Clouds and Precipitation Flashcards
What is a Condensation Nuclei?
Tiny particles upon whose surfaces condensation of water vapor begins in the atmosphere
What is condensation nuclei made out of?
dust, sand, pollutants, etc.
What is an Hygroscopic Condensation Nuclei?
water-attracting nuclei (e.g. salts); water vapor condenses upon these surfaces when RH is lower than 100%
What is an Hydroscopic Condensation Nuclei?
water-repelling nuclei (e.g. waxes); resist condensation when RH is above 100%
What are the two ways clouds form?
mixing and cooling
How do clouds form when mixing?
adding enough moisture to unsaturated air to raise to 100% (saturate it)
How do clouds form when cooling?
cool unsaturated air until it becomes saturated (RH=100%)
What happens during the mixing cloud formation?
air is unsaturated
RH is high
temperature and humidity decline with height
What happens when the dew point and the environmental lapse rate mix at the moist layer of air near the surface?
the produce a deck of stratocumulus clouds
What happens to rising parcels?
pressure declines
volume increases
air cools
What happens to sinking parcels?
pressure increases
volume decreases
air warms
What is rising and cooling air?
the primary method of cloud formation
What are the primary ways clouds form?
surface heating and convection
orographic lifting
cyclone
air fronts
What is an orographic uplift?
lifting of air over a topographic barrier (i.e., mountains
What happens on the windward side of mountain during the orographic lifting?
temperature drops to dew point forming clouds
What happens on the leeward side of mountain during the orographic lifting?
air sinks making the air drier
moisture was removed in the form of clouds and precipitation resulting in a rain shadow
dew point temperature is lower while the temperature is higher producing a low RH
What happens during the convective cloud formation?
-thermal forms (air is warmer than it surrounding)
-air rises, expands and cools (air is cooler than its surrounding)
-condensation, visible cumulus cloud froms
-forms a cumulus humilis, then cumulus congests, and finally a cumulonimbus
How are stratiform clouds formed?
large-scale lifting of stable air; no vertical development
How are cumuliform clouds formed?
vertical development caused by convection; flat cloud base; form in unstable air
What are stratiform clouds (high clouds)?
-“cirro-“
-composed of ice -crystals only
-no shadow cast
-cirrus clouds
-cirrostratus (stratus=sheetlike)
-cirrocumulus (cumulus=puffy)
What are stratiform clouds (middle clouds)?
-“alto-“
-water only or water/ice mix, clouds block direct sunlight, shadow at base
-altostratus
-altocumulus
What are stratiform clouds (low clouds)?
-“strato-“
-composed of liquid water only
-stratus
-stratocumulus
-nimbostratus (nimbo-rain)
What are cumuliform clouds?
-flat cloud base, caused by convection, form in unstable air
-cumulus humilis
-cumulus congestus
-cumulonimbus
What are cirrus clouds?
high cloud composed of ice crystals in the form of thin, white, featherlike clouds in patches
What are cirrocumulus clouds?
high cloud that appears as a white patch of clouds; consists of very small elements in the form of grains or ripple
What are cirrostratus?
High, thin, sheetlike clouds, composed of ice crystals. They frequently cover the entire sky and often produce a halo.
What are altocumulus clouds?
middle cloud, usually white or gray. Often occurs in layers or patches with wavy, rounded masses or rolls.
What are altostratus?
middle cloud composed of gray or bluish sheets or layers of uniform appearance. In the thinner regions, the sun or moon usually appears dimly visible.
What are nimbostratus?
a dark, gray cloud characterized by more or less continuously falling precipitation. It is rarely accompanied by lightning, thunder, or hail.
What are stratocumulus clouds?
a low cloud, predominantly stratiform, with low, lumpy, rounded masses, often with blue sky between them.
What are stratus clouds?
A low, gray cloud layer with a rather uniform base whose precipitation is most commonly drizzle.
What are cumulus clouds?
a cloud in the form of individual, detached domes or towers that are usually dense and well defined.
What are cumulonimbus clouds?
exceptionally dense and vertically developed cloud, often with a top in the shape of an anvil. The cloud is frequently accompanied by heavy showers,
