Significance of Summertime Heat Low over the Northern Part of the Indian Subcontinent in the Changing Climate

The Indian heat low, a strong atmospheric circulation pattern marked by low pressure and high temperatures, significantly influences weather patterns over Pakistan and northern India. Understanding how terrestrial heating patterns changes over time is crucial for understanding climate change. Such changes can profoundly affect large-scale systems such as the heat low and monsoon. The evolving characteristics of the heat low area over the Indian subcontinent from 1940 to 2020 are investigated using a decadal analysis of reanalysis data (ERA5). The results indicate an eastward shift in the heat low over the historical period. Furthermore, ensembles of CMIP5 Global Climate Models (GCMs) under RCP6.0 and RCP8.5 scenarios project a continued eastward shift in this heat low pattern between 2050 and 2100. The eastward shift in the heat low pattern significantly influences the monsoon circulation system, potentially leading to substantial changes in rainfall distribution across the Indian subcontinent, as projected under RCP6.0 and RCP8.5 scenarios—with some differences between them. The results from the GCMs support the idea of an eastward shift in rainfall, indicating the potential for altered precipitation distribution in the future. Furthermore, the study emphasizes the possible drying of the western Indian subcontinent, including Pakistan and western India, because of the altering heat low trend. These findings highlight the necessity of considering changing atmospheric circulation patterns in climate change assessments and the need for a better understanding of the associated implications for regional climate dynamics.