OUTGASSING

TORRENTIAL RAINS PRODUCED LAKES AND OCEANS

DISSOLVED AND UNDISSOLVED ELEMENTS

PRESENT VOLUME 1,360,000,000 km3

VOLUME IS STABLE

Water: An Earth History

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

Some fast-movingmolecules escape from the liquid

In cool air, H2O moleculesare more likely to join nuclei

CHANGES

DOES NOT CHANGE

MASS / VOLUME

g H2O / m3 air

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

MASS OF WATER VAPOUR

TOTAL MASS OF DRY AIR

g H2O / kg air

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

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)

RELATIVE HUMIDITY

SPECIFICHUMIDITY

Sling psychrometer

http://www.csgnetwork.com/canhumidexcalc.html

Why do surfaces facing the wind have more frost?

BLACK FROST

•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)

Source: Dust, volcanoes, factory smoke,forest fires, ocean spray salt, sulphateparticles from phytoplankton

•Hygroscopic or hydrophobic

Fog formsif Td is reached

Cold water advection fog

WHY DOES FOGFORM HERE?

Warm water advection fog

CAN ADVECTION FOG FORM OVER LAND MASSES?

YES

Field Station

Tambito al Cocal River

Base camp2º30´25´´N, 77º00´02´´W, 1450 m