风云三号气象卫星红外分光计探测大气CO_2浓度的通道敏感性分析

Channel Sensitivity Analyses for Space-Based Measurement of Atmospheric CO_2 Concentration by FY-3 Satellite/Infrared Atmospheric Sounder

依据红外分光计(InfraRed At mospheric Sounder,IRAS)光谱通道特征,发展了基于IRAS的大气辐射传输计算模式。以大气分子吸收光谱数据集(HIgh resolution TRANsmission,HITRAN)2004为初始谱线输入资料,利用该模式模拟计算IRAS在CO2吸收带的10个通道辐射率测值对CO2浓度变化的响应,并对比了其与大气温度和水汽、O3等气体浓度误差对辐射率测值的影响,探讨了利用风云三号气象卫星探测大气CO2浓度的可行性。结果表明,IRAS的通道4最适于用来监测大气CO2浓度的变化,当CO2体积混合比浓度变化在10×10-6时,对应的辐射率变化同仪器等效噪声辐射率相当,所以IRAS在理想状态下,最高可分辨的大气CO2浓度变化约为10×10-6。

Based on the spectral characteristics of the InfraRed Atmospheric Sounder （IRAS） channel, an atmos- pheric radiative transfer model for IRAS is developed. Using the High resolution TRANsmission （HITRAN） 2004 molecular spectroscopic database, the sensitivity to changes in atmospheric CO2 concentration of the measured radiance for ten channels of IRAS during the CO2 absorption ring atmospheric CO2 concentration from Fengyun-3 （FY- bands were calculated to explore the feasibility of monito- 3） meteorological satellite, and the uncertainties due to the errors of the atmospheric temperature, water vapor, and minor constituent concentrations were compared. It shows that the channel number 4 is the first choice to monitor atmospheric C02 concentrations, and the ability to identify the changes in CO2 concentration is about 10 × 10^-66 for the currently planned instrument noise.