Physics and Chemistry of Clouds and Aerosols
Physics and Chemistry of Clouds and Aerosols ATOC 5600
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Date Created: 10/29/15
ATOC 5600 Physics and Chemistry of Clouds and Aerosols 12 Thunderstorms II Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich V Overshooling Top or ome Pileus 1 Mammalus I mu P39II I39 4 luRaIn sw Scud NE Wall Cloud Tail Cloud Funnel Cloud or Tornado StuH Meteoro ogv for Scwentwsts and engmeers Ru flat DuncanquotV I If Lemon and Doswell 1979 FFD forwardflank downdraft RFD rearflank downdraft How to cook a supercell Ingredients high humidity nonlocal conditional instability Strong wind shear triggering mechanism to cause lifting A Humidity 329 I332 336 332 325 39L 332 3 6 773487 352 348 344 340 344 I f 336 340 344 348 Oe in Kelvin on 24 May 2006 22 UTC B Static stability Convective availa ble potential Determination of CAPE energy CAPE 6w 3o ZLFC 39 Positive area CAPE 3 0 Stab39e quot 39 f g 0 1000 Marginally unstable 39 1000 2500 Moderately unstable 4ind 4 2500 3500 Very unstable E 3 gt3500 Extremely unstable am Temperature difference wmax 2CAPE12 Conditionally unstable When the rising parcel of air is unsaturated the atmosphere is stable when is 6 Poumm mpenm of nvimnmm parcel Isbsatu rated It atmosphere is unsta e 9 Potantial temperature of lifted air parcel Tha COM Tropopause Cold AIr Strong Winds gt Z Dry Air gt 70 SKa ically Stable Layer Wind Shear 3 Warm Humid Boundary Layer 4X lop 039 strongly ame la er in Inversion base of strongly slab e layer Calculate CAPE 400mb Te 191C Tp 82C h 7605 m 375mb Te 229C Tp 112C h 8082 m 350mb Te 269C Tp 146C h 8583 m 400mb Te 25405 K Tp 26495 K h 7605 m 375mb Te 25025 K Tp 26195 K h 8082 m 350mb Te 24625 K Tp 25855 K h 8583 m 2 26345K 25215K 25215 K 2 26025K 24845K 24845 K CAPE1 CAPE2 4431 Jkg kgmzs39zkg CAPE1 981ms 8082m 7605m 2097 Jkg CAPE2 981ms 8583m 8082m 2334 Jkg c Wind shear No horizontal wind shear Strong horizontal wind shear Rauber Walsh Charlevoix Severe amp hazardous weather MAXIMUM UPDRAFT m squot z u ustanh ZS 3km 30 40 1 J 40 so so too 120 TIME min Weisman and Klemp MWR 1982 Wind at us asymptotic wind speed Zero wind shear u5 0 m 5391 single cell storms Moderate wind shear u5 15 m 5391 sequence of cells Strong shear u5 25 35 45 m 5391 supercells y m y 4m y My w mm 1 m was w L Umdrrectronat Shear create rtghtrmowng and efta movmg Storm Itdrrectronat and speed varres wrth herght agt erther rrght or eftrmovmg Storm rs favored Weismann and Klemp MWR 1982 la INITKAL STORM MAXIUJH VI HI I G 300 own ujsrsann n m ar opa a of SCCO S uq 4 YWI sirl Ts imamtr v o39 IOCO ilf I u I quota I I I J 34 i O S 152025 30 35 045 Ulmsquot In SECONDARY STORM uxwma Manquot 1 l I I r I I 39 I A Mr 4 200 G I w 4 low I 1 l 4 J J1e4 o s h 5262330554045 U5 Irv squot c SPLIT 5mm MAXIWN w Kmquot 39 r r I 1 r4003 l6 Is 1030 y 2 M o N 1 at amt 0 n2 ICOO 3 2 0 23 w 35 0 43 U m I 391 I 539 I8 lms 4 r39 E Multicell cases of modeled thunderstorms gt25 ms15km Supercell cases Internal rotation dynamic pressure perturbation Weismann and Klemp MWR 1982 Horizontal vorticit 39 iT t eT uoward 7 c wilt FEfgt N x iii 7 I 1 C c J 39 J S gt o u S WiiW 0 Vertical oressure gradient associated with eddies on the upward flanks Klemp 1987 Rig ht moving storm dominate left moving storm seldom observed gt associated with directional shear Internal rotation Storm spitting anticyclonic vertical vorticity cyclonic g a 7 venical a l vorticity 3 quot mm streamwise 0 horizontal vorticity Easz Internal rotation Storm spitting Vertical pressure gradient associated with eddies on the upward flanks Right moving storm dominate left H moving storm gmm mit egg iElng vm seldom observed gt J l KR Ti quot l C H e F associated with 1 directional shear JsKf Klemp 1987 H 0 n 2 3 e U D H 0 q q S T 6 8 Z 0 14 gg f uI rLi l h a Symmetric 4 am Nahum Amwng swmu In m anxmvwnq 5mm b Rightmoving c Lenmoving Ls Fiwm Ln rmmnv supmxrs ECHOPRMOVEMENT IS A IL 1972 D 745 Bluestein 1993 c Trigger mechanisms Thunderstorms might initiate NASS Radar Image 2OJun2OD 1225UTC Due to unequal heating at the surface 0 Effect of terrain 0 Along convergence lines cold fronts seabreeze fronts Areas of upperlevel divergence and surface convergence Me teoSw39iss 39 39 v 7 I mmfh 015 025 074 085 39l 16 25 4 63 10 16 25 4O 63 100 raml1 airmass boundary 0903 Tornadoes and other vortex types coldair funnel supercell waterspout dust tornado gustnado tornado devil landspout tornado E V Conservation of Angular Momentum and Tornado Winds r radius v rotational velocity rmeso vmeso rwall vwall rtornado vtornado 4000 m 25 mls 1000 m 10 mls 100 m 100 mls N mesocyclone 5 wall cloud tornado 2005 KendallHunt Publishing 0quot t III I Advection II Stretching III Tilting Tornadogenesis Top down process Bottom up Vortex breakdown Constricted ow dynamic pipe 2005 KendallHunt Publishing vV w Ewynw I 211 StretCh ng velocity 2 veoCle 39 L velocity radius velocity radius 2 radius 2005 KendallHunt Publishing Height km C Copyright Howard B Bluestein MODEL OF TORNADO WTH MULTIPLE SUCYION VORTICES T himsumn men or mum at V mnnoxAL van Amwn volmm ton mmnmm El sumoquot vum of mm mm Morton 1970 IV buoyant updraft REGION III Ia o ter flow Fujita 1981 Ib ore solid body ro ation REGION In I Cyclostr pth balance III corner region strong upflow into core REGION 11 III REGION III W Organizing stage visible funnel touching the ground Mature stage tornado largest 200x60 120 nL 50 80 rns Shrinking stage tunnel decrease to a thin column Tornado UNION CITY OKLAHOMA 24 MAY 973 TORNADO 9 I52I US Decaying stage fragmented contorted destructive funnel Why do NE moving tornadoes have their maximum in speed at the SE side Top View 100 knot 150 knot N W 7 E D WP Lilly 1979 Lines of thunderstorms supercell stormsmulticell storms Rotunno et al 1988 LJTJ gm E Rotunno et al 1988 Nonsupercell tornado Wakimoto and Wilson 1989 Convective cloud is located above a spot of intensified local vertical vorticity along convergence lines Cumulus vertical velocity maxima boundary mountain Vortex stretching vim in pawl C 1 J Wakimoto and Wilson Mon Wea Rev 1989 a 1900 UTC Nebraska qusas Oklahjci ma n 1529 UTC 1 m 011345b7ltmmzum 10040 10020 wgt2 ms tgt2x1o ZdBZ Convedion hiTiu rion a P3Leg 3 1902 1920 JT b P3Leg5 1951 2005 1 c PEILeg 7 2030 2041 100F100 99180 99130w a P1 92 m BEFORE 1 P1 gt 9 BEFORE P2 DURING 3 F2 31 32 AFTER Simpson 1997 Updraft MC CI E Em c ATOC 5600 Physics and Chemistry of Clouds and Aerosols 1 Thermodynamic of dry air Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich Composition of the atmosphere Aerosols solid and liquid material suspended in the air smoke dust pollen Hydrometeors condensed forms of water water droplets ice crystals Table 11 Composition of the Atmosphere Near the Earth39s Surface PERMANENT GASES VARIABLE GASES Percent by Volume Percent Parts per Gas Symbol Dry Air Gas and Particles Symbol by Volume Million Ppmr Nitrogen N 7808 Water vapor H10 0 to 4 Oxygen 02 2095 Carbon dioxide 03 0037 374 Argon Ar 093 Methane CH 000017 17 Neon Ne 00018 Nitrous oxide N30 000003 03 Helium lle 00005 Ozone 0 0000004 00 Hydrogen H2 000006 Particles dust soot etc 000000 00l 0 l S Xenon Xe 0000009 Chloro uomcarbons CFCS 000000002 00002 39l nr 20 374 parts per million means that out of every million air molecules 371 are TO molecules TStratmphcric values at Iltitudcs between i l km and 50 km an about 5 to II ppm Ahrens Meteorology Today Equation of state for dry air 0 Atmosphere is defined by temperature volumedensity pressure molecular weight Atmospheric gases obey the ideal gas equation exactly p pressureforcearea hPa V volume m3 m p m mass kg Ideal gas equation T absolute temperature K KOC27315 a R gas constant p p p p density of the gas 0t specific volume paRT http wwwchemistryOhiostateedubethanealGasLaw Boyle39s law Is hell exothermic release or endothermic absorbs First We postulate that if souls exist then they must have some mass If they do then a mole of souls can also have a mass So at what rate are souls moving into hell and at what rate are souls leaving I think we can safely assume that once a soul gets to hell it will not leave Therefore no souls are leaving As for souls entering hell let39s look at the different religions that exist in the world today Some of these religions state that if you are not a member of their religion then you will go to hell Since there are more than one of these religions and people do not belong to more than one religion we can project that all people and souls go to hell With birth and death rates as they are we can expect the number of souls in hell to increase exponentially Now we look at the rate of change in volume in hell Boyle39s Law states that in order for the temperature and pressure in hell to stay the same the ratio of the mass of souls and volume needs to stay constant Two options exist 1 If hell is expanding at a slower rate than the rate at which souls enter hell then the temperature and pressure in hell will increase until all hell breaks loose 2 If hell is expanding at a rate faster than the increase of souls in hell then the temperature and pressure will drop until hell freezes over So which is it If we accept the quote given to me by Theresa Manyan during Freshman year quotthat it will be a cold night in hell before I sleep with youquot and take into account the fact that I still have NOT succeeded in having sexual relations with her then Option 2 cannot be trueThus hell is exothermic 4 WARM Air columr 2 Air commn 2 Air CDIumn 1 A column 2 COLD Air column 1 AN Column 1 E E E CWT a Cxty 2 City1 b Chy 2 ChtyT a Guy 2 Same pressure Same pressure Same pressure Same pressme 5mm ssure ises smace pressure fa ls mama my Eaummu 3000 lude m a h Idc m 700 ml Fla SH ame unilurm Iemperalure al evew level nn mm 92 slim mo 2002 KendaHHun Puunshmg Hydrostatic balance Hydrostatic balance Net upward force downward force dp Column with unit crosssectional dz Upward area force 4K a dp g p dz I t f Pressure p 6 p b I Pressurep g acteleratlon clue to gravrty 1 I z helg ht gubz V Gravity 3 Wallace amp Hobbs Ground Main laws of thermodynamics 1 Heat is a form of energy 1St law of thermodynamics 2 Energy can neither be created nor destroyed It can only be changed from one form of energy into another Energy is conserved 2nOI law of thermodynamics 3 Heat passes from a warmer body to a colder body 4 It is impossible to cool a body below the temperature of the absolute zero 0 K 27315 0C WORK First law of thermodynamics Energy can not be created nor destroyed It merely changes from one form to another in any ordinary chemical or physical process Energy is conserved Working substance Cylinder o 06 393939 l vl Lquot lts o 390 I 39 o LJ Piston gt Distance r Pressure gt we 1 l I l l T a l W CD General expression for the conservation of energy dq cvdT pda cpdT adp Special processes aIsobaric process dp O dq 01707 6 1 cvdT cljdu c c V V b Isothermal process dT O ldq 0507 pda dwl cIsochronic process da O dq cvdT du dAdiabatic process dq O cpdTadp without loosing or gaining heat cvdT pda 10 Joule39s law The temperature of a parcel containin an ideal as of unit mass changes by the amount AT w en heat Aq is added and changes when work is done on or by the parce AqcVATpAd orlimitAq O dqchTpdd cp specific heat p density p pressure a pl specific volume Conservation of heat ener y When a gas expands without doing external work an without taking in or given out heat the temperature of the gas does not change 11 Relationship between temperature and height Air parcel temperature changes adiabatically as it rises and sinks no mixing with the outside dry adiabatic process Ahrs Meelogy Today Making use of ideal gas equation hydrostatic equation first law of thermodynamics adiabatic processes 12 Poisson equation K p2 Potential temperature is the temperature X a p p that an air parcel would have if it were 6 T 0 expanded or compressed adiabatically from their existing pressure and temperature to p 1000 mb p0 with RcP being 0286 Potential temperature is conserved ie it does not change if an air parcel does not exchange heat with its environment 13 14 Entropy transformation Entropy S is a measure of the unavailability of a system s energy to do work Spontaneous changes in isolated systems occur with an increase in entropy Spontaneous changes tend to smooth out differences in temperature pressure density and chemical potential that may exist in a system and entropy is thus a measure of how far this smoothing out process has progressed d ic dT OCdpde T R39Cp d T Q T T p T 19 d6 o 1 6 7gt1ntegrat1on g1ves cp n Const 15 Second law of thermodynamics The second law of thermodynamics is an expression of the universal law of increasing entropy stating that the entropy of an isolated system which is not in equilibrium will tend to increase over time approaching a maximum value at equilibrium The second law is an expression of the fact that over time differences in temperature pressure and density tend to even out in a physical system that is isolated from the outside world Entropy is a measure 0 how far along this eveningout process has progressed Two important consequences 0 In an isolated system a process can occur only if it increases the total entropy of the system 0 Heat cannot spontaneously flow from a material at lower temperature to a material at higher temperature 0 It is impossible to convert heat completely into work 16 Meteorological thermodynamic charts 200 400 500 800 900 1000 mb 80 70 50 50 40 30 20 10 20 30 40 C 10 20 30 50 100 200 300 gkg Hugh of Shndl rd Atmosphon km A Squot 1 S 9 399 p 3W W Yg 439 1 3 9 39 9 3 09 3 VWV 979 NANAY 9 9 4 G v1 4 Temperature 390 18 Isobars Isotherms I I x r r J I s xquot z 1 l I I 1 1 I I 7 1 y I w l I 1 I 1 1 lt x I 39 4 v V v r 1 x Q f I l a A x I r r 39 I o I quot I z x r x i I Dry Adiabats TheCOME 39 E httpwwwmeteducaredu mesoprimskewt httpweatheruwyoedu upperairsoundinghtm x x X x K 8 40 an 20 1n a 1o 20 30 40 c Tha COMET Program Pro les Plotted on a SkewTl LogP Diagram v y W Wind Pro le WWW 391 r h r Temperalure Prom V v v v 77 quota Dewpolm Pro le at x h c V7 c H O I 20 The COMET Program Measuring Conditions in the Atmosphere with Radiosondes m u Y m d n a S ATOC 5600 Physics and Chemistry of Clouds and Aerosols 9 Shallow layer clouds Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich KelvinHelmholtz Instabilities A L C i h A 1 Batchelor 1967 U2 Fluid 1 will 6 mte Za39E e Houze Cloud dynamics 1993 Instability results from velocity shear between two media do not need to have different densities Stephanie TERRADE 2 Bulk Richardson Number Ratio between stability and vertical shear N2 gpr9paz lt 1 2 2 a u z 4 A7 353E Nimi m WQEKWF NEMCEHG Rosen head 1931 1 T 2 LU 0 Z E 3 lt2 D 239 9 4 0 LL gt 5 O 05 10 15 20 HORIZONTAL DISTANCE gt RayleighB nard Instability convection inside a uid T1 lt T2 system is stable If T2 lt T1 and perturbations occur then for a critical value of the difference of temperature movements inside the fluid appear system is unstable and movements are organized in periodic contrarotative rolls 01010101010 Stephanie TERRADE 6 Rayleigh number aAng3 va oc coefficient of volume expansion g acceleration due to gravity d depth of the layer v kinematic viscosit a thermometric conductivity Ra Critical value of the Rayleigh number for apparition of RayleighBenard instability is 1707 gt 2 rolls inside the fluid rigid conditions for lower and upper boundary If Rayleigh number increases number of rolls increases too T2 LLL T13T2 Stephanie TERRADE 7 2000 l 2 3 Houze Cloud dynamics 1993 WAVE NUMBERg Free surface T2 Atmosphere rigid conditions for lower boundary amp free conditions for upper boundary gt critical value lowers Mesoscale Structure of mixed layer clouds stratocumulus clouds Cloud streets Cellular patterns 391 V Stratus 9quot gt 0 9 3949 la quot 5c strabcumulus quot cloud 1 m element 1 h plum mat I m quotgto 503quot ftolt0 39l b c Boundary layer not 50 er laYEF extremely unstable UnSta e 01 9 777777777777777777777 77777777777777777777 a b Houze Cloud dynamics z i SYNOPllCAilllCYCLlilllCSIIBSlllEllCE l x m Turbulenienlrainmenl E at cluud up CLOUD TOP 3 3 n Cold downdraugm E lmm clnud up 2 a m s as a E E E a g 3 new a i 3 53533259 cmun ans z E Surlace fluxes ol heat and moisture 5 A A 1 g GROUND quot 4 4 4 4 4 4 4 4 4 4 4 4 4 44 4 4 ZAMG Vienna Z A Temperature T and Dewpoint Td Z Equivalent potential temperature 09 Z A Water vapour mixing ratio 11 Z Liquid water content qt ZAMG Vienna They are most often observed over cool waters throughout the year but also over land areas especially in winter North Sea cool oceanic currents adjacent to the North American west coast near the centre of high pressure over land omega Blocking limiting inversio 39 dl 39luenl Blocking Cloud streets 0 Dynamic inflection amp thermal instability Clnudstnm Cluudlrce mmmp39m if Inflection instability is caused by an inflection point me x in the wind velocity component perpendicular to the 39 quot quot roll system gt backing of wind vector caused by Ekmanlayer shearflow amp cold advection occur under stable stratification in an inversion layer cold air flows over warm surface gt thermal instability ZAMG Vienna Dift tinn vmiatiun 9030 deg Heigh39 39r 12 v Height Synoptic environment outbreaks of cold dry air from continents over a neighboring relatively warm ocean behind a cold front CF Open Ila SKIP 7 CldSlreels 7 SSW 1000 1503 kn 13 ZAMG Vienna Cloud streets over sea Height WDir hPa Deg 1007 010 1000 015 925 020 850 350 772 295 700 295 JanMayen WSpeed kt 17 Veering with 17 P height 23 25 23 1 Backing With 23 height ng 39 k 39 yer f tx1 s x gt Unstable stratificatio n 14 i i v i r 1 Iv x N x Qvenslon Cloud streets over land Frequent examples of this type of Cloud Street occur in polar maritime air behind Cold Fonts when a ridge of high pressure is forming Heating of the land surface enhances the instability in the lowest layers The high pressure provides the subsidence inversion which is needed to limit the convection Furthermore because of the cold advection the condition of the turning wind vector is also fulfilled and Cloud Streets can develop As a consequence of a larger variation in terrain roughness the pattern of the Cloud Streets is less regular than over sea Height Wdir Wspeed hPa deg kt 1028 060 12 1000 065 25 925 080 25 850 075 35 15 m HW 700 065 45 DeBiIt The Netherlands ZAMG Vlenna Key parameter Mun 5 ser wand r 10 In 0 20m 1 ZAMG Vienna Cold air advection ZAMG Vienna 17 x A l 1 w 1 150 W 120a 90 60 30 0 30 60 90 120 l50 E Agee et al 1973 Pellew and Southwell 1940 Cloud Layer Subcloud Layer Fiedler 1984 Cirrus uncinus Cloud Becomes Visible Heymsfield 1975 lt Winddirzctian 4 Growth Region lt Nucleation Level Updrall Begins Here Stable Layer EELOEILOF Region Positive Wind Shear 19 STABLE He msfield 1975 a LAYER Positive Wmdshear y I ADIEIEYATIC H WIquotUNCSQHES lt Wind direction LAYER l a b NEGATIVE SHEAR NO SHEAR IN HEAD IN HEAD H SH EVAFOHAIVE HH Hi COOLING RIEGION f b Pusn39ve Wind Shear I STABLE LAYER lt7 Wind direcriun Hey stI Id 1975 DRY ADIABATIC LAYER f I Convevgence Dlvergence Convergence Divergence STABLE LAYER 0 Negative Wmd Shear lt7 Wind direction STABLE LAYER DRY ADIABATIC H H H H 4 Divergence H Dwergence Convergence Icecloud outflow from Ch Radiation A Entrai n ment Collapse Roland L Rolle Lilly 1988 21 a h turbulence BI entrainment KKK Houze Cloud dynamics 1993 Lilly 1988 Houze Cloud dynamics 1993 6 N D 22 ATOC 5600 Physics and Chemistry of Clouds and Aerosols 5 Microphysics of warm clouds Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich r radius um n number per liter of air v terminal fall speed cm s1 Conventional borderline between cloud droplets and raindrops 11 00 39t 70 Typical cloud droplet r10 n1 06 121 Typical raindrop r1000 111 1650 Wallace amp Hobbs Introd Atmospheric Sciences Vapor lt gtLiquid condensation evaporation Liquid lt gtSolid freezing melting Vapor lt gtSolid deposition sublimation gt Increase in molecular order Homogeneous nucleation How do cloud droplets grow larger Temperature 10 C Flat water surface Cloud droplet Ahrens Meteorology Today Saturation vapor pressure over a droplet of pure water The vapor pressure over a curved surface such as a drop is higher than the vapor pressure over a plane surface of water at the same temperature curvature effect Condensation overcome surface tension by strong gradient of vapor pressure 3 Nucleation of water vapor condensation oClouds form when air becomes supersaturated oHomogeneous nucleation hypothetic formation of water droplets by condensation from supersaturated vapor without particles in the air Seinfeld and Prandis 1998 Embryonic droplets will be stable if its size exceeds a certain critical value AE Net energy What determines the critical size Wallace amp Hobbs Atmospheric Sciences Droplets tend to evaporate Droplets grows AE4JTR20 4 in 3 Rate of growth Depends on e Rate of decay Depends on Tdropiet surface tension of droplet R nkT1n e e 5 Kelvin equation Describes the equilibrium vapor pressure over a curved surface of pure water E0 1003 Cloud droplets grow 3 E 1002 I 9 395 Pp g Cloud ale amp 100 1 droplets f sh nk 1000 39 i 2 4 10 20 Droplet Diameter um Ahrens Meteorology Today RH 100 eeS es saturation vapor pressure over flat surface e vapor pressure over curved surface 5 e gt e5 9 RH gt 100 supersaturation Problem The curvature effect is a barrier to droplet formation because the tiniest droplets have the tightest curvature which tends to destroy the droplet by net evaporation rather than allowing the droplets to grow by net condensation Droplets are formed by random collision Homogeneous nucleation occurs seldom in nature requires very high supersaturations which were never observed Heterogeneous nucleation Most condensation in the atmosphere is initiated on a hygroscopiccondensation nuclei consisting of soluble material aerosol particle eg sea salt Diameter 30 pm Diameter 80 pm i Pruppacher amp Klett Microphysics of Clouds and Precipitation Rate of droplet formation number of nuclei Hygroscopic waterseeking hydrophobic waterrepelling nuclei Hygroscopic nuclei sea salt sulfuric nitric acid particles water vapor condenses when relative humidity is considerable below 100 Kelvin equation Raoult s law Hydrophobic oil gasoline paraffin waxes resist condensation and wetting Kelvin equa on Hygroscopic nuclei Hydrophobic nuclei Ahrens Meteorology Today 9 Raoult s law Vapor pressure for a solvent such as water due to the presence of dissolved material such as salt is reduced in proportion to the mol fraction of the solute salt The effect solute salt is added to liquid water some of the liquid water molecules that were in the surface layer are replaced by solute salt molecules If the vapor pressure of the solute salt is less than the solvent water the vapor pressure is reduced in proportion to the amount of the solute salt present Result solution droplet that is in equilibrium at much lower supersaturation than pure water droplet of the same size I I y quot f g no e equilibrium vapor pressure over a 7 7 olution with nEl water molecules and n S esoo n no solute molecules Critical radius r and critical supersaturation S I 02 X I j i Curvature term V em 0er IO 3 continue to grow without the g 539 need for further increase in S g 39 xx diffusional growth E lx 2 100 0 I m I r 39 l 3 1 Iv39 r r J l 4 099 1 A f solution term relative L I j humidityha 1 i JLHVHI i H to be increased H r39 1 20 for the droplet Droplei Radius um to grow I FIG 63 Equilibrium saturuuon ratio oi a solution droplcl formed on an ll c ammonium gullcud condensation nucleus 0139 mass it39l Rogers and Yau A Short Course in Cloud Physics Solution term dominates when r is small r 13ba 5 1x4a3 27b 11 Solution effect Koehler curves for ammonium su fute dashed and sec x S 102 399 cm1 r v on salt so id smumtion mug s 36 p d ED C 60 C 098 Radius um U Lohmann Aerosols Clouds Photo Davis Relative humidity of diquescence RHD point at which a dry particle spontaneously takes up water to from saturated solution 05 0439 quotquotquotquotquotquotquotquot quot Ambient 03 supersaturation Super saturation o Relative humidity 8 01 1 Droplet radius pm Cume 2 solution droplet of 1019 kg of NaCl Cume 5 solution droplet of 1019 kg of NH ZSO4 ATOC 5600 Physics and Chemistry of Clouds and Aerosols 3 Parcel Buoyancy and Atmospheric Stability Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich Static stability 0 Stable conditions Unstable conditions 0 Neutral conditions Conditional instability Convective instability Stable conditions Stable conditions if an air parcel is displaced either upward or downward and is then left to itself ie the force causing the original displacement is removed the parcel will return to its original position i5 Q A 3 v 1 f 7 j 47 y A 55 VJ 1 F3H 0 P 55 J A 7 L 1 7 A Stable equilibrium Ahrens Meteorology Today Stable stratification in unsaturated amp saturated air Temperature oi l39ernperature of r environment 0 ormrm rrnont C 3000 T 18quot 3000 V 18 Envrronrnental i Enwronmental lapse rate lapse rate 4quotC1000rn V 4 Cr39iGUO m rr A 200 9 A 2000 5339 C E 5 r T g L3 3 3 i E j 7 q 6quot R Murat 96 397quot 1000 Dry lOOO quot adiabatic ad39abanc rate rate r 1001000 m 6 Cl 1000 in 1 I l 3039 O l 7 30quot O 10 20 30 C G 10 20 301 3 3 510 68 86 F 32 50 68 86F Temperature of lifted Temperature of lifted unsaturated a Cl saturated 39dlr r 3 dry rate moisl rate a Lifted unsaturated air at each level 18 bolder and b l altod saturated arr at each riosrtion IS colder and warrior than the air around it lt given the chance the hoavror than the air surrounding it lt released the parcel would return to its original position the surface parcel would return to its original position the surface Ahrens Meteorology Today l lt Pd 89 Stable l lt Fm Absolutely stable 4 gt0 t9z Gravity waves I Mountain waves Lee wave cloud Moist arm 39V Dry air Droplets Droplets 39 Moist airj w evaporate Mountain wave cloud Dry air Wallace and Hobbs Atmospheric Science Ahrens Meteoromgy TOday Vertical displacement of Bruntvalsala quell the air arcel Z t Z COS t T g 3 From the sounding below calculate the following quantities a Potential temperature at each pressure level b BruntVaisala frequency and the period of oscillation for the layers 843 to 500 hPa 500to300 hPa N 3 P2az 300 to 100 hPa 9 dz N c Specific humidity at each pressure level d Derive the saturation mixing ratio from the Skew Tlog p diagram and derive the relative humidity 843 hPa 1625 m 5 0C 62 gkg391 500 hPa 5840 m 9 0C 08 gkg391 300 hPa 9570 m 38 0C 03 gkg391 100 hPa 16520 m 64 0C 001 gkg391 Necessary conditions for a stable atmosphere 0 Air aloft warms or surface air cools 0 Air above is replaced by warm air warm air advection and the surface air is not changing 0 Surface cooling eg nighttime radiational cooling cold advection air moving over a cold surface Inversions 1200 4000 l I I 39I 3 l I I39 l i 3000 900 l u I t A I V W V g Warm dry A q sinking air 5 E v J2 V v 8 600 Dew Air Sybsidence 2000 g E point X temperature 39nvers39on lt profile prome lt 300 Base 7 1000 1k 39 quot quot Cool moist marine air 0 I I I I I 0 5 10 15 20 25 C 41quot 50 59 68 77 F Temperature C Donald Ahrens Meteorology Today 2007 Thomson Higher Education Nighttim ragliatriornlal coo ling FQg fh a e smg ln the Po valley VA 7 1 Unstable conditions Absolutely unstable conditions if an air parcel is displaced either upward and is warmer than the environment it will continue to rise constantly moving upward Unstable equilibrium 2007 Thomson Higher Education 1 l k La N B 10 Unstable stratification adiabatic Dry rate 2000 E 1000 Envrronmental lapse rate 11 31000m U I O 10 2O 32 50 68 a The rising unsaturated air parcet al each level Temperature of envrronment C 30 Temperature of lifted in unsaturated air C dry rate rs warmer and Irghtor than the arr around it lf given the Chance the air parcel would accelerate away lronr its original position YgtFd 1 2007 Thomson High 89 az lt0 Unstable unsaturated amp saturated air 3000 Y 2000 33 U 2 E 1 000 o Temperature of environn rent C Environmental lapse rate 11 Cr 1000m l I O 1 0 2O 3 50 68 30C 86 F r err lylorst Ir adiabatic rate 6 C1UUOm 8r l temperature oi tilted saturated air C moist rate b The rising saturated air parcel is warmer than its surroundings If given the chance it also would move away lrorn rts original position Ahrens Meteorology Today Absolutely unstable 11 Neutral stability the laps rate is exactly equal to the dry adiabatic moist adiabatic rate rising or sinking At each level the air would have the same temperature and density as the surrounding air The air tends neither to continue rising nor sinking Unsaturated air Saturated air Y rd Y R 076 Saturated neutral O dz Neutral 12 Conditional instab39 39ty 39n unsaturated and saturated air ally unstable When the rising parcel of air is unsaturated the atmosphere e when Is parcel Is saturated It atmosphere Is u Con on is stabl nstable Tnmpcvalum of Temperarure of auxwoer WC envrrurrmenH C E r v is i 7 a a 7 BUCO apsem e S 0 3000 M V 9 r r I adrabahc ClUOOm mm xi 20m 16 109 2000 scuormm 16 a r l r Eb r 7 Dr 23 zoor r 23 Ar 0 mam m Envxmnmomal are lapsp mic 10 C1000m 7quotC10341rn I r 3a 30 0 r r 300 El it 0 10 20 30L C m 20 30 C A 32 50 58 36 F T 50 ea 86 F llimpemimu rm m Temperarur or mad rrnsamraten arr samrared arr 0 dry rate morsr vale a The unsaturated parce rarr a each elsvanun u The rnea samraled arr parcel re Warmer a each rs A er man u urmunmngs The almnsimeve rs elevanon man rts surroundmgs The atmosphere rs Stable wrm respecl m unsalmaled Hsmq aw unstable wuh vespecl m samramd nsmg err 13 mm Thamsnn ngher Educalmn 1quotLil gt r gt 1quotm Ahrens Memorology Today Level of free convection LFC Level of free convection LFC The level at which a parcel of air lifted dryadiabatically until saturated and saturationadiabatically thereafter would first become warmer than its surroundings in a conditionally unstable atmosphere Pressure l39hPal 400 80 O 80 0 1 CI 0 0 400 800 800 1 33900 14 Convective instability Convective instability The potential instability brought about by the lifting of a stable layer whose surface is humid and whose top is dry Usually associated with the development of severe storms tornadoes thunderstorms 650 3600 b lt Final layer 700 3000 Cools at dry 3 750 adiabatic rate 2470 E D 3 800a 2000 8 Cools at x y TOD Edi moist unsaturated adiabatic 850 rate b 1450 Original layer 900 a 1000 Bottom saturated 950 39 39 39 39 l 550 10 5 O 5 1O 15 200C 14 23 32 41 50 59 68 quotF lvlolsi rate Dry rate I 2007 Thomson Higher Education Elevation m d9 W dz dd W dz dd W dz gt0 lt0 Convectiver Stable Convectively Neutral Convectively Unstable 15 What causes instabilities 0 Air aloft becoming colder cold advection clouds emitting infrared radiation to space 0 Surface air becoming warmer daytime solar heating warm advection air moving over a warm surface 0 Mixing convection wind induced turbulent eddies or lifting orographicaIIy forced 16 Prefrontal cold air advection aloft 1062u1 T Orographic ally forced lifting mmh me 025 m 065 1 m 25 4 w m 5 25 m 53 mo rumh 300 400 500 600 700 800 900 1000 hPa Determine stability 7T Ty above 800 hPa T 500d v TV dashed 39 1 39 30 20 10 0 10 20 30 quot39C 02 06 10 20 30 50 100 200 glkg The COMET ongram 1000 950 hPa 950 850 hPa 850 800 hPa 800 600 hPa 600 550 hPa 550 500 hPa 500 400 hPa 400 300 hPa Nonlocally unstable Mixedlayer depth Mixing of air masses 1 Isobaric mixing 2 Adiabatic mixing ATOC 5600 Physics and Chemistry of Clouds and Aerosols 2 Water vapor and its thermodynamic effects Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich 30 January 2005 030 75 60 45 30 00 MODISTerro MOD08D3HAZOO50300042005032082634hdf cm Dry air mixture of gases excluding water vapor pdad RdT 1 1 Rd 1000R 1000 83145 JK mol Md 2897 g 287 JK39lkg391 Water vapor eav RVT 1 1 Rv 1000R 1000W M 18016 g W 46151 JK39lkg39l R universal gas constant Rd gas constant for 1 kg dry air Md molecular weight of dry air e water vapor pressure RV gas constant for 1 kg water vapor MW molecular weight of water Dalton s law The total pressure exerted by a mixture of gases is equal to the sum of the partial pressure of gases Total pressure 2 pi pt Pd 9 dedT pvR Problem RV depends on the amount of water in the air which varies considerable Solution Retain the gas constant for dry air and use a fictitious temperature gt virtual temperature Virtual temperature is the temperature that 1 1e dry air would need to attain in order to have p the same density as the moist air at the same pressure Because moist air is less dense gt TV gt T Saturated vapor pressure over water eS T 45 4039 75 A 01 90 6 Saturated vapor pressure over Ice esi T 80 Melting point Liquid Water molecul 7O 7 Water gt Water vapor gt condense evaporates Pressure e increases from the vapo 3 60 3 b kt th I39 39d 3 Ice 0 3 e 0 2 Sacgsiw o o 5 pressure 7 O o D O I 0 O i o e o T eS o a o 8 o 0 40 7 o o o o o o co gt o o o a o 0 E30 7 o o o o o o g 0 o 0 Water Water 20 Unsaturated Saturated m 7 gt 0 e lt es e eS C 730 720 40 0 1o 20 so no Saturation mixing ratio wS Pi 22 4 i4 32 50 68 86 104 Temperature mm Mass of saturated water vapor g 92DU7Thnmsnn igherEducatian Ahrens Meteorology Today Saturation vapor pressure over water versus saturation vapor pressure over ice I Figure 430 1 wan w m is pre unfia y ut tmctcz 0 in msus m 3139 Open stopper Waler mulesu es ow toward ice toward the rower pressure 39 2m 2y Boulder Colorado 5 15504002 in 23 20722 km 3 a 2 22 2 4 2quot 2 In gt E I g u new u on 1 o 01 ppmvryeav 392 in i l ms i532 mm was lab 539 6 4 4 J 992 i994 l2 Year 72 4 I 2 Trend lagyear water vapor is a greenhouse gas water molecules absorb microwaves average residence water depletes by water replenishes time of precipitation by evaporation water molecules in the troposphere 10 days Evaporationcondensation The latent heat is defined as the heat that has to be given to a unit mass of a material to convert it from the phase to another phase without a change in temperature HEAT ENERGY TAKEN FROM ENVIRONMENT i gt gt Melting Evaporation 39 lt Ice Freezing Condensation Liquid Vapor Deposition E HEAT ENERGY RELEASED TO ENVIRONMENT Latent heat of meltinqfreezinq Latent heat of evaporationcondensation Lm Lf 334x105 J kg391 1atm 0 C Le L0 225x106 J kg391 1atm 106 C Ahrens Meteorology Today ClausiusClapeyron equation Describes the equilibrium state for a system of water vapor over a flat liquid surface of pure water in which condensation and evaporation occurs at identical rates Equilibrium is reached when 0 o 39 o o o 3 8 o Rate of evaporation Rate of condensation O O OO O O 01 0 gt Air is saturated with water vapor Water Saturated ees Gibbs free energy available energy In thermodynamics the Gibbs free energy is a thermodynamic potential which measures the useful pr processinitiating work obtainable from an isothermal isobaric thermodynamic system It is the maximum amount of nonexpansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process When a system changes state the Gibbs free energy AG equals the work exchanged by the system with its surrounding U internal energy Joule G U pV TS P pressure Pa V volume m3 G H TS T temperature K S entropy J K39l H enthalpy J 10 T C es Pa 1905 3154 5106 8090 12563 19144 28657 42184 61121 87247 122194 170532 233854 316874 424520 5626A5 738127 eiPa 1285 2236 3802 6330 10328 16532 25992 40178 61115 LJ9 2603 2575 2549 2525 2501 2489 2477 2466 2453 2442 2430 2418 2406 LsJ9 2839 2839 2838 2837 2834 eST 6112 exp 1767 T C T C 2435 Dnb 11 Thermodynamics of moist air Mixing ratio Average specific humidity 03 Mass of water vapor i w md Mass of dry air kg 3 Tm R T 6 ampe Vv R39RV mVm0622 g pd p eR T M e e 17 6 P 3 Specific humidity I0 I E 8 q mv Mass of water vapor i 321 3 mv md Total mass of dry azr kg 6 6 6 394 pv 8 z 8 pvpd p1 8e 9 9 Virtual temperature 0 I I I I I I I I I I I 60 50 110 3020 10 O 10 2O 30 4039 5060 North Laniude Soulh 1 2DU7Thomson HigherEducauun Ahrens MeteorologlyZToday Relative humidity watervaporcontent 0 When RH gt 100 gt air is 0 water vapor capacity supersaturated RH E E RHice gt RHwater ws e5 Ahrens Meteorology To m lt Relative humidity Temperature Temperature gt Relative Humidity a l Midnight 600 AM Noon 600 PM Midnight m7 Thummn Hwher Eduulinn Ways of reaching saturation Dew point Td Frost point is the temperature to which air must be cooled p const and w const for it to become saturated ws w with respect to a plane surface of pure water ice Td decreases by 1 C for every 5 decrease in RH eg RH 85 Td T 100 85 Analytical approximation A Td TdwpBln 9 W 0622 14 4 The data below represent the dewpoint temperature and expected minimum temperature near the ground for various clear winter mornings in a southeastern city Assume that the dewpoint remains constant throughout the night a On which morning would there be the greatest likelihood of observing visible frost Explain why b On which morning would frozen dew most likely form Explain why c On which morning would there be black frost with no sign of visible frost dew or frozen dew Explain d On which morning would you probably only observe dew on the ground Explain why Td 0C 2 7 1 4 3 Expected Tmin 0C 4 3 O 45 2 The equivalent temperature Te is the temperature a sample of moist air would attain if all the moisture were condensed out p const L TeT W Cl Equivalent potential temperature 6e K Poisson equation Ideal gas equation First law of thermodynamics VWS He 5 6 exp T Ge a when all water vapor has condensed ws 0 0p 16 The wetbulb temperature TW is the temperature to which air may be cooled by evaporating water into it p const until saturation is reached TW T 3Ae BTw w A 253x108kPa Cpp Wetbulb potential temperature 6W K 17 Lifting condensation level Lifting condensation level LCL is defined as the level to which an unsaturated but moist parcel of air can be lifted adiabatically before it becomes saturated with respect to a plane surface of pure water Environmental temperature T 2quotC T1 3000 4quotC Windward side E T 4 C T1 5 2000 4 C 9 E T 1000 7 1000 120 2000 12 C Air I Dew point temperature temperature T Ta 3 2007 Thomson Higher Education Leeward side T 80C y T 182C 7039 2 30 Rain shadow 18 Ahrens Meteorology Today Moistadiabatic processes Adiabatic process no exchange of heat with the environment Aq 0 Condensation and evaporation results in the exchange of latent heat which does not pass through the boundary of the parceL Saturatedadiabatic moistadiabatic process The condensed water stays with the air in form of cloud droplets reversible process Pseudoadiabatic process All condensed water is falling out immediately non reversible process 19 Moist adiabatic lapse rate Envrrunmentai Rain shadow temperature T izuc TH 3000 7 4quotC Windward side Leeward srde E I T 4c Td 8 C 0 2000 7 4c I 060 r E l E A lt l lt 1 c E10004 33 1000 a 12 C 7 20 C 12 C i Arr Dewypomt 0 temperature temperature T Tu azum Thamson Hum Education warm saturated air produces more condensate than cold saturated air and thus releases more latent heat Near the ground in humid conditions Middle of the Troposphere High altitudes Overall average dT dh 1 m dT dh 1 m dT dh 1 m dT dh 1 m 4 K km1 6 to 7 K km1 98 K km1 6 K km391 20 Net affects by ascent followed by decent 21 Meteorological thermodynamic charts 100 200 300 400 500 600 700 800 900 1000 mb 80 70 50 50 40 gt 30 20 39 u 39 1111 E isn aszf ATOC 5600 Physics and Chemistry of Clouds and Aerosols 4 Fundamentals on Atmospheric Dynamics Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich Kinematics Greek to move is a branch of mechanics which describes the motion of objects without the consideration of the masses forces momentum or energy Dynamics is the branch of classical mechanics that is concerned with the effects of forces on the motion of objects Kinematics of the large scale ow Coordinate system 0 Cartesian coordinates xy 0 within the flow natural coordinate system s n z k localy quotupquot y NORTH meridional 5 U Isotachs contours of constant scalar wind speed V Translation Convergence Divergence A N C A N gtxlt lt gtlt gt CONVERGENCE V DIVERGENCE B N D N gt gt gt gt gt gt gt gt gt gt gt gt gt gt gt gt gt gt gt gt CONVERGENCE DIVERGENCE 5 Courtesy Bob Rauber Anticyclonic rotation Cyclonic rotation Negative VOI39tiCitY Positive vorticity Courtesy Bob Rauber Inertial coordinate system axes do not change direction and are not accelerated Earth not rotating Earth based noninertial coordinate system for meteorological research Axes x positive toward the east y positive toward north 2 positive upward toward zenith Wind components dx u wind component toward east dt zonal dy v wind component toward d1 north meridial dz w wind component toward 9 d zenith vertical Basic equations Equation of state Thermodynamic equation Mass continuity Water continuity Equation of motion 10 Dynamics of the horizontal flow Newton39s first law An object will remain at rest and an object will remain in motion travel at a constant velocity along a straight line as long as no force is exerted on the object Newton s second law Forces F exerted on an object equals its mass m times the acceleration a produced dv Acceleration speeding up slowing down F m a m t changing direction of an object COR Coriolis force Fnet FCOR FPGF FCEF FFRF F5 pressure gradient CEF centripetal force FRF frictional force 11 Pressure gradient force TANK A TANK B gt Higher pressure Net force Lower pressure Ahrens Meteorology Today PGF i a Pia pja pk pax 6x 6x p pressure p density PGFE iniapiap P p 6x p 6y 12 quot 43 60 065 65 1 go 53 64 062 Copyright 2006 by John Wiley amp Sons Inc or related companies All rights reserved Calculate PGF between Dodge City KS and Limon CO distance 500 km 13 Coriolis force Coriolis deflection Cities X and Y are located at the I Figure 69 t City X has a I A I I greater distance TiL rad mum eplmcm s flu I travel in me Bar 1 pu i ii39uL39clt39i by I pin39cr39l fair VI i amount of time m igilmiing a City and hmd l 39 a ing mumI Ciii Y Tir blue IF 3 Latitude 2 rim i rtprr xnnix n mi cP QfIil39 I H Wquot l l l mu39eliiig 39miz City Y in My X In mti Inn39s u Curiolis li rc l rimu tu39 paroch uppmr 2 11 111 ed in 114 rig1f fi39iim Hm mini Ifcivic fun uh flu rii39w mi vfh39ri39i39 3917 x foi c39v is luv in the 111 I39r39imcs in i wear illuxii39rii trrl bare and iii Figure 65 apmifmo39l 39 39mg m COR 29v sinqb 29w cosqb i 29M sinqu 29M cosqbk f 29 sing Q a 2n rad day 1 7292x10 5 s 1 f Coriolis parameters k local vertical unit vector V wind vector 14 q latitude Q Earth s rotation rate 115045 36 0quot 39 o 3am quot 43 60 06595ng 64 3 2 K 92 38 067 024 Copyright 2006 by John Wiley amp Sons Inc or related companies All rights reserved Calculate COR in Limon CO 15 CorioHs Force 020 015 010 40 Knots 20 Knots 10 Knots 15 30 45 60 75 Lalitude Ah rens Meteorology Today Forces that in uence the winds Geostrophic wind upper level charts pressure gradient force coriolis force Gradient wind pressure gradient force coriolis force centripedal force Surface winds surface charts pressure gradient force coriolis force centripedal force friction Thermal wind 17 The geostrophic balance 495 mb P GF PGF PGF T 496 mb PGF 39 d 13 Wind E Wind W39ln 497 mb K PGF C COR E med COR COR COR A8 498 mb North mb 500 mb East Rauber Walsh Charlevoix Severe and Hazardous Weather Air is in geostrophic balance if and only if air is not accelerating speeding up slowing down or changing direction For geostrophic balance to exist isobars or height lines on a constant pressure chart must be straight and their spacing cannot vary 18 Geostrophic wind 0 The wind that would exist if air is in geostrophic balance 0 The geostrophic wind is a function of the pressure gradient and latitude CD PGF gt 2914 s1n p 6y quot COR V AK PGF COR 1 6p lt gt 29vsm p 6x 52 speed of Earth rotation 2n 24 h 0729 10394 5391 19 p density of air Geostrophic imbalance If the pressure gradient PGF and the coriolis COR force are not in a balance air will accelerate All acceleration the parcel will experience will result directly from an imbalance between the PGF and the COR force 0 Everything interesting in the atmosphere on the synoptic scale occurs when these two forces are not in balance 20 Centripetal centrifugal force CF mm2 2m 2u sinq j ZmQu COS q k The centrifugal force arises only in observations taken in a rotating frame of reference and is due to the acceleration of the frame of reference centrifugal force Copyright 2006 by John Wrtey amp Sons Inc or related companies All rights reserved mR 2 CO StL m Rnquot equator 21 Cazjyrrg il EDGE by Jahr Wiley 5 Sons quot12 Cr 39tZlEIL C DCH1Zl3i1ll25 All rtglils 39Ebs39vec Forces that in uence the winds Geostrophic wind upper level charts pressure gradient force coriolis force Gradient wind pressure gradient force coriolis force centripedal force Surface winds surface charts pressure gradient force coriolis force centripedal force friction Thermal wind 22 The gradient wind Pressure gradient force Coriolis force Centripedal force Effect of isobar curvatures on air motion it 295 mb Rauber Walsh Charlevoix Severe and Hazardous Weather Wind continues to flow parallel to isobars VltVg VgtVg 23 Ahrens eteoro ogy Toay 24 M Feb qulate geostrophic and gradient wind at Oklahom Ckyx V 2 mkl f l w m f7 x x 47 4w oquot 4 f 5 2amp4 36 D P 39 1 3 phi 3520N f 84X10 5 Vob5 67 ms 1 7003 17 U C W 6739 39 4 a K quot 35 E Copynght 2006 by John VWey amp Sons Inc or re ated compames All nghls reserved Thermal wind circulation is in hydrostatic and geostrophic balance i 3Z thb0 65 W g dz fT 00 8x 2A stratosphere cold u 10 km Y a lt 0 Z X r y troposphere hot UZ Copyright 2006 by John Wiley amp Sons Inc or related companies All rights reserved p pAp pAp p pAp y X Z TAT V a warm advection Copyright 2006 by John Wiley amp Sons Inc or related companies All rights reserved b cold advection Cyclostrophic flow V2 1 F5 Tornado V 117142 ms1 130 mS39l R N 600 m R p n Calculate pressure gradient 27 Effect of curvature on upper level air flow faster 295 mb than I geostrophic 300 mb Meridonal Pressure I 305 mb4 0amp0 6 Trough ell8 q g V Gs 00 gt c9 IN Zonal geostrophic 2002 KendallHunt Publishing 0 Acceleration causes air to converge into some regions of the atmosphere and diverges out of others 0 Air diverges spreads out in S 9 N branch of trough 0 Air converges piles up in N 9 S branch of trough 28 Rauber Walsh Charlevoix Severe and Hazardous Weather MHES siamle Knms Der haw Ca m Calm 172 172 xrw 1amp20 1amp17 21725 5 22 293 23727 3237 28 32 3343 33737 5820 quotNew 5amp54 43 4 55 60 452 6 56 53757 6777 5amp62 f H 7843 65772 Upper level 500 hPa map FFFFFFFFFFFFFrFr i 971231037107 Gradient flow Geostrophic flow Ahrens Meteorology Today 29 Effect of changing pressure gradient along direction of flow 0 As air moves toward point B the PGF increases Air will accelerate toward low pressure since the PGF exceeds the Coriolis force 0 As air moves toward point D the PGF decreases Air will accelerate toward high pressure since the Coriolis force exceeds the PGF 0 Acceleration of air through a jetstreak has an effect on convergence and divergence pattern Rauber Walsh Charlevoix Severe and Hazardous Weather jetstreak effect A N 290 mb low pressure T 295 mb A D gt E o 300 mb 305 mb high pressure Green arrows denote flow of air if the air was in geostrophic balance B N 290 mb T Nuance region I left exut reguV I 295 mb Cow A 300 mb DVERGENCEquot CONVERGENCE I I right entrance region I right exit region 305 mb Blue arrows denote deflection of air because air is not in geostrophic balance Combined effect of curvature and changing pressure gradient along direction of flow D Divergence C Convergence Red Curvature Green Jetstreak 2002 KendallHunt Publishing Courtesy Bob Rauber Cyclogenesis and Anticyclogenesis tropopause 1 Air Air fills evacuates column column weight Of Weight of air above air above the the surface surface increases decreases 39 397 surface L H 32 Rauber Walsh Charlevoix Severe and Hazardous Weather Cyclogenesis and Anticyclogenesis Divergence aloft Convergence aloft gt 1 Air fills Air 39 quot quot quot column 39 gt 4 evacuates column Weight of air L H Welgbht39gf above the llileasuifacce surface 39nc eases decreases L develops H deVGIOPS 39 r at the surface 33 Friction directed opposite the flow Friction is manifested as A drag force in a thin layer near the surface Turbulent mixing of faster and slower air at altitudes above the surface AreaA V gt 39a Equot I39 390IIA 39o H l H d fluid uz I 7 Z F7 Lg I quot39 a quot quotI3939 old 39o 3 HugNI c Copyright 2006 by John Wiley amp Sons Inc or related companies All rights reserved mechanical turbulence thermal turbulence W f yf llM In shearinduced turbulence 30 ms Wind gt 10 ms Wind M d Effect of friction on the geostrophic wind In the lower atmosphere boundary layer P2AP PAP P2AP PAP P2AP PAP COR I 7 wrnd COR PGF wind COR above boundary layer upper boundary layer lower boundary layer Net result Friction causes air to flow across isobars from high to low pressure in the boundary layer The amount of turning and decrease in wind speed depends on surface roughness 35 Courtesy Bob Rauber Effect of friction on high and low top of friction layer surface Air column filling up at bottom Surface pressure will increase with time top of friction layer surface Air column evacuating at bottom Surface pressure will decrease with time Dynamic Processes in the boundary layer always act to destroy low and high pressure systems 36 Courtesy Bob Rauber Upper level divergence e are dlve gepce A gt LA7 lt tropopause surface gt lt C O nVe l39 e n C e Y 1 la WVxquot H xxx I I I I I I I I I I I I I I 3 2002 KendallHunt Publishing I I I I I I I I I I I I I I 1 N 37 ATOC 5600 Physics and Chemistry of Clouds and Aerosols Overview Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich Fundamentals in thermodynamic 35 weeks Rogers amp Yau 14 Thermodynamics of dry air water vapor and its thermodynamic effects Parcel buoyancy and atmospheric stability Mixing and convection Basic atmospheric dynamics Cloud microphysics 2 weeks Houze 3 Microphysics of warm and cold clouds role and dynamic of aerosols Observing cloud structures and precipitation 15 weeks Houze 4 Introduction to remote sensing instruments radar satellite and insitu instruments rain and snow gauges disdrometers Specific phenomena amp precipitation processes 4 weeks Houze 612 Nimbostratus cumulus dynamics thunderstorms mesoscale convective systems hurricanes extratropical cyclones orographic clouds and precipitation Weather modification and cloud seeding 1 weeks Cotton amp Pielke Main results from weather modification and cloud seeding experiments 2 Objectives Fundamentals of thermodynamic and physical principles for cloud and precipitation formation Learn how to calculate thermodynamical quantities read and analyze SkewTlogp diagrams detailed examination of the advantage limits and operation of remote sensing radar and satellite and insitu instruments rain gauges disdrometer Develop quantitative and qualitative analysis of thermodynamic and microphysical processes relevant for cloud development for nimbostratus clouds extratropical cyclones cumulus dynamics thunderstorms mesoscale convective systems hurricanes and orographic clouds We apply our understanding of cloud microphysics to problems of weather modification by cloud seeding anthropogenic aerosol gas emission as well as numerical modeling of clouds Objectives for prOJect Learn how to search for literature efficiently read scientific papers and withdraw the important information Train to do a poster and oral presentation Learn how to test a scientific hypothesis Train how to get observations from the internet how do read data do simple analysis and plotting Important dates 4 September 9 September 30 September 13 November 2 October 9 October 21 October 9 December Project discussion Homeworkl Homework2 Homework3 Project Part 1 Literature review Excursion to Rocky Mountain Airfield to see research aircraft HIAPER C130 Midterm Exam Project Part 2 Poster presentations Grading version I PROJECT Literature review 10 min overview talk Data analysis poster presentation HOMEWORK 3 assignments EXAMS 2 exams both need to be passed to pass the course 3000 Discussion 4 September Literature overview 2 October talk Poster presentation 9 December 3000 Homework 9 Sept 30 Sept 13 Nov EXERCISE volunteer will receive extra credit that counts to the homework 4000 Mid term exam 21 October Final exam Grading version 11 PROJ ECT Data analysis poster presentation HOMEWORK 3 assignments 2000 Discussion 4 September Poster presentation 9 December 30 500 Homework 9 Sept 30 Sept 30 Nov EXERCISE volunteer will receive extra credit that counts to the homework EXAMS 2 exams both need to be passed to pass the course 4000 5 0lo Mid term exam 21 October Final exam Grading version 111 PROJ ECT Literature review 15 min Talk or 4 page paper HOMEWORK 3 assignments 1 600 Discussion 4 September Paper submission 20 November Talk 9 December 30 700 Homework 9 Sept 30 Sept 30 Nov b EXAMS 2 exams oth need to be passed to pass the EXERCISE volunteer will receive extra credit that counts to the homework course 4000 7 0lo Mid term exam 21 October Final exam Final grades 2 95 0o 900 949 00 850 899 0o 800 849 00 750 799 0o gt not accepted in the PhD program lt 75 0o gt not accepted in the master program Projects 23 students 1 Human impact on regional and climate weather Role of aerosols and pollution on cloud formation and suppression of rain and snow 2 Orographic precipitation in different climate regions eg Cascade Mountains OR Alps Himalayan 3 Climatologycase study on precipitation phenomena eg Hurricanes in FL orographic precipitation in OR WA UT CO upslope snow and rain events in CO monsoon in ARNM supercell thunderstorms in Great Plains lake snow effects around the great lakes Snow storms in central and eastern US 4 Summarize results from field campaigns related to chemistry and physics of clouds and aerosols objectives realization results 5 Rain formation in shallow cumuli what are the principal mechanism 10 6 Design a field campaign to address an open research questions 7 Temporal and spatial variation drop size distribution and its effect on rainfall rate estimation 8 Parameterization of convective and microphysical processes in numerical weather prediction models 11 What are clouds amount and cloud type are observed at weather stations every 6 hours High clouds Cirrus Ci Cirrostratus Cs Cirrocumulus Cc High clouds 714 km Middle clouds Altostratus As v 39 Mediumlevel clouds 27 km Altocumulus Ac 7 A8 Ns Low clouds a a quot 39 7 gt 7 Stratus St Stratocumulus Sc Nimbostratus Ns httpwwwweatheroninecouk Clouds With vertical development Cumulus Cu 12 Cumulonimbus Cb What are clouds amount and cloud type are observed at weather stations every 6 hours OTABLE 54 Common Terms Used in Identifying Clouds TE RM Lenticularis Fractus Humilis Congestus Calvus Capillatus Und ulatus Translucidus Incus Mammatus Pileus Castellanus LATIN ROOT AND MEANING lens lenticula lentil frongere to break or fracture humilis of small size cangerere to bring together to pile up calms bald capillus hair havng hair undo wave having waves translucere to shine through transparent in cus anvil momma mammary pileus cap custellum a castle DESCRIPTION Clouds having the shape ota lens or an almond often elongated and usually with wellde ned outlines This term applies mainly to cirrocumulus al tocumulus and stratocuinulus Clouds that have a ragged or torn appearance applies only to stratus and cumulus Cumulus clouds with generally attened bases and slight vertical growth Cumulus clouds of great vertical extent that from a distance may resemble a head of cauli ower Cumulonimbus in which at least some of the upper part is beginning to lose its cumuliform outline Cumulonimbus characterized by the presence in the upper part of cirriform clouds with brous or striated structure Clouds in patches sheets or layers showing undulations Clouds that cover a large part of the sky and are suf ciently translucent to reveal the position of the sun or moon The smooth cirriform mass of cloud in the upper part of a cumulonimbus that is anvileshaped Baglike clouds that hang like a cow s udder on the underside of a cloud may I i u occur with cirrus 21m rmt n nnrl bus A cloud in the form ofa cap or hood above or attached to the upper part of a cumulifonn cloud particularly during its developing stage Clouds that show vertical development and produce towerlike extensions 14 often in the shape of small castles What are aerosols N Sizes of different aerosols 001 Aitken V Large 7 Giant Q39Wd particles i i Human hair Dust storms Beach sand Viruses Bacteria I Sea salt Smoke from fires H gt i H y H Van x 01 39 1 1 10 100 1000 Size microns Ackerman amp Knox Meteorology5 Sea Salt natural soluble Fig 8 12 Four stages in the production of salt particles by the bubbleburst mecha nism Film cap protrudes from the ocean surface and begins to thin Flow down the sides of the cavity thins the lm which eventually ruptures into many small fragments c Unstable jet breaks into few drops d Tiny salt particles remain as drops evaporate new bubble is formed From Day 1965 with changes Pruppacher amp Klett Microphysics of Clouds and Precipitation S Borrmann S Borrmann Dust natural nonsoluble S Borrmann http1earthobservatorynasagov A large plume of Saharan Dust is blowing northeastward on August 19 2004 over the 17 Mediterranean Sea Smoke natural soluble and nonsoluble Numerous large wildfires were blazing across central Alaska and Yukon Territory Canada on August 22 2004 httpearthobservatorynasagov 18 Pollution humanmade soluble and nonsoluble Soot smoke and gases from regional power plants that consistently have some of the country s highest emission rates began to pile up in the hot humid stagnant air in late summer of 2002 The air quality index exceeded a level considered unhealthy for people with lung or heart conditions 19 http earthobservatory nasagov Why do we care about clouds precipitation a Weather forecasting and 39 impact on severe weather quott T W w 1 r T f 5 e I V y 1 4 Al L i 7 quoti Ji L I 139 Kit 3 V g I 04quot if j m39 iJHE 59 TORNADO WARNING 1 k SPC Mich ang Adv Map TSTM I UPDATED 1913 UTE 0324103 7 3 FLASH FLOOD WARNING 39 Act39 a t b r t Wilts En3 ago8t393 3am I 3W3 Norman gtleahoma 39 b Quantitative precipitation forecasting and flood forecasting Hydrological Cycle Atmosphere 127 Unns Thousand cuboc km lor slmage and thousand cubic kinyr lor exchanges Vegeiahcn Dai and Trenberth 22 c Direct effects on light scattering and climate Outgoing iR energy Outgoing iR energy IR IR emitted absorbed Incoming soiar energy incoming soiar energ a Without greenhouse effect b With greenhouse effect Ahrens Meteorology Today CLOUDS ARE THE MOST SIGNIFICANT AGENT FOR ABSORPTION AND LIGHT SCATTERING IN THE ATMOSPHERE CLOUDS CAN EITHER WARM OR COOL THE EARTH UNCERTAINTY IN THE CLOUD RADIATIVE FORCING IS THE LARGEST 23 UNCERTAINTY IN CURRENT CLIMATE MODELS EARTH39 S ENERGY BUDGET Re ected by Re ected Re ected from atmosphere by clouds earth39s surface 6 20 4 Incoming Radrated to space solar energy from clouds a d 100 a osphere Absorbed by atmosphere 16 to space I from earth Absorbed by clouds 3 6216 s grtie du y land s 51 Absorbed b n and ocea d Vertical and horizontal transort amp removal of chemicals r La heat r sed Convectlon Conduction Ahrens Meteorology Today 0 HEAT TRANSFER BY LATENT HEAT RELEASE IS A MAJOR COMPONENT OF THE ENERGY BUDGET 25 ISCCP Total Cloud Amount 19831990 Percent 26 Why do we care about aerosols direct radiative forcing indirect forcing of climate by aerosols the role of particulates in air pollution visibility and health effects aerosols impact cloud formation and precipitation enhancement depression 27 Anthropogenic and natural forcing of the climate for the year 2000 relative to 1750 Global mean radiative forcing Wm2 3 Greenhouse gases Halocarbons Aerosols clouds N20 CH4 I Warmina CO Tropospherlc rue Mineral ozone Dust Aviation Contrails Cirrus m T T i E 7 Stratospheric ozone Land use albedo only burning The height of a bar indicates a best estimate of the forcing and the awornpan 39ng vertical line a likely range of values Where no bar is present the vertic line only indicates the range in best estimates with no likelihoad LEVEL OF SCIEN l39l l V UNDERSTANDING 39 39 39 s 7 SYR 7 FIGURE 2 IPCC l INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE 002 ppm w3939 a v v39 rvi quot Indicators of the human influence on the atmosphere during the Industrial era Ner w W 1800 aei oso s ieti in SO2 emissions 1mm United Staies umpa mm 3 yr b 39 0 NJ in i 200 1400 i600 1807 2000 SYH FIGURE 21 WG1 FIGURE SPM2 i i 1990 199 1992 1993 The radiative forcing from the1991 Pinatubo volcanic cloud measured by ERBE Minnisj 13 Harrison E F Stowe L L Gibson G G Denn F M Doelling D R and Smith Jr Won Radiative Climate Forcing by the Mt Pinatubo Eruption Science Vol 259 pp 14111415 March 5 1993 1955 1958 1987 1338 1959 View days before the start of the Olympic Summer Games 2008 in Peking Neonatal Infants and Older Adults Affected Most in 1952 London Fog Deaths Registered in London Administrative County Classi ed by Age Bates 1995 lt 1 112 114 1544 4564 6574 75 Month Mo Years Years Years Years Years of Age Old of Age of Age of Age of Age of Age Week 16 12 10 61 237 254 335 Before the Episode Week Afterthe 28 26 13 99 652 717 949 Episode B fre 175 217 13 162 275 282 283 6139 Episode 33 Rat1o 1962 Episode Confirmed the Presence of Acidic H ikseiy SLi iUi ic Acid aridoiquot Ammonium Bieu faiie 5000 4000 3000 Smoke and 802 Mgm3 Changes in cloud area cover due to aerosols Drop et Concentru on 15 cm A S Ackelman O B Toon D E Stevens and J A Coakley Jr Geophys Res Lett 3071381 dol 1010292002GL016634 2003 ATOC 5600 Physics and Chemistry of Clouds and Aerosols 12 Thunderstorms I Duane Physics Bld Room 6131 Tuesdays and Thursdays 200 315 pm Dr Katja Friedrich 0 Small isolated thunderstorms Multicell thunderstorms Supercell thunderstorms Circulation features if large thunderstorms tornadoes gust front downbursts Squall lines lines of thunderstorms a 1900 UTC Nebraska qusas Oklahjci ma N we gt Heighf above MSL km in me urc 2054 2057 2100 quot 39340quot 345 quotK 1 9 K 340quot3 L 4 3 My kg 4m E 388 357w 33659 33540 35420 33310 33210 33100 3799UN 100770 1005017 100270100V03a 99780 99530 99230 99046 9Bsouw Narmwest LaTItudeLongirude n 1529 UTC 1 m 011345b7ltmmzum Singlecell thunderstorms lifetime several minutes to 1 h way of Martin Hagen faffenho39fen 39 Lightning occurs when T lt 15 20 C IC first then CG 510 min afterwards 12 Km a Cumulus b Maiure C Dissipating Early stage vigorous updraft hydrometeors grow rapidly Mature stage active up and downdrafts Dissipating stage strong updraft smmm yam r mumquot mm u woo mum quotmum rumquot 1 MAM 17 mm WWW m Wm l lmmunglv mmm Wm m Dal114 w m TURRET 1 my r PRECIPITATION TRAILS DOWNDRAFTS Hobbs and Rangno JAS 1985 wmAcLow cmunmya awn WllllamS et al 1989 usmnwa 5mm HH NH 3 a mm Augus a l977 Kennedy Space cam 47 HEIGHTUUH MSL was me 312 ram 1SE 516 20 522 824 IBZG 1825 TIME GMT Height km 1435 UTC Azimuth 326 Vquot In8 4 25 7 0 714 32 Range km Height km Hydromwr Type 50 55 60 65 30June1990 Holler et al JAS 1994 Multicell thunderstorms lifetime several hours o 1 3939o 39 39 3939 39 39v 39 quot393939 ou aer39 39 quotZ393939o39 l 39 C 7H Photos courtesv oanan Jewett Unwerswtv ofIHmmS Photos courtesy ofEman Jewett unwersmy omhnms T00 F50 quotWW m 48 V16 44 1 VB 6 DISTANCE AHEAD OF OUTFLOW r4 BOUN THE HAYMER HA LSTORM 9 J U LY 1 973 370 MOT0N 7 we EOEC S i NHCHAFI WACK SURFACE HAINFALL RATE F mmhr 2 o 2 4 e DARY km Browning et al MWR 1976 a V5 Wmd at ow eve ls Vc lt New Dell New cell b Wind at low levels Houze Cloud dynamics Sguall lines develoging along gust front out ow Supercell thunderstorms lifetime several hours producing damaging hail and tornadoes O I39D 39 I o oraareco 33951 H39 v Ic quot u 39 39 quot 39I39 quot I A I quot quot 39 h 3939 ou aer 39A o I U I Upwinds 39 BWER bounded weak echo region Chrisholm and Remick 1972 mom um E 5 S Am u m s m 9 40 a m c mug m m sou msrmz mm sacm 29 mm Ilunwt m H mm mum of W mm a sum M I la la a mm mm Sanweenie um Browning and Facts 1972 P Anle Overshootlng top Storm 1 movement Rearflank L 39 Wallace anq Hopbs downdraft V Atmospheric SCIences Anvil edge Gust front Evinage Nichulsmlls rm v Betha y Spawn foreswark Chum klalm amry L ht 1g ram rudvnnzlly quads Moderate heavy rain K m Small hail m Large hail M Center of mesocyclone Doppler Radar Reflectivity During the 3 May 1999 Tornado Outbreak Reflectivity Doppler velocity Gust fronts STAGE I FORMATV5 STAGE radar efleciivify daracls the advancmg rain or low levels STAGE II EARLY MATURE STAGE 39 Pucmitonon 39 Roll 39 l I STAGE III DISStPATING THUNDERSTORM LATE MATURE STAGE c 39 39 quot Pucipimtion quotI Roll STAGE IV DSSIPATNG STAGE N0 THUNDERSTORM Contact Stage Outburst Stage Extreme Winds 5 x K K E I f If I 39 x CUShion 5 399 Extreme Winds T j a v ya kh quot KK Coldmr H 1 lt 4 q Cushion 0 aw 392 Wakimoto 1982
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