Investigating Spatio-Temporal Trends and Anomalies in Long-Term Meteorological Variables to Determine If Maharashtra is an Emerging Warming State in India

This paper offers a comprehensive investigation of crucial meteorological variables [rainfall (P), surface temperature (T), and relative humidity (RH)] for Maharashtra (307,690 km2 area), a dry-arid state in the western Indian subcontinent, encompassing four meteorological subdivisions: Konkan and Madhya Maharashtra (west) and Marathwada and Vidarbha (east). The central hypothesis posits that Maharashtra is rapidly becoming an emerging warming state. To examine this hypothesis, long-term hydroclimatic time series (1980–2020) data for P, T, and RH were derived from the ECMWF-ERA5 dataset and analyzed using non-parametric Mann–Kendall and Sen's Slope methods at α = 0.05 significance level. Pearson correlation coefficient (PCC) was applied for time series and scatter plot interpretation. Anomalies were identified by comparing data from 2011 to 2020 to the baseline (1981–2020). The results showed significant and positive trends in temperature (T) and rainfall (P) across Maharashtra and its subdivisions. Relative humidity (RH) had an insignificant but positive trend. The highest correlation was between RH and P, followed by T and P, with the weakest association between T and RH. Konkan had the highest RH and P values, while Vidarbha experienced the highest temperatures. Temperature anomalies ranged from 0.19 to 1.29 °C in Maharashtra, with the most significant anomaly in Marathwada (0.62–1.77 °C) and Vidarbha (0.67–1.56 °C). RH and P anomaly values decreased with rising temperatures, especially during summer, winter, and in the eastern region, potentially leading to hotter summers and less cool winters. In conclusion, the findings provide robust evidence of Maharashtra's emergence as a warming state, particularly during the recent decade (2011–2020).