摘要
The spectra of O_2 A-band(0.76 μm) and CO_2 near-infrared emissions(1.6 μm) are simulated by the SCIATRAN radiative transfer model(V3.1.23), and compared with those observed by GOSAT-FTS(Greenhouse gases Observing SATellite-Fourier Transform Spectrometer). Systematic deviations between the observed and simulated spectra are found to exist,especially for the O_2 A-band. The discrepancies are characterized by their mean differences averaged over the observed spectral ranges. A correction is applied to the observed GOSAT-FTS L1B(V141.141) spectra by scaling the spectral intensity measured by TANSO-FTS(Thermal and Near infrared Sensor for carbon Observation Fourier Transform Spectrometer) onboard GOSAT.The average columnar CO_2 concentrations(XCO_2) are retrieved from the observed and the corrected GOSAT-FTS spectra by using the SCIATRAN inversion algorithm. Compared with the GOSAT-FTS L2 XCO_2 data products retrieved from the observed spectra of GOSAT-FTS, the SCIATRAN retrievals from the corrected spectra show a much better agreement, with the relative error less than 1%. But the results of GOSAT TANSO-FTS(V161.160) show smaller residuals than GOSAT TANSO-FTS(V141.141) without mean residual correction. The results indicate that the mean residual correction would increase the precision of XCO_2 retrieval for spectra with systematic deviations.
The spectra of O_2 A-band（0.76 μm） and CO_2 near-infrared emissions（1.6 μm） are simulated by the SCIATRAN radiative transfer model（V3.1.23）, and compared with those observed by GOSAT-FTS（Greenhouse gases Observing SATellite-Fourier Transform Spectrometer）. Systematic deviations between the observed and simulated spectra are found to exist,especially for the O_2 A-band. The discrepancies are characterized by their mean differences averaged over the observed spectral ranges. A correction is applied to the observed GOSAT-FTS L1B（V141.141） spectra by scaling the spectral intensity measured by TANSO-FTS（Thermal and Near infrared Sensor for carbon Observation Fourier Transform Spectrometer） onboard GOSAT.The average columnar CO_2 concentrations（XCO_2） are retrieved from the observed and the corrected GOSAT-FTS spectra by using the SCIATRAN inversion algorithm. Compared with the GOSAT-FTS L2 XCO_2 data products retrieved from the observed spectra of GOSAT-FTS, the SCIATRAN retrievals from the corrected spectra show a much better agreement, with the relative error less than 1%. But the results of GOSAT TANSO-FTS（V161.160） show smaller residuals than GOSAT TANSO-FTS（V141.141） without mean residual correction. The results indicate that the mean residual correction would increase the precision of XCO_2 retrieval for spectra with systematic deviations.
基金
supported by the National Major Project (Grant No. 32-Y30B089001-13/15)
the State Key Program of National Natural Science Foundation of China (Grant No. 41530422)
the National Natural Science Foundation of China (Grant Nos. 61540018, 61275184, 61405153)
the National High Technology Research and Development Program of China (Grant No. 2012AA121101)
the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20130201120047)
