CALIOP观测的渤海、黄海气溶胶类型时空分布特征

Spatiotemporal pattern of aerosol types over the Bohai and Yellow Seas observed by CALIOP

采用14年(2006~2019年)的CALIOP星载激光雷达数据,基于最新的激光雷达气溶胶类型划分方法,辨识了0.28~8.17 km高度范围内渤海、黄海主导气溶胶类型,揭示了各类气溶胶的垂直分布特征,分析了其长期演变趋势和季节差异。研究发现:(1)受到东亚大陆特别是沙尘输运的显著影响,渤海、黄海主导气溶胶类型为沙尘海洋型(36%)、沙尘型(25%)、清洁海洋型(17%)、煤烟型(11%)和污染沙尘型(9%)(合计>97%),其中与沙尘有关的3种气溶胶类型占比合计近七成。(2)各类型气溶胶的垂直分布特点鲜明:清洁海洋型和沙尘海洋型气溶胶主要分布在2.5 km高度以下;污染沙尘型和煤烟型气溶胶则主要分布在2.5 km高度以上;沙尘型气溶胶占比随高度增加而增大。(3)从长期演变来看,14年间污染沙尘型气溶胶占比呈波动下降趋势,清洁海洋型气溶胶占比逐年增加,煤烟型气溶胶占比逐年降低。(4)各类型气溶胶的占比及垂直分布均具有明显的季节差异。

Based on the 14 years(2006-2019)CALIOP data and up-to-date lidar aerosol classification method,the dominant aerosol types and the vertical distribution characteristics over the Bohai and Yellow Sea within the height range of 0.28-8.17 km were identified,and the long-term variability and seasonality were revealed.(1)The dominant aerosol types in the study area are Dusty Marine(36%),Dust(25%),Clean Marine(17%),Elevated Smoke(11%)and Polluted Dust(9%)(totally>97%),with the three types of aerosol related to dust accounting for about 70%.(2)The vertical distribution of various types of aerosols has distinct characteristics.Aerosols of Clean Marine and Dusty Marine are mainly found in the atmosphere with height below 2.5 km.Polluted Dust and Elevated Smoke are mainly above 2.5 km.The proportion of Dust aerosols increases with height.(3)In regards of the long-term variability,the percentages of Polluted Dust show a fluctuating descending trend during the past 14 years,whereas that of Clean Marine aerosol increases steadily,and that of Elevated Smoke decreases monotonously.(4)The proportion and vertical distribution of various types of aerosols exhibit obvious seasonal variability.