Clouds and Precipitation

By: Ben King

When air is heated it becomes less dense as a result lighter

It rises upward above the cool air Air expands because there’s less amount of

pressure higher up in the atmosphere

Adiabatic Temperature Changes and Expansion and Cooling

https://www.meted.ucar.edu/sign_in.php?go_back_to=http%253A%252F%252Fwww.meted.ucar.edu%252Ffire%252Fs290%252Funit6%252Fprint.htm

It means a topographic uplift and forced land lifting

When this type of lifting happens the land forces the air to move to a higher elevation

The temperature of the air cools as is it is lifted up higher in the atmospher http://www.waterencyclopedia.com/Ce-Cr/Climate-Moderator-Water-as-a.html

Orographic Lifting

When warm air and cool air collide Warm air is less dense then cooler air so

it’s wedged upward. This ends up causing fronts that usually

means rain.

Frontal Wedging

Whenever air in the lower atmosphere flows together, lifting results

Air flows in different directions, it has to go somewhere so it goes up

It can lead to adiabatic cooling and cloud formation

Convergence

http://10.85.0.4:8080/ibreports/ibp/bp.html?fn=Students&fp=1&ip=10.182.1.49&ibip=10.85.0.4&ldu=0&re=0&bu=www.islandnet.com/~see/weather/elements/whatgoesup3.htm&bc

Unequal heating of the Earth’s surface may cause pockets of air to be warmed more than the surrounding air

The pockets of air that get warmed more will become less dense than the surrounding air will move upward

These clouds might produce rain

Localized Convective Lifting

Stable air resists vertical movement It won’t get warm, expand, and less dense

and rise. But it also won’t cool and become more dense and sink

Stability

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

It happens when water vapor in the air changes to a liquid

This may result in dew, fog and clouds But for any of those above to happen the air

has to be saturated, it occurs when air is cooled to a dew point. Less often when water vapor is added to the air

Condensation

http://shoalwater.nsw.gov.au/Education/condensation.htm

Clouds are classified based on their form and height

Cirrus- the clouds are high, white and thin Cumulus- clouds are rounded individual

cloud masses Stratus- best described as sheets of paper

that cover much of the sky

Types of Clouds

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

The types of clouds in this category are cirrus, cirrostratus, and cirrocumulus

Cirrocumulus clouds are fluffy masses and cirrostratus are thin white layers

If a cirrus cloud are fallowed by a cirrocumulus or cirrostratus cloud they may warn of stormy weather

High Clouds

http://www.srh.noaa.gov/key/?n=high_clouds

They range from 2000 to 6000 meters in the air

Altocumulus clouds are rounded masses but Cirrocumulus clouds are larger and denser

Covers the sky may mean a light snow or drizzle may come

Middle Clouds

http://www.beijinghikers.com/v2/resources/news/hiking-photos-switchback-great-wall-2009-12-16/

Consists of stratus, stratocumulus, and nimbostratus clouds

It is a fog like cloud that covers most of the sky and occasionally might show light precipitation

Nimbostratus clouds form the most precipitation and form from air being forced upward

Low Clouds

http://chr.wikipedia.org/wiki/File:Low_clouds.jpg

Some clouds do not fit in the three categories

some clouds have bases in the low height range but often extend into the middle or high range

Cumulus clouds with air flowing upward would develop rapidly

Clouds of Vertical Developement

http://www.uwgb.edu/dutchs/EarthSC102Notes/102Clouds.htm

Clouds and fog are basically the same except the place formation fogs just a lot lower

Cause by Cooling- a blanket of fog is produced with warm moist air

Caused by Evaporation- when cool air moves over warm water it often evaporates and makes fog

Fog

http://www.brainharmonycenter.com/brain-fog.html

Bergeron process relies on to physical processes: super cooling and super saturation

The temperature in the air needs to be sometimes -40 degrees Celsius but under 0 degrees Celsius is considered super cooled

It would have to be 100% relative humidity but supersaturated is more than 100% humidity

Cold Cloud Precipitation

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

The mechanism for this is collision-coalescence process

Some water absorbing-particles can remove water vapor and form drops that are large

As they move through the cloud they collide and join together with smaller slower droplets

Warm Cloud Precipitation

http://rst.gsfc.nasa.gov/Sect14/Sect14_1d.html

Rain means drops of water that fall from a cloud and have a diameter of at least .5 mm.

When the temperature is above 4 degrees Celsius the snowflakes continue decent as rain

At temperatures are above -5 degrees Celsius they clump together and make snow flakes

Rain and Snow

http://itunes.apple.com/us/app/snow/id287063264?mt=8

Sleet is the fall of small particles of clear-to-translucent ice

Hail is produced in cumulonimbus clouds they begin as small ice pellets

Each trip through a super cooled cloud just adds a layer of ice

Sleet, Glaze, and Hail