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题名 基于风廓线雷达的沙尘暴和降水过程探测分析
姓名 王敏仲
院系 大气科学学院
专业 气象学
学位名称 理学博士
外文题名 Detection Analysis of Sandstorm and Precipitation Process Based on Wind-Profiling Radar
第一导师姓名 魏文寿
关键词 风廓线雷达;沙尘暴;降水过程;探测分析;参数反演
外文关键词 Wind-profiling radar;Sandstorm;Precipitation process;Detection analysis;Parametric inversion
学科 理学
摘要 利用风廓线雷达开展了对沙尘暴、降雨、降雪过程的探测试验研究,重点分析了沙尘暴过程回波信号和速度功率谱分布特征,计算归纳了沙尘暴的回波强度量值范围,定量反演估算了沙尘暴高空粒子数浓度和质量浓度。此外,从风的精细结构分析、锋面系统判识、温度平流反演、回波强度等角度探讨了高时分辨率的风廓线资料在干旱区降雨(雪)天气分析中的应用技术方法。主要结论如下: (1)CFL-03风廓线雷达在沙尘暴进行探测时,湍流散射回波信号微弱,沙尘粒子群散射回波信号较强,雷达主要识别到沙尘返回信号,往往忽略了大气湍流回波。 (2)CFL-03风廓线雷达在沙尘暴过程测风有效数据获取率较低,大气干燥、湍流起伏较弱、折射率结构分布均匀是影响风廓线雷达有效测风的关键因素。 (3)沙尘暴天气现象在雷达回波强度时间-高度图上有着清晰的印痕,可判识沙尘输送的高度和厚度,可反映沙尘的垂直强度分布。扬沙和沙尘暴天气的雷达等效回波强度约在-1~13dBZe范围变化。 (4)降雨(雪)天气现象在风廓线雷达回波强度时间~高度图上有着清晰的印记和表现,回波强度大值区间与降雨(雪)天气过程、云雨(雪)粒子形成的高度以及降水强度有较好的对应关系。
外文摘要 Using the boundary layer wind-profiling radar we did the detection experiment study on the processes of sandstorm, rainfall and snowfall. The emphasis is put on the analysis of the echo signal and velocity power spectrum distribution during the process of sandstorm, and the observed wind data in the process is evaluated as well. The echo intensity value range of sandstorm is calculated and summarized and the high-level particle number concentration and mass concentration of sandstorm is quantitatively inversed and estimated. In addition, from the perspectives of wind detailed analysis, frontal system identification, temperature advection inversion, echo intensity, etc., we investigate the technical method of applying the high resolution wind profiler data to the rainfall (snowfall) weather analysis in arid areas. The main conclusions are as follows: (1) When the CFL-03 boundary wind-profiling radar works in dry sandstorm weather, atmospheric refraction index is small, turbulence echo signal is weak, but the sand particle group produces strong backscatter to the electromagnetic wave. The wind-profiling radar mainly identifies the returning signal of sands, ignoring the scattering echo signal of atmospheric turbulence. (2) Effective data acquisition rate of the CFL-03 radar is low during the process of sandstorm. The effective data acquisition rate can go over 40% under 2,000 m height, ranges within 20%-40% between the 2,500-4,000 m height and lower than 20% above 4,000 m. One critical factor that impacts the wind-profiling radar to detect wind effectively is the dry atmosphere and low relative humidity. The result that RASS system detects the virtual temperature during sandstorms is not so ideal, and the effective detected height is mostly lower than 500 m. The important cause for the unsatisfactory temperature observation is that the sandstorm reduces acoustic waves seriously and the returning signal is very weak. (3) The sandstorm weather phenomenon leaves clear signets on the radar echo intensity time-height diagram, by which the height and thickness of sands carried by the storm can be identified and the vertical distribution of sands can be reflected. Equivalent radar echo intensity of flying sand and sandstorm weather varies in the range of -1~13dBZe. (4) Vertical shear of horizontal wind and the sustainment of low-level easterly are the dynamic causes for the occurrence of sandstorm weather in Taklimakan Desert. The moment when low-level wind ...
研究领域 极端天气与气象灾害
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