CLOUDS AND PRECIPITATION PROJECTBY: Paul BeanPicture site:

http://science.nationalgeographic.com/science/photos/clouds/

ADIABATIC TEMPERATURE CHANGES AND EXPANSION AND COOLING

• Temperature changes that happen even though heat isn’t added or taken away are called adiabatic temperature changes

• They are the result of air being compressed or allowing air to expand

• as you travel up from earths surface, atmospheric pressure decreases because of fewer gas molecules

• Picture site: http://apollo.lsc.vsc.edu/classes/met130/notes/chapter6/adiab_cool.html

OROGRAPHIC LIFTING

• Happens when elevated terrain, such as mountains, act as barriers to air flow

• As air goes up, adiabatic cooling causes clouds and precipitation

• When air reaches leeward side, it warms adiabatically, causing few clouds and rain shadow

• Picture site : http://www.examiner.com/outdoorsman-in-salt-lake-city/understanding-why-utah-has-the-greatest-snow-on-earth-part-1-orographic-lifting

FRONTAL WEDGING

• Without it, the center of America would be a desert• In central North America, masses of warm air and

cold air collide, producing a front• At a front, cool dense air acts as a barrier over

which the warm less dense air rises, this process is called frontal wedging

• Picture site : http://www.geo.hunter.cuny.edu/~tbw/wc.notes/4.moisture.atm.stability/frontal_wedging.htm

CONVERGENCE

• It’s whenever air in the lower atmosphere flows together

• Goes up because must go somewhere, can’t go down

• Leads to clouds and adiabatic cooling• Picture site :

http://10.85.0.4:8080/ibreports/ibp/bp.html?fn=Students&fp=1&bu=www.islandnet.com/~see/weather/elements/whatgoesup3.htm&bc=Website+contains+prohibited+Web-Based+E-mail+content.&ip=173.49.166.199

LOCALIZED CONVECTIVE LIFTING

• The process that produces rising thermals • Birds use the thermals to go high in the sky

and look down on their prey• May produce mid-afternoon rain showers• Picture site:

http://www.richhoffmanclass.com/chapter4.html

STABILITY(DENSITY DIFFERENCES AND STABILITY AND DAILY WEATHER)

• Stable air resists vertical movement• If a volume of rising air was warmer and less dense

than he surrounding air, it would continue to rise until it would reach an altitude where its temperature equaled its surroundings, this is how hot air balloons work

• Classified as unstable air• Picture site:

http://ocw.usu.edu/Forest__Range__and_Wildlife_Sciences/Wildland_Fire_Management_and_Planning/Unit_7__Atmospheric_Stability_and_Instability_1.html

CONDENSATION

• Happens when water vapor turns into a liquid• Could be dew fog or clouds• For any forms to happen, the air must become

saturated, normally when the air reaches its dew point

• Picture site: http://keep3.sjfc.edu/students/kes00898/e-port/condensation%20page%20for%20unit.html

TYPES OF CLOUDS

• Classified on the basis of their form and height• Cirrus(cirrus=a curl of

hair),Cumulus(cumulus=a pile), and Stratus(stratum= a layer)

• High, middle, and low clouds• Picture site:

http://www.enchantedlearning.com/subjects/astronomy/planets/earth/clouds/

HIGH CLOUDS

• Three types, Cirrus, Cirrostratus, made of flat layers and Cirrocumulus, fluffy masses.

• Don’t normally cause bad weather due to height freezing water.

• Comprised of ice and minimal amounts of water due to altitude.

• Picture site: http://cluods.blogspot.com/p/introduction-cloud-is-composed-of.html

MIDDLE CLOUDS

• Altocumulus and altostratus• Cause infrequent drizzling(rain)and light snow• Altocumulus clouds are larger and denser than

cirrocumulus• Picture site:

http://cluods.blogspot.com/p/introduction-cloud-is-composed-of.html

LOW CLOUDS

• Stratus, fog like, stratocumulus, scalloped bottom and nimbostratus, causes most rain

• Nimbostratus’s Latin name means rainy cloud to cover with a layer

• Nimbostratus clouds form under stable conditions

• Picture site: http://cluods.blogspot.com/p/introduction-cloud-is-composed-of.html

CLOUDS OF VERTICAL DEVELOPMENT

• Some clouds don’t fit into any of the above cloud formations

• These types of clouds are in the low height area, yet can extend to the middle and high height ranges

• They are all related to one another and are associated with unstable air

• Picture snipped from Prentice Hall Book Website

FOG(BY COOLING AND EVAPORATION)

• Can form when earth cools rapidly by radiation

• Can be caused when cool air moves over a warm body of water to produce saturation

• Common over lakes in fall and early winter• Picture site:

http://lupusincolor.blogspot.com/2011/01/lupus-fog.html

COLD CLOUD PRECIPITATION(BERGERON PROCESS)

• Relies on super cooling and super saturation• Whatever water the supercooled water

touches, it freezes that water • Supersaturation allows more water to the ice

crystal to grow • Picture site:

http://www.sleepingdogstudios.com/Network/Earth%20Science/ES_18_Rev_files/frame.htm#slide0021.htm

WARM CLOUD PRECIPITATION(COLLISION-COALESCENCE PROCESS)

• Makes most precipitation• Water absorbing particles remove water vapor

from the air at relative humidities less than 100%, allowing drops to be very large

• As these large drops move along, they join with smaller and slower drops

• Picture site: http://www.cbs6albany.com/sections/weather/research/topics/topicfive/

RAIN AND SNOW

• Definition of rain is specifically drops of water that fall from a cloud and have a diameter of at least 0.5 mm

• Anything smaller is called a drizzle• At very low temperatures, light fluffy snow

forms• Picture site:

http://www.istockphoto.com/stock-photo-2507583-ice-rain-and-snow.php

SLEET, GLAZE AND HAIL

• Sleet is the fall of clear to translucent ice• Glaze is when ice drops are supercooled as they fall

through subfreezing air near the ground• Hail is produced in cumulonimbus clouds, they start as ice

pellets that grow by collecting supercooled water droplets as they fall through a cloud

• Picture site: http://www.lifeslittlemysteries.com/676-how-big-was-the-biggest-hailstone-ever.html

THE END!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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By: Paul BeanPicture site:

http://www.flickr.com/photos/27032673@N02/2615193708

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