Pool of Dust Particles over the Asian Continent: Balloon-borne Optical Particle Counter and Ground-based Lidar Measurements at Dunhuang, China
Pool of Dust Particles over the Asian Continent: Balloon-borne Optical Particle Counter and Ground-based Lidar Measurements at Dunhuang, China
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DOI：
10.1023/b:emas.0000014505.43198.48
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发表时间：
2004-03
影响因子：
3
通讯作者：
Y. Iwasaka;G. Shi;Y. Kim;A. Matsuki;D. Trochkine;D. Zhang;M. Yamada;T. Nagatani;M. Nagatani;Z. Shen;T. Shibata;H. Nakata
中科院分区：
文献类型：
--
作者：
Y. Iwasaka;G. Shi;Y. Kim;A. Matsuki;D. Trochkine;D. Zhang;M. Yamada;T. Nagatani;M. Nagatani;Z. Shen;T. Shibata;H. Nakata
为了了解亚洲大陆荒漠地区大气颗粒物的性质，2001年和2002年在中国敦煌(40°00‘N，94°30’E)进行了气溶胶测量。利用光学粒子计数器在气球上进行的测量表明，不仅在边界混合层中，而且在自由对流层中，粒子的尺寸和浓度在超微米范围内都有明显的峰值。超微米粒子浓度在对流层顶中部(从5公里到10公里；海平面以上，A.S.L.)显著降低。2002年8月在敦煌进行的激光雷达测量表明，即使在平静的天气条件下，沙尘粒子也可能从近地面到约6公里处发生混合，气溶胶中的颗粒物有很大的退偏率。气溶胶层的顶部是在近6公里的高度被发现的。这强烈表明，非球形尘埃粒子(KOSA粒子)经常通过小尺度湍流在塔克拉玛干沙漠上空的自由大气中扩散，是弱COSA事件的可能来源，不仅在春季，而且在日本群岛上空的自由对流层中也发现了这种尘埃粒子。自由对流层中收集的粒子的电子显微镜实验证实，矿物粒子观测到的粗大和非球形粒子是敦煌上空约5公里以下粗模(直径大于1μm)的主要成分，中国。
Measurements of aerosols were made in 2001 and 2002 at Dunhuang (40°00′N, 94°30′E), China to understand the nature of atmospheric particles over the desert areas in the Asian continent. Balloon-borne measurements with an optical particle counter suggested that particle size and concentration had noticeable peaks in super micron size range not only in the boundary mixing layer but also in the free troposphere. Super-micron particle concentration largely decreased in the mid tropopause (from 5 to 10 km; above sea level, a.s.l.). Lidar measurements made during August 2002 at Dunhuang suggested the possibility that mixing of dust particles occurred from near the ground to about 6km even under calm weather conditions, and a large depolarization ratio of particulate matter was found in the aerosol layer. The top of the aerosol layer was found at heights of nearly 6km (a.s.l.). It is strongly suggested that nonspherical dust particles (Kosa particles) frequently diffused in the free atmosphere over the Taklamakan desert through small-scale turbulences and are possible sources of dust particles of weak Kosa events that have been identified in the free troposphere not only in spring but also in summer over Japanese archipelago. Electron microscopic experiments of the particles collected in the free troposphere confirmed that coarse and nonspherical particles observed by the mineral particle were major components of coarse mode (diameter larger than 1 μm) below about 5 km over Dunhuang, China.