ASTER Observations of Water Surface Temperature for Elephant Butte Reservoir in New Mexico

Skin temperature of water is an important variable that is commonly used in studies of surface energy and water balance, yet its spatial measurements above the water surface are a challenge. Using remotely sensed temperature derivation from NASA's Terra satellite is one possible solution that was investigated. Temperature measurements from the Terra satellite using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) five-channel multispectral thermal-infrared (TIR) scanner were compared to ground measurements of skin-temperature of water at Elephant Butte Reservoir in New Mexico. Skin temperature of water was measured using precision infrared thermocouple sensor model IRTS-P (Apogee Instrument Inc., Logan, UT). The sensor was installed on an extended arm of approximately 1 m from an off-shore triangulated tower in deep water of greater than 25 m (location N33:09:51.06 and W107:10:34.56). The infrared sensor was maintained at an average height of less than 1 m above the water surface. Preliminary results indicate a good comparison. The comparison of "surface" measured skin temperature to satellite estimated surface temperature during the clear days of May 23rd and 30th, 2005 show a difference of 0.3 and 0.44 C, respectively.