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ARS Home » Pacific West Area » Tucson, Arizona » SWRC » Research » Research Project #434839

Research Project: NOAA/NSSL and USDA/ARS Cooperative Investigation of Precipitation and Runoff over the Walnut Gulch Experimental Watershed

Location: Southwest Watershed Research Center

Project Number: 2022-13610-012-28-N
Project Type: Non-Funded Cooperative Agreement

Start Date: Aug 30, 2018
End Date: Sep 30, 2020

Objective:
1. Examination of vertical radar variables that Cooperator obtained from the NOAA X-Band Polarimetric radar (NOXP) PPI (Plan Position Indicator), and RHI (Range Height Indicator) data over the USDA-ARS Walnut Gulch Experimental Watershed for microphysical insights. Includes a) comparison with surface 2D Vidio Disdrometer (2DVD) for insights in NASA GPM (Global Precipitation Mission) retrievals, b) utilization with high frequency precipitation isotopes; and c) GOES-based GML and ABI for improvements to QPE in Intermountain West. 2. Basin-wide precipitation estimation from NOXP PPI data. Includes: a) reanalysis using Walnut Gulch rain gauge network, and b) input for hydrologic modeling and assessment of ephemeral channel transmission losses. 3. Streamflow estimation using Sommer Stream Radar. Includes: a) comparison of discharge estimates to USGS LSPIV velocity and conventional Walnut Gulch supercritical flume discharge and the USGS slope area method, and b) validation of watershed hydrologic modeling.

Approach:
Using radar units NOAA/NSSL has installed at the Walnut Gulch Experimental Watershed (WGEW) as part of NOAA/NSSL ongoing research projects, NOAA/NSL and ARS will collect radar scan of precipitation and discharge to offer insights into physical processes with rainfall formulation and evolution. Specifically, NOAA/NSSL NOXP mobile radar will collect radar scan during the 2018 monsoon season (July 15, 2018 through September 30, 2018) for analysis and comparison to precipitation from the WGEW gauge network and to NASA GPM precipitation retrievals over the WGEW. In addition, the NOAA/NSSL Sommer stream radar instrument will observe stream radar of flow events at the WGEW supercritical runoff flume 6. Observations from the stream radar of flow events at flume 6 will be analyzed and compared to three independent runoff discharge measurements to assess the accuracy of the Sommer stream radar measurements. Precipitation estimates from NOXP will also be input into several watershed models to assess how NOXP precipitation estimates might improve flash flood forecasting capabilities. Both Agencies will use this data to guide hydrologic models and to offer insights into physical processes with rainfall formation and evolution. The partnering Agencies will continue to work collaboratively to complete the collection and analaysis of the datasets and publish the results in peer-reviewed journal articles upon completion of the analysis.