Location: Soil and Water Management ResearchTitle: Mapping evapotranspiration in the Texas Panhandle) Author
|Chavez Eguez, Jose|
Submitted to: Texas Experiment Station Field Day Handout
Publication Type: Proceedings
Publication Acceptance Date: 5/24/2007
Publication Date: 5/24/2007
Citation: Chavez Eguez, J.L., Gowda, P., Howell, T.A., Marek, T.H., New, L.L. 2007. Mapping evapotranspiration in the Texas Panhandle. Texas Experiment Station Field Day Handout. p. 23-31. Interpretive Summary:
Technical Abstract: Agriculture in the Texas High Plains accounts for approximately 92% of groundwater withdrawals. Because groundwater levels are declining in the region, efficient agricultural water use is imperative for sustainability and regional economic viability. Accurate regional evapotranspiration (ET) maps would provide valuable information on crop water demand and usage. In this study, a regional ET map was produced for an 11-county area in the Texas High Plains using METRIC (Mapping Evapotranspiration at High Resolution Using Internalized Calibration), a remote sensing based ET algorithm, and meteorological data measured at four ET weather stations maintained by the Texas High Plains Evapotranspiration Network (TXHPET). For mapping ET, a Landsat 5 Thematic Mapper image acquired on 27 June 2005 was used. Performance of the ET model was evaluated by comparing predicted daily ET with values derived from a soil water budget at four different commercial irrigated fields. Good agreement was found between the remote sensing based ET and soil water budget ET for low to moderate ET rates. Less agreement resulted for higher ET rates. Use of METRIC for advective conditions of the Texas High Plains is promising; however, further evaluation is needed using lysimeter or scintillometer derived ET measurements for different agroclimatological conditions and/or a larger number of image scenes.