South West Monsoon

This theme focuses on determining the timing and abruptness of the modern South Asian Monsoon (SAM) onset from geological evidence, dissecting the roles of tectonics and climate, especially in the Miocene epoch, and understanding how large-scale climatic shifts like global cooling and ocean circulations contributed to establishing the current monsoon system.

This theme addresses mesoscale and synoptic dynamics influencing the spatial-temporal monsoon onset over India, including moisture advection by low-level jets, the role of mid-tropospheric dry air intrusions in modulating deep convection, and large-scale circulation changes such as the monsoon trough formation and jet stream shifts. It further relates these physical processes to challenges in seasonal forecasting and model biases.

This theme covers the development, evaluation, and improvements of regional Earth system models (RESMs), high-resolution regional climate models (RCMs), and data assimilation efforts to better represent monsoon mean states, intraseasonal and interannual variability, and extreme rainfall characteristics. It includes model performance assessments, bias evaluation, and climate change projections emphasizing added value from regional downscaling and coupled atmosphere-ocean interactions for Indian monsoon climatology and rainfall extremes.

This theme evaluates the heterogeneity of monsoon rainfall across India, quantifying how different months and meteorologically homogeneous regions contribute to strong versus weak Indian Summer Monsoon Rainfall (ISMR). It investigates intraseasonal and regional disparities in rainfall patterns, with implications for better understanding and forecasting the strength and spatial distribution of monsoon rains crucial for agriculture and water resource management.