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Water: An Earth History. OUTGASSING TORRENTIAL RAINS PRODUCED LAKES AND OCEANS DISSOLVED AND UNDISSOLVED ELEMENTS PRESENT VOLUME 1,360,000,000 km 3 VOLUME IS STABLE. HYDROLOGICAL CYCLE. Water Reservoir. Oceans. 97.24%. Ice caps, glaciers. 2.14%. Ground water. 0.61%.
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Water: An Earth History OUTGASSING TORRENTIAL RAINS PRODUCED LAKES AND OCEANS DISSOLVED AND UNDISSOLVED ELEMENTS PRESENT VOLUME 1,360,000,000 km3 VOLUME IS STABLE
Water Reservoir Oceans 97.24% Ice caps, glaciers 2.14% Ground water 0.61% Fresh-water lakes 0.009% Inland seas 0.008% Soil moisture 0.005% Atmosphere <0.001% Rivers <0.0001% Source: U.S. Geological Survey
Evaporation Some fast-moving molecules escape from the liquid
In cool air, H2O molecules are more likely to join nuclei
CHANGES DOES NOT CHANGE
ABSOLUTE HUMIDITY MASS / VOLUME g H2O / m3 air
SPECIFIC HUMIDITY Specific humidity: the mass of water vapour (g) per mass of air (kg) Maximum specific humidity is the maximum mass of water vapour that can be held by 1kg of air at a given temperature
MIXING RATIO MASS OF WATER VAPOUR TOTAL MASS OF DRY AIR g H2O / kg air
RELATIVE HUMIDITY The ratio of the amount of water vapour in the air to the maximum amount of water vapour that could be present at the same temperature The relative humidity of saturated air is 100% RH = [H20 vapour content/H20 capacity] x 100
VAPOUR PRESSURE The portion of atmospheric pressure that is made up of water vapour molecules (mb or kPa) SATURATED VAPOUR PRESSURE: The pressure that water vapour molecules would exert if the air were saturated (at a given temperature)
VAPOUR PRESSURE vs. TEMPERATURE
DIURNAL PATTERN OF RELATIVE HUMIDITY
SPECIFICHUMIDITY RELATIVE HUMIDITY
HOAR FROST Why do surfaces facing the wind have more frost?
CONDENSATION NUCLEI • A surface is required for condensation • Condensation nuclei >0.1 m best • About 10-1000 large nuclei per cm3 • (more in lower troposphere and over land) • Hygroscopic or hydrophobic Source: Dust, volcanoes, factory smoke, forest fires, ocean spray salt, sulphate particles from phytoplankton
Fog formsif Td is reached A little review...
ADVECTION FOG Cold water advection fog
ADVECTION FOG Warm water advection fog
Base camp 2º30´25´´N, 77º00´02´´W, 1450 m Tambito al Cocal River Field Station