Scintillometry for Improved Estimates of Regional Distributions of Sensible and Latent Heat Fluxes from MODIS Images.
Jan Hendrickx1, Jan Kleissl2, and Sung-ho Hong2. (1) Dept. of Earth & Env. Sci., Socorro, NM 87801, (2) New Mexico Tech, 801 LeRoy Pl, Socorro, NM 87801
Remote sensing algorithms have been developed that derive regional distributions of sensible and latent heat fluxes from MODIS images: SEBAL, METRIC, and ALEXI among others. Although these algorithms use few to no ground measurements, their validation and calibration against ground measurements is critical for further development as well as routine applications for water resources management. Unfortunately, it is very difficult to use ground measurements of heat fluxes obtained from the standard method of eddy covariance since the typical footprint area of these measurements is at least two orders of magnitude less than the size of a MODIS thermal band pixel (1000x1000 m). The relatively new technology of scintillometry holds much potential to overcome this problem. Infrared scintillometers that measure sensible heat fluxes over distances of 0.5 to 10 km, are available off the shelf. Microwave scintillometers that measure latent heat fluxes over similar distances are being developed and close to marketing. The objectives of this study are (i) to present scintillometer sensible heat flux measurements over dry and moist transects (1-5 km) in the Middle Rio Grande Basin, New Mexico, and (ii) to compare these scintillometer measurements with sensible heat flux estimates from SEBALNM using MODIS images.