Amospheric Moisture Flashcards
Atmospheric Lifting Mechanism -Convective
Warm air pushes up from the ground
Cold air sinks around it and the follows the path of the warm air
Orographic
Air hits mountain, rises up and cools to dew point, and then water vapor condenses
On the backside, the descending air warms
Frontal
In the midlatitudes, a cool air front pushes up a warm air front. Warm air has a much better capacity for carrying water, so when it rises it cools, condenses, and rain falls
Convergent
Near the ITCZ, colliding warm air fronts go upwards
Wind over the Mountain
Dry adiabatic rate 10/1000m
Saturated adiabatic rate 6/1000m
When air mass temp is same as dew point, it becomes saturated - change from dry so saturated AR
Goes up windward side, very wet, down leeward side, very dry
Lifting condensation level - when water can change from gas to liquid
Dew point can never be higher than the temperature - it always decreases with altitude - changes with the DAR/SAR
Goes down leeward side in the DAR - all that warm air going down comes from the latent heat transfer when water condensed: it released heat into the air
Global Precipitation Patterns
Low pressure - wet conditions -around equator - ITCZ
High pressure - dry conditions - around SubTropical High
ITCZ shifts with declination of the sun
In January, it is more south
In July, it is more north
Check p 168 figure 6-36 Avg Precipitation
moves pressure system with them
El Nino
Warm trade winds drag warm water west away from Peru
Cold water fills up the gap next to Peru
Upper atmosphere antitrade winds, Walker circulation, moves cold winds west to east
Usually high pressure next to Peru, very dry
Southern Osciallation - H pressure over N Australia, L pressure to the east in Tahiti
Onset
Warm air stocked in Indonesia begins to move East
Creates low pressure, warm waters near Peru
