基于OCO-2卫星观测模拟高精度XCO2的空间分布

本文首次基于OCO-2卫星观测数据,采用高精度曲面建模（High Accuracy Surface Modeling, HASM）的方法来模拟大范围高精度的二氧化碳柱浓度（XCO₂）的空间分布。首先,探讨分析HASM方法应用于模拟OCO-2卫星观测XCO₂的空间分布的可行性。从2014年9月至2015年8月OCO-2观测的12个月的XCO₂数据中,分别随机选取其各个月90%的XCO₂数据用于空间插值,剩余10%作为精度验证点。自验证结果表明,12个月的平均绝对值误差为0.34 ppm。由此可见,HASM适用于模拟OCO-2卫星观测XCO₂的空间分布。然后,采用HASM对OCO-2在2014年9月至2015年8月的各个月观测数据进行空间插值,获取空间分辨率为0.5°×0.5°的各个月均值XCO₂的空间分布,同时基于地基观测TCCON( Total Carbon Column Observing Network)站的XCO₂数据对HASM模拟结果进行交叉验证。验证结果表明,HASM模拟的XCO₂与TCCON站对应观测数据相比,其平均绝对值误差为0.81 ppm,相关系数为0.88。因此,HASM在模拟OCO-2卫星观测的XCO₂空间分布上具有很大的优势。

Modeling the Spatial Distribution of XCO2 with High Accuracy Based on OCO-2's Observations

In this study, high accuracy surface modeling (HASM) is used to simulate the spatial distribution of XCO₂ with high accuracy in a wild range of regions based on OCO-2 satellite's observations. Firstly, we discussed and analyzed the feasibility of HASM simulation of the spatial distribution of XCO₂ observed by OCO-2 satellite. For the OCO-2's XCO₂ from September 2014 to August 2015, 90% of each month's XCO₂ data were randomly selected as the input of spatial interpolation and the remaining 10% were used to verify the result of spatial interpolation.The results show that the mean absolute error of 12 months is 0.34 ppm. Therefore, HASM is suitable for simulating the spatial distribution of XCO₂ observed by OCO-2 satellite. Then we use HASM to simulate monthly XCO₂ distribution at the spatial resolution of 0.5°×0.5° based on OCO-2's observations from September 2014 to August 2015. Simultaneously, the corresponding TCCON (Total Carbon Column Observing Network) observations are used to verify HASM's simulations. The result shows that the mean absolute error between HASM simulations and TCCON observations is 0.81 ppm and the correlation coefficient between them is 0.88. Therefore, HASM has great advantages in simulating the spatial distribution of XCO₂ observed by OCO-2 satellite.