中尺度对流系统对台风“风神”移动路径影响的研究  

The impact of mesoscale convective systems on the track of Typhoon Fengshen (2008)

作　　者：沈新勇[1] 毕明玉[1] 张玲 刘佳[1] 

机构地区：[1]南京信息工程大学气象灾害省部共建教育部重点实验室,南京210044 [2]国家气象中心,北京100081

出　　处：《气象学报》2012年第6期1173-1187,共15页Acta Meteorologica Sinica

基　　金：国家重点基础研究发展计划973项目(2009CB421503);公益性行业科研专项(GYHY200806009);国家自然科学基金项目(41075039;41175065);江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：通过卫星资料分析台风"风神"路径预报之所以出现较大的偏差,可能是由于"风神"西侧中尺度对流系统引起的。为了更好地研究中尺度对流系统对台风的影响,利用中尺度非静力数值模式WRF对"风神"的移动过程开展了高分辨率数值模拟,模拟采用双重嵌套,最高分辨率6km,共积分78h。利用模拟资料,采用PV-ω分部位涡反演方法定量分析了台风外围中尺度对流系统对台风运动的影响,认为PV-ω分部位涡反演方法能够很好地分离出台风外围中尺度对流系统,其对台风引导气流的贡献可达到20%左右。为验证中尺度对流系统的影响,用模式积分的方法,通过3组模拟实验,发现中尺度对流系统使台风路径偏左或偏右可能随着环境引导气流方向而改变,而在此个例中的中尺度对流系统会使得台风向西和向极移动得更远。对比研究了不同中尺度对流系统对台风的影响,发现在"风神"移动过程中,中尺度对流系统之所以引起较大影响是因为中尺度对流系统与台风相对位置变化不大所致。The satellite blackbody equivalent temperature data is used to investigate the possible mechanism leading to the great error in process of track prediction. The results show that the existence of the mesoscale convective system （MCS） may account for it. By using the non-hydrostatic WRF model, the Typhoon Fengshen （2008） is simulated in high-resolution for better understanding the impact of the MCS produced in the west and southwest of the typhoon. In this paper, the simulation is double nesting with the highest resolution of 6 km and the sum of 78 h integrated. The PV-co piecewise potential vortieity retrieval di- agnostics is applied to quantitatively evaluate the impact of the MCS on typhoon movement. It is found that the mean wind of MCSs on the steering level can reach 20 % of the typhoon steering wind. Investigation into the effect of the MCS is also done by considering the MCS existence as an initial-value problem. Three model experiments were conducted and the results show that whether the MCS makes the typhoon turn left or right varies dependently on the direction of the typhoon steering flow and it also shows that the existence of MCS makes the typhoon go farther to the northwest in this case. Two different types of MCSs were investigated and it shows that stable relative position between the MCS and Typhoon Fengshen may be the reason why the MCS has great effect on the track of typhoon.

关 键 词：中尺度对流系统 位涡反演 台风路径 引导气流 数值模拟 

分 类 号：P458.1[天文地球—大气科学及气象学]