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Response of Monsoon Low-Pressure Systems to UNIFORM Geoengineering
Global surface temperature anomalies
My work investigates how Low Pressure Systems (LPS) during the Indian Summer Monsoon respond under the UNIFORM geoengineering experiment, in which stratospheric sulfate aerosols are uniformly prescribed to counteract the warming caused by doubled atmospheric CO₂ using the fully coupled CESM2.1.3 climate model. This idealized framework provides a controlled way to examine how solar dimming through sulfate aerosols influences regional monsoon dynamics while reducing global mean temperature rise. By comparing the UNIFORM, doubled CO₂, and control simulations, I analyze changes in the frequency, intensity, tracks, duration, and rainfall contribution of monsoon LPS. The results indicate that although the aerosol intervention substantially offsets large-scale warming, it also modifies land–sea thermal contrast, atmospheric circulation, and moisture transport, which are key drivers of LPS formation and evolution. This study highlights that geoengineering impacts extend beyond global temperature recovery and can significantly influence monsoon weather systems, regional rainfall patterns, and associated climate risks over South Asia.
Publications
Publications
Singh, M., Bala, G., and Seshadri, A. K., 2026.
106th AMS Annual Meeting, American Meteorological Society, 2026.
Accounting for the bias in the median track of Indian Summer monsoon low-pressure systems in an Earth system model
LPS genesis density and track density in the model simulation versus ERA5.
Indian Summer Monsoon low-pressure systems (LPSs) are among the most important rain-bearing weather systems over the subcontinent, contributing a major share of seasonal rainfall over central, eastern, and northern India. In this study, we examine why many climate models struggle to simulate their location and movement correctly. Using the CESM2.1.3 Earth system model and reanalysis datasets, we show that the model produces a systematic southward shift in LPS genesis and tracks.
This bias is linked to a southward-displaced monsoon low-level jet and stronger intrusion of dry air from West Asia and the Arabian region into northwest India. These circulation errors suppress LPS development and propagation into northern India, leading to reduced rainfall over the monsoon core zone and excessive rainfall farther south. Similar biases are also found across CMIP climate models, indicating a long-standing challenge in monsoon simulation. Improving representation of these processes is important for better seasonal forecasts and future climate projections over South Asia.
Publications
Publications
Singh, M., Bala, G., & Seshadri, A.K (2026).
Accounting for the bias in the median track of Indian Summer monsoon low-pressure systems in an Earth system model
Journal of Climate (2026).
Singh, M., Bala, G., & Seshadri, A. K. (2025).
Biases in model simulations of Indian Summer monsoon low-pressure systems.
EGU General Assembly Conference Abstracts, Vienna, Austria.
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