Department of Environmental Sciences
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Seminar Abstracts
Environmental Sciences Seminar Abstract            

  PRECESSIONAL CYCLES AND THEIR REMOTE INFLUENCE ON THE NORTH PACIFIC AND NORTH ATLANTIC ANTICYCLONES
Damianos Mantsis
Rutgers University

The Northern Hemisphere summer anticyclones are important features of the general circulation of the atmosphere in the subtropics. Several theories regarding the strength and existence of the subtropical highs have been proposed. Here we study how these mechanisms apply when Earth’s climate undergoes large changes due to orbital forcing. The orbital forcing consists of changes in the seasonal cycle of the TOA insolation as the longitude of the perihelion shiftsfrom the winter to the summer solstice of the Northern Hemisphere.

Simulations with the GFDL CM2.1 model show that the North Pacific summer anticyclone experiences a large strengthening as well as an expansion. On the other hand, the North Atlantic subtropical high experiences a smaller change that consists of a slight westward expansion. Experiments with a primitive equation atmospheric model show that these changes represent the circulation response to changes in the diabatic heating. Both local and remote diabatic forcing from changes in the SE Asian and African summer monsoons play a role in the anticyclonic anomalies


Last updated: 01/29/2012