High Asia Refined analysis-based Monsoon precipitation characteristics over Indian Himalayas

The Himalayas, known as the world's third pole, are extremely vulnerable to the ramifications of extreme precipitation events (EPEs), such as flash floods, landslides, and agricultural and infrastructural damages during the Indian summer monsoon (ISM). Complex terrain, high meteorological diversity and uncertainty in observations over this region, make it challenging to comprehend the precipitation disparities and predict the EPEs across the Western Himalayas (WH). Therefore, a better representation of ISM precipitation characteristics over the WH using high-resolution data is crucial for precisely understanding the precipitation variability and mechanisms of climate-triggered localised natural disasters. This study investigates the spatiotemporal variability of precipitation and EPEs using High Asia Refined analysis version 2 (HAR v2), during ISM. It is generated by dynamically downscaling global ERA5 reanalysis data, using Weather Research and Forecasting model (WRF). Before investigating the EPEs, we evaluated HAR v2's ability to represent general characteristics of ISM over the WH against reanalysis, satellite and observational datasets. Preliminary results indicate that, HAR v2 reanalysis better represented the spatiotemporal patterns of precipitation and EPEs across WH. The present study will also investigate the dynamic and thermodynamic processes, associated with EPEs over the study region. Overall, this study aims to provide scientific insights to investigate the potential impacts of climate change on extreme events, which in turn could help mitigate disasters in the Himalayan region. Detailed results of precipitation variability over the Himalayas, and mechanisms altering the atmospheric conditions attributed to the EREs will be discussed.

Keywords: Indian Summer Monsoon, Himalayas, HAR-V2 reanalysis, Extreme Precipitation Events