The influence of sensible heat on monsoon precipitation in central and eastern Tibet

Abstract

The sensible heat over the Tibetan Plateau influences the atmospheric circulation of East Asia and North America, and also the monsoon precipitation on the Plateau. Empirical Orthogonal Function (EOF) analysis of the patterns of the monsoon precipitation at 17 meteorological stations in central and eastern Tibet shows that the sensible heat during May over the central Tibetan Plateau relates closely to the first eigenvector weight time series (EOF1) of the monsoon precipitation for the eastern part of the Plateau from June to September. At the Amdo site the correlation coefficient exceeds 0.7, and the correlation between the EOF1 and the average of sensible heat at five sites (Amdo, Bange, Wudaoliang, Tuotuohe and Gaize) over the central Tibetan Plateau can exceed 0.80. This relationship suggests a mechanism of increased sensible heat flux in central Tibetan Plateau during May causing stronger cyclonic flow and low vortices in this area, resulting in more precipitation during the monsoon season on the eastern Plateau. From May to August, 1979, for example, this sensible heat effect can account for more than half of the precipitation. Based on this relationship, the sensible heat of central Tibet can be used as a 'predictor' of monsoon precipitation in central and eastern Tibet. Copyright © 2010 Royal Meteorological Society.