The Mighty Monsoonal Storms: Tracing Historical Evolution and Future Impacts

COLLOQUIUM TALK

Title: The Mighty Monsoonal Storms: Tracing  Historical Evolution and Future Impacts

Abstract: Monsoonal storms, or Monsoon Low-Pressure Systems (LPS), are vital for South Asia's seasonal rainfall, impacting agriculture and the economy. However, they also trigger severe hydrological disasters and act as a major source of flood during the Indian summer monsoon season. Historical trends in the number of monsoon LPS have been a matter of debate. Detailed analysis, using advanced tracking algorithms on five reanalysis datasets, questions the reported decline in the stronger LPS--monsoon depressions. This suggests that observed decreases might result from changes in observational methods, not an actual decline. The lack of a discernible trend in LPS activity and the increased hydrological extremes over India is intriguing. Increased extremes from a sharp increase in LPS are driven by increased near-surface humidity over India. This intensification is a significant factor in the rising hydrological extremes in Central India. Future projections indicate a shift in LPS genesis from ocean to land, with rainfall increasing by about 7% per degree of warming. These findings highlight the urgent need for precise LPS tracking and forecasting to manage extreme weather risks and safeguard South Asia's socio-economic stability. 
 
Speaker's Bio: Dr. Vishnu S. Nair is an Assistant Professor in the Department of Earth, Environmental, and Sustainability Sciences at IISER Thiruvananthapuram, India. His research focuses on monsoon low-pressure systems, synoptic scale dynamics, and seasonal extremes of the Indian summer monsoon. Dr. Nair has held roles as a Climatologist at Météo-France / IRD-France and a Postdoctoral Scholar at the University of California, Berkeley. He has received several honors, including a gold medal for his PhD thesis from Andhra University and a CSIR-UGC Junior Research Fellowship.