Weather Exam 2

Front 1

Dew point

Back 1

the temp at which saturation occurs.

Front 2

Frozen dew

Back 2

the transformation of liquid dew into tiny beads of ice when air temp drops below freezing.

Front 3

Frost (hoarfrost)

Back 3

a covering of ice produced by deposition on exposed surfaces when the air temp falls below the frost point.

Front 4

Freeze (advection frost)

Back 4

a condition occurring over a widespread area when the surface air temp remains below freezing for a sufficient time to damage certain agricultural crops. A freeze most often occurs as cold air is advected into a region, causing freezing conditions to exist in a deep layer of surface air.

Front 5

Condensation nuclei (cloud condensation nuclei)

Back 5

tiny particles upon whose surfaces condensation of water vapor begins in the atmosphere. Small nuclei less than 0.2um in radius are called Aitken nuclei; those with radii between 0.2 and 1um are large nuclei; radii large than 1um are giant nuclei.

Front 6

Hygroscopic

Back 6

the ability to accelerate the condensation of water vapor. Usually used to describe condensation nuclei that have an affinity for water vapor.

Front 7

Hydrophobic

Back 7

the ability to resist the condensation of water vapor. Usually used to describe "water-repelling"condensation nuclei.

Front 8

Haze

Back 8

fine dry or wet dust or salt particles dispersed through a portion of the atmosphere. Individually these are not visible but cumulatively they will diminish visibility.

Front 9

Dry haze

Back 9

particles that are very small, on the order of 0.1um.

Front 10

Wet Haze

Back 10

larger particles than dry haze.

Front 11

Fog

Back 11

a cloud with its base at the Earth's surface.

Front 12

Fog forms in 2 ways

Back 12

1) by cooling-air is cooled below its saturations point (dew point).

2) by evaporation and mixing- water vapor is added to the air by evaporation, and the moist air mixes with relatively dry air.

Front 13

Radiation fog (ground fog/valley fog)

Back 13

fog produced over land when radiational cooling reduces the air temp to or below its dew point.

Front 14

Advection fog

Back 14

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

Front 15

High inversion fog

Back 15

a fog that lifts above the surface but does not completely dissipate because of a strong inversion (usually subsidence) that exists above the fog layer.

Front 16

Stratus (high fog)

Back 16

a low, gray cloud layer with a rather uniform base whose precipitation is most commonly drizzle.

Front 17

Advection

Back 17

the horizontal transfer of any atmospheric property by the wind.

Front 18

Advection-radiation fog

Back 18

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

Front 19

Ice fog

Back 19

a type of fog that forms at very low temps, composed of tiny suspended ice particles.

Front 20

Radiational cooling

Back 20

the process by which the earth's surface and adjacent air cool by emitting infrared radiation.

Front 21

Upslope fog

Back 21

fog formed as moist, stable air flows upward over a topographic barrier.

Front 22

Evaporation (mixing) fog

Back 22

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

Front 23

Steam fog

Back 23

forms when cold air moves over warm water.

Front 24

Cloud

Back 24

a visible aggregate of tiny water droplets and/or ice crystals in the atmosphere above the earth's surface.

Front 25

Cumulus

Back 25

a cloud in the form of individual, detached domes or towers that are usually dense and well defined. It had a flat base with a bulging upper part that often resembles cauliflower. Cumulus clouds of fair weather are called cumulus humulus. Those that exhibit much vertical growth are called cumulus congestus or towering cumulus.

Front 26

Frontal fog (precipitation fog)

Back 26

forms as warm raindrops evaporate in a cool air mass.

Front 27

Winter chilling

Back 27

the amount of time the air temp during the winter must remain below a certain value so that fruit and nut trees will grow properly during the spring and summer.

Front 28

Fog lamps

Back 28

extra head lamps on automobiles for fog

Front 29

Cirrus

Back 29

a high cloud composed of ice crystals in he form of thin, white, featherlike clouds in patches, filaments, or narrow bands.

Front 30

Cumulonumbus

Back 30

a thunderstorm cloud.

Front 31

Cirocumulus

Back 31

a high cloud that appears as a white patch of clouds without shadows. It consists of very small elements in the form of grains or ripples.

Front 32

Cirrostratus

Back 32

high, thin, sheetlike clouds, composed of ice crystals. They frequently cover the entire sky and often produce a halo.

Front 33

Halos

Back 33

rings or arcs that encircle the sun or moon when seen through an ice crystal cloud or a sky filled with falling ice crystals. Halos are produced by refraction of light.

Front 34

Cumulus fractus

Back 34

ragged-edge cumulus clouds that are smaller than cumulus humilis and scattered across the sky.

Front 35

Altocumulus

Back 35

a middle cloud, usually white or gray. Often occurs in layers or patches with wavy, rounded masses or rolls.

Front 36

Altostratus

Back 36

a 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.

Front 37

Nimbostratus

Back 37

a dark, gray cloud characterized by more or less continuously falling precipitation. It is rarely accompanied by lighting, thunder, or hail.

Front 38

Stratocumulus

Back 38

a low cloud, predominantly stratiform, with low, lumpy, rounded masses, often with blue sky between them.

Front 39

Crepuscular rays

Back 39

alternating light and dark bands of light that appear to fan out from the sun's position, usually at twilight.

Front 40

Lenticular clouds

Back 40

a cloud in the shape of a lens.

Front 41

Banner cloud

Back 41

a cloud extending downwind from an isolated mountain peak, often on an otherwise cloud-free day.

Front 42

Pileus cloud

Back 42

a smooth cloud in the form of a cap. Occurs above, or is attached to, the top of a cumuliform cloud. Also called a cap cloud.

Front 43

Mammatus clouds

Back 43

clouds that look like pouches hanging from the underside of a cloud.

Front 44

Calvus

Back 44

cumulonimbus in which at least some of he upper part is beginning to lose its cumuliform outline.

Front 45

Fractus

Back 45

clouds that have a ragged or torn appearance; applies only to stratus and cumulus.

Front 46

Capillatus

Back 46

cumulonimbus characterized by the presence in the upper part of cirriform clouds with fibrous or straited structure.

Front 47

Incus

Back 47

the smooth cirriform mass of cloud in the upper part of a cumulonimbus that is anvil-shaped.

Front 48

Undulatus

Back 48

clouds in patches, sheets, or layers showing undulations.

Front 49

Translucidus

Back 49

clouds that cover a large part of the sky and are sufficiently translucent to reveal the position of the sun or moon.

Front 50

Contrail (condensation trail)

Back 50

a cloud-like streamer frequently seen forming behind aircraft flying in clear, cold, humid air.

Front 51

Imager

Back 51

special type of advanced radiometer that provides satellite pics with much better resolution that did previous imagers.

Front 52

Nacreous clouds (mother-of-pearl clouds)

Back 52

clouds of unknown composition that have a soft, pearly luster and that form at altitudes about 25 to 30 km above the earth's surface.

Front 53

Noctilucent clouds

Back 53

luminous night clouds; wavy, thin, bluish-white clouds that are best seen at twilight in polar latitudes. Form at altitudes about 80 to 90 km above the surface.

Front 54

Sounder

Back 54

special type of radiometer that gives a more accurate profile of temp and moisture at different levels in the atmosphere than did earlier instruments.

Front 55

Albedo

Back 55

the percent of radiation returning from a surface compared to that which strikes it.

Front 56

Computer Enhancement

Back 56

a process where the temp of radiating surfaces are assigned different shades of gray (or different colors) on an infrared pictures. This allows specific features to be more clearly delineated.

Front 57

Geostationary satellites (geosynchronous satellites)

Back 57

a satellite that orbits the earth at the same rate that the earth rotates and thus remains over a fixed place above the equator.

Front 58

Polar-orbiting satellites

Back 58

a satellite whose orbit closely parallels the earth's meridian lines and thus crosses the polar regions or each orbit.