Coriolis force change with 1 rotation of the earth 2 wind speed 3 latitude I How does a steep pressure gradient appear on a weather map I What is geostrophic wind I Describe how the wind blows around highs and lows aloft and near the surface in the Northern Hemisphere I What are the forces that exerted on air moving near surface What factors Reading Ch 8 in uence the angle at which surface winds cross the isobars I Describe the type of vertical air motions associated with surface high and lowpressure areas I What is the gas law F Fl 39j 39ai fill in Atmospheric Pressure Gas Law I Air temperature air pressure and air density are all interrelated I Air pressure is simply caused by the weight ofthe I P RXTXP air above a given level P pressure I MOSt Of our T temperature atmosphere is P denSItY crowded near the 100 Air pressure surface 3192012 39U A Tale of TM Air column 1 Air column 2 not c o o u n c n a o o 4 unosnuuuus a o a n n n 0000 a a n I cocoa a o ooou a u g g 0001 a o 00 n 0 a a n uoo a o oncenooooln City 1 a Same pressure City 2 Same pressure Ms It takes a shorter column of cold moredense air to exert the same surface pressure as a taller column of warm less dense air Same pressure Air column 2 City 2 Same pressure City 1 b WARM Warm air aloft is normally I I 2 associated With high atmospheric pressure and cold air aloft is associated Pressure Gradient Force PGF with 10W atmospheric pressure COLD Air column 1 c a a o o c a a o c a n u o a g a n n n c c a n a c a n cottonhootoooo i 3 CD 3 r f City 1 0 City 2 Surface pressure rises Surface pressure fails ill Heating and cooling columns of air can establish horizontal variation in pressure It s this horizontal pressure differences that cause Wind to blow ircolumn2 o in r v 3192012 H7 Atmospheric Pressure I Daily Pressure Variations El Thermal tides in the tropics D Mid latitude pressure variation driven by moving of large high and low pressure areas I Pressure Measurements El Barometer barometric pressure I Standard atmospheric pressure 101325mb I Millibar Pascal hectopascal hPa til Aneroid barometers I Altimeter barograph Vacuum r December 1968 399 Glass tube seavlevel pressure Mercu ry column 920 ml 2717 rn Octoben 2005 Mercury in dish October 1979 1084 mb3201 inr Highest recorded sealevel pressure Agata Siberia 1064 mb 3142 in Highest recorded 7 sealevel pressure in the continental United States excluding Alaska Miles City Montana December 1983 lt Strong hight ressure system lt 101325 mb 2932 in Standard Deep low presstire system Hurricane Katrina during landlall R 882 mb 2604 in Hurricane Wllma 7 570 mb 2570 in Lowest recorded sealevel pressure Typhoon TID Aneroid cell Atmospheric Pressure I Pressure Readings D Errors due to temperature change variation in gravity build in error due to surface tension lZl Station pressure El Altitude corrections adjusted to mean sea level sea level pressure I On average at near surface 10mb100m 3192012 Surface Map EmuiuCale cg Ins Learning Small scale local variation in Surface map is a pressure and errors introduced constant height chat by altitude correction Average height of 500mb surface 5600 m 3192012 Approximate Elevation above Sea Level sonnmc sunmciz MB CHARTS 1000 850 700 500 300 200 100 a EmmiOutta mum Learning 120 1460 3000 5600 9180 11800 16200 APPROXIMATE ELEVATION M FT 400 4800 9800 18400 30100 38700 53200 a Surface map a Broniurccb mum Lummn l 500mb surface I FE Surface of constant pressure 57oorn J 39 5640 m 5580 m 5520 m 5520 m F SOOmb map I I quot TAB LE 8l Common lsobanc Charts and Their 1213 Midlatitude cyclonic storms a at b Uppemairmap 500 mb 3192012 Newton s Laws of Motion I An object at rest will remain at rest and an object in motion will remain in motion as long as no force is exerted on the object I The force exerted on an object equals its mass times the acceleration produced I Acceleration speeding up slowing down change of direction D Net force D F ma m TANK A Higher pressure gt Net force TANK B Lowsr pressure High Low Pressure Pressure H t L Point 1 Point 2 a smugcm Bunyan Luammg MAP VIEW 0 200 400 600 Scale km BarodaCol Damage teaming 11912 1916 39 1040 1044 7 l as statute per hour 73155 ELSE rrrrrrrrrffffrm 1 3123 4347 me 5357 5862 9157 am 7amp7 109 107 3192012 Forces that Influence Winds I Pressure Gradient Force caused by difference in pressure over distance I Directed perpendicular to isobars from high to low 13 Large change in pressure over a short distance is a strong pressure gradient and vice versa 1 PGF causes the wind to blow 3 Tightly packed isobars steep pressure gradients stronger wind it I Coriolis Force D Apparent de ection due to rotation of the Earth at De ect to the right in NH and to the left in SH it Stronger wind greater de ection 1 No Coriolis effect at the equator greatest at poles 921 Only in uence direction not speed L Only has significant impact over long distances Ball39s path Apparent path as seen by rotating platform Platform A nonrotating Platform E rotating 3192012 Geostrophic Winds Balance between PGF and CF no friction The stronger the pressure gradient the closer the isobars are the stronger the winds blow In NH geostrophic winds blow with low pressure to its left and high pressure to its right 7 CF 39 Air parcel l7 Approximation of the real world Blmkslcala Cengage Luauring g 7 39 m I Gradient Winds Aloft I Q L El Cyclonic counterclockwise D Anticyclonic clockwise 1 39 D Gradient wind parallel to curved isobars U Cyclostrophic near Equator 7 V CYCLONIC FLOW ANTICYCLONIC FLOW a Isobar or contour pattern b Wind pattern 1 I V V39Kir parcel a Low pressure area cyclone aloft b High pressure area anticyclone aloft 3192012 39 I Winds on Upper level Charts El Winds parallel to contour lines and ow west to east D Heights decrease from north to south Ll V Swag Km P6 hm 18 137 34 54 mm mm 7 2125 1amp2 23a l I 4449 3842 5064 347 3510 th Hemisphere b Southern Hemisphere 555 3952 e EwanCal mm Lsamirw o amwcm oenme Lelmm 613966 5357 quot 577 5352 l 7271 6367 was new FFFFF HFFFFIFFFH lo z g 9128 WEHOT B Rmnk Ir nln Knots r u mquot ca39m I Surface W1nds D Friction layer planetary boundary layer PBL n Friction reduces the wind speed which in turn 152 1 decreases the Coriolis force ms ma D Winds cross the isobars at about 30 average into m m low pressure and out of high pressure 3237 2352 U Buys Ballots Law 3337 4449 3842 5054 4347 6166 5357 6771 5362 7277 6367 8489 7377 0m FFFFFFI39FFFFFWHIO i a b Northern Hemisphere 119123 103107 SmokSIColeV Cengaga Learning Reading Ch 7 2292012 I 1 397 Key Questions I What s the primary difference between a cloud droplets and a raindrop I Describe how the collision and coalescence process produces prec1p1tat10n I What is icecrystal process or Bergeron process I What are warm clouds and cold clouds I Why do heavy shower usually fall from cumuliform clouds Wh does steady precipitation normally fall from stratiform c ouds I How does cloud seeding work What are used to seed clouds I How do the atmospheric conditions that produce sleet from those that produce hall I What are the most common icecrystals forms I What is supercooled water Precipitation Processes I Precipitation is any form of water that falls from a cloud and reaches the ground I Condensation alone is not suf cient to produce precipitation i Cloud droplets are extremely Typical raindrop 0 um 20 O Q al Typic cloud droplet 20 um Condensation nucleus 02 pm 39 e I Equilibrium vapor pressure I When air is saturated with respect to a at water surface it is unsaturated with respect to a curved droplet of pure water Curvature effect W Water molecules are less strongly attached to a curved water surface they evaporate more readily I Smaller droplets require an even greater vapor pressure to keep them from evaporating away Temperature 10 C Flat water surface Cloud droplet 39 if I Collision and Coalescence Process Cl Droplets of different sizes collide and coalesce into larger droplets 1 Terminal velocity I Larger drops fall faster than smaller drops w Large cloud W droplet Small droplets captured in n Small cloud droplets wake I Ice crystal Process 0 Bergeron process i Cold clouds u Supercooled water droplets 1 Ice nuclei id Saturation vapor pressure just above a water surface is greater than the saturation vapor pressure above an ice surface 0 During icecrystal process ice crystals grow larger at the expense of the surrounding water droplets 2292012 Cloud droplet 1000 pm I39 Warm cloud Cloud droplet 100 Hm Raindrop 5000 um 391 Cold Clouds Ice only glaciated r 40 C 7600M 2500020 39 39 5500 m39 Mixed ice and water 18000 ft 1 V 020 C l 6 Freezing level 0 C Liquid water only 1000 m 3000 it 2292012 I ICECrystals grow Waterdrpplet mammal larger at the expense of the surrounding water droplets d iffe ence Liquid Temperature 1 5 Vapor pressure difference mb Temperature 15 C Temperature C 39 I 39 1 I Cloud Seeding and Precipitation 3 Inject cloud with small particles that act as condensation nuclei starting the precipitation process 7 NEED CLOUDS seeding does not generate clouds Cold clouds with a low seed ration best Dry ice silver iodide 3 Falling ice crystals may freeze I3 Falling ice parlrcles may collide 2 Falling ice crystals may collide supercooled droplets on contact and immune into many tiny and slick lo clher ice crystals accretion producrng larger ice secondary ice panlcles aggregation producing particles snowflakes 2292012 1 Natural cloud seeding I I Precipitation in Clouds Precipitation Types D Starts quickly in minutes El Most precipitationforrned through accretion l Rain falling ClI Op 0f liquid water D Many times rain starts as ice D Dlt 05 mm drizzle I Virga III Cloudburst 7 I Snow frozen water falling from sky crystal or Diffusion Large crystals El Most precrpitation starts as snow Aggregate 439 D Freezing level snow amp cloud appearance fall streaks Shula akes I drifting snow blizzard I A blanket of snow is a good insulator Melt Hi Snow 2292012 Column Dendrite Needle Fallstreaks 0 to 4 32 to 25 Thin plates g 030 4 to 6 25 to 21 Needles g 6 to 10 21 to 14 Columns 03920 10 to 12 14 to 10 Plates E 010 12 to 16 10 to 3 Dendrites plates g 16 to 22 3 to 8 Plates 00 I 4039 39 I 415 39 50 22 to 40 8 to 40 Hollow columns I 7 I Average annual snowfall 39 Centimeters Inches 00 i 00 01 76 01 30 77lt 152 31 650 153305 6l 120 308609 121 240 11 610914 241 360 9 915 1219 361 480 1220 1829 481 720 gt183 gt720 11 Brookslcde Cengage Leaming he snowies ci y in he US 2292012 I Sleet air below freezing then travels through a layer of air above freezing begins to melt and then falls through a layer of air below freezing just above the ground surface I Freezing Rain ground surface is freezing as rain hits the surface it freezes Above freezing Nimbostratus Cloud Snowflake Snowflake melts Raindrop Temperature C r 39Ep Average annual number of days with freezing rain and freezing drizzle over the cold 8 Snow Freezing Freezing 0 C warm cold 0 C warm b Sleel Freezing 10000quot cold 0 C warm rd Rain 2292012 39 Precipitation Types I Snow Grains solid equivalent of drizzle no bounce or shatter I Snow Pellets larger than grains bounce break crunch underfoot I Graupel ice particle accumulation with rime I Hail graupel act as embryo in intense thunderstorm grow through aggregation as pushed up by updraft Fuginqs 39w ajaiig I 4 39 Ice crystal v I Rimed ice A35 crystal l I 38 23 8 Temperature C l A i a momma seam Legran Snowflake lg Emmycole sergng team Rimed snowflake Graupel snow pellet lt 3 BrooksCale Candace Leaminu Hail too large for cloud to hold falls to earth causing strong cold downdraft Hail Formation Hail growing incirculating convection currents Freezing Level ZRain drops being sucked into the updraft 6 Erooksfcale 2292012 1 ld GE0203 Exam 2 Study Guide Chapter 3 4 5 Find the answers in your notes or the textbook What is saturation Saturation is an equilibrium condition in which for each molecule that evaporates one condenses When air is saturated Air is considered saturated when the dew point reaches 100 No more water can be absorbed How are temperature dew pointtemperature and wetbulb temperature related Warm air can hold more water than cold air Temperature Dew point temperature the point where moisture condenses out of the air turn to water The higher the temperature the higher the dew point WetBulb is the temperature that no more evaporation can occur What is saturation vapor pressure The pressure that the water vapor molecules would exert if the air were saturated with vapor at a given Temperature What determines saturation vapor pressure The air temperature What is vapor pressure The pressure exerted by water vapor molecules in an air parcel Dalton s Law of Partial Pressure Fraction of total vapor pressure 1 or so More water molecules higher vapor pressure What determines vapor pressure The amount of water molecules the higher the higher the vapor pressure the lower the lower vapor pressure Solid most molecules moving the fastest What does vaporpressure measure Water vapor pressure measures how much water vapor is in the air Consider an air parcel containing some moisture how do the followingchange as the air parcel rises ltemperature As an air parcel rises it will expand and cool 2 vapor pressure As an air parcel rises it s vapor pressure decreases 3 saturationvapor pressure As an air parcel rises saturation vapor pressure decreases 4 specific humidity Remains constant 5 relative humidity Moves with Saturation 6 absolute humidity Decreases as it rises 7 dew point temperature Rises with higher temperature vice versa How do dew frozen dew and frost form and under what conditions do theyform Dew formswhen a surface cools through loss of infrared radiation down to a temperature which is colder than the dewpointof the air next to that surface Frozen dew forms when the air temperature drops below freezing Frost forms during overnight cooling and will only form on a surface when the temperature is at or below freezing What are the four types of fog How do they form and where do theytypically form in the US 1 Radiation fog ground cools through conduction and radiation Most common in late fallwinter Found in the valleys 2 Advection Fog warm moist air moves horizontally adverts over a cool surface cooling the air to its dew point to produce fog Commonly found in the summer on the pacific coast 3 Upslope Fog moist air flows up an orographic barrier Found on the east side of the Rockies Goes up the mountains 4 Evaporation Fog Steam fog cold air moves over warm water In the cold winter and after a summer rain shower What are condensation nuclei Why are they important for haze and fogformation Particles suspended in the air that around which water condenses or freezes Hygroscopic waterseeking Hydrophobic water repelling Dry condensation nuclei create a bluish haze Wet condensation nuclei creates a greyish or white haze What are the major characteristics of each principle cloud type At what aretheir typical elevations What are they composed of What type of weather istypically associated with each type of clouds High clouds CirrusCi Pleasant Weather CirrostratusCs Form in ahead of advancing storm Cirrocumulus Cc RainyWindy Air cold and dry white in color Low Clouds StratusSt Uniform grayish light to moderate raid StratocumulusSc light to dark grey rarely precipitation NimbostratusNsDark Grey light to moderate precipitation Middle Clouds Altostratus As Grey humid late afternoon thunderstorms AltocumulusAc Greyish Continuous precipitation Clouds with vertical development CumulusCu CumulonimbusCb Stratus sheetlike cloud Cumulus puffy cloud Cirrus wispy cloud pleasant weather PPN Nimbus rain cloud What are the ways to change relative humidity 1 Change vapor content 2 Change saturation What is specific heat How does specific heat of water and soil affect thetemperature variation at different regions The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius What is windchill factor What does it indicate The effect of the felt air temperature on exposed ski due to win It s always lower than the air temperature What is heat index What does it represent Apparent temperature Human perceived equivalent Combines air temperature and relative humidity What are the processes associated with phase change of water How does heatflow during each process and how does it affect the environment Evaporation Liquid gt Gas Heat energy absorbed Condensation as air cools From gas gt liquid Heat energy released Sublimation Solid gt Gas Head energy absorbed PPP Deposition Gas gt Solid Heat energy released What is heatingdegreeday Coolingdegreeday How are they defined andcalculated HDD people heat when temperature below 65 degrees Fahrenheit Calculated by take the average temperature on any given day and subtract it from the base temperature CDD people cool when temperature above 65 degrees Fahrenheit Using what you learned about temperature and humidity explain why summertime California is more comfortable than Alabama Water causes breezes and cooler temperatures in California than in Alabama How do you use temperature and dew point J 39 39 39 39 39 quot T Amount of moisture in the air current tempmax moisture air could hold dew point How does cloud affect radiation balance and surface temperature variation in quotJ What are the major factors affecting the global variation r Latitude solar angle and day length Land 8L water specific head Ocean Currents warm and cold currents Elevation cooling and increase range What is dew point temperature Can you use dew point temperature todetermine daily minimum temperature Dewpoint temperature is the temperature to which air would have to be cooled for saturation to occurwithout adding more water vapor and changing air pressure Low dew points means low water vapor content which means low humidity Which means a lower daily temperature What is wetbulb temperature What does it represent How is it related tohuman comfort The lowest temperature that can be reached by evaporating water into air Due to an increase in temperature in a heated home there is a decrease in relative humidity causing more evaporation from the body plants etc Need to water plants more buy humidifier Hydrate more What is thermal conductivity The property of a material s ability to conduct head Explain why visible and infrared images can be used to distinguish highclouds from low clouds thick clouds from thin clouds n infrared images low clouds appear gray and high clouds appear white CONDENSATDON DEW FOG amp CLOUDS Reading Ch 5 2142012 Key Questions I Explain how dew frozen dew and visible frost each form How can fog form when the air s relative humidity is less then 100 How to distinguish among dry haze wet haze and fog Name and describe four types of fog List and describe three methods of fog dispersal How do radiation fog and advection f0g form List at least two distinguishable characteristics of each of the ten bas1c clouds How can you distinguish altostatus from cirrostratus Explain why visible and infrared images can be used to distin uish high clouds from low clouds thick clouds from thin c ouds I Why can you see your breath on a cold morning Does the air temperature have to be below freez1ng for th1s to occur 39 Review of Humidity Specific Humidity mass of water vapor mass of air Mixing ratio mass of water vapor mass of dry air Vapor pressure the pressure exerted by water vapor molecules in an air parcel Dalton s Law of Partial Pressure Relative Humidity ii actual water vapor saturation water vapor100 E1 RH can be changed two ways I Change vapor content I Change saturation by changing temperature Dew point is the temperature at which saturation occurs when cooling an air parcel without adding more water vapor and changing pressure IF W I r The Formation of Dew and Frost I Temperature near surface cools t0 dew 0th temperature ue t0 radiative cooling I Saturation occurs I When T lt 0 C frozen dew forms I More likely to form on clear calm nights associated with large fair weather high pressure systems I When Td lt 0 C T reaches Td frost form I Freeze and black frost L Condensation Nuclei I Particles suspended in the air that around which water condenses or freezes E Hygroscopic waterseeking E Hydrophobic waterrepelling Hygroscopic nuclei Hydrophobic nuclei H1 Haze I Dry condensation nuclei T gt dew point re ect and scatter sunlight creating blueish haze I Wet condensation nuclei 75 relative humidity re ect and scatter sunlight creating grayish or white haze 2142012 area of 39mnowf alla 4935 mm new Hangman 37 fww A quotWalk W mugs amp 777 2 wt v Wright Pam slaughter plants a a W 563 2011 cungle Map am zou Gongle DodgeCity KS unusual snowfall Jan 19 2011 39 l 7 quot Fog I Condensation is a continuous process beginning when water vapor condenses onto hygroscopic nuclei at RH 75 I Condensation forms a cloud near the ground with visibility lt 1km I Fog in city air vs over the ocean I Fog forms in two ways E1 By cooling D By evaporation and mixing 2142012 I Radiation fog ground cools through conduction and radiation ground fog Most common over land in late fall and winter E Valley fog created by cold air drainage 39 I High inversion fog in California s Central Valley 9 i i I l V T quot 539 K y in 1quot r BmoksiCnle Cangage Learning 1 I Advection Fog warm moist air moves horizontally advects over a cool surface cooling the air to its dew point to produce fog El Summer fog on the Pacific coast it Evaporate and disappear inland 3 Radiation fog BaronCole Cengage Learning I Upslope Fog moist air ows up an orographic barrier E East side of the Rockies 2142012 39 39 r 2 r f J I Evaporation Fog g I In general fog not common for most location in 3 Steam fog the US However several areas do exist with a I Cold air moves over warm water frequency Of fog TWO causes 11 Breath in cold winter D Elevation LIquot Evaporation fog after summer mith nwer 4 Ocean currents Vii 39 V m 11 l r x a N 7 l VEE39Advecti d39at39 l 3 Itsi V 2 DO0 O 39 ODltDgt 0 O J T l2 393 x H L 5 l 20 h l Arlvectj onriadiatimn4r 4 39 20 30 1O it CIOUdS TABLE 52 The Four Major Cloud Groups and Their Types I Classification of clouds 1 High clouds 3 Low clouds u Latin words to describe clouds as they appear to ground Observers Cirrus C1 Stratus St 39 Stratus 39 Sheebhke dOUd Cirrostratus Cs Stratocumulus Sc I Cumulus puffy cloud I Cirrus WiSpy Cloud Cirrocumulus Cc Nimbostratus Ns I Nimbus rain cloud primary cloud groups A1 A m 11 I Four groups based on height low mid high vertical tosn atus S cu L us cm I Within each group types identi ed by appearance shape Altocumulus AC cumulonimbus Cb density color is BrenksKZole Cengage Learning 2142012 H G H C LO U 08 Cirrostratus A Cirrocumulus Mackerel sky Cirrus 1 lt 5 gt 399 1 G1 BrooksObie Cangaga Learning L Anvil lop I High clouds I Air is cold and dry I Composed almost exclusively of ice crystals I White except near sunrise and sunset I Cirrus Ci El Thin wispy El Horse tails I Usually moving from west to east El Fair pleasant weather annk nlw PmnmP Learning I Cirrocumulus Cc 1 Small rounded white puffs II Individually or in rows II Resemble the scales of a fish I Associated with waves in the upper troposphere El Rain or windy weather is likely to come I In I Cirrostratus Cs En Thin sheet like El Often covers the entire sky El Sun and moon are visibl through the clouds En Halo El Thick Cs often form ahead of an advancing storm En Rain or snow in 12 24 hour especially middle clouds are moving in too 2142012 191 39 Middle Clouds I Altostratus As 1 cloud base between 2km and 7km 1 Water droplets and ice crystals D Gray or bluegray U Often covers the entire sky C Sun dimly Visible E Water droplets and some ice c stals I Altocumulus Ac E Water droplets D Gray puffy masses D No shadow when As E Looks larger than Cc presents B One part of a cloud is another D Often form ahead of storms having widespread E In humid summer morning often and relatively continuous means thunderstorms may occur by precipitation late afternoon 39i 39E Low clouds I Stratocumulus Sc D Base below 2km B Low lumpy clouds E composed 0f water 1140 7 7 7 El Blue sky Visible between 39 l 39 clouds I Nimbostratus Ns a Light to dark gray El Water droplets D Dark gray wet lo layer D Lower base than Ac 391 U Larger than Ac E Continuous rainfal 1 Light tomoderate precipitation E Darker than As r 7 7 U Precipitation occur El Stratus fractus Scu 39 rarely 2142012 I r 39 I Stratus St V I I Cumulus Cu El Uniform grayish 39 D Puffy El elevated fog V l 39 39 i 39 3 iquot quot D Floating cotton with sharp outlines UFl h39 l39 h D No prec1p1tatlon or at base W 1te 01quot 1 t gra light rain drizzle Ell Cu are detached Sc are 1n groups or patches W D Cu has dome or tower D Lower and darker than shaped top Sc has at top El Uniform base As El Fair weather El Light to moderate Ell In summer can develop to rain associated with Tcu convection and showery Ns precipitation 39 7 39 I Cumulonimbus Cb El Thunderstorm clouds U Dark base 600m B Top extended to tropopause D Violent up a D Huge atten cumulonim l osmokslcm Cengaga Learning Cumulus congestus Towering cumulus Tcu 2142012 39 IE Some Unusual Clouds I Not all clouds can be placed into the ten basic cloud forms I Unique atmospheric processes and environmental conditions create dramatic and exotic clouds I Unusual clouds and weather balloons often cause of UFO reports httpphotoaccuweathercomphotogallery Cloud Observations I Sky conditions cloud coverage divided into eighths and each amount associated with term such as scattered clouds D Clear sky a few clouds scattered with clouds partly cloudy mostly cloudy overcast TAB I 55 Description of Sky Conditions Ei n i M Clear cm or SKC u m 5 0 No clouds Few gt5 m 525 u a 9 Few clouds visible Sumcred SCI gt25 to 550 3 to 4 Partly duudy Bmkeu BKN gt50 m 587 5 to 7a Mostly cloudy Overcast OVC gt117 o lUU39Vu 1 Sky Is covered by clouds Sky obscured 7 s 39 39 39 39 r I 39 ml so mun rather than l7 clnud cover AIR MASSES AND FRONTS Reading Ch 11 4H2012 Key Questions I What is an air mass What regions are good source region for air mass What are the major air masses that affect the US List the temperature and moisture characteristics of each of the major air mass types What are lakeeffect snows and how do they form On which Side of a lake do they typically occur What is a front Describe and draw the typical side Views of a typical cold front warm front and col occluded front What are the typical weather associated with each type of fronts I Given a weather forecast can you determine what type of front Will most likely pass the area Ia Air Masses I Extremely large body of air whose temperature and humidity are similar horizontally I Source Regions area where air mass originates usually at and uniform composition with light surface winds 20 p Arctic air 55quot 39 Air Masses I Classification D Classi cation based upon temperature and humidity TABLE 1 some REGION Ln id Comingmake irl arcr Maritime m BrooksICole oangaga Leanung 472012 Air Mass Classi cation and Characteristics hot dry stable air aloft unstable surface air n Emoksrcoim Canaan LeaInn 39 EF I North America cP and cA El Source region N Canada Alaska D Dry cold stable Altitude km quot Heavy I Showers 1 I North American mP D Source region North Pacific North Atlantic D Cool moist unstable 472012 Cold damp air Stationafy39fr j ff 39 Station Model l l I at the surface quot quot quot39e 68 042 biggie Signi cant cloud weather I T 111 dewpoint gt cwixgr temperature direction Fahrenheit I Wind 4 wind speed Significant Weather Cloud Cover I Slgnlflcant Il lellhllT 6 RAIN SHOWER 0 CLEAR weather 39 MODERATE R FREEZING RAIN RAIN SCATTERED FEW I Cloud cover 2533quot FOG 5 CLOUDS LIGHT 2 8 997 0 O 5535 MODERATE SNOW 4 BLOWING snow o 283 HEAVY THUNDERSTORM SNOW K OVERCAST 2 6 A SLEET NO SIGNIFICANT ICE PELLETS WEATHER OBSCURED a Source region Gulf of Mexico Caribbean SE Pacific l1 Wet warm unstable a Pineapple Express Bermuda High Hawaii a Bmokslcala sewage naming I North American CT 3 Source Region SW US Mexican Plateau 3 Hot dry stable 472012 La Rummin mmma I nmlnn a Emukslcma Cenmu Laammq 4H2012 3931 Fronts I Transition zone between two air masses of different densities I Identi cation on Charts ll Sharp temperature change Sharp change in dew point Shift in wind direction Sharp pressure change Clouds and precipitation Frontolysis and fronto genesis Arctic front front wi f Albig wU mP SIMPLIFIED KEY Cold from Warm front Stationary front Occluded from Light snow Light rain sleet Wind direction N Wind speed 10 knots wiiiii 0 500 km 0 2 22 Air temperature 0 200 400 mi 1 ew pom a monksCole mam teaming 39 Fronts I Stationary Fronts III Front with no movement III Alternating red and blue line with blue triangles and red semi circles III Winds parallel but opposite direction III Variable weather I Cold Fronts III Cold dry stable air replaces warm moist unstable air III Blue line with blue triangles III Clouds of vertical development III Thunderstorms squall lines 472012 a Emnkslcme swag Learnan WARM Am WARM WATER A titude km EamonCm Sewage Lezmlng a amwwe Ccnvaca Learning 47201 2 39t j 39 p A back door cold front E Fronts I Warm fronts E Warm moist unstable air overrides cold dry stable air E Red line with red semicircles E Horizontal cloud development with steady rain I Topic Dry Line E Not a cold or warm front but a narrow boundary of steep change in dew point I Occluded Front E Cold front catches up to and over takes a warm front D Purple line with purple triangles and semicircles E Cold occlusion warm occlusion a amokucale carMe Igni Warm Fronts Drylines 7 M 39 tropical alr warm moist 600 km 7 gmmmcwggmmm aaW a cWWmm 472012 Occluded Fronts Cold Occlv s quot a Bmulstoula sumac ummng Initial occlusion C Cold occluded front C a Emnklrcab mm Luman a Bmuxslibln Clnglm Llamlng 4H2012 Warm occlusion a oamuume Cmgaas Leammu JCold b E Warm occluded front E a Bmukyl abei1 lvgua Lzaming Meteorology Study Guide EXAM 2 Saturation is when the air is holding the maximum amount of water vapor so that the number of molecule escaping into the atmosphere equals the number of molecules being condensed When air is saturated the temperature dew point temperature and wetbulb temperature are ALL the SAME Saturation vapor pressure is the pressure that the water vapor would exert if the air were saturated This is depends on the temperature Vapor pressure is the pressure exerted by water vapor molecules in an air parcel Vapor pressure is dependent on the dew point temperature As an air parcel rises a Temperature decreases due to cooler molecules bumping against the warm molecules b Vaporpressure will stay the same because the number water vapor molecules is constant c Saturation vaporpressure will also decrease because Sat VP is dependent on temperature d Relative humidity is the VPSat VP and since the Sat VP decreases the RH will increase e Absolute humiditywill decrease since it is the mass of watervolume of air and the parcel will expand with increasing height f Dew point temperature will stay the same since the number ofwater molecules does not change 4 When the air reaches saturation water molecules will form on the surface a Dew forms when the Td and T are above 0C b Frozen dew forms when the Td is above DC but the T goes below DC in the night c Frost is formed when the Td is below 0C so the molecules immediately form ice crystals 5 Types offog a Radiation fog forms when the ground cools to or below it s Td through conduction and radiation It is often found in the Central Valley area of California b Advection fog forms when warm moist air moves horizontally over a cool surface cooling the airto its Td It is most commonly found in in the paci c NW because the Paci c Ocean winds blow across the surface Upslope fog occurs when moist air flows up an orographic barrier which causes the T ofthe airto decrease until it reaches Td Most commonly found in the Eastern Rockies however it is NOT COMMON since there is not much eastern winds Evaporation fog occurs when cold air moves over a warm water This is most commonly seen in the summertime across the country after rain showers You can also see this type of fog in the Great Lakes in the fall Condensation nucleiare particles suspended in the air which water molecules condense or freeze around Two types a Hydroscopic water seeking Ex Sea salt b Hydrophobic water repelling Ex Wax Oil These particles are important because without them RH of several hundred percent would be required for condensation to begin H20 couldn t clump as fast 7 Cloud types a HIGH CLOUDS composed ofice crystals i Cirrus Ci 0 Thin wispy 0 Pleasant fair weather ii Cirrocumulus Cc 0 Small rounded puffs 0 Rain or windy weather on the way I A O Q 0 iii Cirrostratus Cs 0 Thin sheet like halo 0 Before an advancing storm b MID LEVEL CLOUDS composed of water droplets and ice crystals i Altocumulus Ac 0 Gray puffy masses 0 Thunderstorms later in the afternoon ii Altostratus As 0 Bluegray Covers entire sky No shadow o Expect widespread storms with continuous precipitation c LOW CLOUDS composed of water droplets i Nimbostratus Ms 0 Dark gray wet looking layer 0 Continuous light rainsnowfall ii Stratocumulus Sc 0 Lumpy light to dark gray can see sky in between NO at bottom or defined top 0 Pleasant weather iii Stratus St 0 Uniform gray clear bottom elevated fog 0 Light to moderate rain ii Cumulus Cu 0 Puffy flat base white or light gray individual clouds 0 Fair weather iii Cumulus CongestusTowering Cumulus Tcu 0 Still developing domelike top have not reached Tropopause o Expect to turn into cumulonimbus storms ahead iv Cumulonimbus Cb 0 Dark base top at Tropopause anvil top 0 Thunderstorms Relative Humidity can be changed from changing the vapor content ofthe saturation Specific Heat is the heat capacity ofa substance per unit mass per degree Dependent on substance Since the specific heat of water is higher compared to soil it takes longer for the water to heat or cool Because of this the air that passes over the water becomes warmer and causes the temperature of those regions to stay higher 10Wind Chill index measures how much heat our body is losing due to wind When the wind is high we feel cooler because the wind blows away air that our body has transferred energy to making it warmer 11Heat Index is the apparent temperature or the temperature our body feels it is As RH increases heat index increases cooo 13A heatingdegreeday is when the temp is below 65F 65F current temp HDD A cooling degreeday is when temp is above 65F Current65F CDD 14Summertime in Cali is more comfortable than Alabama because the Td is farther away from the T it is farther from saturation making the heat index less 15 lfthe Td is close to the T then the RH will be high because the air is close to saturation 16Clouds effect radiation at the surface because the reflect some ofthe incoming energy back to space why we see them as white and because they reflect some of the energy the earth is emitting back to the earth keeping it warm 17 The difference between the speci c heat ofsoil and water affect the global temperatures as well as wind and ocean currents 3252012 I Key Questions What are the spatial scales of air motion in the atmosphere What causes wind gusts Why are winds near the surface typically stronger and more gusty in the afternoon Describe the land and sea breeze What is convergence and divergence How is that related vertical motion Describe how Monsoon circulation works Describe the three cell model for global circulation What are the typical weather you nd in each zone How do the permanent highs around the US affect weather over California and Southeast US What is jet stream What are the major jet streams affecting the US Where do you expect to find the jet streams in the Nort ern Hemisphere What is Ekman transport How does Ekman transport affect water temperature in US west coast What are the major ocean currents near US coasts I What is ENSO How does it affect global climate Atmospheric Circulation Reading Ch 910 39 kg Scales of Atmospheric Motion Global 5000 km scale Macroscale gt Synopuo 2000 m scale D area s Hurricanes Wgall ef imms Tropical storms Mesoscaie 20 km 1 39 hmoikvwind S amia Aria wiricl mi Microscale 2m minim i ros ale 1 as care C s no no scale 20M c M as H v P eddles muco owmammm Seconds Minutes Hours Days lK quot O quot lO quot i0 minutes hours days a week or more LIFE SPAN EmuuCcie Czngaue Learning 39 I Thermal turbulence El Gusty surface winds are more likely to occur when the atmosphere is unstable El Surface Winds are usually stronger in the afternoon wt gusts 4x 0 Small ddiresv 21 Stable air b Unstabie air Brooksr Cule Cengage Learning 3 Force of the Wind El Bridges and hills or rises can modify Wind increasing the force at specific locations E http wwwyoutubecomwatchVj zchXanw a Smuksfcole Cengags Learning Emokslcme Cen age Leain 3252012 a 511mva Cenyigu Lam 39 HfDetermine Wind Speed and Direction I Wind characterized by direction speed and gustiness I Wind direction describes the direction from which it is blowing D Onshore offshore U Sea breeze land breeze 325201 2 le h J m 39 I In uence of Prevailing Winds U Prevailing most frequently observed direction during a given time period D Impact human and natural landscape I City planning I Home building D Wind rose NW N NE W E 0 5 1o 15 ll SW SE Scale Local Winds Thermal circulation Sea and land breezes Local winds and water bodies Monsoon Mountain and valley breezes Katabatic winds Chinook winds Santa Ana winds Desert Winds 3252012 I I Thermal Circulation i i 11 Sea and Land Breeze I Heating and cooling 96W El Uneven heating of of the atmosphere land and water 2mquot above the grOund El Day land hot water create cold core high L M920 1 001d 2 sea breeze and warm core 10W 3g El Night water hot land 0 pressure cells 2 001d land breeze sum I Wind travels from m 0km El Sea breeze front sea I I b 1k breeze convergence high to low and uses L 92 m until it cools and E E 96 be glns to s1nk 7 M em 0 WWW an wrw r Emnksloob Oenglgl Learning 3252012 Divergence gt o 39 gt Air flow gt e ankslccl swans Learnan Monsoon I Arabic for seasonal El Winds change direction seasonably causing extreme dry and wet season 1 Eastern and southern Asia North America j South Chma Sea N ar Winter Monsoon A N by Summer Monsoon e BlanksGale Damage Leamlng Precipitation in 140 Chen apunp 120 FMAMJJASOND Month Precl plta o n cm Mountain and Valley Breeze D On mountain slopes warm air rises during the day creating a valley breeze during night nocturnal drainage of cool air creating a mountain breeze El Associated with cumulus clouds in the afternoon Valley breeze Mountain breeze a BlanksOak camus mmmg mau Local Winds Thermal circulation Sea and land breezes Local winds and water bodies k Monsoon E Alllluda x1000 Ir Mountain and valley breezes Katabatic winds Chinook winds Santa Ana winds Desert Winds 3252012 39 h 7 General Circulation of the Atmosphere I General refers to the average air ow actual winds will vary considerably I Average conditions help identify driving forces I The basic cause of the general circulation is unequal heating of the Earth s surface EH Warm air is transferred from the Tropics to the Poles EH Cool air is transferred from the Poles to the Tropics II7 D Thermal Circulation Isobanc surfaces I Heating and cooling of the atmosphere above the ground create cold core high and warm core low pressure cells I Wind travels from high to low and rises until it cools and begins to sink Bmokstole Cengage Learning I Q Q SingleCell Model 900M Polar region Sub 39olarre39ion 13 p 9 600N Wilde fmzpa ata awu 903 Polar region b 3 Brooksmole Cengage Learning 3252012 I 939 i l Single Cell Model D Assume J uniform water surface 2 Sun always directly overhead the Equator 3 Earth does not rotate U Result I huge thermally direct convection cell Hadley I Three Cell Model I Allow earth to spin El Result I Three cells Hadley Ferrell Polar Alternating belts of pressure starting with L at Equator Alternating belts of wind with NE just North of Equator 21 ThreeCell Model Subpolar low 1 I 39 Lain I Average Surface Wind and Pressure The Real World D Semi permanent high and lows El Northern vs Southern Hemisphere D Major features shift seasonally with the high sun I North in July I South in December acifl v M01 Latitude a January I 80 90 O Longitude ammonia Sausage anmg 3252012 Los Angeles Atlanta 39 p 1 Precipitation in 03 Precipitation cm N Pacific High Bermuda High musicals Conway Learning 0 JFMAMJJASOND a amokucaln vanum Lamina Average wind flow aloft Average wind flow aloft Latitude Latitude 0 Longitude Jet Streams I 100200 kt winds at 1015km thousands of km long several 35 100 km wide and a a few km thick polar and subtropical Subtropical jet stream Subtropic flat stream 3252012 Q Stratosphere 70 20 Subtropical jet 7 7 60 Polar T 50 15 40 g 30 g 10 2o 2 g 1o 5 O Mf P449 Equator Brookleole Cengage Learning Altitude 1000 ft U Jet Streams I Polar and Subtropical Jet D Established by steep temperature and pressure gradients between circulation cells D Between tropical mid latitude cell subtropical and mid latitude polar cell polar U Gradients greatest at polar jet 1O a 3D View Cold air E Warm air Low heights W High heights b SOOmb chart Brook 9ch Census Learning 3252012 I W 7 IE Angular momentum and Jet stream In the producl m X v x r Bringing In her arms extended arms mean decreases har radius and larger radius and smaller therefore Increases her velocity of rolatlon rolatlonal velocity Jet stream Center of Earth copyrigm a Addison Wesley a Emucm caning Learning IE1 Atmosphere Ocean Interactions I Global Winds and Surface Ocean Currents i3 Ocean surface dragged by wind basins react to high pressure circulation forming gyres i Cold current owing north to south on west side of continent El Warm current owing south to north on east side of continent D Oceanic front 11 3252012 Brightness temp C 0 510152025 N Paci c Drill roshio California Currenl Current N Equatorial Current Lahtude o I s Equatoria Currenl 30 139 PeruH umbolt Current Antarctic Circumpalar Current West Wind Drill I l O 180 90 O Longitude smugw Cengaaa mmm Atmosphere Ocean Interactions I Upwelling EkInan spiral EkInan transport D Water moving away from the coast causes upwelling I El Nina and the Southern Oscillation lt53 D El Nino irregular warrn episode off west coast of South g f 39 p W doe39no America g to 939 I m D Southern Osc111at10n rlse 1n pressure over W Pac1f1c fall In 66 saf39flimnc39Sm p the E Pacific equatorial countercurrent WC D ENSO A 39 r 0 39 Los Angeles I B La Nlna 31 D teleconnection A L 12 EXAM 4 STUDY GUIDE 1 Iquot 3 4 5 High and low pressures are marked by capital quotHquots and L s on the map Other ways they can be determined is on a small scale is by the difference in temperatures On an upper level chart the ridges and troughs tell us high and low pressures On the left side of a trough we should expect a convergence high pressure at surface level and on the right side in between the through and the ridge we expect a divergence low pressure at surface level The warm air rises where it s warm which creates a high pressure in the upper atmosphere and low H War H gt L pressure in the lower atmosphere and cool air sinks creating a low pressure in the upper atmosphere and high pressure in the lower atmosphere Because of the difference in the pressure the warm light air will flow toward the cool dense air which causes the cool dense air to sink creating a high pressure at the surface level Air always moves from high to low pressure so the cold high pressure air will move toward the warm low pressure air As the air warms it will rise and complete the cycle This cycle will continue until equilibrium is reached Monsoons are caused by a Winds change direction seasonally b Tibet plateau Breezes a Caused by the difference in temperature from the land to the sea Since the specific heat of water is higher it takes longer to warm and cool b Sea breeze blows toward land onshore c Land breeze blows toward the sea offshore Scales of Atmospheric Motion a Microscale i Couple cm to couple m ii Life span is short minutes b Mesoscale i m to km ii Medium life span daysweeks c Synoptic scale i 2000 km ii Long lifespan weeksmonths 6 Wind direction around Highs and Lows a Upper Level i Winds blow clockwise and outward around HIGH pressure ii Winds blow counterclockwise and inward around LOW pressure b Surface i Winds blow directly from HIGH to LOW pressures because of the difference in weight 7 If the wind is blowing at 315quot then the wind is coming from the North West or it is a Northwesterly wind 8 Gusts are caused by the mixing of air between the upper and lower levels a When strong wind from the top comes to the surface we experience a change in wind direction and speed a gusts b Surface winds are stronger in the afternoon because the atmosphere is less stable 9 Threecell circulation model a In the polar cell winds blow in a clockwise motion creating a polar high pressure b In thefarrell cell is where the quotwesterliesquot blow Winds blow away from the 30 markThis air sinks because ofthe change in direction which creates a subtropical high Nicknamed the quothorse latitudes because of it s lack of wind c In the Hadley cell winds blow toward the equator and west Creating a convergence at the equator and causes lots of clouds and rainfall ITCZ 10 Three cell nicknames a InterTropical Convergence Zone ITCZ is located at the equator b Doldrums are located on the equator c The horse latitudes lie at the 30 and are called this because of their lack of wind 11 Highs a Pacific high i Summer brings cool dry air into the west coast during the summer keeping it cool ii Winter high moves farther south and brings in warm moist air to the west coast creating more rainfall b The Bermuda high i Warm moist air to the east coast all year long creating an increase in rainfall 12 lets a Produced by strong pressure gradient in a short distance b Flow west to east c Temperature change affects the strength of the jets d Polar Jet i Get stronger in the winter when the isobars are closer ii Between mid latitude and polar cells e Subtropical i Between tropical and mid latitude cells 13 Ocean currents a Pacific Ocean i N Pacific Drift Califonria Current N Equatorial Current Kuroshio Current b Atlantic Ocean i Labrador Current North Atlantic Drift Canary Current Gulf Stream N Equatorial Current c Ocean currents on the surface follow the prevailing wind and go in the opposite direction below d Currents in the NORTHERN hemisphere move clockwise 14 The Ekman spiral a The wind is blowing parallel to the shoreline which causes stress on the water However due to the coriolis effect the water is not moving in the direction of the wind it is moving 45quot right b Because there is less help from the wind as we get deeper in the water the coriolis effect gets stronger and creates a clockwise spiraling motion downward until the wind and the water current are going in opposite directions c When the current hits the shore it goes away from the land causing the bottom water to come up this is upwelling i This causes the temperature at the shore to be much cooler on the west coast 15 El Nino a Generally in southern America the current flows from SE to NW which allows cool water to upwell in southern Mexico and Central America b In Christmas time the warm current from the pacific ocean gets warm water no upwelling which causes nutrients to die c El Nina and Southern Ocolations change in pressure happens at the same time ENSO d Causes the jet stream to be farther south so the upper part of the US will be warmer and drier e Also causes the Amazon and southeast Asia to get warmer and drier 16 An air mass is extremely large body of air whose temperature and humidity are the same horizontally 17 Source Regions a P polar is cold b T tropical is warm c A artic is the coldest d m maritime is moist e c continental is dry 18 The US is effected by cA from Northern Canada cP from Canada and mT from the gulf cost 19 Fronts Transition zone between two air masses of different densities a Cold front 39 Cold dry dense stable air ll generally coming from Canada iii Cloud develop vertically iv Thunderstorms v Cold wind blows toward front warm wind in front blows in parallel vi Very steep curved side view b Warm Front i Warm moist light unstable air ii From south gulf coast iii Horizontal cloud development iv Clouds and light steady rain v Warm wind blows toward front cool air in front blows in parallel with the front vi Shallow linear slope from side view c Stationary Front i No movement ii Winds parallel but in opposite directions d Occluded front 39 Cold front catches up with warm front ii Cold occlusionwarm occlusion iii mid latitude cyclone iv very cold air pushes against the occluded front warm air blows against the warm front in the warm sector cold air blows in parallel with the occluded front on the warm side 20 We will see higher clouds that grow horizontally and expect light steady rain 2222012 Key Questions I What is environmental lapse rate How is environmental lapse rate related to atmospheric stability How do 1temperature 2dewpoint temperature change as an air parcel rises sinllts in the atmosphere What is an adiabatic process What is dry adiabatic rate What is moist adiabatic rate Why are they different If provided with environmental lapse rate can you determine the temperature and dew point temperature within the air moving over a mountain What is convective instability What are the ways to make an atmosphere layer more stable or more unstable What are the four ways to trigger cloud development Can you use adiabatic charts to determine temperature and dew point temperature of an air parcel moving around in the atmosphere STABILITY lt34 QLQUD DEVELQPMENT Reading Ch 6 39 quot2 Importance of Clouds Concept of Stability I Release heat to atmosphere I Help regulate energy balance V y I Indicate physical processes I l r 39 Stable equilibrium I What processes are associated with cloud development Unstable equilibrium Brcnkxlwle mums Learning w Atmospheric Stability 2222012 l 2000 Expands and 1000 cools Altitude m Compresses and warms iir parcel 0 0 I Atmospheric Stability I A rising parcel of air expands and cools while a sinking parcel is compressed and warms I Adiabatic process no heat exchange 7 Dry adiabatic rate 10 C1ooom unsaturated 39 Moist adiabatic rate 6 C1ooom saturated average value if Dry gt Moist because of latent heat g Moist rate is not constant 39 I Determine Stability I Compare air parcel temperature with its surroundings I Compare air parcel lapse rate to environmental lapse rate I The atmosphere stability is determined by environmental lapse rate Lapse rate change in temperature change in height T2T1H2H1 39 I ExerCIse 100 12 200 11 10 9 300 8 7 400 6 500 5 4 600 3 700 2 800 1 900 0 1000 80 70 6O 50 40 30 20 1O 0 10 20 30 40 Temperature C l l Determine Stability Temperature ol environment Cl 15 I 3000 18 0quot a Environmental lapse rate 4 CI1000 m r quot A 2000 22a 10quot E 7 3 t 2 l rarer 1000 0 a i Dry 26 20 adiabatic rate 10 C1000 m quot In rt AA inquot 0 10 20 30 C a 32 50 68 as F Temperature olliited unsaturated air quotCl a Lifted unsaturated air at each level is colder and heavier than the air around it It released the parcel would return to lie original posilion the surface Altitude m Temperature of environment C 3000 18 Environmental lapse rate r ewe1000 m 2 45 2000 r I39 1 O Moist N5 00 adiabatlc 26 rate 6quotC1000m 7 II n 30quot rm 0 to 20 30 C 32 5O 68 86 9F Temperature of lifted saturated air a moisl rate in Lifted saturated air at each level is colder and heavier than the air surrounding it If released the parcel would return to its original position the surface 2222012 as I Stable environment tj Environmental lapse rate less than moist lapse rate El If an air parcel is forced it will spread horizontally and form stratus clouds lCl Usually a cool surface radiation advection El Inversion warm over cool ii 7 Dete m39n39ng Stab39l39ty Temperature ol Temperature ol environment Ct environment 0 fjjsl 3000 c 73 0 3000 3quot o Dry adiabatic K v Moist v rate I quot I 1DnC1000 m r 4 adiabatic A 2000 8quot 10quot A 2000 rate E E 6 C1000 m l OJ 9 390 13 3 2 E D74 2 3525 1000 19a 1000 19a EnvironmentalV Environmenta lagse rate lapse rate r 11 1000m 39 s 11 C1000rn 39 1515 O 30quot a o 30 x 0 10 20 30 C 0 10 20 30 C 32 50 GB 88 F Temperature oi lifted 32 50 68 86 F Temperature of tilted unsaturated air C saturated air 0 moist rate a The rising unsaturated air parcel at each level is b The rising saturated air parcel at each level is warmer and lighter than the air around it It released the warmer than its surroundings If released it also would air parcel would accelerate upward away from its move upward away from its original position original position ml El I An Unstable Atmosphere til Environmental lapse rate greater than the dry adiabatic lapse rate D As air parcel rises it forms a vertical cloud l3 Convection thunderstorms severe weather Altitude m 39 1 Ni Determine Stability Temperature at environment Cl 32 50 68 86 OF Temperature of lilted unsaturated air quotCt dry rate a The lilted unsaturated parcel of air at each level is colder than its surroundings The atmosphere is stable with respect to unsaturated rising air Temperature at environment quot0 2222012 t nu Daft 3000 9 0 3000 I 9 l j Environmental lapse rate 7 in r g I39 u a gt 7 31000 m I r adiabatic 2000 16quot 10 A 2000 rate 16 18 i E BDCITOOOm 3 0 3 I 31quot 12 nLz tOOO 23 20 1000 23 54 Dry r l adiabatic Environmentt39V rate lapse rate NYC1000 m quot39 Am 7 C1000 m 39 39 trip at 0 an an 0 am Jim 0 10 20 30 C 0 10 20 30 quot C 32 50 68 86 GF Temperature at lifted saturated air Ct moist rate b The lifted saturated air parcel at each level is warmer than its surroundings The atmosphere is unstable with respect to saturated rising air L I A Conditionally Unstable Atmosphere l Moist adiabatic lapse rate is less than the environmental lapse rate which is less than the dry adiabatic lapse rate 1 Stable below cloud unstable above cloud base l Atmosphere usually in this state 39 1 Determine Stability Conditionally r Absoluter unstable stable atmosphere atmosphere s 8 s i i 3 Moist lt Absolutely adiabatic unstable rate atmosphere Dry adiabatic rate i i I If A K Temperature gt I be Stabilize the Atmosphere I Nighttime radiative cooling of surface I An in ux of cold surface air 14 C 1000 m I Air moving over a cold surface Environmental lapse rate I Environmental lapse rate 6 C 1000 m quot 00ft Lair 18 C z Colder sudace air l I Subsidence Inversions Associated with large high pressure areas 2222012 I a Destabilize the Atmosphere 39 l 500 5600 Original 39 quot39 7 layer s warms 3 600 X quot awry 4200 E g adiabatic v CD rate 8 5 700 r x t 3000 g 8 x gt cu 2 i Lu 0 800 X s 900 39 X y39 Final 1000 t Pry rate layer 1000 4 I 1 l Xl l 100 40 30 20 1 0 0 l O 20 30 C quot40 22 4 14 32 50 68 86 F e BlocksCole congage Leammg 39 I ill 7 7 B A EnVIronmental lapse rate before mixing E t I I I lalvsl ogl een a Warmlng Coonng after mixing Altitude gt Temperature gt Mixing tends to steepen the lapse rate makes the layer less stable I Cooling of the EMF 14 C air aloft l l cold advection l l clouds I Of Environmental lapse rate surface 6 C1000 m Ll daytime solar heating of the surface Cl An in ux of warm 0 m T surface air a ll Air moving over a warm surface 39 I 500 X39 Final 5600 Zx39f ye39 A600 x c I 4200 A g x as g Q adiabatic E g 700 x rate 3000 a g x E 1 800 V N 2000 J 900 lt s x original 1000 Dry rate layer 1000 l 1 l l WW I 1100 4O 30 20 10 O 10 20 30 C 40 22 4 14 32 50 68 86 F Lifting of an entire layer of air tends to increase the instability of the layer 2222012 39 I 7 Convective Cloud Development instability 650 A 39 3600 I Associated I Clouds develop as an air parcel rises and cools with the 700 3000 below the dew point development 3 9 egg wry I Iflsually aftrlgger or process 1s need to 1n1t1ate a I39 amk rate n of severe f 750 2470 g t e rise 0 an air parce storms 3 55 D Surface heating and free convection g 800 Co t 2000 g 0 mg a 5 Top U Uplifting along topography 335m A nsamrated D Widespread ascent due to convergence b 850 Original 1450 U Uplift along weather front Kayer 900 a 1000 Bottom saturated ncn l i l ccn A10 75 5 10 15 20 C 714 23 32 41 50 59 68 F I 5km gt a Conveclion 50 km gt b mung along opagraphy c Convevgence of air d Lining along weather quotam I Convection and Clouds I Differential land surface heating creates areas of high surface temperature I Air above warm land surface heats forming a bubble of warm air that rises 0r convection I Condensation level is the cloud base 2222012 Condensation level e EmmaCave Cungaie Learning awashCale Can e Leamm 39 39 CIOUd Development The stability of the air above the condensation level plays a major role in determining the vertical growth of a cumulus cloud E summer 1 0 v is Is rea g I W E Cienm txonaly x unstable 24 quotEng 25 V g cums 1mm Lew or 5 we 3 v convection m U l W A r s Temperature gt Temperature gt Temperature gt 20 25 an 35 we 7 20 25 3o 35 40 so so 100 v 58 77 as 95 F Remg an 68 77 86 95 R Ia a Cumulus humllls b Cumulus congestus c Cumulonlmbus e We Temperalure Tempe39a w humldyly m e EwanGabe mm Learning a Mnis rale b Dry rate a EmmaGale Damage Leammg 2222012 U I Topography D Orographic uplift U Orographic clouds D Windward leeward rain shadow j Lenticular clouds Envlrunmental temperature Windward sltde Leeward side 8 8 I x 5 T4 c T Anilude m 1000 12 Flam shadow Aw Dewpoint Temperature lemperatwe m m a swam Cunuuvu Lenmmn quotr1 Cloud Development Lee wave cloud I Changing cloud forms MO39St arm 3 Stratus clouds can change to cumulus clouds if the top of the cloud cools and the bottom of the cloud warms Dry air 53 Alto cumulus castellanus towers on alto stratus ngogel gse 49321 Fgre fe D If moist stable air without clouds is mixed or stirred it Morst alr V E can form stratocumulus clouds Mountain wave cloud Dry air a amencue cenqu Lumm z Erwkircolu Camus Lvnmlnu 2222012 WE Brookstula Can a e Leam m Iabatic Chart Ad Ev BrooksCole Cengage Learning coaSIOna y s Irrlng o a mOIs ayer of s able air will produce a deck of s ra ocumulus cloud epnllll v39 lJOOOLSEagoomqNO gll llll l 039 l T O O CO 8 c 2 09 7 3 dd 9 8 O E 39 2 I O N a o o o o 0039 5 O O O O O 3 qweJnsseJd epnllll v uooms eoom mo l Ll l H l H i Luxv m 1 1 oO 0 0 NA 0 L OCD 1 3 3 9 08 E I O T o s N O O O C CO 5 I CO C O E uneJnsseJd E 2 E D Q E E a g 25 E E lt E E C O O D 93 3 9 CD 0 S F a Before mixing BrooksCole Cengage Learning IL EXAM 3 STUDY GUIDE 1 lt9 12 Cloud development is triggered by Atmospheric Stability When a rising air parcel expends and cools and a sinking parcel warms and compresses Determined by environmental lapse rate Lapse Rate T2T1H2H1 a Stable when environmental lapse rate is less than the moist lapse rate Clouds will spread horizontally think stratus INVERSION warm over cool Fair weather b Unstable when environmental lapse rate is more than the dry adiabatic lapse rate Vertical clouds CONVECTION Thunderstorms To stabilize the atmosphere a Nighttime radiative cooling of the surface b In ux of cold surface air c Warm air moving over a cool surface To UNstablize the atmosphere a Cooling of the air aloft i Clouds ii Cold advection b Warming of the surface i Daytime heating ii Warm air moving over a surface Adiabatic Process when there is NO heat exchange a Dry adiabatic rate 10 C1000m unsaturated b Moist adiabatic rate 6 C 1000m saturated average value NOT constant c Dry gtMoise because oflatent heat Environmental Lapse Rate ATAheight a If the ELR is less than the moist LR then the atmosphere is stable b If the ELR is greater than the dry adiabatic rater then the atmosphere is unstable c Atmospheric stability helps us determine cloud devolvement and predict weather Terminal velocitysays that the heavier the object the faster it will fall to the Earth Ice Crystal Process a First the ice crystal must form Grow at the expense of super cooled water droplets b When they fall they either fall into each other and shatter or collide to form snow akes c MOST important to Cirrus Clouds Super Cooled Water droplets that are at a temperature at or below the freezing point yet are not frozen The difference between a cloud droplet and a rain drop is simply size The Curvature effect is where air is saturated in respect to a at surface and unsaturated in respect to a curved surface Molecules are less strongly attracted to a curved surface and evaporate more easily Cloud devolvement and stability a When a layer of air is stable above a cloud it cannot develop vertically and we get horizontal clouds b When a layer of air above a cloud is unstable the cloud will continue to develop vertically to form a cumulonimbus cloud Convective Instability when cool dry air moves over warm moist air a Convection occurs due to the heating of the earth b Lifting along topography beside mountains and hills c Convergence of air Low Pressure d Lifting along weather fronts warm air moves above cool air as a front comes in Find th GE0203 Exam 2 Study Guide Chapter 3 4 5 e answers in your notes or the textbook What is saturation When air is saturated how are temperature dew point temperature and wet bulb temperature related What is saturation vapor pressure What determines saturation vapor pressure What is vapor pressure What determines vapor pressure What does vapor pressure measure Consider an air parcel containing some moisture how do the following change as the air parcel rises 1temperature 2 vapor pressure 3 saturation vapor pressure 3 specific humidity 4 relative humidity 5 absolute humidity 6 dew point temperature How do dew frozen dew and frost form and under what conditions do they form What are the four types of fog How do they form and where do they typically form in the US What are condensation nuclei Why are they important for haze and fog formation What are the major characteristics of each principle cloud type At what are their typical elevations What are they composed of What type of weather is typically associated with each type of clouds What are the ways to change relative humidity What is specific heat How does specific heat of water and soil affect the temperature variation at different regions What is wind chill factor What does it indicate What is heat index What does it represent What are the processes associated with phase change of water How does heat flow during each process and how does it affect the environment What is heating degree day Cooling degree day How are they defined and calculated Using what you learned about temperature and humidity explain why summer time California is more comfortable and Alabama How do you use temperature and dew point temperature determine relative humidity How does cloud affect radiation balance and surface temperature variation What are the major factors affecting the global temperature variation controls of temperature What is dew point temperature Can you use dew point temperature to determine daily minimum temperature What is wet bulb temperature What does it represent How is it related to human comfort What is thermal conductivity Explain how dew frozen dew and visible frost each form How can fog form when the air s relative humidity is less than 100
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