Spatio-Temporal Changes in Cold Wave Characteristics Over the Diverse Meteorological Sub-Divisions of India

Abstract

Cold wave (CW) and Severe Cold wave (SCW) prevail over India as a seasonal episode during winter season. The present study analyzes the changing spatio-temporal characteristics and trends of cold waves over India's meteorological subdivisions from 1951 to 2021 (Dec–Feb). It uses minimum temperature data obtained from the India Meteorological Department (IMD) at a spatial resolution of 0.5° × 0.5°. A declining trend in both CW and SCW days is found with a decrease of − 0.29 days/decade in CW days and 0.02 days/decade in SCW days. The study also explored the trend of spells of three, five and seven days of CW and SCW and found a significantly decreasing trend of − 0.02 days/decade and − 0.05 days/decade in 3 and 5-day SCW spell respectively. A consistent significant increase of 0.027 °C/decade in minimum temperature post 1980s is also reported in the study with a simultaneous decrease in cold wave. While the northwestern and northern meteorological subdivision record highest CW and SCW spells, a declining trend is reported in these regions, highest being in West Rajasthan (− 1.3 days/decade) and Punjab (− 1.3 days/decade). A significant increasing trend has been observed in CW, SCW days/spells in the eastern, eastern coastal and southern subdivisions such as Bihar (0.16 days/decade), Jharkhand (0.05 days/decade) and Odisha (0.2 days/decade). Overall, the study reports a decline in cold waves and identifies new cold wave-prone regions in the country. The study also highlights the emerging severe impact on agriculture sector in the scenario of declining cold extremes over major wheat producing belts.