[AAS11-P15] Simultaneous estimate of surface temperature and surface emissivity from GOSAT/TANSO-FTS TIR spectra
Keywords:GOSAT, thermal infrared band, surface temperature, surface emissivity
We here defined wavelength channels with a transmittance above 0.95 without considering any continuum as a “smooth part” in the spectral range between 800 and 1000 cm-1, and then estimated surface parameters on the basis of the “smooth part” channels. First, we applied the method to a TIR spectrum obtained over the ocean in mid-latitudes. We calculated surface emissivities by changing a surface temperature by 1 K in the range from 286 K to 310 K, and adopted the surface temperature when the calculated surface emissivities became smoothest with respect to wavelength. The estimated surface temperature was 294 K, which was close to the nearby MODIS sea surface temperature (SST) value (293.4 K). The simultaneously-estimated surface emissivity at 900 cm-1 was 0.97, which was also close to the sea surface emissivity of Aster Spectral Library, 0.99.
Furthermore, we applied our developed method to several TANSO-FTS TIR spectra obtained over the ocean (10−20°N, 160−170°E) on 1−3, January, 2013. We compared surface temperatures estimated by our method and nearby MODIS SST data. When their differences were small, the simultaneously-estimated surface emissivies were quantitatively close to the sea surface emissivities of Aster Spectral Library. However, when their differences were relatively large, the structures of the simultaneously-estimated surface emissivies were far from those of the sea surface emissivities. In the presentation, we will discuss the accuracy of our estimates of surface parameters, results of other seasons and regions, and the effect of changing several parameters in our method on estimated surface parameters.