| 西北太平洋热带气旋迅速增强特征及其影响因子 |
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| 引用本文： | 梅双丽,江静.西北太平洋热带气旋迅速增强特征及其影响因子[J].热带气象学报,2012,28(1):1-11. |
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| 作者姓名： | 梅双丽 江静 |
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| 作者单位： | 南京大学大气科学学院,江苏南京,210093 |
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| 基金项目： | 国家重点基础研究发展项目(2006CB403600);国家自然科学基金(40775043);教育部博士点基金(200802840022)共同资助 |
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| 摘 要： | 选取西北太平洋上热带气旋(TC)24小时风速变化累积频率达95%所对应的15.4 m/s作为迅速增强(RI)的标准,研究了RI个例的基本特征以及TC自身特征因子与环境因子对RI的作用。结果表明,TC迅速增强过程的持续时间平均为33小时,最长可达78小时,并且TC经过迅速增强过程几乎都达到了台风级别以上,其中,一半以上达到了强台风级别以上。对比迅速增强(RI)和非迅速增强(non-RI)个例得到,RI个例相对于non-RI个例发生区域偏南偏东,两者的移动速度没有明显差异,但RI个例有较大向西移动分量并且前12小时增强较大;相对于non-RI个例,RI个例离最大潜在强度较远并且发生在较暖水区和55%～75%的低层相对湿度的条件下;RI个例发生在较小的垂直风切变和较弱的对流层上层东风气流情况下,由上层槽或冷低压引起的强迫弱于平均状况时RI较易发生。TC前12小时强度变化(DVMX)、海表面温度(SST)和垂直风切变(SHR)是影响迅速增强的主要因子,当DVMX≥6.3 m/s时RI发生的可能性最大,达到17.2%。当有若干个影响因子共同起作用时发生RI可能性显著增加,其中以较大的前12小时强度变化(DVMX≥6.3 m/s)、较高的海表面温度(SST≥29.4℃)、较弱的垂直风切变(SHR≤5.9 m/s)、较小的相对涡旋角动量通量辐合(REFC≤-1.6 m/(s.d))、偏东经度(LON≥138.2°E)和低纬度(LAT≤16.7°N)共同作用时,RI发生的可能性达到最大,可达66.7%。
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| 关 键 词： | 气候学 热带气旋迅速增强 统计方法 影响因子 可能性 |
| 收稿时间： | 2011/3/22 0:00:00 |
| 修稿时间： | 2011/1/28 0:00:00 |
CHARACTERISTICS AND INFLUENCE FACTORS OF RAPID INTENSIFICATION OF TROPICAL CYCLONES IN THE WESTERN NORTH PACIFIC |
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| MEI Shuang-Li and JIANG Jing.CHARACTERISTICS AND INFLUENCE FACTORS OF RAPID INTENSIFICATION OF TROPICAL CYCLONES IN THE WESTERN NORTH PACIFIC[J].Journal of Tropical Meteorology,2012,28(1):1-11. |
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| Authors: | MEI Shuang-Li and JIANG Jing |
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| Institution: | School of Atmospheric Sciences, Nanjing University, Nanjing 210093, China;School of Atmospheric Sciences, Nanjing University, Nanjing 210093, China |
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| Abstract: | In this study,rapid intensification(RI) of tropical cyclone(TC) was defined as a maximum sustained surface wind speed increase of 15.4 m/s over a 24 h period,which was approximately the 95th percentile of 24 h intensity changes of TCs.By using the TC best-track data in the western North Pacific from the Joint Typhoon Warning Center,the basic characteristics of RI samples were studied,the effects of large-scale environmental factors on RI were discussed,and the RI probability was estimated.The results were as followings.The average duration of RI over the western North Pacific was thirty-three hours,and the longest duration was seventy-two hours.Almost all tropical cyclones that underwent RI reached typhoon intensity,and more than half of them became intense typhoons.Comparing to non-RI cases,the RI cases preferred forming in farther east and south regions with warmer water.No significant differences were found between the translational speeds of the RI and non-RI cases,but the RI cases had a more westerly component of motion and much larger intensification during the previous 12 h than the non-RI cases.In addition,the RI cases were farther from their maximum potential intensity,and under the condition that the lower-level relative humidity was between 55% and 75% comparing to the non-RI cases.Also,the RI cases were more likely to occur in regions with lower vertical shear,more easterly upper flow,and lower relative eddy flux convergence than the non-RI cases.The intensification during the previous 12 h(DVMX),sea surface temperature(SST) and vertical shear(SHR) were dominant factors that influenced RI.When DVMX was greater than or equal to 6.3 m/s,the probability of RI was 17.2%,the highest probability for a single factor.The probability of RI can be increased significantly by combining several influence factors together.Among these,the highest probability of RI is 66.7% when great previous 12 h intensity change(DVMX greater than or equal to 6.3 m/s),high sea surface temperature(SST greater than or equal to 29.4 ℃),low vertical shear(SHR less than or equal to 5.9 m/s),low relative eddy flux convergence(REFC less than or equal to-1.6 m/(s·d)),high longitude(LON greater than or equal to 138.2 °) and low latitude(LAT less than or equal to 16.7 °N) worked together. |
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| Keywords: | climatology rapid intensification of tropical cyclone statistical methods influence factors probabilities |
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