Characteristics of Extreme Precipitation Events in High Mountain Asia as Inferred from High-Resolution Regional Climate Modeling

The mountains of High Mountain Asia are home to the largest mass of snow and ice outside of the Polar Regions and serve as an important source of water for roughly one billion people living downstream. The Eastern Himalaya receive large amounts of precipitation during the Indian Summer Monsoon, while the mountains of the Western Himalaya and Karakoram receive a larger portion of their annual precipitation from winter westerly disturbances that move through the region. Previous research has indicated that a small number (<5) of these storms supply a majority of the wintertime precipitation in the Western Himalaya. Remote and complex terrain, along with a lack of available weather station data, has limited research of these events. This research utilizes high-resolution (4km) numerical simulations performed using the Weather Research and Forecasting (WRF) Model to analyze characteristics of the largest winter storms impacting the Western Himalaya and Karakoram and understand what atmospheric conditions lead to the largest precipitation events in the region. Regression analysis is used to understand how certain synoptic scale conditions correlate with intense precipitation within the region. Vertically integrated atmospheric water vapor and vapor transport are also used to better characterize system dynamics that lead to intense precipitation, as well as add to the current understanding of the source regions for moisture that eventually falls as precipitation in High Mountain Asia. By increasing the understanding of storm dynamics and interannual precipitation variability in the region, this work aims to provide information that may prove helpful to the growing populations that will continue to rely on runoff from the region in a changing climate.