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郑婧, 许彬, 许爱华. 2017: 远距离台风“康森”与高空西北气流共同作用对大暴雨的影响. 暴雨灾害, 36(4): 329-338. DOI: 10.3969/j.issn.1004-9045.2017.04.005
引用本文: 郑婧, 许彬, 许爱华. 2017: 远距离台风“康森”与高空西北气流共同作用对大暴雨的影响. 暴雨灾害, 36(4): 329-338. DOI: 10.3969/j.issn.1004-9045.2017.04.005
ZHENG Jing, XU Bin, XU Aihua. 2017: The effect of remote typhoon"Conson"and NW flow on a rainstorm event in Jiangxi. Torrential Rain and Disasters, 36(4): 329-338. DOI: 10.3969/j.issn.1004-9045.2017.04.005
Citation: ZHENG Jing, XU Bin, XU Aihua. 2017: The effect of remote typhoon"Conson"and NW flow on a rainstorm event in Jiangxi. Torrential Rain and Disasters, 36(4): 329-338. DOI: 10.3969/j.issn.1004-9045.2017.04.005

远距离台风“康森”与高空西北气流共同作用对大暴雨的影响

The effect of remote typhoon"Conson"and NW flow on a rainstorm event in Jiangxi

  • 摘要: 利用GFS 0.5°×0.5°再分析资料、中国地面与CMORPH融合0.1°×0.1°逐小时降水产品、FY2E卫星资料和常规观测资料,对2010年7月14—15日江西东北部大暴雨天气进行分析,重点讨论了15日远距离台风与高空西北气流的相互作用。结果表明:(1)暴雨发生在副高北缘和高空为西北气流的背景下,低层存在台风“康森”的远距离水汽输送,低涡切变、副热带高压、远距离台风、西风槽、中尺度低压等多尺度系统协同作用导致了强降水的发生,其中远距离台风“康森”与西北气流起了主导作用;(2)由于副高结构不够深厚强盛,强降水发生于南亚高压东侧偏北气流、500 hPa大陆高压和海上副高之间的西北气流、700—850 hPa副高西侧的西南急流中:台风“康森”北侧强劲的东南急流和副高西侧西南急流叠加将低纬大量的水汽和热量沿着大陆高压和海上副高之间的甬道向北输送,使江南北部成为高温高湿高不稳定区,200 hPa上16~20 m·s-1西北气流带动500—700 hPa干空气向南移动,与同步加强的暖湿气流相遇形成斜压锋区,使辐合系统稳定于江南北部;(3)高空西北气流和远距离台风的共同作用使斜压锋区的水平和垂直梯度加大、垂直风切变加强,有利于气旋性涡度发展、锋生加剧,强烈的上升气流穿越锋区,引起强的水汽辐合,加大了层结不稳定,在斜压区激发出多个中尺度涡旋,促进对流发展、强降水发生。(4)预报业务中,关键在于对副高、500 hPa冷槽、台风等外强迫系统强弱的预估,一方面需关注上下层系统作用对比的强弱,找出占主导地位的天气系统,另一方面应注意低层扰动环境的改变。

     

    Abstract: A composite analysis is performed for the rainfall in Jiangxi province during 14-15 July 2010 based on GFS reanalysis data, merged precipitation products, conventional observation data and satellite data. Intensive discussions are made about the effects of the remote typhoon and NW flow. The results show as follows. (1) The storm rainfall is caused by the interactions of multi-scale weather systems, including the vortexes, subtropical high, remote tropical depressions, west trough, meso-scale system with the situation of NW flow. (2) The interactions between remote typhoon and NW flow are beneficial to the stability and development of the vortexes. It also makes the upper level divergence synchronously strengthened with low level convergence. (3) Abundant water vapor and energy are transported from low-latitude areas to storm rainfall regions by the converging southern air flows, which are favorable for the accumulation of water vapor and unstable energy. Cold air from upper level and warm moisture air are mixed up over the rainstorm area, which simulates the baroclinic frontal zone. (4) Horizontal and vertical gradient of baroclinic frontal zones increase with the effect of NW flow and remote typhoon, which also strengthen the vertical wind shear. All these factors are favorable for the development of cyclonic vorticity and frontogenesis. Strong upward flow comes across the frontal zone, which simulates the vapor convergence and convection, and leads to the rainstorm. (5) In prediction, intensity of external forcing systems should be estimated, such as subtropical high, cold trough on 500 hPa, typhoon, etc. For one thing, forecasters should contrast the intensity of upper and lower systems to find out the leading one. On the other hand, change of lower disturbance environment may also be noticed.

     

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