Mountain torques and atmospheric oscillations

Articles:

Title:: Mountain torques and atmospheric oscillations
Author(s):: Lott, François
Robertson, Andrew W.
Ghil, Michael
Date:: 2001
Type:: Articles
Department:: International Research Institute for Climate and Society
Volume:: 28
Permanent URL:: http://hdl.handle.net/10022/AC:P:14372
Book/Journal Title:: Geophysical Research Letters
Abstract:: Theoretical work and general circulation model (GCM) experiments suggest that the midlatitude jet stream's interaction with large‐scale topography can drive intraseasonal oscillations in large‐scale atmospheric circulation patterns. In support of this theory, we present new observational evidence that mountain‐induced torques play a key role in 15–30‐day oscillations of the Northern Hemisphere circulation's dominant patterns. The affected patterns include the Arctic Oscillation (AO) and the Pacific‐North‐American (PNA) pattern. Positive torques both accelerate and anticipate the midlatitude westerly winds at these periodicities. Moreover, torque anomalies anticipate the onsets of weather regimes over the Pacific, as well as the break‐ups of hemispheric‐scale regimes.
Subject(s):: Atmospheric sciences
DOI:: http://dx.doi.org/10.1029/2000GL011829