短波红外通道CO2观测的温度敏感性分析

Temperature sensitivity analysis of carbon dioxide measurement in SWIR band

近红外通道观测大气CO2含量是利用其对太阳辐射的吸收作用,温度是影响吸收气体吸收的一个重要因子,文中讨论了CO2观测的温度敏感性.首先阐述了温度对气体吸收谱线的强度、增宽的影响;然后根据CO2反演过程中使用的大气温度产品的精度水平,利用逐线积分辐射传输模型模拟计算了1 K的随机温度误差对垂直大气观测的影响,以及由此导致的CO2反演误差,并与模拟的1 ppm和2 ppm的CO2浓度变化所造成的观测与反演变化量进行了比较.通过对比分析六种大气模式下的模拟计算结果,得出1 K大气随机温度误差是影响高精度大气CO2观测反演的重要因子.

Carbon dioxide has an absorption band of solar spectra in SWIR, and temperature is a key factor to the absorption effect. Researches on the CO2 observation sensitivity of temperature are done in this paper. First, the dependences of spectral line parameters on temperature are discussed. Then, according to the accuracy level of atmosphere temperature profile product, we simulate the change of measurement in nadir mode by importing 1 K temperature uncertainty, using line-by-line radiative transfer mode under 6 different atmosphere modes, and calculate the corresponding change of retrieval result. In contrast, simulations of measurement change resulted from 1 ppm and 2 ppm CO2 column density differences are also done. After comparison, we come to a conclusion： 1 K uncertainty of atmosphere temperature profile is an important factor which has significant influence to high precise atmospheric CO2 observation.