Warm Up 3/18/08Warm Up 3/18/081) 1)The wet adiabatic rate of cooling is less than the The wet adiabatic rate of cooling is less than the dry rate because ____dry rate because ____aaof the dew pointof the dew pointbbof the release of latent heatof the release of latent heatccwet air is unsaturatedwet air is unsaturateddddry air is less densedry air is less dense!) !)"ool air acts as a barrier o#er which warmer$ "ool air acts as a barrier o#er which warmer$ less dense air rises$ in a process %nown as ____less dense air rises$ in a process %nown as ____adi#ergenceadi#ergencecorographic liftingcorographic liftingbfrontal wedgingbfrontal wedgingdsubductiondsubduction3) 3)&rographic lifting is associated with ____&rographic lifting is associated with ____amountainsamountainscfrontscfrontsb'at plainsb'at plainsdri#ersdri#ers(nswers) 1) b!) b3) a(nswers) 1) b!) b3) a "loud Types and "loud Types and *recipitation*recipitation"hapter 18$ +ection 3"hapter 18$ +ection 3 Types of "loudsTypes of "louds"louds are classi,ed on the basis of "louds are classi,ed on the basis of their form and heighttheir form and heightCirrusCirrus clouds are high$ white$ and thinclouds are high$ white$ and thinCumulusCumulus clouds consist of rounded clouds consist of rounded indi#idual cloud masses$ they normally indi#idual cloud masses$ they normally ha#e a 'at base and the appearance ha#e a 'at base and the appearance of rising domes or towersof rising domes or towersStratusStratus clouds are sheets or layers clouds are sheets or layers that co#er much or all of the s%ythat co#er much or all of the s%yThere are three le#els of cloud heights) There are three le#els of cloud heights) high$ middle$ and lowhigh$ middle$ and low Three cloud types ma%e up the family of high Three cloud types ma%e up the family of high clouds -abo#e .000 meters)) cirrus$ cirrostratus$ clouds -abo#e .000 meters)) cirrus$ cirrostratus$ and cirrocumulusand cirrocumulus(ll high clouds are thin and white and are often (ll high clouds are thin and white and are often made up of ice crystalsmade up of ice crystals"louds that appear in the middle range -/!0000"louds that appear in the middle range -/!0000.000 m) ha#e the pre,1 .000 m) ha#e the pre,1 alto-alto-2iddle clouds may cause infre3uent light snow and 2iddle clouds may cause infre3uent light snow and dri44ledri44leThere are three members in the family of low There are three members in the family of low clouds -below !000 m)) stratus$ stratocumulus$ and clouds -below !000 m)) stratus$ stratocumulus$ and nimbostratusnimbostratus5imbostratus clouds are the main precipitation 5imbostratus clouds are the main precipitation ma%ersma%ers6ertical de#elopment clouds ha#e their bases in 6ertical de#elopment clouds ha#e their bases in the low height range$ but e1tend through the the low height range$ but e1tend through the middle or high altitudesmiddle or high altitudes"umulonimbus may produce rain showers or "umulonimbus may produce rain showers or thunderstormsthunderstorms "lassi,cation of "louds"lassi,cation of "louds "oncept "hec%"oncept "hec%What does the 7atin word What does the 7atin word stratusstratus mean8mean8+tratus means 9to co#er with a +tratus means 9to co#er with a layer:layer: ;og;ogFogFog is de,ned as a cloud with its base at or is de,ned as a cloud with its base at or #ery near the ground#ery near the ground( blan%et of fog is produced in some West ( blan%et of fog is produced in some West "oast locations when warm$ moist air from the "oast locations when warm$ moist air from the *aci,c &cean mo#es o#er the cold "alifornia *aci,c &cean mo#es o#er the cold "alifornia "urrent and then is carried onshore by "urrent and then is carried onshore by pre#ailing windspre#ailing winds;ogs also can form on cool$ clear$ calm nights ;ogs also can form on cool$ clear$ calm nights when as the rising water #apor meets the cold air$ it rising water #apor meets the cold air$ it immediately condenses and rises with the air immediately condenses and rises with the air that is being warmed from belowthat is being warmed from below ?istribution of ;og?istribution of ;og "oncept "hec%"oncept "hec%"ompare and contrast clouds and "ompare and contrast clouds and fogsfogs"louds and fogs are physically the "louds and fogs are physically the same;ogs are clouds with their same;ogs are clouds with their bases at or #ery near the groundbases at or #ery near the ground @ow *recipitation ;orms@ow *recipitation ;orms;or precipitation to form$ cloud droplets must grow in;or precipitation to form$ cloud droplets must grow in #olume by roughly one million times #olume by roughly one million timesBergeron Process Bergeron Process a theory that relates to the formationa theory that relates to the formation of precipitation to supercooled clouds$ free4ing nuclei$ andof precipitation to supercooled clouds$ free4ing nuclei$ and the diAerent saturation le#els of ice and li3uid water the diAerent saturation le#els of ice and li3uid waterSupercooled Supercooled water in the li3uid state below 0 water in the li3uid state below 0B" -in theB" -in the atmosphere pure water can reach 0C0B" without free4ing) atmosphere pure water can reach 0C0B" without free4ing)Supersaturated Supersaturated the condition of air that is more highlythe condition of air that is more highly concentrated than is normally possible under gi#enconcentrated than is normally possible under gi#en temperature and pressure conditions temperature and pressure conditionsDecause the le#el of supersaturation with respect to iceDecause the le#el of supersaturation with respect to ice can be 3uite high$ the growth of ice crystals is rapidcan be 3uite high$ the growth of ice crystals is rapid enough to produce crystals that are large enough to fall enough to produce crystals that are large enough to fallCollision-Coalescence Process Collision-Coalescence Process a theory of raindropa theory of raindrop formation in warm clouds -abo#e 0B") in which large cloudformation in warm clouds -abo#e 0B") in which large cloud droplets collide and Eoin together with smaller droplets todroplets collide and Eoin together with smaller droplets to form a raindrop form a raindrop The The Dergeron Dergeron *rocess*rocess "ollision0"oalescence "ollision0"oalescence *rocess*rocess "oncept "hec%"oncept "hec%What must happen in order for What must happen in order for precipitation to form8precipitation to form8"loud droplets must increase in "loud droplets must increase in #olume by about one million times#olume by about one million times ;orms of *recipitation;orms of *recipitationThe type of precipitation that reaches