近海加强台风“威马逊”(1409)环境条件及结构特征的数值研究  

Numerical analysis on circulation features and structure of offshore intensified typhoon Rammasun(1409)

作　　者：林晓霞[1,2] 王硕甫 冯业荣[1] LIN Xiaoxia WANG Shuofu FENG Yerong(Institute of Tropical and Marine Meteorology // Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, CMA, Guangzhou 510641, China School of Atmospheric Science, Chengdu University of Information Technology, Chengdu 610225, China Meteorological Bureau of Foshan City, Foshan 528000, China)

机构地区：[1]中国气象局广州热带海洋气象研究所∥广东省区域数值天气预报重点实验室,广东广州510641 [2]成都信息工程大学大气科学学院,四川成都610225 [3]佛山市气象局,广东佛山528000

出　　处：《中山大学学报（自然科学版）》2017年第5期101-111,共11页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：公益性行业专项基金(GYHY201406009);佛山市气象局科研项目(201403);广州市科技计划项目(201604020012);国家自然科学基金(41675099)

摘　　要：利用新一代区域数值模式GRAPES对1409号超强台风"威马逊"强度急剧变化过程进行数值模拟试验,模拟结果较好地再现了台风"威马逊"在南海的路径和强度的变化特征,进一步利用数值模拟结果对"威马逊"发展的环境条件及其结构变化特征展开分析。分析结果表明,"威马逊"急剧发展期间高层辐散低层辐合同时增加,且高层辐散明显强于低层辐合;低层水汽流入增加,主要的流入边界是东南边界,且总水汽净流入量与台风强度变化有较好对应关系;环境风垂直切变较弱,且"威马逊"强度在深层和高层切变减小后24 h达到强盛。台风开始发展前动力和热力结构上均具有显著的不对称性结构,对流运动东南强、西北弱。强盛期南强北弱,东西方向趋于对称发展,且台风低层眼壁迅速收缩,高层有向外扩张趋势;切向风迅速增大,有很强的经向梯度,中高层气旋性环流显著增强。温度场上具有显著的暖心结构,强盛期台风中心正温度距平可达到11℃以上,集中于台风中心高空300~200 h Pa之间,并向高低层传播。低层不断有正涡度流入,台风中心附近正涡度增大,正涡度柱呈铅直发展并向对流层中上层传播。这些结构的变化都有利于"威马逊"强度的发展。The GRAPES（Global/Regional Assimilation and Pr Ediction system） model was used to study the rapid intensification of Super Typhoon Rammasun（1409） offshore China in this paper.On the basis of successful simulation of the intensity change and track,the model output was further analyzed to determine the large-scale environmental condition of Typhoon Rammasun and the mechanism for its rapid intensity change.The results show that the favorable background field with low-level convergence and highlevel divergence occurred during the rapid intensification,abundant water vapor transport at lower-levels provided favorable energy for Typhoon,which was mainly transported by the southeastern boundary.Besides,the weak vertical wind shear lower than 6 m/s was in favor of gathering the latent heat of condensation and maintaining the＂warm heart＂structure,and there was a time lag of about 24 hours between the vertical wind shear reduced and Typhoon’s increased sharply.Analyses on the structure showed that the dynamic and energetic fields were highly asymmetric during its strengthening stage but became structurally symmetric during its mature stage.Convection was stronger in the southeast of the typhoon than in the northwest during its strengthening stage.The range of eyewall was small in the low-level but extended in the high-level.Positive vorticity increased in the eye of the typhoon and expanded to the mid and uppertroposphere.Besides,the tangential-wind speeds increased with the increasing of typhoon intensity,especially during the process of rapid intensification.Furthermore,there was evidently warm-core structure in the lower and mid-upper level which highly concentrated to the center of Rammasun,and the positive temperature anomaly of the typhoon center exceeded 11℃,while the warm-core extending towards to lower and higher layer.All above happened during the rapid intensification were the main reasons of the intensification of Rammasun.

关 键 词：天气学 近海加强台风 数值模拟 环境条件 结构变化 

分 类 号：P444[天文地球—大气科学及气象学]