HR: 0800h
AN: A21D-0904    [Abstracts]
TI: Utilization of the Water Vapor Saturated Absorption Band to Retrieve CO₂ Column Density From Space by GOSAT Under the Cirrus-Existing Condition
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: Aoki, T
EM: aoki.tadao@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: Eguchi, N
EM: eguchi.nawo@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Yoshida, Y
EM: yoshida.yukio@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: Greenhouse gases Observing Satellite (GOSAT) of Japan is planned to be launched in 2008. GOSAT is equipped with a Fourier Transform Spectrometer (FTS) to monitor CO₂ column density globally. The FTS covers a near infrared band and two short wavelength infrared (SWIR) bands, which cover 0.76 micron, 1.6 micron, and 2.0 micron spectral regions, respectively. Retrieval algorithms to estimate CO₂ and CH₄ column densities from these bands data are now being developed. It was confirmed that these column densities can be retrieved relatively easily under the clear sky condition. However, the non-clear sky conditions with cirrus clouds and aerosols would seriously affect retrieval precision of the gas column densities by utilizing the data from space. A retrieval algorithm under the cirrus-existing condition has been developed. In this algorithm, a strong water vapor absorption area included in the 2.0 micron band, where the reflected radiance from a ground surface is absorbed completely by water vapor, is utilized to estimate path radiance from cirrus layers. This is one of the significant advantages of the GOSAT spectral coverage. The cirrus vertical profile (i.e., existing height distribution) is estimated from the 0.76 micron band data. By using signals from 1.6 micron, and 2.0 micron spectral regions, the cirrus optical depth, ground surface albedo, and column densities of CO₂, CH₄ and H₂O are retrieved simultaneously and precisely. The error estimation results of the retrieval simulation will also be presented.
DE: 0360 Radiation: transmission and scattering
DE: 1610 Atmosphere (0315, 0325)
DE: 1640 Remote sensing (1855)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005