黄土高原的近地小尺度大气结构

The Small-scale Atmospheric Structures near the Surface in the Huangtu plateau

本文通过对９３年两个代表月在黄土高原的系留探测数据的分析，说明了黄土高原的近地小尺度大气结构是近地大气湍流活动形成的，其出现概率、尺度和沿高度的分布因季节和时间的不同而不同。结果表明，这里的小尺度大气结构６月份明显多于１０月份，且６月份中上午的小尺度大气结构多于下午的，１０月份的情况相反；它们主要集中在近地的２００ｍ之内，其垂直尺度多为５～１５ｍ。这些结果可以作为和黄土高原类似地区的代表性数据。本文也描述了试验中观察的４００ＭＨｚ电波的基本传播现象，并对６月份观察到的一个特例作了详细的介绍和讨论，说明了这里的近地小尺度大气结构对电波传播有很大的影响，在最劣月份（６月份）可影响及传播电路的正常工作。

in this paper,the tether-sonde data in the Huangtu Plateau are analyzed,which were obtained inJune and October 1993,and show the occurrence characteristics of the small--scale atmospheric structures near the surface in the Huangtu Plateau.The results show that the occurrence probibilities,sizes and distributions with altitude of these structures vary with seasons and times of day. The occurrences of these structures in June are more frequent than in October,The structures at morning are more than that at afternoon in June, otherwise the structuresat afternoon are more in October.The vertical sizes of these structures are always among 5 to 15 meters,the structures within this range are more at morning than at afternoon in June, in October more of them are at afternoon.These structures are mainly in 200 meters above the surface.All these results can be taken as typical data for roughareas similar to the Huangtu Plateau in weather and relief. Here the effects Of the small--scale atmospheric structures in the Huangtu Plateau on 400Mm EM wave are described, which were observed during the experiment. After the basic phenomena being described, an anomalous propagation case is described in details: Based on the data being scuded, the phenomena is explained;It is concluded that the small--scale atmospheric structures in this area canseverely affect wave propagation,and especially in bad months the interruption of signal can be resulted.