Summary of Abstract Submission

Abstract Submission No. IO50-05-0029PresentationPoster

UNDERSTANDING THE DYNAMICS OF BREAKS IN THE MONSOON AND ITS REVIVAL

Govardhan D*1

1 University of Hyderabad, India

ABSTRACT :

In this report, we suggest a criteria of dynamical mechanism involved in the revival of summer monsoon. In this context, we carry out a diagnostic analysis using the datasets from National Centres for Environmental Prediction reanalysis-2 for the period 1979-2007 to identify a robust mechanism that typifies breaks and subsequent revival of monsoon. We find that during the peak of significant breaks, an anomalous southward shift of subtropical westerly jet stream, which is invariably accompanied by anomalous northward shift of a stronger-than-normal easterly jet. These major changes during a break facilitate an instability mechanism that, which apparently leads to formation of a synoptic disturbance. Formation of such a disturbance is often critical in the subsequent revival of summer monsoon. Our computation of energetics suggests an increase in the eddy kinetic energy at the expense of the mean kinetic energy during the breaks in agreement with the formation of the synoptic disturbance. This demonstrates that barotropic instability in the presence of a monsoon basic flow is the primary physical mechanism that controls monsoon breaks, and subsequent revival of summer monsoon in the Indian region.