| 一次北方台风暴雨(9406)能量特征分析 |
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| 引用本文： | 张苏平,李春,白燕,雷小途.一次北方台风暴雨(9406)能量特征分析[J].大气科学,2006,30(4):645-659. |
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| 作者姓名： | 张苏平 李春 白燕 雷小途 |
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| 作者单位： | 1.中国海洋大学物理海洋教育部重点实验室暨海洋-大气相互作用和气候实验室,青岛,266003;上海台风研究所,上海,200030 |
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| 基金项目： | 上海市台风研究基金;教育部科学技术研究项目 |
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| 摘 要： | 从能量角度分析了9406号台风在我国北方造成大范围暴雨过程,定量讨论了台风变性过程中显热能、潜热能和动能的时空分布特征、北方暴雨区远距离降水突然增幅过程中能量的变化、以及动能的补充来源.发现:(1)虽然潜热能比显热能小1个量级,但潜热能平流大于显热能平流.热带气旋在获得西风带斜压能量之前,其总能量的维持主要来自潜热能的贡献,潜热能的贡献约是显热能的两倍.(2)台风远距离降水的突然增幅是中低纬度系统相互作用的结果.来自热带气旋的显热能平流与西风带显热能平流非线性叠加,导致槽前显热能明显增加,西风带槽迅速加深,降水突然增幅.同时,暴雨区高空动能下传的突然增强对暴雨突然增幅有贡献,而该高空动能下传的增加与6小时之前台风环流区大量潜热能量释放相对应.(3)台风进入影响区之前,在整个对流层有潜热能、显热能和动能直接从台风区输入暴雨区;在台风进入影响区之后,只有低空显热能平流保持继续向暴雨区输送能量.(4)台风进入影响区之后,北方暴雨区动能的补充主要来自对流层上层动能的下传、斜压不稳定能量向动能的转化和北方暴雨区西边界动能的输入.5个类似台风的合成分析支持了以上主要结论.得出的暴雨增幅模型可对预报台风远距离降水有指示作用.
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| 关 键 词： | 热带气旋 北方暴雨 能量分析 |
| 文章编号： | 1006-9895（2006）04-0645-15 |
| 收稿时间： | 2005-02-22 |
| 修稿时间： | 2005-02-222005-11-25 |
Energy Analysis on a Heavy Storm Case in North China Caused by Typhoon No. 9406 |
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| ZHANG Su-Ping,LI Chun,BAI Yan and LEI Xiao-Tu.Energy Analysis on a Heavy Storm Case in North China Caused by Typhoon No. 9406[J].Chinese Journal of Atmospheric Sciences,2006,30(4):645-659. |
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| Authors: | ZHANG Su-Ping LI Chun BAI Yan and LEI Xiao-Tu |
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| Abstract: | A heavy storm case over the northern part of China caused by typhoon No.9406(Tim) is investigated by means of energy analysis.Very strong enhancement of precipitation occurs in the northern regions when the typhoon is still far away.When the typhoon comes close to the westerlies,it gradually shows the characteristics of mid-latitude cyclones.This paper focuses on the energy variations between the typhoon and storm regions.The temporal and spatial distributions of apparent energy,latent energy and kinetic energy are discussed in the process of the typhoon's transition.The variations in the energies in the process of abrupt enhancement of remote precipitation and the kinetic energy balance are studied quantitatively.In order to further prove the conclusions drawn from the case study,composite analysis is made including 5 other typhoons which are similar to the typhoon No.9406.The main results are as follows: (1) Though the magnitudes of the latent heat energy are less than the apparent one,the advection of the former is stronger than the latter's.The maintenance of the total energy is largely due to the contributions of the latent heat energy before the tropical cyclone captures baroclinic energy when it comes close to the westerlies.The contributions made by the latent heat energy are about two times larger than those made by the apparent heat energy.While the apparent heat energy could reflect the process quite clearly in which the typhoon is transformed into mid-latitude cyclone.(2) The causes for the abrupt enhancement of precipitation far away from the typhoon are rather complicated.The apparent heat energy field shows the interactions between the tropical cyclone and the mid-latitude trough.The apparent heat energy advection associated with the tropical cyclone gets together with the apparent heat energy advection coming from the westerly trough to lead to the rapid energy increases in front of the trough,which could result in the sudden deepening of the trough and thus the enhancement of the precipitation.On the other hand,the kinetic energy coming down from the upper troposphere seems to play a role in the enhancement of the precipitation.The rapid coming down of the kinetic energy may be connected with the strong latent heat released about 6 hours earlier by the convections in the typhoon cell in the southern areas.These processes depict to a certain degree the mechanism of sudden enhancement of remote precipitation caused by typhoon,and these patterns can be used in the prediction of precipitation in northern storm regions.But the mechanism for the sudden coming down of kinetic energy should be studied further.(3) The advection through the south boundary of the northern storm region shows that before the typhoon enters the boundary,the apparent heat energy,the latent heat energy and the kinetic energy are transported directly from the typhoon area into the northern storm regions in the whole troposphere.After the typhoon enters the boundary,only the apparent heat energy keeps transporting into the northern storm regions in the lower troposphere.(4) After the typhoon enters the boundary,the losses of kinetic energy in the northern storm regions are compensated by the incoming kinetic energy from the west boundary of the storm regions,by the downward transport of the kinetic energy from the subtropical jet aloft and by the conversion of the baroclinic potential energy into the kinetic one. |
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| Keywords: | tropical cyclone heavy storm in northern regions of China energy analysis |
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