Clouds and PrecipitationBy: Courtney Smith

Adiabatic Temperature Changes and Expansion and Cooling Temperature changes that happen even though heat isn’t added

or subtracted from the atmosphere are adiabatic temperature changes.

Air that is not saturated cools 10 degrees Celsius for every 1000 meters it goes is the dry adiabatic rate.

Wet adiabatic cooling is when air rises and condensation begins to happen, then latent heat in water vapor from condensation is released.

http://apollo.lsc.vsc.edu/classes/met130/notes/chapter6/adiab_warm.html

http://apollo.lsc.vsc.edu/classes/met130/notes/chapter6/adiab_warm.html

Orographic Lifting When land masses, such as mountains, block air flow, orographic lifting of the air happens.

Clouds and precipitation occur due to adiabatic cooling and cause precipitation.

Much of the air’s humidity is lost when air reaches the leeward side of the mountain.

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

Frontal WedgingA front is when hot air and cold air meet in the atmosphere.Frontal wedging is when cool and dense air barriers warm

and less dense air that is rising.Storm-system weather fronts are also known as middle

latitude cyclones.http://www.wou.edu/las/physci/taylor/gs106/atm2_precip_fil

es/frame.htm#slide0004.htm

Convergence Convergence is when air in the lower part of the atmosphere flows

together and causes lifting. Florida’s weather is an example of convergence. When air flows in more than one direction, it begins to rise. It

leads to adiabatic cooling and sometimes cloud formation.

Localized Convective Lifting Thermals: Rising clumps of air warmer than the air around it. Localized Convective Lifting: The process that makes the rising

thermals. Clouds can form when the warm air clumps rise above the

condensation level. http://rst.gsfc.nasa.gov/Sect14/Sect14_1c.html

StabilityStable air resists moving upward.Unstable air rises as stable air stays in the

same place.When air increases with height, air is the

most stable. This is a temperature inversion.

CondensationAir must be saturated for condensation to

happen.Condensation nuclei occur when there is

condensation in the air above the ground.When condensation nuclei is in the air,

relative humidity goes over 100% http://keep3.sjfc.edu/students/kes00898/e-port/condensation%20page%20for%20unit

.html

Types of CloudsClouds are classified by form and height.Cirrus clouds are thin, white, and high in the

air.Cumulounds clouds are round, individual

clouds. Stratus clouds are big clouds that cover almost the whole sky.

http://eo.ucar.edu/webweather/cloud3.html

High CloudsCirrocumulous clouds are fluffy clouds.Cirrostratus clouds are flatter clouds.Cirrus clounds are high, white, and thin

clouds.

Middle CloudsAltocumulouds clouds are large, dense, and round clouds.Altostratus clouds are white and grayish clouds that cover

the sky, moon, and sun but they are still noticeable through it.

Middle clouds are from 2000 to 6000 meters in the air.http://www.allstar.fiu.edu/aero/fltenv3.htm

Clouds of Verticle DevelopmentMost start in the low range but are vertically

long and go to the high or medium ranges in the air.

Caused by unstable air.Made by upward movement, and powerful

acceleration. http://www.free-online-private-pilot-ground-school.com/Aviation-Weather-Principles.html

Low CloudsStratus clouds are clouds that look like fog

and cover the sky.Stratocumulus clouds are clouds that have a

scalloped bottom that looks like long rods or patches.

Nimbostratus clouds are rain clouds. http://www.free-online-private-pilot-ground-school.com/Aviation-Weather-Principles.ht

ml

FogA cloud that is very close to the ground.Happens when Earth cools rapidly by

radiation.Cool air goes over warm water, evaporation

occurs, air becomes saturated, and water vapor meets cold air and it condenses and mixes with the warm air being warmed.

http://photoshoptutorials.ws/photoshop-tutorials/photo-effects/fog.html

Cold Cloud PrecipitationSupercooled water is water in the liquid state

at 0 degrees Celcius that will freeze when it hits a solid object.

When air is saturated with water, it is supersaturated with ice.

http://nanopatentsandinnovations.blogspot.com/2010/06/amount-of-dust-pollen-matters-for-cloud.html

Warm Cloud Precipitation The collision-coalescence process is the process that creates

raindrops. Particles, such as salt, in the air absorb water so realitive

humidity goes below 100% makeing large rain drops. The large drops go through the cloud and they join with smaller

water droplets. https://www.meted.ucar.edu/sign_in.php?go_back_to=http%253A%252F%252Fwww.

meted.ucar.edu%252Ftropical%252Ftextbook_2nd_edition%252Fprint_5.htm

Rain and Snow Snowflakes usually melt when the temerature at the surface is above 4

degrees Celcius, so snowflakes usually melt before they hit the ground. When there is a low humidity, snow crystals form. Snow crystals mix together into clumps when the temerature is above -5

degrees celcius. http://kohd.com/page/213587 http://roymiller.hubpages.com/hub/quotes-about-rain

Sleet, Glaze, and Hail Sleet is small pieces of ice falling from the clouds. Glaze is freezing rain that happens when rain is supercooled. Hail is small ice pieces that grow as they fall by collecting supercooled

water. Hail can become very, very large. Some can even be the size of softballs.

http://en.wikipedia.org/wiki/File:Sleet_on_the_ground.jpg http://www.tornadochaser.net/hail.html

The End!