| 西北太平洋热带气旋移动方向变化异常的环流特征 |
| |
| 引用本文： | 周宜卿,余锦华.西北太平洋热带气旋移动方向变化异常的环流特征[J].气象科学,2015,35(6):720-727. |
| |
| 作者姓名： | 周宜卿 余锦华 |
| |
| 作者单位： | 南京信息工程大学 气象灾害教育部重点实验室 大气科学学院, 南京 210044,南京信息工程大学 气象灾害教育部重点实验室 大气科学学院, 南京 210044 |
| |
| 基金项目： | 国家自然科学基金资助项目(41575083,41375098) |
| |
| 摘 要： | 基于中国气象局和上海台风研究所整编的1972-2011年热带气旋(TC)best-track资料,采用极端天气气候事件定义的百分位法确定TC移动方向异常变化的阈值,利用Lanczos滤波法将大气环流分解成为季节内振荡(MJO)、准两周振荡(QBW)和天气3种尺度环流场,研究这3种尺度环流对热带气旋在南海地区异常北折的影响。结果表明:近40 a的资料统计显示,热带气旋12 h内移向逆时针方向偏转50°以及顺时针方向偏转47°为TC移动方向变化的95%分位数值,将12 h移动方向变化大于该数值的TC定义为移动方向变化异常。TC异常路径平均每年发生2.68次,9月份发生的概率最大,约为7%,最常发生在南海海域。分析3个发生在南海地区热带气旋异常北折的引导气流发现,在TC转向前,向西的引导气流纬向速度减慢,经向分量先向南加速,随后突然转为向北加速。天气尺度对应的引导气流对TC异常右偏影响最为明显,对流层中高层热带气旋中心东南侧强天气尺度西南气流引导TC异常右偏。
|
| 关 键 词： | TC移动方向变化 统计特征 引导气流 多时间尺度环流 |
| 收稿时间： | 2014/12/11 0:00:00 |
| 修稿时间： | 5/5/2015 12:00:00 AM |
Circulation characteristics of track variation anomaly of tropical cyclone in the northwestern Pacific |
| |
| ZHOU Yiqing and YU Jinhua.Circulation characteristics of track variation anomaly of tropical cyclone in the northwestern Pacific[J].Scientia Meteorologica Sinica,2015,35(6):720-727. |
| |
| Authors: | ZHOU Yiqing and YU Jinhua |
| |
| Institution: | Key Laboratory of Meteorological Disaster of Ministry of Education, College of Atmospheric Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China and Key Laboratory of Meteorological Disaster of Ministry of Education, College of Atmospheric Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China |
| |
| Abstract: | Based on the best-track datasets of the tropical cyclone(TC) from 1972 to 2011 reoganized by China Meteorological Administration(CMA) and Shanghai Typhoon Institute(STI), the threshold of TC track variation anomaly was determined by percentile method defined by extreme events; the atmospheric circulation was divided into Madden-Julian oscillation(MJO),quasi-biweekly oscillation(QBW) and synoptic scale components by Lanczos filter method, moreover,the influences of the above three circulation scales on the abnormal northward of TC over South China Sea were also analyzed in this paper. Results showed that based on 40 years of statistical data, the TC with an anticlockwise deflection more than 50° or with a clockwise deflection more than 47° within 12 hours is defined as 95% quantile of TC abnormal direction change. TC abnormal direction changes on the average reached 2.68 times a year and it generally occurred in the South China Sea with the 7% highest probability in September. The analysis on the steering component of three abnormally northward turning TC over the South China Sea found that before TC turning, the zonal velocity of westward steering component slowed down and the meridional component speeded up firstly southward, then suddenly turned to the north.The synoptic scale steering had the most obvious effect on the anomalous right-turning, and the synoptic-scale southwest steering component on the southeast side of TC center in the upper troposphere made the TC moving northward abnormally. |
| |
| Keywords: | Deflection of TC Statistical characters Steering flow Multi-time scale circulation |
|
| 点击此处可从《气象科学》浏览原始摘要信息 |
| 点击此处可从《气象科学》下载免费的PDF全文 |
|
