HR: 0800h
AN: A41C-0060    [Abstracts]
TI: Columnar and Upper Level CO2 Concentration as Retrieved from IMG/ADEOS Thermal Infrared Data
AU: * Imasu, R
EM: imasu@ccsr.u-tokyo.ac.jp
AF: Center for Climate System Research, University of Tokyo, General Research Building Room No. 315b, 5-1-5 Kashiwanoha , Kashiwa, Chiba, 277-8568 Japan
AU: Ota, Y
EM: ota@ccsr.u-tokyo.ac.jp
AF: Center for Climate System Research, University of Tokyo, General Research Building Room No. 315b, 5-1-5 Kashiwanoha , Kashiwa, Chiba, 277-8568 Japan
AB: Two types of retrieval method have been applied to retrieving CO2 columnar and upper level concentrations from the thermal infrared radiation spectra observed by a Fourier Transform Spectrometer (FTS) sensor, Interferometric Monitor for Greenhouse gases (IMG), aboard the ADvanced Earth Observing Satellite (ADEOS). In the first method, temperature profiles were assumed to be those from the re-analysis data of ECMWF, ERA 40, and CO2 concentration at 600hPa were retrieved with a minimum variance method from the spectrum data at 15 micron absorption band. On the other hand, the principle of the second method used for estimating columnar CO2 concentration was similar to that of the occultation method considering the ground surface as a strong radiation source. The spectral biases that were attributable to temperature and water vapor retrieval errors were reduced through a baseline correction procedure. For this analysis, spectrum data measured at a weak absorption band, a laser band, of CO2 located around 940 cm-1 were used. Although most of Jacobian components of this week absorption band have peaks in the troposphere, the contribution from the Non-LTE effects was briefly estimated. The retrieved results showed concentration contrast between the northern and the southern hemisphere and seasonal change of this feature for the data of 1997. These results were mostly consistent with ground based CO2 data of CMDL/NOA, but systematic biases of concentration existed in both types of retrieved results.
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005