Special Topics EAS 8803
Popular in Course
Popular in Earth And Space Sciences
This 0 page Class Notes was uploaded by Adrienne Oberbrunner on Monday November 2, 2015. The Class Notes belongs to EAS 8803 at Georgia Institute of Technology - Main Campus taught by Irina Sokolik in Fall. Since its upload, it has received 15 views. For similar materials see /class/233960/eas-8803-georgia-institute-of-technology-main-campus in Earth And Space Sciences at Georgia Institute of Technology - Main Campus.
Reviews for Special Topics
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 11/02/15
Lecture 23 Total radiative heatingcooling rates Obiectives 1 Solar heating rates 2 Total radiative heatingcooling rates in a cloudy atmosphere 3 Total radiative heatingcooling rates in an aerosolladen atmosphere 4 Global distribution of radiative heating cooling rates Required reading L02 35 452 461 462 47 824 1 Solar heating rates Recall that IR radiative cooling rates in the cloudfree conditions were discussed in Lecture 11 No emission in solar gt no cooling only heating due to absorption The net ux is often de ned as Fz FTz Fz 231 so the net ux divergence is AFM FM 2 AZ FM 2 d J 1 dF g dF 232 dt solar cpp dz 5p 511 F0 00 0 FTzAz F zAz T pAp L zAz T P i z Fiz 1142 ps 0 NOTE Instantaneous heatingcooling mtes are the mtes calculated for a given moment of time eg at a given sun angle for solar heating Hourly diurnally monthly and annually averaged rates are also used NOTE L02 de nes the solar net ux asFW2 Fl 27 FTZ This de nition is commonly used in the literature Then divergence is calculated as M2E12AZEEZAZ and heating mtes are calculated With Eq232 0 In cloud and aerosolfree conditions the main absorbers of solar radiation are ozone Water vapor and some C02 Tropical Conditions solar zenith of 30 Altitude km a a Shortwave Radiative Heating c per Day Figure 231 Representative heating pro les due to solar absorption in a cloudfree tropical atmosphere for H20 03 and C02 NOTE To rst order the differences in heating pro les in Fig231 mirror the differences in mixing ratios of these gases 0 In cloud and aerosolfree conditions total solar heating is the sum of solar heating due to individual gases 2 Total me in a cloudv atmosphere Total rates solar rates IR rates NOTE V Because rates can have different signs in solar and IR one needs to be careful While computing total rates V Total rates are o en called net rates V Depending on a sign oftotal radiative rates an atmospheric layer experiences either radiative heating or cooling IR and solu distribution Shannan Atmosphorl ALYITUDE km clouds with ditTerent vertical Ammo xm Amruoz um Am runs km ALTVTIHJE my nmrune km ALYITUDE my 2 u a m comma an own gure 232 IR and um ALTlTUDE rm 0 2 a A 4 sons HEATING an 39Cuulnr day for clear vulu cloudy atmospheres 100 cloud cover is assumed Solar heating rates were calculated for a solar constant of1360 Wmz surface albedo of015 cosine of solar zenith angle 05 and solar time duration of 12 hours modi ed from Liou and Zheng 1984 gt Cirrus clnllds me E El sunaw 57 E g e 0 o 0 5 29 Haur 02A Mounnnltwchnu Kenn VCduy Lland3km Vzrh mu rates were calculated fur a snlar cnnstant nr 1360 Wmz surface albedn are 15 cnsme er snlar zenth angle 0 5 and snlar nme durahnn nr 12 hnurs Lmu 1m Man edurex Strung IR Ennlmg abnve 3 turns Bland and strung Warmmg belnw Maximum nfsnlar heaung accurs at thetnp nfa ems dnud 3 Total radiative 39 quot Gcooling rates in an aerosol laden 39 o Radiative heatingcooling rates in an aerosolladen atmosphere depend on optical properties of aerosols and their vertical distribution solar angle for solar heating rates surface albedo for solar heating rates and atmospheric conditions e g presence of clouds Altitude A I I Background conditions of Midlatitude Summer 4 Km CleaFSKYOF Fourth layer cloud aerosol aerosol 3 Km aerosol aerosol aerosol Third layer 2 Km aerosol Clear Sky aerosol Second layer cloud 1 Km aerosol aerosol ClearSky First iayer cloud 7 quotClear quotClear quotClear orCloud orCloud orCloud abovequot betweenquot beloW39 Figure 234 Schematic representation of the aerosolcloud clear sky vertical distribution for calculations of heatingcooling rates shown in gures 236238 12 Afhgan dust A Liquid w ater normalized extinction coefficient 0 00 i 01 1 7 Pm 10 100 08 7 06 7 Saharan dust 04 7 Afhgan dust 02 7 single scattering albedo 01 1 10 100 Liquid w ater Afhgan dust aymmetry parameter 0 390 i Saharan dust 01 1 1mm 10 100 Figure 25 Spectra ot a normallzed eXt1nctlon coeIIlclent hextKeth um b single scattering albedo no and c asymmetry parameter g calculated for strong absorbing dust Saharanlike dust model weak absorbing dust Afghanlike dust model and marine stratus cloud Quijano Sokolik and Toon 2000 NOTE Saharan dust model selected in this study has lower values of the single scattering albedo in the solar Alums Km Healmg Pale Wday Figure 236 Solar longdashed lines infrared shortdashedlines andtotal solid lines radiative heating rates of Saharan anol Afghan dust and for clear sky over the desert r503 at m 08 open squares are for clear sky mangles are for Saharan dust diamonds are for Afghan dust quotClear abovequot andram0s pm 05 Quljano Sokollk and Toon 2000 M 39 gala Maximum solar andtotal heating rates occur at the top ofan aerosol layer IR cooling rates lt solar heating rates gt total heating Total heating rates in an aerosol layer gt total heating rates of clear sky gt Over dark surfaces Altitude Km 0 Oiiiiiiiiiii 6240123456789 Net Heating Rate Kday Altitude Km 6240123456789 Net Heating Rate Kday Altitude Km 3536 1 2 3455 7 89 Net Heating Rate Kday Figure 237 Total radiative heating rates by dust and cloud over ocean at uo 08 for a quotClear or Cloud abovequot b quotClear or Cloud betweenquot and c quotClear or Cloud belowquot open diamonds are for quotOnly Thin Cloudquot open triangles are for quotOnly Thick Cloudquot open squares are for only dust solid diamonds are for quotDust and Thin Cloudquot solid triangles are for quotDust and Thick Cloudquot Saharan dust and Edust 05 pm l Quijano Sokolik and Toon 2000 V Over bright surfaces 7 a 7 d A 6 A 6 D 4 D 4 3 3 3 3 g 2 g 2 1 1 0 0 1086420246810 1086420246810 Solar Heating Rate Kday Solar Heating Rate Kday 7 be A 6 g 5 a 4 3 3 g 2 1 0 10 8 6 4 2 0 2 4 6 8 10 Infrared Heating Rate Kday 7 C 7 f A 6 A 6 D 4 D 4 3 3 3 3 E 2 E 2 lt 1 lt 1 0 0 10 8 6 4 2 0 2 4 6 8 10 10 8 6 4 2 0 2 4 6 8 10 Net Heating Rate Kday Net Heating Rate Kday Figure 238 Radiative heating rates over the desert r503 of a solar b infrared and 0 net at Mo 08 and of d solar e infrared and f net at Mo 025 open squares are for quotClear abovequot diamonds are for quotThin cloud abovequot triangles are for quotThick cloud abovequot Saharan dust and must 05 pm 05 Quijano Sokolik and Toon 2000