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
Some fast-moving
molecules escape
from the liquid
In cool air, H2O molecules
are 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
SPECIFIC
HUMIDITY
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)
•Hygroscopic or hydrophobic
Source: Dust, volcanoes, factory smoke,
forest fires, ocean spray salt, sulphate
particles from phytoplankton
Fog forms
if Td is reached
Cold water advection fog
WHY DOES FOG
FORM HERE?
Warm water advection fog
CAN ADVECTION
FOG FORM OVER
LAND MASSES?
YES
Base camp
2º30´25´´N, 77º00´02´´W, 1450 m
Field Station
Tambito al
Cocal River