HR: 0800h
AN: A51C-0789    [Abstracts]
TI: Retrieval Precision Tests of CO$_{2}$ Column Amount from Simulated Data of the GOSAT SWIR FTS by Applying Rodgers_f Method
AU: * Ishihara, H
EM: hironari@ilas2.nies.go.jp
AF: Fujitsu FIP Corporation, 2-45 Aomi, Koto-ku, Tokyo, 135-8686 Japan
AU: Uemura, N
EM: uemura@ilas2.nies.go.jp
AF: Fujitsu FIP Corporation, 2-45 Aomi, Koto-ku, Tokyo, 135-8686 Japan
AU: Nobuta, K
EM: nobuta@ilas2.nies.go.jp
AF: Fujitsu FIP Corporation, 2-45 Aomi, Koto-ku, Tokyo, 135-8686 Japan
AU: Yokota, T
EM: yoko@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Higurashi, A
EM: hakiko@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Morino, I
EM: morino@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Oguma, H
EM: oguma@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Aoki, T
EM: aoki.tadao@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Inoue, G
EM: inouegen@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AB: A SWIR (Short Wavelength InfraRed) FTS sensor aboard GOSAT (Greenhouse gases Observing Satellite) will measure CO$_{2}$ and CH$_{4}$ column amounts from space. The measurement geometry is a nadir looking observation of solar-lights scattered by ground-surfaces. The measurement spectral regions are 2.0 micron band (4710 - 5320 cm$^{-1}$), 1.6 micron band (5500 - 6535 cm$^{-1}$), and 0.76 micron band (12755 - 13280 cm$^{-1}$) for CO$_{2}$ and CH$_{4}$ column amount estimation. We have performed sensitivity studies and error analyses by using computer simulation data of the FTS outputs in order to investigate retrieval algorithms. The algorithms used for the error estimation mainly consist of two parts; the radiative transfer calculation part and the retrieval part. In the former part, HSTAR code, which is based on the RSTAR code developed by T. Nakajima_fs group at CCSR, is used. HSTAR simulates total radiance with high spectral resolution by line-by-line calculation. Rayleigh scattering and the path-radiance effects caused by aerosols and clouds are considered in the HSTAR. As for the retrieval part, we have tested Rodgers' optimal estimation method, which utilizes a priori knowledge on targets (e.g., climatological data). Some possible error sources of the CO$_{2}$ and CH$_{4}$ measurement in the SWIR region are aerosols, cirrus cloud, water vapor, surface pressure (altitude), surface albedos, temperature profile, and the line parameters of absorption gases. In case of aerosols or cirrus clouds are contaminated in the measurement field of view, retrieval precision strongly depends on the retrieval conditions; the target unknown parameters and constraint condition of a priori data. The results of error analyses under several retrieval conditions will be presented.
DE: 1640 Remote sensing
DE: 0360 Transmission and scattering of radiation
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting