Investigating Land‐Atmosphere Interactions in the North West Himalaya Through Recycled Precipitation: Seasonal Dynamics, Trends, and Topographic Impacts

Abstract The North West Himalaya (NWH), due to complex topography and seasonal influence of western disturbances and the Indian summer monsoon, is subjected to substantial variations in precipitation. These factors make isolating the mechanisms governing land‐atmosphere interactions in the NWH challenging. This study examines the link between terrestrial and atmospheric segments of land‐atmosphere interactions and their trends in summer and winter over two decades (2001–2020) in NWH. We use the Weather Research and Forecasting (WRF) model to simulate terrestrial and atmospheric variables at 10‐km resolution. The atmospheric segment of land‐atmosphere interactions is characterized using recycled precipitation calculated using an Eulerian water vapor tagging tool coupled with WRF model. We observe a high recycling ratio of 0.3 during summer due to a high availability of thermal energy. Recycled precipitation is higher at lower elevations during summer and higher elevations during winter. To assess the link between terrestrial and atmospheric segments, we relate recycled precipitation to the soil moisture (SM)‐latent heat flux sensitivity index. High sensitivity is observed in the foothills during both summer and winter, but only in the summer in the higher Himalaya as the region remains predominantly snow‐covered during winter. Sub‐seasonal variations in SM modify energy partitioning, influencing near‐surface air temperature and atmospheric moisture ultimately affecting the recycled precipitation. In case of trends, although terrestrial segment of land‐atmosphere interactions showed significant trends, they do not always affect the trends of atmospheric segment. The nature of trends in the two segments is found to be influenced by location, topography, and seasonality.