一次冷涡暴雨过程分析

【作者】 宋新辉；

【导师】 寿绍文；

【作者基本信息】 南京气象学院 ， 气象学， 2003， 硕士

【摘要】 本文从一次东北冷涡的发生发展过程出发，利用9210系统广播的实况数据及T213数值预报的再分析产品，研究讨论了特定冷涡形势下辽西地区暴雨的发生机制，对其产生暴雨时的相关物理量及诊断量进行了分析。从分析中可以看出，虽然东北冷涡是天气尺度系统，但是由于气压场形势的配置不同、冷涡中心的位置和冷空气的移动方向不同、高低空气压场形势演变等原因，造成的局地天气差别是很显著的。通过对物理量的分析可以看出，降水发生时的垂直运动场、水汽通量、T-LOGP的稳定度参数等物理量值，非常有利于暴雨的产生、发展和维持，也就造成了这次辽西地区大范围的暴雨过程。 最后，用MM5中尺度预报模式对这次冷涡暴雨过程做了数值模拟，并对输出的部分结果与实况做了对比。从对比分析的结果看，MM5对高空、地面的环流形势模拟的非常接近实况；对物理量场的模拟，与降水发生的实况所需要的理论条件相吻合，强垂直运动区对应着强降水发生地；Q-矢量的极大值也与降水中心一致，可以应用于定点预报实践。在降水场的模拟中，降雨带的范围与实况接近，强降水中心位置和强度略有偏差，通过修正意见对提高预报准确率会有很大帮助。 综合分析认为：(1)、这次冷涡在其发生发展过程中，其移动路径是沿经圈直线南压，携带的冷空气势力较强，形成槽后较强的垂直运动；(2)、西太平洋副热带高压偏北位置与东北冷涡南压形成的急流轴，把源源不断的西南暖湿气流输送到辽西地区，也就是急流轴的左前方位置，为这次暴雨的产生提供了充足的水汽来源；(3)、低空急流不但为暴雨输送水汽，其造成的较强的垂直环流也是产生强降水的一个主要原因；(4)、MM5模式以四维同化资料作为初始场，最大限度地避免了观测误差可能造成的积分不稳定，提高了模拟结果的参考价值。该模式对这次冷涡暴雨的形势模拟与实际形势场极其接近，是一个成功的应用范例；(5)、MM5模式对各种物理量和降水场的模拟结果与实况接近，在精细化的定点定量预报实践中具有很好的参考价值；(6)、MM5模式预报降水范围和强度与实况还有一定偏差，需要进一步深入的工作来改进。更多还原

【Abstract】 The North-East Cold Whorl (NECW) is one important weather systems, which inflect the weather and climate of the North-East, and is wide studied by meteorological workers, they make many progress. They make sure the definite of the NECW, the spread of the NECW, the start time of the NECW. Above all, the study of the meso-scale system gives much help in analysis the NECW. Mr. Shou Shaowen studied the wet whorl Q-vector divergence and relative whorl’ in several rainstorms, which occurred in Guizhou, and get some useful conclusions. Mrs. Wu Haiying studied the different time of a cyclone, and fined the relations of the rainstorm and a cyclone. Mrs. Yuan Jiashuang studied the warm quantity in a cyclone’ life. Mr. Yue Caijun studied all the Q-vector parameters, and compared them, searched their relationship. He find that the semi-earth Q-vector, the half-earth Q-vector, the non-earth Q-vector, the wet Q-vector, some are useful in analysis the cyclone, others are not.By using the data from 9210 broadcast system and T213 numeric forecast re-analysis data, we studied the starting and developing of one NECW, and discussed the mechanism of West-Liaoning rainstorm at a definite NECW circumstance. We can see, although the NECW is weather scale system, the distribution at difference level contacts very important information. Thus it makes various weathers at definite region. By analysis physical diagnose quantities, we can easily find that the vertical movement, the vapor transfer, the stability at T-LOGP chart, all related with the precipitation when rainstorm occurs. They gave plus effects to the rainstorm.After, we analyses the related physical and diagnose quantity when the rainstorm occurred. At the end, we calculated the rainstorm progress by using MM5 meso-scale forecasting system model, and compared the result with the fact data. The result is excited. The calculating circle is very near compared with the fact. And many physical diagnose quantities thus as high vertical movement, Q-vector divergence, 0-6 km shear etc. all contact with the rainstorm. We can use the MM5 model in definite time, definite area weather forecasting.We conclude that: : □ The moving route of this NECW in its developing progress was direct-south along latitude, the cold air is rough, and just this made the rough vertical velocity; □ The NECW southern moving and conflicting with the West Pacification Sub-Tropical High makes rough jet steam. The plenty south-west warm and wet air made by the jet stream gave the rainstorm demanded vapor; □ .The rough vertical velocity by jet stream is a main reason in this rainstorm; □ The MM5 model uses four-direction analysis data as its input, this avoids some errors occurred in observe and transfer, thus made the result more useful. The circumstance calculated by MM5 forecast system is very near compared with the real one; □. The physical quantity and precipitation calculated by MM5 forecast system should be well used in work; □ The area and numeric of the precipitation forecasted by MM5 have some difference compared with the fact, that needs more some more work to make progress.更多还原