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Accuracy Assessment of NOAA Gridded Daily Reference Evapotranspiration for the Texas High Plains
Author(s) -
Moorhead Jerry,
Gowda Prasanna,
Hobbins Mike,
Senay Gabriel,
Paul George,
Marek Thomas,
Porter Dana
Publication year - 2015
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/1752-1688.12303
Subject(s) - evapotranspiration , environmental science , wind speed , data assimilation , meteorology , air temperature , climatology , geography , geology , ecology , biology
The National Oceanic and Atmospheric Administration ( NOAA ) provides daily reference evapotranspiration ( ET ref ) 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 ref , which is essential for regional scale water resources management. Data used in the development of NOAA daily ET ref maps are derived from observations over surfaces that are different from short (grass — ET os ) or tall (alfalfa — ET rs ) reference crops, often in nonagricultural settings, which carries an unknown discrepancy between assumed and actual conditions. In this study, NOAA daily ET os and ET rs maps were evaluated for accuracy, using observed data from the Texas High Plains Evapotranspiration ( TXHPET ) network. Daily ET os , ET rs and the climatic data (air temperature, wind speed, and solar radiation) used for calculating ET ref were extracted from the NOAA maps for TXHPET locations and compared against ground measurements on reference grass surfaces. NOAA ET ref maps generally overestimated the TXHPET observations (1.4 and 2.2 mm/day ET os and ET rs , respectively), which may be attributed to errors in the NLDAS modeled air temperature and wind speed, to which reference ET ref is most sensitive. Therefore, a bias correction to NLDAS modeled air temperature and wind speed data, or adjustment to the resulting NOAA ET ref , may be needed to improve the accuracy of NOAA ET ref maps.