%0 Journal Article
%A Jacob Schewe and Anders Levermann
%D 2012
%J Environmental Research Letters
%N 4
%V 7
%P 044023 
%T A statistically predictive model for future monsoon failure in India
%U http://stacks.iop.org/1748-9326/7/i=4/a=044023 
%X Indian monsoon rainfall is vital for a large share of the world’s population. Both reliably
projecting India’s future precipitation and unraveling abrupt cessations of monsoon rainfall found
in paleorecords require improved understanding of its stability properties. While details of monsoon
circulations and the associated rainfall are complex, full-season failure is dominated by
large-scale positive feedbacks within the region. Here we find that in a comprehensive climate
model, monsoon failure is possible but very rare under pre-industrial conditions, while under future
warming it becomes much more frequent. We identify the fundamental intraseasonal feedbacks that are
responsible for monsoon failure in the climate model, relate these to observational data, and build
a statistically predictive model for such failure. This model provides a simple dynamical
explanation for future changes in the frequency distribution of seasonal mean all-Indian rainfall.
Forced only by global mean temperature and the strength of the Pacific Walker circulation in spring,
it reproduces the trend as well as the multidecadal variability in the mean and skewness of the
distribution, as found in the climate model. The approach offers an alternative perspective on
large-scale monsoon variability as the result of internal instabilities modulated by pre-seasonal
ambient climate conditions.
%@ 1748-9326