Kumar et al. (2026) Investigating Heatwave Features: Creating an Intensity-Duration-Frequency Model for India’s Principal Climate Zones

Identification

• Journal: Earth Systems and Environment
• Year: 2026
• Date: 2026-01-13
• Authors: Priyankar Kumar, Arun Chakraborty, Akshay Kumar Sagar, Mansour Almazroui, Muhammad Mubashar Dogar, Rabin Chakrabortty
• DOI: 10.1007/s41748-025-00979-3

Research Groups

• Centre for Ocean, River, Atmosphere and Land Sciences (CORAL), Indian Institute of Technology Kharagpur, West Bengal, India
• Center of Excellence for Climate Change Research, Department of Meteorology, King Abdulaziz University, Jeddah, Saudi Arabia
• Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, UK
• Research Institute for Global Change, Agency for Marine-Earth Science and Technology, Yokohama, Kanagawa, Japan
• School of Environment Resources and Development, Asian Institute of Technology (AIT), Phatum Thani, Thailand
• National Centre For Medium Range Weather Forecasting, Noida, India

Short Summary

This study develops Heatwave Intensity-Duration-Frequency (HWIDF) curves for six climatic zones in India to assess heatwave characteristics under anthropogenic and natural conditions. It reveals that human-caused warming significantly increases heatwave intensity and frequency, particularly in Arid and Humid Subtropical zones, underscoring the need for targeted climate adaptation.

Objective

• To investigate the relationships among intensity, duration, and frequency of heatwave events across six climatic zones in India using Heatwave Intensity-Duration-Frequency (HWIDF) curves.
• To assess changes in heatwave intensities across varying return periods under both anthropogenic and natural conditions.
• To provide insights into the relative contributions of anthropogenic and natural influences on heatwave characteristics to inform targeted climate adaptation strategies.

Study Configuration

• Spatial Scale: Six principal climatic zones of India (Arid, Semiarid, Montane, Humid Subtropical, Tropical Wet, and Tropical Wet & Dry). Data resolution: 1°×1° for IMD observations, 100 km for MRI-ESM2-0 model.
• Temporal Scale:
  • Observational data: Summer season (April to July) from 1990 to 2020.
  • Model data (historical and natural simulations): 1990 to 2014.
  • Heatwave durations: 1 to 10 consecutive days.
  • Return periods: 2, 5, 20, 40, and 100 years.

Methodology and Data

• Models used:
  • Heatwave Intensity-Duration-Frequency (HWIDF) model, employing the block maxima approach.
  • Non-parametric kernel distribution for probability density fitting (identified as the best fit).
  • Earth System Model Version 2.0 (ESM2.0) from the Meteorological Research Institute (MRI-ESM2-0), part of the Coupled Model Intercomparison Project Phase 6 (CMIP6).
  • Bias correction methods: Delta method and Quantile mapping.
• Data sources:
  • Observational data: Daily air maximum temperature (Tmax) and minimum temperature (Tmin) gridded dataset from the India Meteorological Department (IMD).
  • Model data: Tmax and Tmin datasets from MRI-ESM2-0 for historical (including anthropogenic and natural forcings) and natural (only natural forcings) simulations.

Main Results

• The Arid zone experiences the highest heatwave intensities, with maximum and average values of 44.32 °C and 36.56 °C, respectively, for 1-10 day durations at 2-year return periods.
• The Montane zone consistently exhibits the lowest heatwave intensities across all durations and return periods.
• The Humid Subtropical zone shows a significantly increased likelihood of extreme heatwaves, with a 23.07% higher probability for 5-day heatwaves with average temperatures ≥ 35 °C under anthropogenic emission scenarios compared to natural conditions.
• Historical conditions (including anthropogenic factors) present a higher risk of intense heatwaves over consecutive 5- and 10-day periods compared to natural conditions (e.g., Arid zone 10-day heatwave, 2-year return period: 34.2 °C under historical forcing vs. 33.42 °C under natural forcing).
• Heatwave intensity generally increases for a given duration as the return period lengthens, while intensity decreases as the duration increases for a given return period.
• A non-parametric kernel distribution was found to be the best fit for modeling heatwave intensities across all climatic zones.

Contributions

• Introduces an innovative HWIDF curve methodology for a comprehensive frequency analysis of extreme heatwave events, integrating intensity, duration, and frequency to avoid biases.
• Provides a robust framework for understanding and anticipating heatwave patterns across India's six diverse climatic zones.
• Quantifies the relative contributions of anthropogenic and natural influences on heatwave characteristics, highlighting the significant role of human-caused warming.
• Identifies specific regional vulnerabilities (e.g., Arid and Humid Subtropical zones) that require targeted climate adaptation strategies.
• Offers valuable insights for the design of climate-resilient infrastructure systems, such as electric grids and power plants, to better prepare for future heatwave challenges.

Funding

There is no Funding for this work.

Citation

@article{Kumar2026Investigating,
  author = {Kumar, Priyankar and Chakraborty, Arun and Sagar, Akshay Kumar and Almazroui, Mansour and Dogar, Muhammad Mubashar and Chakrabortty, Rabin},
  title = {Investigating Heatwave Features: Creating an Intensity-Duration-Frequency Model for India’s Principal Climate Zones},
  journal = {Earth Systems and Environment},
  year = {2026},
  doi = {10.1007/s41748-025-00979-3},
  url = {https://doi.org/10.1007/s41748-025-00979-3}
}