2003—2022年东北地区气溶胶光学厚度变化特征

Variation Characteristics of Aerosol Optical Depth in Northeast China from 2003 to 2022

  • 摘要: 利用2003—2022年我国东北地区MODIS(moderate-resolution imaging spectroradiometer)大气气溶胶光学厚度(aerosol optical depth, AOD)数据和中国多尺度排放清单模型(multi-resolution emission inventory for China, MEIC), 分析东北地区AOD的空间分布特征及年际变化趋势, 讨论气象因子和人为排放对东北地区AOD变化的影响。结果表明: 辽宁AOD较高, 最大值为0.6, 出现在辽宁中部, 其次是吉林西部, AOD平均值为0.4, 黑龙江AOD平均值为0.3。东北地区AOD高值区出现在春季和夏季, AOD空间分布在秋季呈减小趋势, 冬季分布范围增加。不同季节AOD最高值均出现在辽宁, 东北地区夏季AOD增加主要与环境湿度有关, 边界层气象条件对冬季AOD具有一定影响。辽宁AOD在0.1, 0.2)和0.2, 0.3)范围内年平均发生频率最高为50%, 吉林和黑龙江AOD在0.1, 0.2)范围的年平均发生频率最高为25%~30%, 特别是黑龙江极端清洁状况AOD在0.0, 0.1)范围内年平均发生频率最高为15%。东北地区AOD区域平均值在2003年和2014年较高, 主要受到边界层气象要素和人为排放SO2、PM2.5、有机碳和NO2影响。东北地区夏季AOD年代际变化趋势从2012年之前的增长趋势(0.1·(10 a)-1)向2013以后的减少趋势(-0.3·(10 a)-1)转变。

     

    Abstract: Based on the MODIS (moderate-resolution imaging spectroradiometer) AOD (aerosol optical depth) and MEIC (multi-resolution emission inventory for China) in Northeast China from 2003 to 2022, the spatial distribution and interannual trend of AOD in Northeast China are analyzed. Effects of meteorological factors and anthropogenic emissions on AOD changes in Northeast China are discussed. Results show that the AOD maximum in central Liaoning is 0.6, followed by an average AOD of 0.4 in western Jilin and 0.3 in Heilongjiang. The average AOD in Northeast China is lower than that in north China, Yangtze River Delta and other frequent pollution areas. High AOD occurs in spring and summer in Northeast China, and it decreases spatially in autumn while increases in winter. The summer AOD in Liaoning is significantly higher than that in other regions, when the average value in central Liaoning and the Bohai Rim increases to 0.6. The highest values of AOD in different seasons occur in Liaoning, followed by Jilin and Heilongjiang. The increase of AOD in summer is mainly related to environmental humidity, and adverse meteorological conditions and local emissions have certain effects on near-surface atmospheric extinction in winter. The annual occurrence frequency of AOD in the range of 0.1, 0.2) and 0.2, 0.3) in Liaoning is up to 50%, the annual occurrence frequency of AOD in the range of 0.1, 0.2) in Jilin and Heilongjiang is up to 25%-30%, and the annual occurrence frequency of extreme clean condition in Heilongjiang is up to 15%. Affected by dust events in spring, the occurrence frequency of AOD 0.2, 0.3) and AOD 0.3, 0.4) in Northeast China is 25%. The regional average value of AOD in Northeast China is higher in 2003 and 2014, which is mainly influenced by boundary layer meteorological elements and anthropogenic emission of SO2, PM2.5, organic carbon (OC) and NO2. In Northeast China, AOD is negatively correlated with boundary layer height and average wind speed, and positively correlated with anthropogenic emissions. The correlation coefficient between AOD and anthropogenic emissions of SO2, PM2.5 and OC is the highest in Liaoning. From 2003 to 2022, AOD in Liaoning shows a weak negative growth trend (about-0.1 per decade), while the AOD in Jilin and Heilongjiang shows little change trend. From the perspective of seasonal interannual trend, there is a transition from a negative increasing trend in spring to a positive increasing trend in summer before 2012. After 2013, the summer AOD in Northeast China shows a negative growth trend (-0.3 per decade), which confirms that the contribution of summer aerosol to atmospheric extinction in Northeast China is decreasing in the past 10 years.

     

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