卫星遥感监测全球大气气溶胶光学厚度变化

 全球大气气溶胶类型和含量变化与气候变化和大气环境污染密切相关,是气象学、环境学和医学研究关注的热点问题。为认识全球气溶胶分布基本特征,发现和跟踪全球气溶胶显著变化地区,本文利用美国NASA 发布的C6 版MODIS气溶胶光学厚度产品分析全球大气气溶胶光学厚度时空年变化特征及其影响因素;分析气溶胶光学厚度分布与中国霾区的关系,提出霾区治理的气溶胶光学厚度年平均值参考标准。分析2003-2014 年卫星监测的气溶胶光学厚度(AOD)空间分布特征显示,全球气溶胶光学厚度稳定高值区位于亚洲东部及其邻近太平洋海区、印度半岛及其邻近印度洋海区、非洲北部和中部及其邻近大西洋海区;重点变化关注区为俄罗斯西伯利亚东部增量区和南美洲亚马逊平原热带雨林减量区。气溶胶光学厚度高值地区的形成与沙尘暴、火山喷发、生物质燃烧、工业排放等自然源,以及工业污染物排放、交通运输、秸秆焚烧等人类活动造成的人为源气溶胶排放直接相关,并受气象因素和山脉等地形阻挡因素影响,这些因素的稳定性与季节变化最终形成全球气溶胶的时空分布特征。中国东部气溶胶光学厚度年平均值大于0.5 的区域为主要霾天气区,其中华北南部、黄淮、江淮、江汉地区和四川盆地为全球气溶胶光学厚度极端高值区,年平均极端高值达到0.8~1.0,为霾天气常态化发生区;通过全球气溶胶光学厚度量值分析认为,气溶胶光学厚度年平均值0.5 可作为中国大气环境最大承载量,中国东部地区高于此值的区域为主要大气污染控制区,大范围工业生产污染物减排可带来整体环境改善,通过工业结构调整有望降低的气溶胶污染中位比率为33%,平均比率为26.5%。

Global change of aerosol optical depth based on satellite remote sensing data

The aerosol type and the concentration variation are the hotspots related to the climate change, the environment and the human-health. The AQUA/MODIS aerosol optical depth (AOD) product issued by NASA is used to analyze the temporal and spatial changes of the multi-yearly and annual mean AODs in the whole world and in China for diagnosing the aerosol events that directly emitted or affected, such as the haze, the dust storm or the volcano eruption. The results show that the eastern Asia, the Indian peninsula, the northern and central Africa and their adjacent ocean areas have relatively high AODs. The significantly changing areas include the east area of Siberia due to the smoke by fire and the Amazon rainforest for bioaerosols by vegetation emissions. These high and sensitive AOD regions are closely related with the aerosol emission by natural and human activities, and they are also influenced by weather and terrain. In China, the regions in the eastern China with the yearly mean AOD higher than 0.5 are the haze weather areas. In particular, the Huanghe-Huaihe River basin, the Yangtze-Huaihe River basin and the central part of China have the highest mean AODs of 0.8-1.0, where serious haze weather often occurs. The highest AOD is caused by the highest emission from the industrial and agricultural productions, constructions, and heavy transportations. So, based on the reference the AOD (background 0.2, natural events impact 0.15, human living impact 0.15) obtained from the aerosol distinctive area, the annual mean AOD of 0.5 is defined as a threshold for delimiting the haze area and the pollution control district. In China, the environmental improvement depends on the cutting back the industrial emissions in the regions with annual mean AOD higher than 0.5, and the middle cutting ratio is 33% and the averaged cutting ratio is 26.5%.