2001～2017年全国气溶胶光学厚度时空分布及变化趋势

为探究全国大气气溶胶光学厚度（AOD）的分布及变化特征，利用最新的MODIS/Terra C6.1 550 nm AOD月数据分析了2001~2017年全国AOD的时空分布及变化趋势.结果表明，空间特征：年均AOD空间分布呈现两个显著的高值中心和低值中心，第一高值中心位于以人为气溶胶为主的华北平原、华中地区、长三角地区、珠三角地区和四川盆地，第二高值中心位于以尘埃气溶胶为主的塔克拉玛干沙漠地区，两个低值中心分别位于内蒙古地区东部至东北地区北部以及青藏高原.时间特征：各区域AOD峰值主要出现在春、夏季，塔克拉玛干沙漠地区、四川盆地和珠三角地区AOD在3~4月达到峰值，华北平原、华中地区和长三角地区AOD在5~7月达到峰值.趋势特征：2001~2006年，我国西北地区和内蒙古地区AOD呈现减少趋势，我国中东部地区和西南地区东部AOD呈现增长趋势.2007~2012年，青藏高原和塔克拉玛干沙漠地区AOD变化趋势由减少转为增长，华北平原和四川盆地AOD的增幅减弱，长三角地区AOD呈现弱的下降趋势.2013~2017年，我国大部地区AOD呈显著地下降趋势.

Temporal-Spatial Characteristics and Variability in Aerosol Optical Depth over China During 2001-2017

Based on the latest monthly data of moderate resolution imaging spectroradiometer (MODIS)/Terra C6.1 aerosol optical depth (AOD), the temporal-spatial distribution and variability trend in AOD over China during 2001-2017 are analyzed to explore the distribution and variation characteristics of AOD in China. Regarding the spatial characteristics, the first prominent high-value center of the annual mean AOD was located in the industrially and economically developed areas of the North China Plain, Central China, the Yangtze River Delta region, the Pearl River Delta region, and the Sichuan Basin. The second prominent high-value center of the annual mean AOD was located in the dust aerosol-dominated areas of Taklimakan Desert. Two low-value centers of the annual mean AOD were located in the eastern part of Inner Mongolia to the north of Northeast China and the Tibet Plateau. Regarding the temporal characteristics, the AOD value peaked in eight areas in spring and summer. The annual mean AOD values in the Taklimakan Desert, Sichuan Basin, and Pearl River Delta peaked from March to May, and those in the North China Plain, Central China, and Yangtze River Delta peaked from May to July. The trend characteristics showed that during 2001-2006, the AOD in Northwest China and Inner Mongolia showed a downtrend, and that in the east-central China and the eastern part of southwest China showed a growth trend. During 2007-2012, the trend of AOD in the Tibetan Plateau and the Taklimakan Desert changed from decreasing to increasing. The growth trend of AOD in the North China Plain and the Sichuan Basin was weakened, and the AOD in the Yangtze River Delta showed a weak downward trend. During 2013-2017, the AOD in most areas of China showed a significant downward trend.