土木工程与力学学院知识库

随着人们对沙尘暴研究的日益深入，沙尘暴中电场的存在逐渐得到广泛认可， 并且作为新兴的研究领域，逐渐得到学者们的重视。目前对风沙电场的研究工作 主要还局限于近地表附近。对更高处的风沙电场认知仍十分模糊。为了弄清楚沙 尘暴中垂向电场的空间演化规律，本文在 QLOA（Qingtu Lake Observation Array） 进行了一系列的野外观测工作。相比于其他的野外观测实验，本文实验特点主要 在于：1）多因素测量：本论文除测量电场强度外，还测量了三维风速、粉尘浓 度以及环境温度。并将多种因素进行综合分析。2）实时高频测量：本论文实验 所用的所有仪器均使用 SPC（沙粒数计数设备）时间进行计时，以确保实验数据 的同步性。三维风速以及温度测量频率达到 50Hz，沙尘浓度和电场强度测量频 率达到 1Hz。3）测量高度以及空间分辨率高：测量实验将高度提升到了 30m，三 维风速和环境温度测量高度 11 个，PM10 浓度测量高度 12 个，垂向电场强度测 量高度 24 个（空间分辨率达到了 1m），为研究垂向电场强度空间分布规律以及 其与风速和沙尘浓度空间分布规律的关联提供了保证。4）测量周期长：本论文 观测实验为期约 3 个月，观测到的沙尘天气 20 余场，使得实验数据较为全面， 提高了实验结果的可靠性。 通过对实验结果的研究分析，本论文得到的主要结论如下：1）验证了沙 尘暴中垂向电场的分层现象确实存在，给出了其高度廓线以及两个较为明显的两 个方向转变的临界高度，并且发现上升下降期分层结构依然存在，只是强度小于 稳定期。2）将垂向电场与粉尘浓度进行对比研究，发现垂向电场的分层现象可 能是由于沙尘浓度空间变化趋势分层造成的。3）将垂向电场与风速以及温度进 行了对比研究，表明在风速在 0.3m/s~0.35m/s 范围，垂向电场大小主要由沙尘 颗粒荷质比所主导。0.2m/s~0.3m/s 以及 0.35m/s~0.5m/s 范围主要由沙尘浓度 主导。大气温度对不同高度处的垂向电场的定量上的影响是一致的，即随温度增 加，垂向电场强度增大。 

With the deepening of the study of sandstorm, the existence of electric field in dust storm has been widely recognized, and as a new research field, scholars have gradually paid attention to it.At present, the research of sandstorm electric field is mainly confined to the near surface. The
cognition of the sandstorm electric field on high is still very vague. In order to find out the spatial evolution of vertical electric field in the dust storm, a series of field observation work was carried out in QLOA (Qingtu Lake Observation Array). Compared with other field observation
experiments, the experimental characteristics of this paper are as follows: 1) Multi-factor measurement: In addition to measuring the electric field intensity, the three-dimensional wind speed, dust concentration and ambient temperature were also measured. And a comprehensive analysis on variety of factors was done. 2) Real-time high-frequency measurement: In this paper, all the instruments used in the experiment were SPC (sand counting equipment) to ensure the synchronization of the experimental data. Three-dimensional wind speed and temperature measurement frequency reached 50Hz, dust concentration and electric field strength measurement
frequency reached 1Hz. 3) Measurement height and high spatial resolution: The measurement experiment had raised the height to 30m, the three-dimensional wind speed and the ambient
temperature measurement height was 11, the PM10 concentration measurement height was 12, the vertical electric field strength measurement height was 24 (the spatial resolution reached 1m ),which provided a guarantee for studying the spatial distribution of vertical electric field strength
and its association with the spatial distribution of wind speed and dust concentration. 4)Measurement cycle length: The observation experiment lasted for about 3 months, and the
observation of dust weather more than 20 fields, which made the experimental data more comprehensive and improved the reliability of the experimental results.
Through the research and analysis of the experimental results, the main conclusions of this paper are as follows: 1) It is proved that the stratified phenomenon of the vertical electric field exists in the dust storm does , the height profile and two obvious critical height of a change in
two-direction were given, and found that the rise and fall of the layered structure still exists, but the intensity is less than the stable period. 2) The vertical electric field and dust concentration were compared and found that the vertical electric field stratification phenomenon may be caused by the
stratification of the spatial variation of dust concentration. 3) The vertical electric field was
compared with the wind speed and temperature, indicating that the wind speed in the range of 0.3m / s ~ 0.35m / s, the vertical electric field size is mainly dominated by the dust particle size ratio. 0.2m / s ~ 0.3m / s and 0.35m / s ~ 0.5m / s range is mainly dominated by dust concentration.
The effect of atmospheric temperature on the vertical electric field at different heights is consistent, that is, with the increase of temperature, the vertical electric field intensity increases.