Mapping 100 m multi-depth soil moisture with WRF-Hydro over Tibetan Plateau

Abstract

The Tibetan Plateau (TP), a critical area impacting regional and global climate systems, faces significant hydrological changes due to global warming. Understanding these changes requires high solution soil moisture (SM) profiles, which are fundamental for analyzing water and energy exchanges. To achieve high-precision and high-resolution SM products over the TP, this study conducted long-term WRF-Hydro simulations based on a variety of input data, with the option of enabling or disabling lateral flow processes. Ultimately, the most suitable settings for the SM simulation in the TP were identified, leading to the development of region-specific SM datasets at both 100 m and 1 km spatial resolution. High-resolution, multi-depth SM data were generated for four distinct regions: Ali and Naqu (August 2010 to December 2018), Maqu (January 2009 to December 2018), and Pali (June 2015 to December 2016), each at 100-meter spatial resolution and hourly temporal resolution. By comparing these datasets with existing global SM products (SMAP L4, GLDAS Noah and ERA5-Land), we observed an average improvement in correlation by 0.22, 0.263 and 0.137, and a reduction in unbiased RMSE by 14 %, 21.82 % and 25.86 %, respectively. This research emphasizes the importance of using high-resolution models, incorporating lateral flow processes, and high-precision input to capture the complex hydrological dynamics of the TP. It offers valuable insights into regional hydrological processes, potentially aiding future climatological and hydrological forecasts. The resulting dataset is made publicly available for further research and applications.