Understanding the spatio-temporal structure of recent heat waves over India

Abstract

Major heat waves are occurring over India during the hottest months of May and June. Since the temperature extremes have major impact on human health and agriculture, better understanding the dynamics behind its evolution and propagation will help us to develop effective mitigation strategies. Understanding the spatio-temporal distribution, evolution and dynamics associated with heat waves is lacking over this region, due to the lack of high-resolution weather information. Here, we developed a high-resolution (4 × 4 km) dynamically downscaled hourly climate data for April to June during period of 2001-2016. The downscaled daily surface temperature is in good agreement with station observations, which is also in agreement with the observed features of temperature distribution during this period. Based on the Indian meteorological department definition, intensity of the heat waves is identified and re-classified into minor and severe category. The spatio-temporal distribution of each heat wave shows variation in its spatial coverage and also in its intensity. The distributions of heat waves are mainly over central India, North-West India and states such as Odisha, Andhra Pradesh and Telangana during pre-monsoon season. Results show that the increase in meridional heat transport is higher than the zonal advection component, and intensification of heat waves is linked with heat accumulation over a particular region associated with weakening of heat transport. The further amplification associated with depletion of soil moisture will result in the reduction in evaporative cooling, and it will further amplify the surface air temperature.

Projected Changes in Socioeconomic Exposure to Heatwaves in South Asia Under Changing Climate

“…South Asia (SA) is highly susceptible to climatic extremes due to its intricate landscape, highly dense population, climate variations, rapid urbanization, and less coping capacity (Khan et al., 2019; Liu et al., 2021; Neethu et al., 2020; Rohini et al., 2019). Like other regions, SA ranked among the top hotspots region to climate extremes such as droughts, floods, and HWs (Mie Sein, Ullah, Saleem, et al., 2021; Ullah et al., 2021a, 2021b).…”

Changing spatio‐temporal trends of heat wave and severe heat wave events over India: An emerging health hazard

“…Whereas, other regions have shown negative to no correlation with either of HW or SHW events. Prevailing synoptic conditions such as recurving of cyclones, increased sensible heat flux, local accumulation of heat as a result of land‐atmosphere coupling also played a greater role in increasing the mortality (Ghatak et al ., 2017; Neethu et al ., 2019).…”

Investigation of the Indian summer in the state's popular capital and correlation between IMD and ERA5 dataset during the past five decades (1973–2022)

“…across average, May and June are the warmest months across the Indian subcontinent. [10] The National Disaster Management Authority (NDMA) reports that 2018 saw more heatwaves than prior years. India saw the largest heatwave anomalies over the central states of the country, making this year the sixth warmest since 1950.…”

“…Temperature deviations from the mean of 4-5°C are regarded as heatwaves, and deviations of 6°C or more are regarded as severe heatwaves. [9,10] Multiple industries, including health, agriculture, ecology, and the national economy are severely harmed by heatwaves. Extreme heat waves in India pose a serious threat to people's lives and increase the risk of deaths from heat stroke and heat stress.…”