论文部分内容阅读
利用南海季风试验提供的同化资料, 分析了1998年春、夏季发生在南海上空低空急流形成机制, 其中重点分析了1998年6月8~10日珠江三角洲暴雨过程中的低空急流过程, 并用MM5中尺度模式进行了数值模拟. 结果表明, 在低空急流形成过程中, 动能向上输送, 造成南海低空急流从对流层低层向高层发展. 其形成过程可以概括为: 在华南西部的天气尺度低压向东移动和西太平洋的一个高压扰动向西移动过程中, 二者的共同作用使南海地区上空对流层低层的气压梯度力加强, 由于气压梯度力作功提供了低空急流形成所需要的动能, 导致南海上空低空急流在这两个系统之间形成. 由于南海季风加强往往以低空急流的形式表现出来, 因此南海低空急流的形成机制也可以解释南海季风加强.
Based on the assimilation data provided by the South China Sea monsoon experiment, the formation mechanism of low-level jet stream over the South China Sea in spring and summer 1998 was analyzed. The low-level jet stream during the heavy rainfall in the Pearl River Delta from June 8 to June 8, 1998 was analyzed. The results show that during the formation of low-level jet stream, the kinetic energy is transported upward, causing the low-level jet stream in the South China Sea to develop from the lower troposphere to the upper troposphere.The formation process can be summarized as follows: In the course of a westward movement of a high-pressure disturbance in the Pacific Ocean, the pressure gradient force in the lower troposphere over the South China Sea is strengthened by the interaction of the two, and the kinetic energy required for the formation of low-level jet stream is provided by the pressure gradient force, resulting in the low-level jet stream over the South China Sea The formation of the two systems.As the strengthening of the South China Sea monsoon is often manifested in the form of low-level jet stream, the formation mechanism of low-level jet stream in the South China Sea can explain the strengthening of the South China Sea monsoon.