【作者】 董长宝；

【导师】 杨德保； 杜继稳；

【作者基本信息】 兰州大学 ， 气象学， 2008， 硕士

【摘要】 本文研究了秦岭北麓降雨与渭河洪水的洪峰流量、洪水总量的关系,认为秦岭北麓山区是渭河洪水的重要产流区,利用秦岭北麓降雨和气象部门的降雨数值预报,可以预估渭河下游洪水情况,并通过对渭河流域53次致洪暴雨过程的统计分析,总结了致洪暴雨的发生发展规律,并根据诱发原因和降水分布等特点将致洪暴雨过程分为四种致洪暴雨类型。同时,应用天气学原理和湿有效位能等知识对致洪暴雨个例进行了分析,总结出了致洪暴雨的天气学模型,讨论了暴雨型和天气型之间的对应关系。在此基础上,应用常规气象观测资料、水文实测资料和NCEP全球再分析资料(空间分辨率1°xl°),对发生在2005年秋季的陕西渭河流域致洪暴雨过程从环流形势、物理量场等方面进行了初步的分析,发现这次暴雨过程是在有利的天气形势下,受500hPa低槽、副高以及中尺度低涡等共同作用产生的,并且涡度、散度等物理量场的高低空配置有利于维持较强的垂直速度,对暴雨的产生和维持有利。通过WRF模式对2005年秋季渭河流域致洪暴雨模拟结果显示,暴雨雨带走向、强降雨中心位置以及强降水出现的时间段等都与实况基本吻合,预报时效可达36-48小时;模式能成功地模拟出暴雨的主要影响系统和不同时段的风场演变变化。另外湿位涡诊断表明:强降水发生时,暴雨区上空低层是MPV＜0的不稳定区,MPV负中心出现在暴雨中心附近,并且有MPV1＜0,MPV2＞0且∣MPV1≥MPV2∣的环境大气,有利于暴雨的产生。最后,通过地形的敏感性试验进一步揭示了地形对致洪暴雨的增幅作用。分析表明,利用WRF模式可以对不同类型暴雨进行机理分析和研究,能够作为客观预报陕西渭河流域致洪暴雨的一种重要技术手段和工具。更多还原

【Abstract】 This paper studied The North of Qinling Mountains rainfall,which was the relationship between the total flood and the Weihe River flood peak flows,and to consider The North of Qinling Mountains that is the important Weihe River flood runoff area,to utilize The North of Qinling Mountains rainfall and the rainfall numerical weather prediction can be expected in the Weihe River downstream flooding,and statistical analyzed the process of flood-inducing heavy rain occurred 53 times in Weihe River basin,and summarized the rule of the flood-inducing heavy rain.According to the characteristics of induced reason,precipitation distribution and so on,the process of flood-inducing heavy rain were divided into four kinds.We analyzed a flood-inducing heavy rain using the synoptic meteorology principle and the moist-specific available energy knowledge,summarized the synoptic meteorology model of heavy rain and discussed the corresponding relations between the kinds of rainstorm and the weather.The process of flood-inducing heavy rain occurred on "05.10" in Weihe River Basin of Shanxi province were studied by means of the conventional observation data,the hydrological data and the NCEP reanalysis data(spatial resolution 1°xl°),from the two aspects:circulation situation and the physical vector fields.The results indicated that the severe storm which influenced by the reciprocity of the 500hPa low altitude slot,subtropical high and mesoscale characteristic and so on, occurred under the advantageous large scale weather conditions.Moreover,the physical vector fields of jet stream in upper and low level such as vorticity and divergency was advantageous to the maintenance stronger vertical velocity,which benefitted to this rainstorm.WRF model through the 2005 flood caused by heavy rain fall Weihe River Basin simulation results show that,with rain to heavy rain,strong rainfall center,as well as heavy rainfall,and so the time of the anastomosis with the basic fact,forecasting spent up to 36-48 hours;mode successfully simulated rainstorm and the main system in different time slots of the evolution of wind changes.The diagnosis of moist potential vorticity(MPV)shows that there are the instability area of MPV<0,and the negative focus of MPV located at the focus of heavy rainfall Above the rainfall area,when heavy rainfall happening.Moreover,MPV1<0,MPV2>0 and | MPV1≥MPV2 | are the favorable environment of heavy rainfall generating,finally,Sensitivity experiments further reveal the amplifying effect of terrain on the heavy rain.Analysis shows that the model can be used on different types of heavy rain for analysis and research,to a future objective of the Weihe River Basin flood forecasting Shaanxi rainstorm forecasting an important technical means and tools.更多还原