HR: 1330h
AN: H22D-0951    [PDF]
TI: Estimating broadband emissivity of North Africa using satellite thermal infrared multispectral radiometers
AU: * Ogawa, K
EM: kenta@sa.uno.ne.jp
AF: USDA/ARS Hydrology and Remose Sensing Lab., Rm 104, Bldg 007, BARC-West, Beltsville, MD 20705-2350 United States
AU: Schmugge, T
EM: schmugge@hydrolab.arsusda.gov
AF: USDA/ARS Hydrology and Remose Sensing Lab., Rm 104, Bldg 007, BARC-West, Beltsville, MD 20705-2350 United States
AB: Surface broadband (8-13.5 micrometer) emissivity in the thermal infrared region is an important parameter for the studies of energy budget and surface energy balance. This paper focuses on estimating broadband emissivity using two sensors on NASA_fs Earth Observing System (EOS) Terra satellite, Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER) and MODerate resolution Imaging Spectrometer (MODIS). We developed a method to estimate broadband emissivity using two regressions. The first regression is to relate the broadband emissivity to the emissivities for the five ASTER channels using libraries of spectral emissivity. This regression is used for mapping the broadband emissivity, which is necessary for the calibration of the second regression. The second regression is to extend the map to continental scales using the relationship between (a) the ASTER broadband emissivity map and (b) spectral emissivity and spectral reflectance data from MODIS data. The broadband emissivity values calculated from first regression were used to calibrate the second regression. We applied this regression to MODIS data and generated a broadband emissivity map over the Sahara Desert. The range of the broadband emissivity was found to be between 0.86 and 0.96 for the desert area. The expected RMS error of the map is about 0.02. Such emissivity map could be used as an input of climate model and could contribute to improve the surface and air temperature up to 1 degree C.
DE: 1640 Remote sensing
DE: 3307 Boundary layer processes
DE: 3319 General circulation
DE: 3322 Land/atmosphere interactions
DE: 9305 Africa
SC: Hydrology [H]
MN: 2003 Fall Meeting