Comparing simulated atmospheric carbon dioxide concentration with GOSAT retrievals  

大气反演模型模拟的CO_2浓度与GOSAT卫星观测值的对比(英文)

作　　者：张慧芳 陈报章 许光 严建武 车明亮 陈婧 房世峰 林晓凤 孙少波 

机构地区：[1]State Key Laboratory of Resources and Environment Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Department of Tourism and Environmental Sciences, Shaanxi Normal University

出　　处：《Science Bulletin》2015年第3期380-386,I0002,共8页科学通报（英文版）

基　　金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05040403);the National High Technology Research and Development Program of China (2013AA122002)

摘　　要：Satellite observations of atmospheric carbon dioxide （CO2） provide a useful way to improve the understanding of global carbon cycling. In this paper, we present a comparison between simulated CO2 concentrations from an inversion model of the CarbonTracker Data Assimilation System （CTDAS） and satellite-based CO2 measurements of column-averaged dry air mole fraction （denoted XCO2） derived from version 3.3 Atmospheric CO2 Observations from Space retrievals of the Greenhouse Gases Observing SATellite （ACOS-GOSAT） L2 data products. We examine the differences of CTDAS and GOSAT to provide important guidance for the further investigation of CTDAS in order to quantify the corre- sponding flux estimates with satellite-based CO2 observations. We find that the mean point-by-point difference （CTDAS-GOSAT） between CTDAS and GOSAT XCO2 is -0.11 4-1.81 ppm, with a high agreement （correlation r = 0.77, P 〈 0.05） over the studied period. The latitudinal zonal variations of CTDAS and GOSAT are in general agreement with clear seasonal fluctuations. The major exception occurs in the zonal band of 0°-15°N where the difference is approximately 4 ppm, indicating that large uncertainty may exist in the assimilated CO2 for the low- latitude region of the Northem Hemisphere （NH）. Additionally, we find that the hemispherical/continental differences between CTDAS and GOSAT are typically less than 1 ppm, but obvious discrepancies occur in different hemispheres/continents, with high consistency （point-by-point correlation r = 0.79, P 〈 0.05） in the NH and a weak correlation （point-by-point correlation r = 0.65, P 〈 0.05） in the Southern Hemisphere. Overall, the difference of CTDAS and GOSAT is small, and the comparison of CTDAS and GOSAT will further instruct the inverse modeling of CO2 fluxes using GOSAT.大气CO2反演法是碳浓度／源汇估算的重要方法，其估算精度一直受观测数据不足的制约，而CO2卫星观测数据的出现必将改变这一现状．将大气反演模型CTDAS模拟浓度与GOSAT-ACOS3．3卫星观测值作对比，以分析观测与模拟CO2浓度间的误差分布特征，为CTDAS同化GOSAT数据作前沿性技术探讨结果表明，CTDAS与GOSAT的CO2数据相关性较好，其全球浓度平均差异（CTDAS—GOSAT）为（-0．11±1．81）ppm．在2009～2010年之间，观测与模拟值问的最大纬度偏差出现在0°-15°N间，其纬度问的误差达～4ppm，说明该区的CTDAS浓度模拟值可能存在很大的不确定性．同时，我们也对不同半球及不同洲际间的CO2浓度作了对比研究表明，全球各区的平均浓度差异均小于-1ppm，但不同区域间CO2差异分布明显不同．其中，北半球陆地CO2差异的相关性明显优于南半球．总之，CTDAS与GOSAT的CO2数据有较好的一致性，其对比结果将为下一步的卫星同化工作提供重要指导．

关 键 词：CTDAS model Satellite-based CO2 concentration GOSAT Comparison Inversion method 

分 类 号：P412[天文地球—大气科学及气象学]