Work

Formulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulations

Year: 2025

Type: article

Abstract: This study formulates and implements a dynamic convective adjustment time-scale [Formula: see text]) in the convective parameterization scheme of CESM1.2, replacing the default fixed [Formula: see text]. By allowing [Formula: see text] to vary spatiotemporally with convective cloud depth and updraft velocity, the approach significantly improves Indian summer monsoon simulations. The scheme reduces longstanding precipitation biases, such as excessive precipitation over the Himalayas, Western Ghats, and peninsular India, and underestimations over the eastern equatorial Indian Ocean. The scheme also enhances cloud cover characteristics, particularly the low cloud cover, radiative forcing, and large-scale circulation (subtropical westerly Jet and Somali Jet). Limited improvement in the monsoon quasi-biweekly and intraseasonal mode and precipitation variability, is seen. Despite these improvements, regional biases, extreme event underestimation, intraseasonal oscillations, and ocean-atmosphere coupling limitations persist. These findings underscore the potential of dynamic convective adjustment in reducing key monsoon simulation biases and improving long-term climate projections in global models.

Source: Scientific Reports

DOI: 10.1038/s41598-025-15073-x

Authors: Raju Pathak, Sandeep Sahany, Saroj Kanta Mishra, Jingyu Wang

Institutions: Nanyang Technological University, Earth Observatory of Singapore, Indian Institute of Technology Delhi, National Institute of Education

Language: English

Topic: Meteorological Phenomena and Simulations

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $2,690