中文摘要：

通过地基观测站点的实测数据,首次证实大气温室效应是由人为排放造成的,地表能量平衡受二氧化碳（CO2）浓度水平的影响。因此,分析CO2浓度时空分布特征,从而探究其源汇、控制其排放尤为重要。本文采用AIRS（Atmospheric Infrared Sounder）对流层中层CO2浓度数据及GOSAT（Greenhouse gases Observing SATellite）近地面CO2浓度数据,对比研究了CO2浓度在对流层中层及近地面的时空分布特征差异。结果表明,AIRS探测到的对流层中层CO2浓度,在时空上普遍高于GOSAT探测到的近地面CO2值,高值区位于30°~90°N,浓度多集中在390~395 ppm,这与AIRS探测的对流层中层CO2浓度已充分混合相关;而GOSAT CO2浓度高值区则位于热带、亚热带人口众多的地域,如非洲和中国东部沿海地区等人类活动活跃地带,这也表明GOSAT探测近地面CO2的重要性,其可弥补地基站点测量在空间分布上的不足。本文进一步对比分析了CO2浓度在海陆及南北半球的差异特征及影响原因,CO2在海洋及陆地区域的平均浓度具有相似的时间波动特征,但其浓度在陆地几乎始终高于海洋,这与人类活动释放大量的CO2密切相关。CO2浓度在南北半球存在明显的差异,这是因为南半球的季节变化规律与北半球相反,且由于化石燃料燃烧及土地利用变化等主要集中在北半球,因而北半球CO2浓度高于南半球。此外,本文还对NUCAPS（NOAA/NESDIS/STAR NOAA Unique Cr IS/ATMS Processing System）反演得到的Cr IS（Crosstrack Infrared Sounder）CO2柱平均浓度及廓线产品做了初步分析,发现其与AIRS、GOSAT CO2分析结果一致。

英文摘要：

Recently, direct observational radiance evidence at two ground- based stations in Southern Great Plains and the North Slope of Alaska confirmed that the theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions and provided empirical evidence of how the rising CO2 levels affected the surface energy balance. Therefore, it is important to retrieve CO2 concentration with high precision globally and further to analyze its sources and sinks. This research focuses on the comparison between near-surface and midtropospheric CO2 difference characteristics. First, the CO2 products from AIRS（Atmospheric Infrared Sounder）and GOSAT（Greenhouse gases Observing SATellite） were compared globally during 2010 to 2013. Time series result showed that the mid- tropospheric CO2 concentrations in each month from AIRS were all higher than the near- surface CO2 retrieved from GOSAT, which maybe because of the well- mixed of CO2 in mid- troposphere.And the spatial distribution of four year average CO2 was different between AIRS and GOSAT. As for AIRS, the high value region was between 30°N to 90°N, which affected by large amount of land and high human activity.However, the high value region for GOSAT CO2 occurred in tropical and subtropical area, such as Africa and Eastern China with a large population, which is not revealed by AIRS mid- troposphere CO2. The result demonstrates the significance of satellite sensitive to near-surface CO2 like GOSAT, which can provide important information in near- surface to make up the lack of ground- based stations. Moreover, the differences of CO2 between ocean and land, North Hemisphere（NH） and South Hemisphere（SH） were analyzed. The seasonal features of mean CO2 in ocean and land were similar, while CO2 value of land were higher than that of ocean due to human activity. In addition, different characteristics of CO2 in NH and SH was related to the opposite seasonal patterns in both hemispheres. And higher CO2 value occurred in NH because of the burn of