长江上游中小洪水天气学分型及特征  

Synoptic patterns and characteristics of medium and small flood events in the upper reach of the Yangtze River

作　　者：王海燕[1] 李波[2] 李子进 李银娥[1] 李进[2] 

机构地区：[1]武汉中心气象台,武汉430074 [2]三峡梯调通信中心,宜昌443000 [3]湖北省宜昌市气象局,宜昌443000

出　　处：《暴雨灾害》2015年第4期293-301,共9页Torrential Rain and Disasters

基　　金：中国长江电力股份有限公司项目"长江上游流域中小洪水天气特征分析"(2414020008)

摘　　要：基于1981—2012年宜昌水文站流量资料,普查出128例长江上游中小洪水过程。然后,利用国家气象站雨量资料和NCEP再分析资料,从环流背景出发,结合降水特点,将上述中小洪水过程分为纬向环流型、经向环流型、两高之间型和偏东气流型,其中经向环流型又分为贝湖槽类和东北槽类。最后,归纳各类天气型的主要影响系统、物理量特征、洪水特征,并建立天气学模型。分析表明:纬向环流型新疆北部低槽比常年同期偏强,经向环流型贝湖槽类和东北槽类分别是贝加尔湖低槽和东北地区低槽比常年同期偏强,两高之间型则是在青藏高压与副热带高压之间形成切变,偏东气流型受台风影响较多;致洪强降水一般发生在高层辐散、可降水量较大、中层正涡度且水汽通量辐合、中低层有暖平流的区域;从各型日最大流量增幅及过程流量平均增幅看,纬向环流型最大,偏东气流型最小。Based on flow data from Yichang hydrological station from 1981 to 2012, firstly, we found that 128 medium and small flood events over the upper reach of the Yangtze River by a general survey. Secondly, using rainfall data from national weather stations and reanalysis data from NCEP, we classified these medium and small flood events into four patterns, namely, the zonal circulation-pattern, the meridional circulation-pattern, the between two high pressures-pattern, and the easterly flow-pattern. On the basis of background circulation and rainfall characteristics, the second pattern is again divided into the Bay Lake trough-type and the Northeast China trough-type. Lastly, we summarized the main influence systems, physical quantity feature and flood characteristic for the four patterns, and established corresponding weather models. Results showed that for the first pattern, low troughs in Northern Xinjiang are stronger than they are during the same period of normal years. For the second one, low troughs in Bay Lake and Northeast troughs in Northeast China are stronger than they are during the same period of normal years. For the third one, there are shear lines formed between the Tibetan high and the subtropical high. For the last one,most of them are influenced by typhoons. Flood-causing severe precipitation occurs in the region where there are divergence in the upper level, with high precipitable water vapor, positive vorticity and moisture flux convergence in the middle level, and warm advection in the midand low-level. Of all four patterns, both the diurnal flow extreme increment and the mean flow increment of event are the greatest for the first pattern, but the smallest for the last one.

关 键 词：中小洪水 天气学分型 纬向环流型 经向环流型 两高之间型 偏东气流型 

分 类 号：P426.616[天文地球—大气科学及气象学]