| 风向变化特征在季风模拟评估中的应用 |
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| 引用本文： | 张丽,李建平.风向变化特征在季风模拟评估中的应用[J].大气科学,2008,32(1):53-66. |
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| 作者姓名： | 张丽 李建平 |
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| 作者单位： | 1.中国科学院大气物理研究所大气科学和地球流体力学国家重点实验室,北京,100029;中国科学院研究生院,北京,100049 |
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| 基金项目： | 中国科学院创新团队国际合作伙伴计划项目“气候系统模式研发及应用研究”，优秀国家重点实验室研究项目40523001 |
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| 摘 要： | 作者抓住季风风向具有季节性反转这一最本质的特征，引入了“有向转角”的新概念，它与传统盛行风夹角的概念不同，能够反映风向逐日变化的方向性和旋转角度的大小。用欧拉观点揭示了季风风矢量随时间演变的旋转特点， 体现了季风风向独具特色的季节演变过程。同时，发现不同地区风向的季节循环有6种基本类型:（I）先顺时针后逆时针旋转、（II）先逆时针后顺时针旋转、（III）完全顺时针旋转、（IV）完全逆时针旋转、（V）风向稳定型和（VI）风向变化不稳定型。且季风风向的季节性反转主要通过前四种旋转方式来实现。分析了这6种风向变化型的全球分布特征，研究了它们与大气环流系统演变的联系。并进一步将“有向转角” 概念用于IPCC第四次评估报告AMIP试验8个模式的模拟评估，结果表明，这一概念的引入能从逐日变化的角度凸显风向变化过程，不仅能够客观反映模式模拟季风风向逐日变化的动力过程以及风矢量旋转方式的全球分布，还能体现模式对大气环流系统季节演变的表征能力。研究还发现在这8个模式中，大多数模式基本能把风矢量旋转方式的全球分布形式模拟出来，但对于季风区风矢量旋转方式的模拟还有待于进一步提高。
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| 关 键 词： | 季风 有向转角 风向变化 模式评估 |
| 文章编号： | 1006-9895（2008）01-0053-14 |
| 收稿时间： | 2006-06-05 |
| 修稿时间： | 2006-09-21 |
The Application of the Variation Characteristics of Wind Direction in Evaluating Monsoon Simulation |
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| ZHANG Li and LI Jian-Ping.The Application of the Variation Characteristics of Wind Direction in Evaluating Monsoon Simulation[J].Chinese Journal of Atmospheric Sciences,2008,32(1):53-66. |
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| Authors: | ZHANG Li and LI Jian-Ping |
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| Abstract: | It is acknowledged that seasonal reversal of wind vector is the essential characteristic of monsoon in widely recognitions and definitions.So the variation of wind direction with seasonal evolution is significant for monsoon research.On the other hand,how to evaluate the monsoon simulation well on daily scale in dynamic way is an important work in model evaluation as there are major shortcomings in our ability to simulate even basic aspects of the monsoon with atmospheric general models.Then based on the seasonal reversal of wind vector which is the essential characteristic of monsoon,a new concept,directed rotary angle that is quite different from the previous studies of angle between wind vectors,has been presented.Define the positive angles indicate counter-clockwise rotation of daily wind vector to reference vector(say January climatology wind) and negative angles indicate clockwise rotation.It reflect the daily variations of wind direction including the rotary direction and the degree of rotary angle,and reveals the inimitable features of monsoon seasonal evolution.Meanwhile,based on the concept,six categories of wind vector rotation with seasonal cycle have been detected and classified as follows:(I) Clockwise to counter-clockwise rotation;(II) counter-clockwise to clockwise rotation;(III) full clockwise rotation;(IV) full counter-clockwise rotation;(V) stable rotation;(VI) instable rotation.In addition,the wind in monsoon regions almost rotates in the forms of the first four categories.The authors analyze the global distribution character and investigate the relationship between the variation of wind direction and annual evolution of atmospheric circulation.It shows that different rotary styles of wind vector are closely related to annual evolution of atmospheric circulation,including the strength of trough and ridge,movement of trough and ridge,development of anticyclone or cyclone,movement and split of anticyclone or cyclone.Also,different monsoon systems indicate different rotary styles,which are possibly related to different circulation systems that influence the formation and onset of monsoon.Then the new concept is applied in evaluating the model output of 8 AGCMs of AMIP in IPCC 4th assessment.The results show that it reflects not only the dynamic process and global distribution of wind vectors' rotation styles in monsoon simulation,but also the ability to reproduce circulation seasonal variation.And most of models can simulate the global distribution pattern.However,so little skill is showed in the monsoon rotation style of some models,especially in the South China Sea and West Africa.A few models such as GISS-MODEL-E-R,INM-CM3-0,MIROC3.2-MEDRES,MPI-ECHAM5 and FGOALS-g1.0 can reproduce the rotation styles correctly in some monsoon regions. |
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| Keywords: | monsoon directed rotary angle wind vector variation of wind direction |
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