Climate Variability Flashcards
1
Q
describe surface atmospheric pressure
A
- high pressure –> weight of the air is relatively large
- low pressure –> weight of the air is relatively small
- if temp of air is colder than the surrounding –> dense air –> high pressure
- if temp of air is warmer than the surrounding –> light air –> low pressure
2
Q
describe relationship between warm air and low surface pressure
A
surrounding air moves to low pressure –> pushes surface air up –> rising motion
3
Q
describe relationship between cold air and high surface pressure
A
air will move out to lower pressure zones –> air will sink to replace the diverging air –> winds
4
Q
low pressures associated with __
A
rising motion, condensation, rain
5
Q
high pressures associated with ____
A
sinking motion, dry, sunny conditions
6
Q
describe the southern oscillation
A
pressure high over the eastern pacific –> low over the maritime continent
7
Q
describe non el Nino conditions
A
- trade winds blow strongly across pacific from east to west
- generates upwelling along the equator across most of pacific –> piles up warm water in the west
- thermocline is deep in west and shallow in east
- equatorial upwelling brings colder water to the surface along the equator in the east
- east-west contrast in sea surface temp sets up an atmospheric flow w/low pressure & rising motion in the west with warm temps
- low temps, high pressure and sinking in the east
- surface winds blow from high to low pressure, east to west
8
Q
describe conditions during El Nino
A
- trade winds reduced, warm water above the thermocline flows eastward
- upwelling goes down bc trade winds are weaker
- sea surface temps become warmer in central and eastern equatorial pacific where thermocline deepens
- surface pressures drop –> rising motion & rain in central and eastern pacific
- no longer a strong surface pressure contrast from east to west –> trade winds reduced
