In Texas High Plains, every millimeter of irrigation water saved greatly affects profit margins. If available, high-resolution daily ET maps would help producers plan their irrigation schedule effectively. The ET maps derived from satellite sensors with daily coverage such as MODIS do not satisfy producer needs because their pixel size is larger than individual fields in the region. Given this problem, a research opportunity exists to utilize simultaneously acquired high resolution visible, NIR, SWIR and TIR images from MODIS and other sensors such as ASTER or Landsat TM to improve coverage frequency and spatial resolution for ET mapping. This paper presents a proposed multi-institution research plan to improve existing ET mapping capabilities for the semi-arid Texas High Plains. The main research objectives include: evaluation of land surface energy balance and crop coefficient-based models for their ability to estimate ET at point, field, landscape, and regional scales; evaluation of effects of thermal remote sensing pixel resolution on modeled energy balance components in irrigated and dryland crops, and rangelands; and develop and evaluate algorithms to improve spatial resolution of surface temperature data derived from Aircraft/Landsat/ASTER/MODIS thermal images using high resolution visible, NIR, SWIR and TIR images. The proposed study concentrates on the region in and around the Conservation and Production Research Laboratory (CPRL), USDA-ARS at Bushland, Texas. Data from four large monolithic weighing lysimeters at the CPRL will be used for evaluating ET models. Field campaigns will be conducted during the 2007 cropping season. Data collection includes reflectance and thermal data from aircraft, ASTER, Landsat, and MODIS sensors, crop parameters, scintillometer sensible heat flux measurements, and ground measurements of surface reflectance and temperature, net radiation and soil heat fluxes. The proposed research is the most comprehensive ET modeling study at point, field, landscape, and regional scales in the Texas High Plains.