To develop a statistical model for the analysis of heat wave intensity duration frequency curve for major climatic zones of India

A Heat-wave-Intensity-Duration-Frequency (HWIDF) curve is employed to establish the relationship between the intensity, duration, and frequency of heat wave incidents. This approach offers a more comprehensive understanding of heat waves by considering their intensity, duration, and frequency. The HWIDF curves for India's six climate zones, namely, The Arid zone, Semiarid zone, Montane, Humid subtropical zone, Tropical wet, and Tropical wet & dry zone, are considered for the study. These curves are used to evaluate the probability of encountering heat waves with varying levels of intensity and duration. They also help measure changes in heat wave intensities for different return periods in relation to the evolving climate. Subsequently, the MRI-ESM2-0 models were employed to assess the disparities in HWIDF (Heat Wave Intensity-Duration-Frequency) by comparing scenarios with and without human emissions. This analysis aimed to determine the specific impact of human activities on heat waves. The analysis shows that heat waves in arid zones, lasting from one to ten days, with maximum and average intensities of 44.32℃ and 36.56 ℃ or less, occur with a frequency of once every two years (probability=0.5). These heat waves have higher intensities compared to other zones. On the other hand, montane zones experience lower intensities compared to other zones. Our findings indicate that heat wave intensity poses a greater danger under historical conditions when compared to natural conditions, particularly over a span of five and ten consecutive days. The likelihood of experiencing severe heat waves in the Humid Subtropical and Montane zones is more or less compared to other zones. Hence, our study indicates that the rising probability of severe heat waves, in terms of their severity and duration, could be attributed to anthropogenic warming.