39Hydro Linking Groundwater and Land Surface Processes with the Coupled NASA Land Information System and ParFlow Framework

Understanding the interactions between the atmosphere, the land, and the subsurface is essential to hydrology and is critical for accurately assessing the effects of climate change and human management on hydrological systems. However, many land surface models simplify the subsurface hydrology and thereby these interactions. In this study, we couple the land surface model Noah-MultiParameterization (Noah-MP) included in the NASA Land Information System (LIS) with the integrated hydrologic model ParFlow (ParFlow-LIS) using the Earth System Modeling Framework (ESMF) and the National United Operational Prediction Capability (NUOPC). This integration improves the simulation of water and energy cycle processes by incorporating three-dimensional, variably saturated, and heterogeneous subsurface flow using advanced, nonlinear physics-based equations. The coupled system also leverages advancements in satellite remote sensing-based data assimilation of the land surface, benefiting the integrated hydrologic modeling and data assimilation community. We utilize the High Plains aquifer located in the central United States as a testbed to assess the coupled ParFlow-LIS system. This enhanced ParFlow-LIS system incorporates the effects of topographically driven flows on the land surface, generating more detailed patterns of land surface states and fluxes compared to the standalone LIS. Moreover, ParFlow-LIS allows for the consideration of subsurface water storage impacts on evapotranspiration, which is crucial in regions and periods with dry soils, such as during drought conditions or in areas affected by a cone of depression due to pumping.