Submitted to: International Geoscience and Remote Sensing Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 21, 2001
Publication Date: N/A
Interpretive Summary: With the launch of NASA's Terra satellite in December 1999 a new tool for studying the earth's surface has become available, multispectral thermal infrared. These data can be used the emissivity of the land surface on a global basis. The emissivity of the surface has a major effect on the radiation energy balance at the earth's surface. Therefore knowledge of the spatial variation of the surface emissivity is important for quantifying the radiation balance at the earth's surface. This paper presents preliminary results of a technique for observing this spatial variation. While these results were obtained using data from an aircraft sensor, it is extendable to data from satellite platforms and thus could be used on a global basis.
On May 9, 2000 the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) on the Terra satellite obtained data over the Jornada Experimental Range test site along the Rio Grande river and the White Sand National Monument in New Mexico. ASTER has 14 channels from the visible (VNIR) through the thermal infrared (TIR) with 15 m resolution in the VNIR and 90 m in the TIR. The overpass time is approximately 11 AM. With 5 channels between 8 and 12 microns these multispectral TIR data from ASTER provide the opportunity to separate the temperature and emissivity effects observed in the thermal emission from the land surface. Ground measurements during these overflights included surface temperature, vegetation type and condition and limited surface emissivity measurements. There was also an aircraft flight with the MODIS/ASTER simulator on June 14, 2000, unfortunately not coincident with a satellite overpass. Preliminary results indicate good agreement between ASTER brightness temperatures and ground measures. Analysis of earlier aircraft data has shown that the multispectral TIR data are very effective for estimating both the surface temperature and emissivity. These results will be compared with those obtained from the ASTER data for this site. With multispectral thermal infrared observations provided by ASTER it is possible for the first time to estimate the spectral emissivity variation for these surfaces on a global basis at high spatial resolution.