Clouds and PrecipitationClouds and PrecipitationPressure and Windclick here for 9/page to printStability of AtmosphereStability of Atmosphere• Air rises due to a number of factors• Expands as it rises: cools as it does so–Can calculate the new temperatureCan calculate the new temperature – Use the adiabatic lapse rate: •Dry for unsaturated•Dry for unsaturated• Wet for saturated–Compare the temperature of the air that has–Compare the temperature of the air that has risen to the temperature of the air at that height–Use the environmental lapse rate–Use the environmental lapse rate• Higher density air that has risen is stable (cooler)•Lower density air that has risen is unstable (warmer)Lower density air that has risen is unstable (warmer)Stable conditionsStable conditionsStabilityStability• Environmental lapse rate¾5°C/1000 m• Dry adiabatic lapse rate¾10°C/1000¾10°C/1000 m• Rising air is cooler than area it rises intog• Stable!!Absolute instabilityAbsolute instabilityConditional stabilityConditional stabilityCloud DevelopmentCloud Development• Air cools upon rising•Cools to dew–point temperatureCools to dewpoint temperature• Condensation begins• “Lifting condensation level”Cloud ShapesCloud Shapes• Cirrus—curl (of hair): thin wisps•Stratus—blanket: extensive layersStratusblanket: extensive layers• Cumulus—pile: puffy massesAdditional modifier of name• Nimbus = rain¾Cumulonimbus: puffy rain clouds¾Cumulonimbus: puffy rain clouds¾Nimbostratus : layered rain cloudsCloud GroupsCloud Groups• High clouds—6000 m or more above surface•Middle clouds—2000 m to 6000 m aboveMiddle clouds2000 m to 6000 m above• Low clouds—less than 2000 m above surface• Clouds of vertical development–Present through more than one levelPresent through more than one level– Product of atmospheric instabilitycirruscirrusCirrocumulusCirrocumulusCirrostratusCirrostratusAltocumulusAltocumulusAltostratusAltostratusNimbostratusNimbostratusCumulusCumulusCumulonimbusCumulonimbusCloud classificationleftCloud classification—leftCloud classificationrightCloud classification—rightFogGolden Gate BridgeFog—Golden Gate BridgeFogTule FogFog—Tule FogWillamette Valley FogWillamette Valley FogWeather radar displayWeather radar displayStorms of 2011Storms of 2011• Tornadic activity at all time high in May•Wide swath across southeastWide swath across southeast• http://media.nola.com/weather_impact/phot/th27 110745tto/severe-weather-27apr11-0745-utc-animatedgif-4f51095f52e087b4.gifHigh rainfall led to severe flooding• 75-year flood?•Last happened in 1937Last happened in 1937…• Some areas are at record levelsGiant hailstoneGiant hailstoneHail damageHail damageCondensation in cloudsCondensation in cloudsCollision coalescenceBergeron Process of ice-crystal growthBergeron ProcessBergeron Process• Snow falls from clouds•Melts as it is fallingMelts as it is falling• Result is rain • Most common method of precipitation in the o p ec p tat o t emid-latitudesForms of precipitationForms of precipitation•Mist: tiny droplets•Mist: tiny droplets• Drizzle: small droplet• Rain: larger drops•Sleet: small frozen raindrops•Sleet: small frozen raindrops• Glaze: rain that freezes upon contact• Rime: frost deposition•Snow: solid flakeshaped crystals•Snow: solid flake-shaped crystals• Hail: solid concentric balls• Graupel: collected snowflakesGlaze iceGlaze iceRime iceRime icePogonipPogoniphttp://grannysatticquilts.com/pogonip.htmlPrecipitation measurementPrecipitation
View Full Document
Unlocking...