Ch.6 Flashcards
Cirrus
High, thin, feathery
Cumulus
Globular, cottonlike, rising domes
Stratus
Sheets or layers
High Clouds
bases at 6000 meters(20,000 ft)
Middle clouds
2000-6000 meters
Low clouds
below 2000 meters(6500 ft)
Cirrus rank
High cloud, hooked “mares” tail
Cirrostratus
High cloud, thin white sheet makes the sky look milky, can produce halo around sun/moon
Cirrocumulus
High cloud, ripples, waves or globular in a row, “mackerel sky” Least common high cloud
Altocumulus
Middle cloud, “sheepback clouds”
Altostratus
Middle Cloud, Veil of cloud that may produce light preceip, sun or moon may show up as bright spot, no halo
Stratus
Low Cloud, low layer resembling fog,drizzle
Stratocumulus
Low Cloud,Soft gray globular, rolls may join to form continous cloud
Nimbostratus
Low cloud, dense billowy, flat bases,primary precip clouds
Cumulus
Vertical development cloud, dense billowy, may occur as isolated or closely packed.
Cumulusnimbos
Vertical development cloud, towering, “anvil head” Heavy rainfall, thunder, lightening, hail, tornadoes.
Clouds
Form when air rising and cools adiabatically
Fog(evaporation fog)
results from cooling or when air becomes saturated through the addition of water vapor
radiation fog
results from the radiaiton cooling of the ground and adjacent air
advection fog
happens when warm moist air blows over cold surface and becomes chilled by contact. winds are usually reqiured
upslope fog
happens when relatively humid air moves up a gradually sloping landform.
freezing rain
falls as liquid then freezes
Bergeron process
Ice cycles grow at the expense of cloud droplets until they fall
Collision-Coalescence process
collisions of water molecules to form rain. most apparent where water molecules are biggest ex:rain forest-humid and clean air
rain
must have diameter of .5 mm
sleet
rain freezes in air as travelling. Less dangerous than freezing rain
Virga
a mass of streaks of rain appearing to hang under a cloud and evaporating before reaching the ground.
Big snow flakes vs small
Warmer temps- big
colder-smaller
Cloud seeding
Triggering precip with stimulants
Barometer
an instrument measuring atmospheric pressure, used especially in forecasting the weather and determining altitude.
Isobars
Are used to show the distribution of pressure on maps, shows equal air pressure
Large vs. small pressure gradient and relationship to wind
The larger the gradient, the stronger the wind.
Coriolios force
changes the direction of a moving body to the right in northern hemisphere and left in southern.affects only wind direction, not speed. is affected by wind speed. Strongest at poles and less at equater.
Trough
Cyclonic air flow.bring in cooler and cloudier weather
Ridge
Anticyclonic air flow. tend to bring warmer and drier weather.
Cyclone
Counterclockwise airflow in northern hemi and clockwise in southern.
Anticyclone
Centers of high pressure, clockwise in northern and counter in southern.
Airflow around a surface cyclone (Northern Hemisphere)
Counterclockwise
Airflow around a surface anticyclone (Northern Hemisphere)
Clockwise
Anemometer
an instrument for measuring the speed of the wind, or of any current of gas.
wind vane
A wind vane is a device that measures the direction of the wind. The wind vane is usually combined with the anemometer. Wind direction is the direction from which the wind is blowing.
aerovane
a weather vane that is equipped with a propeller and is used to measure both wind speed and direction
Sea breeze
develops as colder air over the water moves landward toward area of lower pressure
Land breeze
land cools more rapidly than the sea, so this is airflow off the land
mountain breeze
Rapid heat loss along the mountain slopes cools the air, which drains unto the valley.
Valley breeze
air along mountain slopes heat more intensely and that air glides up the mountain slope.
Chinook Wind
Warm dry winds that move down slopes of moutains
Santa Ana Wind
Hot dry Santa Ana wind increase the threats of fire in southern california
Country Breeze
Large urban areas hold heat and this wind curns and basically keeps heat and pollutants in the center of city
Zonal Flow
Zonal means “along a latitude circle” or “in the west–east direction”
Merdional Flow
meridional means “along a meridian” or “in the north–south direction”.
Intertropical convergence zone
moist hot air region marked with abundant precip. low pressure and where trade winds converge, it is near equater
Hadley Cell
Zone between equator and 30 degrees latitude north and south. Warm air rises from equator and rise release latent heat and form cumulus towers.
Subtropical High
Either side of equator where westerlies and trade winds originate and go separate ways, High pressure zone. weather is normally warm and dry.
Subpolar low
low pressure region corresponding to polar front. polar easterlies and westerlies crash. this zone responsible for much stormy weather, especially in winter
Polar high
near earths poles, where polar easterlies orginate.
Why wind speeds increase with height
Surface friction forces the surface wind to slow and turn near the surface of the Earth, blowing directly towards the low pressure, when compared to the winds in the nearly frictionless flow well above the Earth’s surface
Monsoon
a seasonal prevailing wind in the region of South and Southeast Asia, blowing from the southwest between May and September and bringing rain (the wet monsoon ), or from the northeast between October and April (the dry monsoon ).
Rossby waves
Rossby waves, also known as planetary waves, are a natural phenomenon in the atmosphere and oceans of planets that largely owe their properties to rotation. Rossby waves are a subset of inertial waves. Atmospheric Rossby waves on Earth are giant meanders in high-altitude winds with major influence on weather.
