Premium
Himalayan rainfall and vorticity generation within the Indian summer monsoon
Author(s) -
Kennett E. J.,
Toumi R.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl021925
Subject(s) - vorticity , monsoon , climatology , bengal , potential vorticity , geology , bay , atmospheric sciences , environmental science , vortex , meteorology , geography , oceanography
The Himalayas are an integral part of the Indian monsoon dynamics. In this paper we examine the European Centre for Medium‐Range Weather Forecasts 40‐year Reanalysis (ERA40) data set in order to quantify the importance of Himalayan rainfall in terms of vorticity generation. We find that Himalayan rainfall is a powerful source of vorticity due to the multiplicative effect of steep vertical gradients in latent heating combined with a large Coriolis parameter. ERA40 shows a maximum in column‐integrated and near‐surface vorticity generation in the monsoon region over the southern slopes of the Himalayas. We estimate that the total generation of vorticity over the Himalayan region as a whole is at least half that over the Bay of Bengal. Thus Himalayan rainfall is likely to play a central role in amplifying the circulation of the monsoon.