论文部分内容阅读
本文对１９９８年西北太平洋上（包括南海，下同）热带气旋（不含热带低压，下同）特征进行了分析，得出，该年西北太平洋上生成的热带气旋个数和登陆我国的个数之少，第一个热带气旋出现时间及登陆初台出现时间之晚均创半个世纪以来的历史记录。而热带气旋生成的地理位置偏西，１５０°Ｅ以东太平洋洋面无热带气旋生成及热带气旋强度弱、生命史短的特征在过去几十年中也是罕见的。文章对盛夏５００ｈＰａ环流场进行了分析，得出：西北太平洋副热带高压强大、脊线位置偏南、西伸脊点偏西、过赤道气流弱、赤道辐合带偏南且不活跃是造成１９９８年热带气旋频数少等特征的主要因素。
In this paper, the characteristics of tropical cyclones (excluding tropical depression, the same below) on the Northwest Pacific (including the South China Sea, the same below) in 1998 were analyzed, and the number of tropical cyclones and the number of landfalling in China in the western North Pacific in that year The history of the first tropical cyclone and the time since its arrival in the initial stage have hit a record of half a century. The tropical cyclones are geographically westward. There is no tropical cyclone formation on the Pacific Ocean to the east of 150 ° E and the weak tropical cyclone intensity and short history of life are rare in the past few decades. The paper analyzes the 500hPa circulation field in midsummer. It is concluded that the northwestern Pacific is strong with strong subtropical high, the ridgeline is southward, the westward ridge is westward, the weak equatorial flow is weak, and the equatorial convergence zone is southward and inactive. Year tropical cyclone frequency characteristics of the main factors.