Accuracy Assessment of NOAA Gridded Daily Reference Evapotranspiration for the Texas High Plains1. (18th April 2015)

• Record Type: Journal Article
• Authors: Moorhead, Jerry; Gowda, Prasanna; Hobbins, Mike; Senay, Gabriel; Paul, George; Marek, Thomas; Porter, Dana
• Is Part Of: Journal of the American Water Resources Association. Volume 51:Number 5(2015)
• Page Start: 1262
• Page End: 1271
• Publication Date: 2015-04-18
• Subjects: Water-supply -- Periodicals; Hydrology -- Periodicals; Water resources development -- Periodicals; Water resources development -- Environmental aspects -- Periodicals; 333.9100973
• DOI: 10.1111/1752-1688.12303
• Languages: English
• ISSNs: 1093-474X

Abstract

<abstract abstract-type="main" id="jawr12303-abs-0001"> <title>Abstract</title> <p>The National Oceanic and Atmospheric Administration (NOAA) provides daily reference evapotranspiration (ET<sub>ref</sub>) maps for the contiguous United States using climatic data from North American Land Data Assimilation System (NLDAS). This data provides large‐scale spatial representation of ET<sub>ref</sub>, which is essential for regional scale water resources management. Data used in the development of NOAA daily ET<sub>ref</sub> maps are derived from observations over surfaces that are different from short (grass — ET<sub>os</sub>) or tall (alfalfa — ET<sub>rs</sub>) reference crops, often in nonagricultural settings, which carries an unknown discrepancy between assumed and actual conditions. In this study, NOAA daily ET<sub>os</sub> and ET<sub>rs</sub> maps were evaluated for accuracy, using observed data from the Texas High Plains Evapotranspiration (TXHPET) network. Daily ET<sub>os</sub>, ET<sub>rs</sub> and the climatic data (air temperature, wind speed, and solar radiation) used for calculating ET<sub>ref</sub> were extracted from the NOAA maps for TXHPET locations and compared against ground measurements on reference grass surfaces. NOAA ET<sub>ref</sub> maps generally overestimated the TXHPET observations (1.4 and 2.2 mm/day ET<sub>os</sub> and ET<sub>rs</sub>, respectively), which may be attributed to errors in the NLDAS modeled air temperature and wind speed, to which reference ET<sub>ref</sub> is most sensitive. Therefore, a bias correction to NLDAS modeled air temperature and wind speed data, or adjustment to the resulting NOAA ET<sub>ref</sub>, may be needed to improve the accuracy of NOAA ET<sub>ref</sub> maps.</p> </abstract>