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