Observation technique development on atmosphere wind field and preciepitation

• Main Authors: Ching-Lun Su, 蘇清論
• Other Authors: Yen-Hsyang Chu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/04761707727415347687

博士 === 國立中央大學 === 太空科學研究所 === 93 === The earth is surrounded with atmosphere layer. The variation and structure of the atmosphere not only affects our living environment but also protects all creatures on the earth. From ancient times to the present, the research of atmosphere has been conducted by Scholars around the world. My major research is on the study of the neutral wind around 80~150km height and the study of lower atmosphere phenomena. At first, the precipitation observations were conducted with different resolutions at 2μs and 4μs pulse width. The precipitation particles were found to reveal non-uniform distribution that is not consistent with the traditional assumption of uniform distribution in the radar volume. The rain drops distribution can be described by exponential type equation, N(D)=Noexp(-δD), or by the Gamma equation, N(D)=NoD^(-μ)exp(-δD) , The important coefficients ,αandβin the power-law relationship, it is successfully deduced for the first time. While observing by the vertical beam and 17 degree tilt beam at the same time, the aspect sensitivity is verified through the precipitation echo power analysis. The antenna pattern is carefully analyzed and calibrated in order to prove these important characteristics. The height distribution of the solid ice crystal and the liquid water particle can be differentiated by the radar echo return power from each other. It was proved that the extend range of liquid water and super cool water should be confined within one kilometer. The half power beam width and the gain of the antenna change with environment, especially under precipitation. The wind field deduction around 80~150km height is based on the TMA experiment results. To conduct the TMA experiment, a very high resolution digital camera system was set up. High accuracy of image position determination method was developed by using spherical trigonometry and surface trigonometry techniques. The turbulence vortex structure was detected. The distribution scale from north to south, east to west was found to be 5km and 1.3km and the thickness is 2 km. The neutral wind can be deduced after the TMA trail location has been precisely determined. The reason of ring type trail formation can be explained successfully through this analysis.