南海台风"悟空2000"生成及发展的数值模拟

应用NCAR/PSU中尺度非静力模式MM5模拟了南海台风"悟空2000"从一个热带扰动发展为强台风的过程。模拟结果表明,MM5模式能够很好地模拟出"悟空2000"台风的强度和最大风速,清晰显示出南海台风发展中具有的阶段性和爆发性。从水汽和位涡等诊断量的分析出发,分析了模拟的台风结构和台风眼生成的可能影响因素。敏感性试验结果显示,南海海面温度对台风发生发展有至关重要的作用:如果海表温度降低1℃,模拟的台风最大风速将降低近10m/s,风速达到台风级别(32.8m/s)的时间推迟约7个小时;如果海表温度降低2℃(SST仍高于26.5℃),该热带扰动将不能发展到台风的强度。

Numerical Study of the Genesis and Development of Typhoon WUKONG (2000) over South China Sea

The Fifth generation NCAR/PSU mesoscale nonhydrostatic model(MM5) was used to simulate the process that a tropical disturbance developed into a strong typhoon WUKONG over the South China Sea in September 2000. The MM5 model could forecast the maximum wind and intensity of the typhoon with considerable accuracy. The natural developing characteristics of South China Sea Typhoon which involved step-by-step deepening and drastic strengthening were also well simulated. Based on some diagnostic variable analysis, the potential factors on typhoon structure as well as the genesis of typhoon eye were briefly analyzed. Sensitivity experiments on sea surface temperature (SST) effect indicate that the SST is of vital importance to the genesis and development of typhoon over South China Sea. If SST is degraded by 1 degree, the simulated typhoon would have a decrease of 10?m/s on maximum wind and a nearly seven-hour delay to reach typhoon level intensity (surpass 32.8?m/s). If SST is degraded by 2 degree (with SST still being between 26 and 27 degree), the initial tropical disturbance could hardly develop into typhoon.