Lidar Observation and Numerical Simulation of a Kosa (Asian Dust) over Tsukuba, Japan during the Spr
Lidar Observation and Numerical Simulation of a Kosa (Asian Dust) over Tsukuba, Japan during the Spr
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今年春天日本筑波上空的亚洲沙尘激光雷达观测与数值模拟
DOI：
10.2151/jmsj1965.66.3_457
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发表时间：
1988
影响因子：
3.1
通讯作者：
Y. Nikaidou
中科院分区：
文献类型：
--
作者：
K. Kai;Yoshitaka Okada;O. Uchino;I. Tabata;Hajime Nakamura;T. Takasugi;Y. Nikaidou
1986年3月初，亚洲大陆的沙漠和黄土地区发生了多次沙尘暴和沙尘暴。几天后，满载尘埃的空气被西风从黄海输送到日本。3月12-13日，日本多个气象台报告了一种“亚洲沙尘”现象。1986年3月13日日本标准时间15时至21时，在日本筑波对KOSA进行了激光雷达观测。给出了激光雷达观测到的KOSA层的垂直结构和时间变化。在JST 15时，在4公里处和2公里处分别存在两个KOSA层。上层的厚度约为1公里，散射比为3.2。下层的散射比为2.6，似乎与背景气溶胶混合在一起。随后，4公里处的KOSA层厚度和散射强度增加，厚度为1.5公里，散射比为5.7。18JST时，4公里处的科萨层在4.5公里处和3.5公里处分成两个亚层。上层和下层总厚度为2.3公里。激光雷达获得的光学厚度为694.3 nm，光学厚度为0.086。从日本夏令时18时至20时，科萨层逐渐下降0.5公里。20JST时，KOSA层在4.0公里、3.2公里和2.7公里处分成3个亚层。对并行探空资料的分析表明，上层和下层是干燥的，而中间亚层是潮湿的。对KOSA颗粒的长程输运进行了数值模拟。模拟的示踪物水平和垂直分布与筑波的激光雷达观测、日本和中国的常规气象观测结果吻合较好。特别是，观测到的两个KOSA层的结构被很好地模拟出来。两个KOSA层被发现起源于源区不同的高度。数值模拟揭示了黄土高原及其邻近沙漠是COSA的重要来源。另一种可能性包括塔克拉马坎沙漠。KOSA颗粒从黄土高原及其邻近沙漠到达日本的旅行时间为2至3天，从塔克拉玛干沙漠到达日本的旅行时间为5至6天。
A number of duststorms and/or sandstorms occurred in the deserts and loesslands of the Asian Continent in early March of 1986. After a few days the dust laden air was transported over the Yellow Sea to Japan by westerly winds. On 12-13 March, a number of Japanese meteorological observatories reported a "Kosa (Asian dust)" phenomenon. The lidar observation of the Kosa was made at Tsukuba, Japan from 15 JST to 21 JST on 13 March 1986. The vertical structure and time change of the Kosa layer observed by the lidar are presented. At 15 JST, two Kosa layers existed at 4km and 2km, respectively. The upper layer had a thickness of about 1km and a scattering ratio of 3.2. The lower layer had a scattering ratio of 2.6 and appeared to be mixed with background aerosols. Subsequently, the Kosa layer at 4km increased in thickness and scattering intensity, with a thickness of 1.5km and a scattering ratio of 5.7. At 18 JST the Kosa layer at 4km separated into two sublayers at 4.5km and 3.5km. The total thickness of the upper and lower sublayers was 2.3km. The lidar derived optical thickness was 0.086 (wavelength 694.3 nm). From 18 to 20 JST, the Kosa layer gradually lowered 0.5km. At 20 JST the Kosa layer separated into three sublayers at 4.0km, 3.2km and 2.7km. Analysis of concurrent radiosonde data showed that the upper and lower sublayers were dry, while the middle sublayer was humid. A numerical simulation was carried out to investigate the long range transport of the Kosa particles. Simulated horizontal and vertical distributions of the tracers were in good agreement with the lidar observation at Tsukuba and the routine meteorological observations in Japan and China. In particular, the observed structure of the two Kosa layers was well simulated. The two Kosa layers were found to originate from different altitudes over the source regions. The numerical simulation reveals the Loess Plateau and its neighboring deserts as important sources for the Kosa. Another possibility includes the Takla Makan Desert. Travel time of the Kosa particles to reach Japan was two to three days from the Loess Plateau and its neighboring deserts, and five to six days from the Takla Makan Desert.