| Numerical Simulation on Development Mechanism of Meso-βScale Flow Field During a Heavy Rain Process in Henan Area |
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| 引用本文： | 廖移山,张兵,李俊,李武阶,宇如聪.Numerical Simulation on Development Mechanism of Meso-βScale Flow Field During a Heavy Rain Process in Henan Area[J].Acta Meteorologica Sinica,2007,21(1):64-74. |
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| 作者姓名： | 廖移山 张兵 李俊 李武阶 宇如聪 |
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| 作者单位： | Wuhan Institute of Heavy Rain CMA,Wuhan Institute of Heavy Rain,CMA,Wuhan Institute of Heavy Rain,CMA,Wuhan Institute of Heavy Rain,CMA,Wuhan Institute of Heavy Rain,CMA,Wuhan 430074,Wuhan 430074,Wuhan 430074,Wuhan 430074,Wuhan 430074 |
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| 基金项目： | Supported by the National Natural Science Foundation of China under Grant No.40575029,the Commonweal Special Project "Study of flood-leading rainstorm forecast and warning system in South China" of the Ministry of Science and Technology. |
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| 摘 要： | Numerical simulation of a heavy rainfall case in Henan area during 16-17 July 2004 is performed using the LASG (State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics) mesoscale model AREM (Advanced Regional Eta Model) developed by Yu (1989) and Yu et al. (1994). The results are shown: the air in the middle part of troposphere within the horizontal range of meso-βscale convective system is heated by condensation latent heat. The isobaric surface in the middle and upper part of troposphere is rising, and thus meso-βscale high is formed; the isobaric surface in the lower part of troposphere is depressed, and thus meso-βscale low is formed. The interaction between the high and low layer flow promotes the strong development of the vertical motion. While the rising motion is developing strongly, obvious compensation sinking motion appears around it. In the south of rising motion region, the divergence current in the upper part of troposphere backflows towards south, which leads to the vertical circulation appearing in the upper part of troposphere. The sinking branch of the circulation integrates in the compensation sinking air current in the south of rising motion region and takes the horizontal momentum of upper air to the lower part of troposphere and forms a new meso-βscale jet. In the north of the rising motion region, a mesoscale vertical circulation develops in the low layer of troposphere. The divergence current of the sinking branch of the circulation, which flows southward, converges with warm and humid air current in the low layer of troposphere which flows from southwest, and forms a meso-βscale convergence line. Then it strengthens the convergence over the low level of heavy rain area. In the east of the rising motion region, a mesoscale vertical circulation also develops in low layer of troposphere. The divergence current of the sinking branch of the circulation, which flows westward, causes originally more consistent southwest air current in this region to the east deflection, and thus forms the cyclone curve in the southwest air current. The convergence is further strengthened in the meso-βscale convergence line. The strong development of ageostrophic vorticity in the lower part of troposphere is the important factor of the formation of the meso-βscale cyclone. At last the three-dimensional structure chart of development of heavy rain meso-βscale stream filed is given.
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| 关 键 词： | heavy rainfall meso-β scale three-dimensional structure vertical circulation numerical simulation |
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