Great Lakes Observing & Forecasting Systems

Assimilation of lake and reservoir levels into the WRF-Hydro National Water Model to improve operational hydrologic predictions

Overview and Objectives

This project will improve the representation of reservoir mass balance and storages in the operational NOAA National Water Model (NWM) through the implementation and evaluation ofa new reservoir level data assimilation scheme and new reservoir process representations. Beginning in the summer of 2016, the NOAA National Water Center (NWC) in partnership with the National Centers for Environmental Prediction (NCEP), the National Center for Atmospheric Research (NCAR) and other academic partners will produce operational hydrologic predictions for the nation using a new National Water Model (NWM) that is based on the community WRF-Hydro modeling system (Gochis et al., 2015). This system will operationally produce a variety of hydrologic analysis and prediction products, including gridded fields of soil moisture, snowpack, shallow groundwater levels, inundated area depths, evapotranspiration as well as estimates of river flow and velocity for approximately 2.7 million river reaches. Also included in the NWM are representations of more than 1,200 reservoirs, which are linked into the national channel network defined by the USGS NHDPlusv2.0 hydrography dataset. Despite the unprecedented spatial and temporal coverage of the NWM, a number of known deficiencies exist in the representation of lakes and reservoirs, including no representation of the U.S. Great Lakes system.

The WRF-Hydro system is a physics-based, distributed hydrologic modeling system and has been used in several streamflow prediction applications in the U.S. and around the world (Yucel et al., 2015; Senatore et al., 2015; Givati et al., 2016; Xiang, et al., 2016; Lin et al., 2016). The modeling system provides users with a multi-physics and multi-scale modeling framework for representing a large range of terrestrial hydrologic processes such as infiltration, runoff, lateral flow, channel flow, soil moisture, snowpack, evapotranspiration as well as various water management components.


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