摘要
应用Qiu等提出的两步变分反演法,由厦门、长乐两部雷达观测资料反演0604号台风"碧利斯"登陆福建霞浦前的风场,并利用反演的水平风场检验几种常用的台风涡旋模型对此次台风的合理性,以期对雷达资料应用于台风过程分析和模拟有更进一步的认识。结果表明,两步变分法可以较好地反演出台风的水平、垂直风场特征,水平风场呈现不对称性且有明显的偏心结构,流场随高度表现出漏斗形特征,垂直风速与水平流场对应较好,台风中心有下沉气流,外围有上升气流。通过对台风物理量的分析发现,此次台风过程存在以最大风速半径随高度向外倾斜的主环流圈和低层向中心流入,高层向外流出的次环流圈。利用反演的水平风场对常用的对称风场涡旋模型进行了验证,发现在最大风速圈内取Rankine模式,最大风速圈外取Chen3模式对此次台风过程拟合较好。
A two-step variational method proposed by Qiu et al. is employed to retrieve three-dimension wind fields before 0604 typhoon Bilis making landfall at Xiapu, Fujian Province, in which dualDoppler radar observations located at Xiamen and Changle are used. By utilizing the retrieval horizontal wind to test the rationality of the common typhoon vortex model, hoping to further recognize the radar data in applying to analyze and simulate typhoon process. The results show the method has ability to retrieve the horizontal and vertical wind field characteristics of typhoon. The asymmetrical structure can be obviously seen from the horizontal wind field. The wind field took on the funnel shape characteristic with increasing height. The downdraft occurred in the inner core and the updraft in the external part of the typhoon. By analyzing on the variables, it is found that there are a principal circulation in which the radius of the maximum wind speed dipped outward with the height and a secondary circulation with the inflow at the lower layers and outflow at the higher layers. Verified the conventional vortex models against the retrieved wind fields, the simulation on the typhoon wind structure is optimal when Rankine model is used within the maximum tangential velocity and Chen 3 model is used in its outside.
出处
《高原气象》
CSCD
北大核心
2010年第1期187-196,共10页
Plateau Meteorology
基金
国家973项目(2004CB418305)
国家自然科学基金项目(40505022)资助
