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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.
- 4) Solvency: 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
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Distribution of H2O
- Oceans: 97.2%
- Fresh water 2.8% (includes ice caps,glaciers, ground water, streams and rivers)
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Hydrologic Cycle
- 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.
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Evaporation
- - process by which liquid water is converted to gaseous water vapor.
- - stored energy and is heat removed from water body: evaporative cooling - 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
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Condensation
- 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
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Transpiration
- transfer of moisture form planet leaves to the atmosphere.
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Precipitation
process in which moisture is removed from ATM
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Infiltration
downward movement of water through the soil layer and regolith.
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Initial Abstraction
portion of the precipitation that does not runoff or infiltrate, short term ponding of water
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Runoff
flow of water from liquid to ocenas by overland flow, streamflow and groundwater flow.
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Humidity
- - amount of water vapor in the air
- - depends on temperature of the air parcel
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Absolute Humidity.
- mass of water vapor over vol of air
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Specific Humidity
- mass of water vapor over mass of air
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Relative Humidity
- - 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
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Dew Point
- Dew: condensation of breads of water on relatively cold surfaces
- Dew point: critical air temperature at which saturation is reached (100% RH)
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Adiabatic Process
- natural cooling of air to dew point returns water vapor from ATM to earths surface
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Adiabatic Cooling
- cooling by expansion in rising air
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Adiabatic Warming
- - warming by contraction in descending air
- - moisture holding (when it rises) the RH lowers
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Clouds
- - composed of water vapor and supercooled ice
- - formed when rising air is cooled, reachers LCL and the water vapor turns into clouds.
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Unstable air/ Stable air
- - unstable air rises- clouds
- - stable air doesn't rise- no clouds
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Classification of Clouds (Forms)
- Forms (appearance)
- 1) cirriform - high altitude thin wispy clouds
- 2) Stratiform- real broken up grayish sheets or layers.
- 3) Cumuliform- narrow tall massive rounded clouds.
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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
- Low Clouds: (below 6,500 ft): Stratocumulus, stratus, nimbostratus(rain)
- Clouds of vertical development: cumulus, cumulonimbus(rain).
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Fog
- - 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
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Radiation Fog
- A fog produced by condensation near the ground, whose air is cooled to the dew point byy contact with cooler ground.
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Advection Fog
A fog that results when warm, moist air moves horizontally over a cold surface
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Orographic (upslope) fog
A fog caused by adiabatic cooling when humid air is caused to ascend up a slope (like a mountain).
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Evaporation Fog
Fog that results from the addiction of water vapor to cool air that is already near saturation.
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