Phys. Geo Chapter 6
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Phys. Geo Chapter 6
Chapter 6...Atmospheric Moisture/precipitation
Water Characteristics (6)
1) High boiling point (100C) and low Freezing pint (0c), allows a lot of liquid water on planet
2) High Heat Capacity(specific Heat), store large amounts of heat, aids in keeping the earths climate moderate.
3) High Heat of Vaporization
: water absorbs large quantities of heat when converted to vapor.
: universal solvent, dissolves large amounts of materials
5) High surface Tension
: attraction between molecules that causes surface to contract and is responsible for liquid waters capillarity.
6) Expands when freezes
: ice has a lower density than water, water freezes from top down which prevents aquatic ecosystems
Distribution of H
Fresh water 2.8% (includes ice caps,glaciers, ground water, streams and rivers)
- series of storage areas interconnected by various transfer processes, in which there is a ceaseless interchange of moisture in terms of its geographical location and its physical state.
- process by which liquid water is converted to gaseous water vapor.
- stored energy and is heat removed from water body
- amount and rate of evaporation is a function of temperature of air and degree of saturation.
- greater the temp, greater chance of evaporation
- greater motion in air, quickly dispersed moisture
process by which water vapor is converted to liquid
air must be saturated
temperature cools to dew point and water droplets grow and causes clouds
- transfer of moisture form planet leaves to the atmosphere.
process in which moisture is removed from ATM
downward movement of water through the soil layer and regolith.
portion of the precipitation that does not runoff or infiltrate, short term ponding of water
flow of water from liquid to ocenas by overland flow, streamflow and groundwater flow.
- amount of water vapor in the air
- depends on temperature of the air parcel
- mass of water vapor over vol of air
- mass of water vapor over mass of air
- amount of water vapor over moisture holding capacity
- varies with vapor content and temp.
- moisture added to ATM, RH goes up
- air mass cools then moisture holding capacity goes down therefore RH goes up
: condensation of breads of water on relatively cold surfaces
: critical air temperature at which saturation is reached (100% RH)
- natural cooling of air to dew point returns water vapor from ATM to earths surface
- cooling by expansion in rising air
- warming by contraction in descending air
- moisture holding (when it rises) the RH lowers
- composed of water vapor and supercooled ice
- formed when rising air is cooled, reachers LCL and the water vapor turns into clouds.
Unstable air/ Stable air
- unstable air rises- clouds
- stable air doesn't rise- no clouds
Classification of Clouds (Forms)
1) cirriform - high altitude thin wispy clouds
2) Stratiform- real broken up grayish sheets or layers.
3) Cumuliform- narrow tall massive rounded clouds.
Cloud Types (height)
High Clouds (above 20,000 ft)
: Cirrostratus, Cirrocumulus, Cirrus -- most water is solid
Middle Clouds (6,500ft-20,000ft)
: Altocumulus, altostratus -- puffy layered, liquid water
: (below 6,500 ft): Stratocumulus, stratus, nimbostratus(rain)
Clouds of vertical development
: cumulus, cumulonimbus(rain).
- no physical difference between fog and clouds just the height of the base.
- defined as a cloud whose base it at or very near ground level
- A fog produced by condensation near the ground, whose air is cooled to the dew point byy contact with cooler ground.
A fog that results when warm, moist air moves horizontally over a cold surface
Orographic (upslope) fog
A fog caused by adiabatic cooling when humid air is caused to ascend up a slope (like a mountain).
Fog that results from the addiction of water vapor to cool air that is already near saturation.