Does climatic divergence in the Indian Western Ghats influence natural vulnerability? Exploring rainfall extremes in...

The Western Ghats region of India, being one of the most ecologically significant regions globally, it is crucial to understand the critical impacts of climate change in this region. In the present study, we have investigated the precipitation patterns across the Northern and Southern Peaks of the southernmost region of the Western Ghats (i.e., falling in the Kerala state, India), by employing precipitation indices recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI), World Climate Research Programme (WCRP), and through statistical analysis of India Meteorological Department (IMD) precipitation data during 1986-2022 time periods using the non-parametric modified Mann-Kendall test and Sen's slope estimator. The results indicated that the Northern Peak region of Kerala state witnessed lower average rainfall and less variability, as compared with the Southern Peak region, with distinct differences in extreme precipitation patterns. The Northern Peak is characterized by extended dry spells, as evidenced by increased positive trends in consecutive dry days (CDD), in addition to consecutive wet days (CWD), total precipitation (PRCPTOT), and extreme rainfall events, such as PRge1 and PRge2.5 days. These changes are accompanied by an upward trend in the simple daily intensity index (SDII), indicating a shift towards more intense and variable rainfall. In contrast, the Southern Peak shows significant decreases in CWD, PRCPTOT, and SDII. Despite high precipitation in the Southern Peak, there is a reduction in extreme rainfall indices such as rainfall exceeding 1 mm or 2.5 mm (PRge1/PRge2.5 days) and heavy precipitation days (R10mm, R20mm, R30mm), reflecting a decline in rainfall intensity and frequency. The study revealed distinct precipitation patterns, where the Northern Peak faces increased intensity and variability in rainfall, while the Southern Peak shows reduced rainfall intensity and variability. Understanding regional differences in topography and microclimate is crucial for mitigating the impacts of extreme weather events, such as floods, droughts, and landslides. Developing effective management strategies tailored to the specific climate challenges of vulnerable areas in each peak is essential for enhancing resilience to natural calamities in the Western Ghats, India.