Exam #2

atm_sc1050

Water is consisted of

two positive hydrogen molecules separated at 105 degree angle and one negative oxygen molecule

Amount of salt water in the world

97.2%

Amount of ice/glaciers in the world

2.2%

Amount of subsurface water in the world

0.6%

Amount of lake/stream water in the world

0.01%

Amount of atmospheric water in the world

0.0001%

Gas

molecules are far apart, molecules move about freely, they mix well with neighboring atoms and molecules, can be transported great distances

Liquid

water molecules are much closer together, they constantly bump into each other

Solid

the molecules arrange themselves into an ordinary pattern, each molecule is locked into a rigid position

Sublimation

ice to vapor

Phase change

water changes its energy level

Melting

ice to liquid

Evaporation

liquid to vapor (molecules escaping)

Freezing

liquid to solid

Condensation

vapor to liquid (molecules returning)

Deposition

vapor to solid

Saturation

in a covered glass, the number of evaporating molecules will eventually balance the number that are condensating

Evaporation is ____ than condensation

larger

Water would evaporate more quickly

on a windy, warm, dry summer day than on a cold, calm, dry winter day

Mixing

(wind) will cause air to become unsaturated; more molecules leave the surface and evaporation increases

Factors that increase evaporation

increasing wind, increasing temperatures

Warm water

molecules move faster

Condensation nuclei

bits of dust, smoke, and salt that water easily adheres to

In cool air

the molecules are moving slower and they are more likely to stick and condense to nuclei

Condensation occurs

as the atmosphere is cooled

Quantifying Humidity

measuring moisture

Air parcel

a volume of air that has flexible walls and cannot mix with the environment around it (has water vapor, nitrogen, oxygen)

Relative humidity

the ratio of the amount of water vapor actually in the air to the maximum amount of vapor required for saturation at that temperature (and pressure)

Relative humidity equation

water vapor content(the amount of moisture in the atmosphere) or actual vapor content/water vapor capacity (how much moisture can be in the atmosphere) or saturation vapor pressure X 100%

The two ways to change the relative humidity of an air parcel

Change the vapor content or change the temperature

Adding water vapor

increases the relative humidity

Warming the air

will decrease the relative humidity (inverse relationship)

Cooling the air

will increase the relative humidity (inverse relationship)

Because vapor content changes slowly over most regions

temperatuer changes dictates relative humidity

Dewpoint

the temperature to which air would have to be cooled for saturation to occur

High dewpoint

higher overall moisture content

Low dewpoint

low overall moisture content

When the air temperature and depoint are close together

relative humidity is high

When air temperature and dewpoint are far apart

relative humidity is low

Heat Index

the apparent temperature, a combination of air temperature and relative humidity

If temperature and humidity are equal, dew point will always be

100% (causes snow, rain, fog)

Fog

a cloud in contact with the ground, forms when condensation begins to form on less active nuclei, usually when relative humidity is closer to 100%

Fog is formed in two ways

Cooling the air to its saturation point (dew point) and melting and evaporation (adding more vapor content to the atmosphere)

Fog is maintain by

Forming new fog droplets, adding moisture to the atmosphere (puddles, lakes, recent rains/snow melt, etc.)

Stratus

layers

Cumulus

heap

Cirrus

curl of hair

nimbus

violent rain

High clouds

form above 20,000 feet, almost exclusively ice-crystal clouds, little moisture available-thin clouds

Cirrus clouds

most common high cloud, thin and wispy clouds, move from west to east, indicate the wind direction at elevation, generally pleasant and fair weather

Cirrocumulus Cloud

high cloud, small, rounded, white puffs, isolated or in rows, rarely cover a small portion of the sky

Rows

rippling appearance; scales of fish

Isolated

little piles of sand

Cirrostratus Cloud

thin, sheet-like high clouds, so thin sun and moon can shine through, usually produce a halo, form ahead of approaching storms

Middle Clouds

cloud bases: 6,500-23,00 feet, water droplets and ice crystals, thicker clouds that sometimes dim the sun

Altocummulus clouds

Gray, puffy, masses-waves or bands, can be an overcast cloud, sometimes look like little castles, precursor of summer afternoon thunderstorms

Altostratus clouds

gray, bluish color-covers the sky, a milky look, sun is dimly visible, one big thin blanket, won’t see any shadows, forms ahead of storms producing widespread rain

Low clouds

cloud bases below 6,500 feet, comprised of water droplets (mostly), gloomy looking sky-often in winter

Stratocummulus clouds

low and lumpy clouds, appear in rows or patches, blue sky is sometimes visible, usually precipitation free cloud

Nimbostratus clouds

dark gray, wet-looking clouds, associated with continuous light precipitation (drizzle, rain, snow), very low-lying clouds, though tops can exceed 10,000 feet, visibility is low, can sometimes break apart in the wind

Scud clouds

broken apart clouds in the wind, they form irregular shreds with a ragged appearance, often seen on the fringes of thunderstorms and are sometimes misreported as tornadoes or funnel clouds

Stratus Clouds

uniform, grayish cloud, covers the entire sky, resembles fog although it doesn’t touch the ground, light precipitation can fall

Vertically developed clouds

cloud bases are 1,000-5,00 feet, cloud tops are 5,000-8,000 feet, comprised of ice and water

Cumulus clouds

variety of shapes, cotton ball, sharp outlines and puffy, base is light and gray, detached clouds and have dome-like tops, show slight vertical growth

Cumulus humilis

fair weather clouds

cumulus congestus

towering cloud

Cumulonimbus clouds

continuously growing, thunderstorm, base may start at 2,000 feet and tops can grow to 40,000 feet and higher, vertical growth depends to updrafts and downdrafts inside the thunderstorm

Anvil

flat top of a tall cumulonimbus cloud, shows movement of the thunderstorm by the direction it is pointing

Castellanus

castle or tower like

Vertical extensions

found on cumulus clouds

Clouds form by

cool air, condense air

Lenticular

shaped like a UFO that hovers over a mountain, forms as moist air crosses over a mountainous area and then takes on a lens shape appearance

Pileus

thin scarf over the top of a thin cloud, forms as moist winds are deflected up and over the top of cumulus or cumulonimbus clouds

Mammatus

pouch-like sacs that hang underneath the anvil portion of cumulonimbus clouds, forms as sinking air remains cooler than the surrounding air near the underside of a thundercloud (anvil area), strong winds make the rounded “udder-like” appearance

Contrail

short for condensation trail, forms in the wake of jet aircraft engines, high ice/water cloud that forms from vapor and exhaust particles

Undulatus asperatus

described as visible air motions rolling through the sky

Wall clouds

a low hanging cloud that usually rotates and spins in a counter-clockwise direction from a cumulonimbus cloud, tornadoes can form from these

Shelf cloud

cool, sinking air from a thunderstorm downdraft spread out across the land. this outflow cuts under the warm air being drawn into the storm’s updraft. as the lower, cooler air lifts the warm moist air, the water condense, creating a cloud

Clear conditions

no clouds present

Few clouds

1/8-2/8 of the sky

Scattered clouds

3/8-4/8

Broken sky/clouds

5/8-7/8

Overcast

total sky covered by clouds

Geostationary orbiting satellite

orbits at the equator at the same rate the Earth spins

Polar orbiting satellite

passes over north and south poles as Earth turns, takes many orbits to see the entire Earth, but in great detail

Visible imagery

a type of satellite imagery. light is reflected from the clouds and only available when the sun is out. thicker clouds reflect more and appear white. very clear and concise picture of the clouds/Earth

Infrared imagery

type of satellite imagery. amount of radiation increases with temperature. warm clouds are lower in the atmosphere (darker, closer to warm ground). cloud cloud are higher in the atmosphere (brighter, temperature decreases in the troposphere)

Water vapor imagery

type of satellite imagery. shows areas of high moisture content in the atmosphere. very useful at showing upper-level storm systems. darker areas (dry air) are orange and black, lighter areas (moist air) are green, gray, and white

Frozen dew

if the air temperature should drop to freezing or below, the dew will freeze, becoming tiny beads of ice

haze

a layer of dust or salt particles

radiation fog (ground fog)

fog produced by Earth’s radiational cooling. forms on clear nights when a shallow layer of moist air near the ground is overlain by dryer air. the moist lower layer (chilled rapidly by the cold ground) quickly becomes saturated and fog forms

Advection fog

occurs when warm, moist air moves over a cold surface and the air cools to below its dew point

Advection-radiation fog

fog that forms as relatively warm moist air moves over a colder surface that is cooled mainly by radiational cooling. advection fog that forms on land

Evaporation fog (mixing fog)

fog produced when sufficient water vapor is added to the air by evaporation and the moist air mixes with relatively drier air

Steam fog

common form of evaporation fog is steam fog, which forms when cold air moves over warm water

Frontal fog (precipitation fog)

type of evaporation fog. forms when warm rain falls through a layer of cold moist air

Hygroscopic

condensation nuclei that have affinity for water vapor

Dewpoint

mugginess of the atmosphere. it is related to the quantity of moisture in the atmosphere

Stability

a condition of equilibrium, measures the tendency of the air to rise or sink

stable equilibrium

a displaced object tends to return to its original location