Open AccessLast Glacial Maximum's effect on the Walker circulation
Author(s) -
Schultz Colin
Publication year - 2011
Publication title -
eos, transactions american geophysical union
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.316
H-Index - 86
eISSN - 2324-9250
pISSN - 0096-3941
DOI - 10.1029/2011eo430015
Subject(s) - humidity , precipitation , climatology , atmospheric circulation , environmental science , atmosphere (unit) , atmospheric sciences , troposphere , walker circulation , equator , sea surface temperature , meteorology , geology , latitude , geography , geodesy
Over the tropical Pacific Ocean the Walker circulation is an atmospheric flow pattern that runs parallel to the equator, with ascending motion over the western Pacific and a horizontal tropospheric return flow that carries air back to the east. Scientists predict that the Walker circulation will weaken with global warming through a mechanism known as the Held, Soden, and Vecchi (HSV) mechanism. According to this system, as surface ocean temperatures increase, atmospheric humidity and precipitation rates will also increase. Conversely, as surface ocean temperatures decrease, atmospheric humidity and local precipitation will decrease. Humidity levels change much more easily than precipitation rates; as temperatures rise, this disparity leads to a decrease in vertical air motion as the atmosphere tries to maintain a balanced flow of air. If temperatures fall, vertical air motion will increase. Although the HSV mechanism is a robust feature of climate models, its observed sensitivity to changing temperatures remains uncertain.