State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences (UCAS), Beijing, 10049, China.
Environ Pollut. 2019 Oct;253:207-220. doi: 10.1016/j.envpol.2019.06.111. Epub 2019 Jul 10.
Characterizing the vertical distribution of aerosol optical properties is crucial to reduce the uncertainty in quantifying the radiative forcing and climate effects of aerosols. The analysis of four-year (2007-2010) Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) lidar measurements revealed the existence of tropospheric aerosol layers associated with the Asian summer monsoon. The measurements of five typical aerosol optical and microphysical parameters were used to explore the properties, spatial/vertical distributions, annual evolution of tropopause aerosols over the South Asia region. Results extracted from various latitude-height and longitude-height cross sections of aerosol extinction coefficient at 532 and 1064 nm, backscatter coefficient at 532 nm, and depolarization ratio at 532 nm demonstrated that a large amount of aerosols vertically extended up to the tropopause (12 km) during the monsoon season over the north Arabian Sea, India, north Bay of Bengal, and equatorial Indian Ocean, finally reaching the southeast of the Tibetan Plateau. Convective transport associated with Asian summer monsoon is an important factor controlling the vertical distribution of tropopause aerosols. The evolution of aerosol scattering ratio at 532 nm indicated that from equatorial Indian Ocean to South Asia, there exists an upward tilting and ascending structure of the aerosols layer during the monsoon season, which typically indicates enhanced aerosols over the Asian monsoon region. Information on aerosol size distribution and detailed composition are needed for better understanding the nature and origin of this aerosol layer. Enhancement of the tropopause aerosols should be considered in the future studies in evaluating the regional or global climate systems. Further satellite observations of aerosols and in-situ observations are also urgently needed to diagnose this aerosol layer, which likely originate from anthropogenic emissions.
描述气溶胶光学特性的垂直分布对于降低量化气溶胶辐射强迫和气候效应的不确定性至关重要。对四年（2007-2010 年）云气溶胶激光雷达和红外探路者卫星观测（CALIPSO）激光雷达测量结果的分析表明，存在与亚洲夏季季风有关的对流层气溶胶层。利用五个典型的气溶胶光学和微物理参数的测量值，探讨了南亚地区对流层顶气溶胶的特性、空间/垂直分布和年演变。从各种纬度-高度和经度-高度气溶胶消光系数 532nm 和 1064nm、532nm 后向散射系数和 532nm 退偏振比的截面中提取的结果表明，在阿拉伯海北部、印度、孟加拉湾北部和赤道印度洋季风季节期间，大量气溶胶垂直延伸至对流层顶（12km），最终到达青藏高原东南部。与亚洲夏季季风有关的对流输送是控制对流层顶气溶胶垂直分布的重要因素。532nm 处气溶胶散射比的演变表明，从赤道印度洋到南亚，季风季节期间存在气溶胶层向上倾斜和上升的结构，这通常表明亚洲季风地区的气溶胶增加。需要有关气溶胶大小分布和详细成分的信息，以更好地了解该气溶胶层的性质和来源。在评估区域或全球气候系统时，应考虑增强的对流层顶气溶胶。未来的研究还迫切需要对气溶胶进行卫星观测和现场观测，以诊断这种可能源自人为排放的气溶胶层。
