Applications of the Western Land Data Assimilation System

Numerical modeling of the land surface is a way to provide physically consistent, spatially and temporally continuous information about the water and energy budgets of the surface, subsurface, vegetation canopy, and snowpack. As much of the western United States exists in a near-constant state of freshwater scarcity, information about the amount of water available is critical for decision makers. The Western Land Data Assimilation System (WLDAS) is a custom instance of the NASA Land Information System that combines land surface parameters, meteorological forcing data, and satellite products within a land surface model to produce daily estimates of the water and energy budget variables for the western United States using the Noah-Multiparameterization Land Surface Model. WLDAS was configured with stakeholder input to support groundwater sustainability planning and drought assessment activities. The publicly available output dataset has a 1 km grid resolution and spans 1979-present, and the length of record makes it suitable for water resources assessments. We discuss the configuration of WLDAS, including the assimilation of satellite products, and demonstrate applications of the system related to groundwater recharge and drought monitoring.