Feasibility of evapotranspiration monitoring of riparian vegetation with remote sensing

Quantification of evapotranspiration (ET) continues to be challenging especially when attempting to evaluate ET at basin scales. Extending approaches to whole basins or larger regions is difficult due to issues related to landscape heterogeneity and scale. Reliable areal estimates of ET are essential for accurate modelling of the hydrological cycle and for assessing water-use of different ecosystems. A riparian corridor along the Rio Grande (USA) dominated by Tamarisk (salt cedar) is being studied to determine daily and total seasonal water-use. Local estimates of ET in the Tamarisk were made using eddy covariance instrumentation mounted on two towers. Radiometric temperature at the top of the canopy was also measured using a fixed-head infrared thermometer. The combination of these data will be used to evaluate evapotranspiration estimates along the corridor using data remotely sensed from an aircraft platform that have been acquired periodically for a large extent of the riparian zone.