2010-2012年江淮黄淮地区暖季强对流过程统计分析

发布时间：2019-03-10 18:58

【摘要】：中国江淮和黄淮地区是强对流天气的多发区域,本文利用三年(2010-2012年,4-10月)常规观测资料、再分析资料以及探空资料,对江淮黄淮地区(30-37° N,110-122° E)发生的1009个强对流天气过程进行了统计分析,得到该地区强对流发生的时空特征,典型环境背景以及对流关键参数的统计特征。统计发现,江淮黄淮地区强对流天气过程从2010年至2012年是逐年减少的。月分布上,强对流主要发生在6-9月,8月最多,呈单峰型;空间分布上,从4月开始强对流从南向北逐渐增多,到8月在全区范围达到最多,而后8月至10月又从北向南逐渐减少;江淮黄淮地区有明显的三块强对流多发区域,按其在研究区域所占比率大小分别是东部平原地区、山东泰山周边地区、大别山和黄山一带。从日变化来看,强对流过程主要发生在15-21时(LST),持续时间为1小时的强对流过程和总的强对流过程分布形态一致,呈单峰型,持续时间大于等于3小时的强对流过程在15-21时为主峰,在06-09时出现次峰,呈双峰型。日变化在空间分布上,从早至晚强对流过程有自西北向东南发展的规律。在强度上持续型强对流降水强度普遍要大于短时强对流类型。根据500hPa形势场将个例分成了低槽型、副高型、冷涡型、台风型四大类,其中低槽型716例,副高型226例,冷涡型30例,台风型37例。通过合成分析得到不同环境背景下天气系统与强对流发生时的平均位置特征,以及平均环境要素特征。发现副高型和台风型可降水量最大,低槽型适中,冷涡型就明显不如前三类;不稳定条件上,副高型和台风型最不稳定,低槽型适中,冷涡型不稳定度最低。利用探空资料统计强对流发生前的环境参数,发现副高型的水汽更多的集中在边界层低层,而台风型水汽分布更多在深厚的对流层中,低槽型水汽条件适中,冷涡型相对较小;副高型潜在不稳定最大,属于强对流较易触发类型,低槽型适中,而冷涡型潜在不稳定度相对较小,并且对流抑制能量最大,台风型潜在不稳定度在发生前与发生时改变很大,发生前最小,而发生时为最大。动力条件上,发现各个类型都有有利于垂直运动发展的环境条件。对比不同维持时长强对流,发现无论在水汽条件、不稳定条件以及动力抬升条件上,持续型强对流都是最强的,这与不同维持时长强对流的强度特征一致,对流抑制能量持续型与短时强对流相差不大。最后通过与已有研究对比,发现江淮黄淮地区的强对流过程潜在不稳定度偏弱,但具有较湿的环境场。
[Abstract]:The Jianghuai and Huang-Huai regions in China are prone to severe convective weather. In this paper, using the three-year (2010-2012, April-October) routine observation data, reanalysis data and sounding data, to the Jianghuai Huang-Huai area (30 掳N, 37 掳N), 1009 severe convective weather processes occurred in 110 掳E are statistically analyzed, and the spatial and temporal characteristics of strong convection occurrence in this area, the typical environmental background and the statistical characteristics of the key convection parameters are obtained. It is found that the severe convective weather process decreases year by year from 2010 to 2012 in the Huanghuai area of the Yangtze River and Huaihe River. In the monthly distribution, the strong convection occurred mainly from June to September, and the most occurred in August, showing a single peak type. In spatial distribution, strong convection gradually increased from south to north in April, reached the maximum in August, and then decreased from north to south from August to October. There are three strong convective regions in the Huanghuai area of the Yangtze River and Huaihe River. According to their proportion in the study area, they are the eastern plain area, the area around Mount Tai in Shandong Province, the Dabie Mountains and the Huangshan Mountains. According to the diurnal variation, the strong convective process mainly occurs at 15-21:00 (LST), duration of 1 hour, and the distribution pattern of the total strong convection process is the same as that of the total strong convection process, showing a single peak pattern. The strong convection process with duration greater than or equal to 3 hours is the main peak from 15 to 21:00, and the secondary peak appears from 06 to 09:00, showing a bimodal pattern. The diurnal variation develops from northwest to southeast in spatial distribution from early to late strong convection. The intensity of continuous strong convective precipitation is generally larger than that of short-term strong convection. According to the 500hPa potential field, the cases are divided into four types: low trough type, sub high type, cold vortex type and wind type. Among them, there are 7 16 cases of low trough type, 226 cases of sub high type, 30 cases of cold vortex type and 37 cases of wind type. The average location characteristics and average environmental factors of weather system and strong convection under different environment background are obtained by synthetic analysis. It is found that the subtropical high type and the wind type have the largest precipitable amount, the low trough type is moderate, the cold vortex type is obviously inferior to the first three types, the sub-high type and the wind type are the most unstable, the low trough type is moderate, and the cold vortex type is the lowest. Using sounding data to calculate the environmental parameters before the occurrence of strong convection, it is found that the water vapor of sub-high type is more concentrated in the lower layer of boundary layer, while the distribution of wind-type water vapor is more in the deep troposphere, the low-trough type of water vapor is moderate, and the cold vortex type is relatively small. The potential instability of the subtropical high type is the largest, belonging to the strong convection type which is more easily triggered, the low trough type is moderate, while the cold vortex type is relatively small in potential instability, and the convection suppression energy is the largest, and the potential instability of the wind type changes greatly before and after the occurrence. It is the smallest before the occurrence, and the largest at the time of occurrence. In terms of dynamic conditions, it is found that all types have environmental conditions conducive to the development of vertical motion. Compared with different duration strong convection, it is found that the continuous strong convection is the strongest in water vapor condition, unstable condition and dynamic uplift condition, which is consistent with the intensity characteristic of strong convection in different maintenance length. There is no significant difference between the persistent type of convective suppression energy and the short-term strong convection. Finally, through the comparison with the previous studies, it is found that the potential instability of the strong convective process in the Yangtze-Huaihe-Huai region is weak, but it has a relatively wet environmental field.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P458.1

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