5:15 PM - 6:45 PM
[ACG36-P10] First O3 observations from GOSAT-2: the retrieval of O3 profile using thermal-IR band of TANSO-FTS-2 over Kanto region
Keywords:Retrieval, Ozone, GOSAT-2, Optimal estimation
With an increasing concern on the impact of tropospheric O3 on the climate and ecosystem, international efforts are converging to extend and unify operational satellites to provide long-term record of O3 [1]. Among operational IR sounders, the Greenhouse gases Observing SATellite-2 (GOSAT-2, launched on October 29, 2018) has shown immense potential in observing O3, considering its concentrated observations via targeting mode and the ability to simultaneously observe CO [2]; yet the retrieval of O3 using GOSAT-2 has not been well analyzed. Meanwhile, the metropolitan areas are regarded as a major source of tropospheric O3 due to high emission of precursors (VOC + NOx + CO). A novel satellite O3 dataset is therefore necessary for better understanding the O3 features near its source.
In our study, we aim at providing the first results of O3 profile retrieval using thermal infrared (TIR) band from the nadir-looking instrument Thermal And Near infrared Sensor for carbon Observation – Fourier Transform Spectrometer-2 (TANSO-FTS-2) onboard GOSAT-2. The retrieval is focused on the urban area of Tokyo, Japan (35.68° N, 139.65° E) by the targeting mode of FTS-2 with around 40×40 km2 domain. In the retrieval process, we basically apply the optimal estimation [3] and the Line-By-Line Radiative Transfer Model (LBLRTM) as the forward model [4], with the spectroscopic line parameters from HITRAN 2016 database. Meanwhile, we utilize sequential retrieval approach, using the JRA-55 reanalysis data and the MIPAS O3 dataset in Tokyo as the a priori profile. For validation, we conduct theoretical error analysis, and compare the retrievals with ozonesonde data obtained in Tsukuba, Japan (36.06° N, 140.13° E) smoothed by averaging kernel. The performance of retrieval is evaluated by the degree of freedom of signal (DOFS), root-mean square error (RMSE) and mean bias (BIAS), in comparison with previous satellite missions such as TES and IASI.
Our results provide first retrieval and validation of O3 profile using TANSO-FTS-2, providing new remotely sensed dataset of O3.
References
[1] Tarasick, D., Galbally, I. E., Cooper, O. R., Schultz, M. G., Ancellet, G., Leblanc, T., et al. (2019). Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties. Elementa: Science of the Anthropocene, 7(39). https://doi.org/10.1525/elementa.376
[2] Imasu, R. (2019). Expected scientific achievement by GOSAT-2 – Science Plan. Journal of The Remote Sensing Society of Japan, 39(1), 9-13. https://doi.org/10.11440/rssj.39.9
[3] Rodgers, C. D. (2000). Inverse methods for atmospheric sounding: Theory and practice. Singapore: World Scientific.
[4] Clough, S. A., Shephard, M. W., Mlawer, E. J., Delamere, J. S., Iacono, M. J., Cady-Pereira, K., et al. (2005). Atmospheric radiative transfer modeling: a summary of the AER codes. Journal of Quantitative Spectroscopy & Radiative Transfer, 91, 233-244. https://doi.org/10.1016/j.jqsrt.2004.05.058
In our study, we aim at providing the first results of O3 profile retrieval using thermal infrared (TIR) band from the nadir-looking instrument Thermal And Near infrared Sensor for carbon Observation – Fourier Transform Spectrometer-2 (TANSO-FTS-2) onboard GOSAT-2. The retrieval is focused on the urban area of Tokyo, Japan (35.68° N, 139.65° E) by the targeting mode of FTS-2 with around 40×40 km2 domain. In the retrieval process, we basically apply the optimal estimation [3] and the Line-By-Line Radiative Transfer Model (LBLRTM) as the forward model [4], with the spectroscopic line parameters from HITRAN 2016 database. Meanwhile, we utilize sequential retrieval approach, using the JRA-55 reanalysis data and the MIPAS O3 dataset in Tokyo as the a priori profile. For validation, we conduct theoretical error analysis, and compare the retrievals with ozonesonde data obtained in Tsukuba, Japan (36.06° N, 140.13° E) smoothed by averaging kernel. The performance of retrieval is evaluated by the degree of freedom of signal (DOFS), root-mean square error (RMSE) and mean bias (BIAS), in comparison with previous satellite missions such as TES and IASI.
Our results provide first retrieval and validation of O3 profile using TANSO-FTS-2, providing new remotely sensed dataset of O3.
References
[1] Tarasick, D., Galbally, I. E., Cooper, O. R., Schultz, M. G., Ancellet, G., Leblanc, T., et al. (2019). Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties. Elementa: Science of the Anthropocene, 7(39). https://doi.org/10.1525/elementa.376
[2] Imasu, R. (2019). Expected scientific achievement by GOSAT-2 – Science Plan. Journal of The Remote Sensing Society of Japan, 39(1), 9-13. https://doi.org/10.11440/rssj.39.9
[3] Rodgers, C. D. (2000). Inverse methods for atmospheric sounding: Theory and practice. Singapore: World Scientific.
[4] Clough, S. A., Shephard, M. W., Mlawer, E. J., Delamere, J. S., Iacono, M. J., Cady-Pereira, K., et al. (2005). Atmospheric radiative transfer modeling: a summary of the AER codes. Journal of Quantitative Spectroscopy & Radiative Transfer, 91, 233-244. https://doi.org/10.1016/j.jqsrt.2004.05.058