[A-CG36] 衛星による地球環境観測

[ACG36-13] Towards Retrieving Atmospheric HCOOH from the GOSAT-2 TIR Band: Forward Simulations and Sensitivity Analysis

*Fengxin Xie¹、Ryoichi Imasu¹、Naoko Saitoh²、Yu Someya³ (1.Atmosphere and Ocean Research Institute, The University of Tokyo、2.Center for Environmental Remote Sensing, Chiba University、3.National Institute for Environmental Studies)

キーワード：GOSAT-2, Formic acid, Thermal infrared band, Radiative transfer model, Spectral sensitivity

Formic acid (HCOOH) plays a critical role in atmospheric acidity, yet the understanding of its budget remains incomplete. In regions affected by biomass burning, the precision of HCOOH profiles simulated by chemical transport models (CTMs) is significantly compromised, leading to underestimated emissions. In this study, we utilized GOSAT-2 satellite spectra as a space-based perspective to retrieve HCOOH profiles from the thermal infrared (TIR) band. Given the presence of other strong absorbing gases such as water vapor and ozone within the same absorption range of HCOOH, we developed a radiative transfer model (RTM) for mixing gases to accurately simulate the GOSAT-2 TIR band with the spectral range from 750 to 1450 cm^-1. This RTM's accuracy and reliability were confirmed by comparing it with LBLRTM under identical atmospheric conditions. Subsequently, we conducted an in-depth analysis of the GOSAT-2 TIR data, focusing on the spectral sensitivity to variations in the selected trace gas profiles, temperature profile, and surface temperature. This sensitivity analysis facilitated preliminary step-wise retrieval results. Prior to retrieving HCOOH profiles, the next phase of our research will focus on validating the retrieval effectiveness based on the Bayesian optimal approach for other atmospheric parameters, such as water vapor, temperature, and ozone. The retrieved results will be compared with OzoneSonde measured data in the Tsukuba area, employing the Japanese 55-year Reanalysis (JRA55) database as as a priori values for these components.