10:15 〜 10:30
[ACG37-06] Retrieval of tropospheric ozone using TANSO-FTS-2 on GOSAT-2: a global analysis and validation
キーワード：Infrared sounder, Tropospheric ozone, GOSAT-2, Optimal estimation, Thermal contrast
Ozone (O3) is one of the most important gaseous species in the atmosphere: it safeguards lives in the stratosphere, but irritates repository system in the troposphere. In addition, ozone is regarded as third most potent greenhouse gas and short-lived climate forcer (SLCF). Although satellite observations using ultraviolet sensors, such as the Ozone Monitoring Instrument (OMI) and the TROPOspheric Monitoring Instrument (TROPOMI), have revealed the distribution of tropospheric ozone in wide-area, satellite observations using thermal infrared sensors are capable of obtaining nighttime data. Thus, thermal infrared sensors can provide better temporal coverage of ozone observations.
In this study, we conduct retrieval and validation of tropospheric ozone using the Japanese Greenhouse Gases Observing SATellite-2 (GOSAT-2, launched on October 29, 2018). We select the thermal infrared (TIR) band from the nadir-looking instrument Thermal And Near infrared Sensor for carbon Observation – Fourier Transform Spectrometer-2 (TANSO-FTS-2) for the retrieval. In the retrieval process, we basically apply the optimal estimation and the Line-By-Line Radiative Transfer Model (LBLRTM) as the forward model, with the spectroscopic line parameters from HITRAN 2016 database. The climatological mean of tropospheric ozone is applied as the a priori profile. For validation, we use ozone-sonde data obtained from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC). The ozone profiles convolved with the averaging kernel of satellite measurement are used for validation of the retrieval. The performance of retrieval is examined 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. The comparison with the predecessor GOSAT (launched on January 23, 2009) will be emphasized. It is expected that the retrieval performs better over urban area than rural area because of high thermal contrast defined by the temperature difference between the atmosphere and the surface.
Our study presents the first 3-year tropospheric ozone retrieval using GOSAT-2, focusing on global and regional variation of ozone. Meanwhile, our results facilitate the assessment of tropospheric ozone through satellite data, advancing the data application of GOSAT-2.
In this study, we conduct retrieval and validation of tropospheric ozone using the Japanese Greenhouse Gases Observing SATellite-2 (GOSAT-2, launched on October 29, 2018). We select the thermal infrared (TIR) band from the nadir-looking instrument Thermal And Near infrared Sensor for carbon Observation – Fourier Transform Spectrometer-2 (TANSO-FTS-2) for the retrieval. In the retrieval process, we basically apply the optimal estimation and the Line-By-Line Radiative Transfer Model (LBLRTM) as the forward model, with the spectroscopic line parameters from HITRAN 2016 database. The climatological mean of tropospheric ozone is applied as the a priori profile. For validation, we use ozone-sonde data obtained from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC). The ozone profiles convolved with the averaging kernel of satellite measurement are used for validation of the retrieval. The performance of retrieval is examined 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. The comparison with the predecessor GOSAT (launched on January 23, 2009) will be emphasized. It is expected that the retrieval performs better over urban area than rural area because of high thermal contrast defined by the temperature difference between the atmosphere and the surface.
Our study presents the first 3-year tropospheric ozone retrieval using GOSAT-2, focusing on global and regional variation of ozone. Meanwhile, our results facilitate the assessment of tropospheric ozone through satellite data, advancing the data application of GOSAT-2.