Coupling the ParFlow Integrated Hydrology Model within the NASA Land Information System: A case study over the Upper Colorado River Basin

Abstract. Understanding, observing, and simulating Earth's water cycle is imperative for effective water resource management in the face of a changing climate. NASA's Land Information System (LIS)/Noah-MP and the ParFlow groundwater model are the two widely used modeling platforms that enable studying the Earth's land surface and subsurface hydrologic processes, respectively. The integration of ParFlow and LIS/Noah-MP models and harnessing their strengths can provide an opportunity to simulate surface terrestrial water processes and groundwater dynamics together while enhancing the accuracy and scalability of hydrological modeling. This study introduces ParFlow-LIS/Noah-MP (PF-LIS/Noah-MP), which is an integrated, physically based hydrologic modeling framework. PF-LIS/Noah-MP enables the user to simulate land surface processes in conjunction with subsurface hydrologic processes while considering the interactions between the two. In this study, we compared the results of the coupled PF-LIS/Noah-MP and standalone LIS/Noah-MP models with a suite of in-situ and satellite observations over the Upper Colorado River Basin (UCRB) in the United States. This analysis confirmed that integrating ParFlow with LIS/Noah-MP not only enhances the capability of LIS/Noah-MP in estimating land surface processes over regions with complex topography but also enables it to accurately simulate subsurface hydrologic processes.