10:45 AM - 12:15 PM
[HTT17-P08] Analysis on increases in concentration of carbon dioxide in each layer in the globe inferred from GOSAT/TANSO-FTS data
Keywords:GOSAT, vertical profiles of carbon dioxide, concentration increases
Vertical profiles of carbon dioxide (CO2) concentration have been retrieved from thermal infrared spectra obtained by thermal infrared (TIR) band of TANSO-FTS (Thermal And Near-infrared Sensor for carbon Observation – Fourier Transform Spectrometer) on board GOSAT (Greenhouse gases Observing SATellite) [Saitoh et al., 2016]. In this study, we have calculated increases in CO2 concentration from 2010 to 2012 in each retrieval layer from surface to 161.56 hPa in the globe using the vertical CO2 profile data.
Saitoh et al. [2016, 2017] reported that the TANSO-FTS TIR original CO2 concentration data had negative biases. Therefore, we have corrected the biases by the bias correction values evaluated through comparisons of TANSO-FTS TIR CO2 data and CO2 data obtained by CME (Comprehensive CO2 Measurement Equipment) of CONTRAIL (Comprehensive Observation Network for Trace gases by Airliner) project [Machida et al., 2008]. Then, we have calculated increases in CO2 concentration from 2010 to 2012 using the method of Nakazawa et al. [1998]. The calculated increasing rate of the TIR bias-corrected CO2 data were generally ~0.1-0.6 ppmv/yr larger than that of the original CO2 data.
Our results show that increases in CO2 concentration in the UTLS (upper troposphere and lower stratosphere) region were larger than those in the LTMT (lower and middle troposphere) region in most of the analysis regions. In the European region, for example, the CO2 increase on ~260 hPa was 1.95 ppmv/yr, while the increase on ~800 hPa was 1.56 ppmv/yr. This may be attributed to the difference in the bias correction methods for the TIR CO2 data between UTLS and LTMT regions; it is suggested that biases in the original TIR CO2 data in LTMT were not corrected sufficiently.
Saitoh et al. [2016, 2017] reported that the TANSO-FTS TIR original CO2 concentration data had negative biases. Therefore, we have corrected the biases by the bias correction values evaluated through comparisons of TANSO-FTS TIR CO2 data and CO2 data obtained by CME (Comprehensive CO2 Measurement Equipment) of CONTRAIL (Comprehensive Observation Network for Trace gases by Airliner) project [Machida et al., 2008]. Then, we have calculated increases in CO2 concentration from 2010 to 2012 using the method of Nakazawa et al. [1998]. The calculated increasing rate of the TIR bias-corrected CO2 data were generally ~0.1-0.6 ppmv/yr larger than that of the original CO2 data.
Our results show that increases in CO2 concentration in the UTLS (upper troposphere and lower stratosphere) region were larger than those in the LTMT (lower and middle troposphere) region in most of the analysis regions. In the European region, for example, the CO2 increase on ~260 hPa was 1.95 ppmv/yr, while the increase on ~800 hPa was 1.56 ppmv/yr. This may be attributed to the difference in the bias correction methods for the TIR CO2 data between UTLS and LTMT regions; it is suggested that biases in the original TIR CO2 data in LTMT were not corrected sufficiently.