Original paper
The role of aerosol trends in rainfall over India
Cherian, Ribu; Quaas, Johannes
Meteorologische Zeitschrift Vol. 34 No. 1 (2025), p. 25 - 34
published: Jul 10, 2025
published online: Apr 3, 2025
manuscript accepted: Dec 23, 2024
manuscript revision received: Nov 14, 2024
manuscript revision requested: Aug 23, 2024
manuscript received: Jan 15, 2024
Open Access (paper may be downloaded free of charge)
Abstract
Anthropogenic aerosol emissions have shown an increasing trend over India since the beginning of the twenty-first century, in contrast to many other regions. The associated aerosol radiative effects are thus expected to be gradually enhanced. Here, using satellite observations and Coupled Model Intercomparison Project Phase 6 (CMIP6) model simulations, the influence of emission trends on regional effective radiative forcing (ERF) and rainfall during the Indian summer monsoon season are analyzed from 2001 to 2018. CMIP6 models capture the sign of observed trends in aerosol loading and rainfall over the Indian region, but underestimate the magnitude by a factor of 2 to 5. The simulated short-wave ERF trends show cooling at the top-of-the-atmosphere and surface, but warming in the atmosphere (1 to 5 W m−2 decade−1) over India which is consistent with the observed absorbing aerosol trends. Due to enhanced atmospheric warming, the energy budget changes influenced the circulation and water cycles, thereby the observed regional rainfall wetting trends (20–50 W m−2 decade−1 (in energy flux units)).
Keywords
atmospheric aerosols • CMIP6 • monsoon • climate modelling • air pollution • aerosol-cloud interactions