建国以来当年登陆我国最早的台风“浣熊”的特点及成因

利用海表温度、向外长波辐射及再分析等资料，对台风“浣熊”的特点及成因进行分析。结果表明，“拉尼娜”事件触发了热带西太平洋西侧海洋的异常活跃的状况，为“浣熊”的形成提供有利环流背景。西太平洋副热带高压脊线偏北，西脊点处于120°E附近，配合中南半岛高压环流，使“浣熊”处于鞍型场，偏北移动路径稳定。同时高空强辐散流场对“浣熊”起到非常重要的维持作用，使“浣熊”成为2008年登陆我国最早的台风。地形辐合作用配合台风右侧潮湿东南气流向中纬度槽前输送大量水汽，加上高空强辐散，使登陆阳江的台风“浣熊”主要风雨区在珠江口两侧及粤东地区。另外，应用多普勒天气雷达速度图对环境引导风的判别，把握好“浣熊”登陆前路径转折的可能，及时调整登陆地段预报。

Characteristics and Cause of Noguri,the Earliest Landed Typhoon in a Year since 1949

Typhoon NOGURI is the earliest landfalling typhoon since 1949. With short life cycle and rapid intensity change, it brought tremendously heavy rainfall and damaging wind. Analyses on maritime conditions and large -scale circulations show that, the La Nina Event has triggered anomalously active convections over west flank of Tropical West Pacific, which is favorable for the tropical cyclone genesis; the west pacific subtropical high ridge, located more northward and stretching west to 120°E, together with the South Asia High trapped typhoon NOGURI in a saddle - shape field, which kept it moving on a steady northward track ; strong divergence at upper layers maintained the intensity of NOGURI. Terrain - induced convergence and the moist southwest air stream in lower layers transported abundant water vapor towards the front of mid - latitude trough, which tends to produce rainfall distributed around Pearl River estuary and southeast Guangdong. The patterns of Doppler radial velocity with TC affected by quasi - environmental wind （QEW） are also investigated. The steering effect of QEW on offshore TC proves to he of significant reference for NOGURI＇s track forecasting right before its landfalling.