基于本底与卫星资料的全球CH_4浓度变化与时空特征研究

Global Atmospheric Methane Variation and Temporal-Spatial Distribution Analysis Based on Ground-based and Satellite Data

利用大气制图扫描成像吸收光谱仪(SCIAMACHY)获得的2003年到2009年7年间的全球CH4浓度产品,与全球本底观测数据进行长时间序列的对比验证。研究显示,SCIAMACHY的CH4浓度产品误差约为2%,但数据系统性偏低,相关性较差。相比本底观测方法,SCIAMACHY获得了大范围的长时间序列的CH4数据,能够在一定程度上反映全球CH4的浓度变化与时空特征。卫星与本底观测资料显示,2003年至2006年4年间,全球CH4浓度年增长率接近于零;从2007年开始,CH4浓度增长速度有所提高。CH4浓度随着纬度从北到南逐渐降低,海洋地区纬度分布特征明显,而陆地区域由于受到排放源及海拔变化等因素的影响,在空间分布上表现出一些高值与低值区域。受CH4源汇变化的影响,大气CH4浓度呈现出明显的季节变化特征,并存在明显的南北纬度差异。北半球的CH4浓度在夏季最低,冬季最高,而南半球刚好相反。北半球季节波动幅度明显大于南半球,且不同站点的波动幅度差异较大;而南半球站点的波动幅度较小且站点间差异较小。

The global methane（CH4） concentration products retrieved from SCIAMACHY between 2003 and 2009 for seven years have been compared to the ground-based observation records.The results show that the accuracy of CH4 products was about 2%,but it was slightly lower than the ground-based observations and lack of correlation.Compared to the ground-based observation method,SCIAMACHY obtained a long time series of global CH4 data,can reflect the global temporal and spatial distribution of methane to a certain extent.The investigation of satellite and ground-based observations have proved that the annual growth rate of CH4 concentration was close to zero from 2003 to 2006 for four years and had gone up since 2007.It also indicated that the global CH4 concentration was decreased gradually from the north to the south,more obvious in the ocean area,but less in the land area,where showed some high and low value regions in the spatial distribution due to the effects of emission sources and changes in altitude.There is a significant seasonal variation in CH4 concentration and obvious differences in northern and southern hemispheres,the former reached a valley most likely in autumn and a peak in winter,but the latter was just the reverse.The northern hemisphere was significantly greater in seasonal fluctuation and larger differences in the amplitude between sites,while the sites in southern hemisphere were relatively stable and less differences with each other.