中国近15年气溶胶光学厚度时空分布特征

Spatial distribution and temporal variation of aerosol optical depth over China in the past 15years

利用MODIS 04_L2气溶胶日产品统计其月度、季度及年度均值数据,研究中国大陆地区近15a气溶胶光学厚度(AOD)空间分布状况;通过Spearman秩相关检验法,探讨中国大陆地区近15a的AOD年均值与季均值的逐年变化趋势.结果表明:在空间分布上,我国AOD多年均值高值中心主要位于四川盆地、南疆盆地、华中地区、长江三角洲、华北平原、关中平原,珠江三角洲地区也有小范围的高值区;低值中心主要位于川西和藏东南、内蒙和冀北交界以及河套地区.在逐年变化趋势上,西北地区AOD值主要呈下降趋势,其中川西和藏东南、陕甘宁交界呈显著下降趋势;东部地区AOD值主要呈现上升趋势,且华中地区、长江三角洲、华北平原以及关中平原呈显著上升趋势;在全国范围内AOD年均值整体呈现上升趋势,但趋势不显著;AOD值随季节变化较显著,具体表现为春夏较高、秋冬较低;AOD高值区以及呈上升趋势的地区基本都处在胡焕庸线东南,表明人类活动对AOD值影响比较显著.

Characteristics of spatial distribution and temporal variation of aerosol optical depth(AOD,on 550nm)in 2000~2014 in China's Mainland were analysed in this paper with monthly,seasonally and yearly mean data,derived from the NASA MODIS04_L2 product.Specifically,we used spearman-test method to investigate the seasonally and yearly variation trends of AOD over China from 2000~2014.The results were as follows:all-year high value of AOD occurred in the Sichuan basin,the southern Sinkiang basin,the central China region,the Yangtze river delta,the north China plain,the Guanzhong plain and the Pearl River delta;while all-year low value of AOD,in the western Sichuan,the southeast Tibet,the border of Inner Mongolia and northern Hebei Province,and part of the Hetao area,occurred.The value of AOD in Northwest China showed a decreasing trend,of which the junction of western Sichuan and southeast Tibet and Shaanxi-Gansu-Ningxia showed a significant downward trend.The AOD value in the eastern part of China mainly showed an upward trend,and there was a marked upward trend in central China,the Yangtze River Delta,the North China Plain and the Guanzhong Plain.AOD value changes more significantly with the seasons,the specific performance is higher in spring and summer,autumn and winter lower.The high value area of AOD and the area of upward trend are basically located in the southeast of Heihe-Tengchong Line,indicating that human activities have a significant impact on the AOD value.