Nonlinear Processes in Geophysics www.nonlin-processes-geophys.net 1023-5809 1607-7946 17 5 2010 10.5194/npg-17-371-2010 http://www.nonlin-processes-geophys.net/17/371/2010/ http://www.nonlin-processes-geophys.net/17/371/2010/npg-17-371-2010.html http://www.nonlin-processes-geophys.net/17/371/2010/npg-17-371-2010.pdf 371 381 2010-09-01 Spatial structures and directionalities in Monsoonal precipitation over South Asia N. Malik malik@pik-potsdam.de N. Marwan J. Kurths Potsdam Institute for Climate Impact Research, P.O. Box 601203, 14412, Potsdam, Germany Institute of Physics, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany Department of Physics, Humboldt University, Newtonstr. 15, 12489 Berlin, Germany Precipitation during the monsoon season over the Indian subcontinent occurs in form of enormously complex spatiotemporal patterns due to the underlying dynamics of atmospheric circulation and varying topography. Employing methods from nonlinear time series analysis, we study spatial structures of the rainfall field during the summer monsoon and identify principle regions where the dynamics of monsoonal rainfall is more coherent or homogenous. Moreover, we estimate the time delay patterns of rain events. Here we present an analysis of two separate high resolution gridded data sets of daily rainfall covering the Indian subcontinent. Using the method of event synchronization (ES), we estimate regions where heavy rain events during monsoon happen in some lag synchronised form. Further using the delay behaviour of rainfall events, we estimate the directionalities related to the progress of such type of rainfall events. The Active (break) phase of a monsoon is characterised by an increase(decrease) of rainfall over certain regions of the Indian subcontinent. We show that our method is able to identify regions of such coherent rainfall activity. 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