| 西北太平洋热带气旋路径异常偏折的分类特征 |
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| 引用本文： | 王敏,徐祥德,李英.西北太平洋热带气旋路径异常偏折的分类特征[J].热带气象学报,2019,35(2):177-186. |
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| 作者姓名： | 王敏 徐祥德 李英 |
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| 作者单位： | 中国气象科学研究院灾害天气国家重点实验室，北京 100081 |
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| 基金项目： | 国家自然科学基金项目41475055国家自然科学基金项目41475061国家自然科学基金项目41575063 |
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| 摘 要： | 基于中国台风网CMA-STI热带气旋（TC）最佳路径资料，对1949—2016年西北太平洋TC路径发生异常偏折的地理位置进行K-means聚类分析，并将其分为五个区域。对各区TC路径异常偏折的频数、方向变化、周期及时间变率等特征进行分析。结果表明:(1)不同分区TC异常偏折高频月份不同，纬度较高区域主要发生在夏季，纬度较低区域则主要发生在秋季。(2)异常右折TC在发生偏折前移向主要为西北向，偏折后为北向；异常左折TC偏折前主要为北向，偏折后主要转为西北向。(3)西北太平洋TC异常偏折总频数存在准2~4年、准3~6年的年际变化周期，其长期变化趋势表现为20世纪80年代中期之前呈增加趋势，其后呈减少趋势, 低纬区域年变化与之最为相似，中高纬区域变化趋势不明显。（4）将研究区域按5 °×5 °进一步栅格化统计TC异常偏折频数的时间变率，发现其地理分布表现为中国沿海为正、台湾岛以东海域为负的变化特征。其中沿海的增加趋势主要由异常右折增加引起，台湾岛以东洋面的减弱趋势主要由异常左折的减少引起。(5)异常右折TC强度增强的高频中心主要位于菲律宾半岛以东洋面，次中心位于中国南海中部，而强度减弱位于台湾岛西南区域；异常左折TC强度增强的高频中心位于南海中部，强度减弱中心位于我国东南沿海。
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| 关 键 词： | 热带气旋 异常路径偏折 K-means聚类分析 |
| 收稿时间： | 2018-03-04 |
THE CHARACTERISTICS OF UNUSUAL TURNING TRACKS OF TROPICAL CYCLONE OVER THE WESTERN NORTH PACIFIC |
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| WANG Min,XU Xiang-de and LI Ying.THE CHARACTERISTICS OF UNUSUAL TURNING TRACKS OF TROPICAL CYCLONE OVER THE WESTERN NORTH PACIFIC[J].Journal of Tropical Meteorology,2019,35(2):177-186. |
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| Authors: | WANG Min XU Xiang-de and LI Ying |
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| Institution: | State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, 100081, China |
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| Abstract: | Based on the best track data of tropical cyclones(TCs) over the period 1949-2016 available from Shanghai Typhoon Institute, China Meteorological Administration. K-means cluster method is applied to classify unusual turning locations of TCs in western North Pacific into five regions. Then, a statistical analysis is performed to study occurrence、directional change、period and temporal variability of unusual turning TCs in different regions. Results show that: (1) Differences manifest in different regions for the occurrences of unusual turning TCs, while mainly occur in warmer summertime around higher latitude area, and mainly occur in autumn around the lower latitude area. (2) Analyses of their directions reveal that TC moving directions are mainly northwestward before the turning time, while tend to northward direction after the turning time for the unusual right-turning TCs. Motions occur mainly in the northward direction before the left-turning time, while they tend to northwestward direction after left-turning. (3) There are obvious periods of 2~4 years、3~6 years for the unusual turning TCs, variability shows that they are ascended before Mid-1980s, while declined after that time. And the annual variation in the lower latitude region is more similar to the total, but there are no obvious features existing in the higher latitude. (4) The temporal variability of unusual turning occurrence frequencies within 5 ° × 5 °grids represents positive tendency around Chinese Mainland coastal area, the negative tendency in the east of Taiwan Island. It is found that the increase of unusual right-turning TCs mainly contribute to the coastal area with increasing tendency, while unusual left-turning TCs mainly contribute to the decreasing tendency in the east of Taiwan Island. (5) During unusual right-turning period, there are two high-frequent centers, where the intensity of TCs are strengthened, one is in waters near Philippines, and the other is in the central part of South China Sea, respectively. While the high-frequent center of the weakened TCs is in the southwestern area of Taiwan Island. For the unusual left-turning TCs, the strengthened highest-frequent center of TCs is located in the central part of South China Sea, and the weakened center is located in the southeastern coast of China. |
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| Keywords: | tropical cyclone unusual turning tracks K-means cluster analysis |
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