Lecture 5 Atmospheric water Many phases of water

Atmospheric Water

1. ATMOSPHERIC WATER
ATTY. RENATO S. PACALDO, PHD
PROFESSOR, COLLEGE OF FORESTRY AND ENVIRONMENTAL STUDIES, MSU-MAIN CAMPUS, MARAWI CITY
VISITING PROFESSOR, KASTAMONU UNIVERSITY, TURKIYE
FRE 223 -Ecophysiology

2. MANY PHASES OF WATER
Saturated Condition: Evaporation -Condensation =
0
•Windpreventssaturatedconditionby
blowingawaywatervapor;thiscreatinga
pressuredifference;hence,moreevaporation
•Warmwaterenhancesevaporationbecause
heatspeedsupmovement ofwater
molecules;hence,easilybreakssurface
tension
•Inatmosphere,watermixedupwithdust,
smoke,salt,andotherparticulateand
condenseswiththem--condensationnuclei,
andasthetemperaturecoolsdown,the
speedofwatermoleculesmovementalso
slowdownandcoalesceandformdropletsof
cloud

3. •Condensation primarily occurs
when air is cooled because
speed of molecules movement
reduces with decreasing
temperature; hence, water
saturation occurs likely in cool
air than in warm air
•Warm air can hold more water
vapor molecules before
becoming saturated than cold
air or warm air has a greater
capacity for water vapor than
does cold air
•Warming of air temperature due
to climate change results in
higher capacity of air to hold
water; hence, intense rainfall

7. SATURATION VAPOR PRESSURE -the
pressure that the water vapor molecules
would exert if the air were saturated with
vapor pressure at a given temperature

9. LATITUDINAL DISTRIBUTION OF
SPECIFIC HUMIDITY
•Highest average values of
humidity are observed in the
tropics
•In desert, which is located at
about 30 degrees latitude,
the average moisture content
is about twice the water
vapor that the air in areas
within 50 degrees latitude.
Hence, the air in the desert is
not really not dry nor water
content very low.

10. RH = WATER VAPOR CONTENT X 100
WATER VAPOR CAPCITY
•Air with 100 % RH is said
to be SATURATED
because it is filled to
capacity with water
vapor
•Air with more that 100
% RH is said to be
SUPERSATURATED

11. TEMPERATURE AND RELATIVE HUMIDITY

13. The Influence of soil moisture on the partitioning of surface heat fluxes with a
fixed amount of availbaleenergy (Hsu and Dirmeyer2023)