热带气旋-海洋的相互作用对南海一个强热带气旋过程影响的数值模拟

Numerical simulation of effects of cyclone-sea interaction on a strong tropical cyclone process in South China Sea

采用中尺度海-气耦合模式MCM v1.0对南海强热带气旋“黄蜂”(No.0214)进行了数值模拟试验,并就热带气旋-海洋的相互作用对热带气旋的影响进行了定量分析。结果表明,耦合试验中热带气旋后期路径有显著改善,36h和48h路径误差分别减小22km和110km,登陆点位置误差减小22km;气旋强度与非耦合结果基本一致,36—48h气旋强度减弱得更快;热带气旋中心大风区地面风速增大1—3m.s-1,眼区附近风速减小2—5m.s-1;近地层(取925hPa)气温降低1℃以上,且气温降温区与较大的SST下降区域大致吻合;改进了热带气旋暴雨的落区及降水强度,且主要落区误差的修正位于热带气旋移动路径的右侧并同主要的SST降温区相关;热带气旋-海洋相互作用通过SST下降减少向上的热通量,潜热通量的减少对SST的下降更敏感。

Numerical experiments were performed on a strong tropical cyclone Vongfong （No. 0214）in the South China Sea by a Mesoscale Coupled Model （MCM v 1.0）. The quantitative effects of mesoscale airsea interaction on the cyclone process were analyzed. The results indicate that the track of the cyclone are improved significantly. The track errors decrease by 22km and 110km for 36h and 48h simulations respectively, and the landing position error decreases by 22km. The cyclone intensity in the coupling test is similar to that of the uncoupling one, and the cyclone intensity decreases faster in the coupling test than in the uncoupling one from the 36^th hour to the 48^th hour. The wind speed of the tropical cyclone increases by 1- 3m·s^-1 in the gale zone, whereas decreases by 2--5m·s^-1 in the eye zone. The atmospheric temperature of lower level （925hPa） whose area is obviously related to the SST changed area, decreases by more than 1℃. The distribution and intensity of mesoscale rainfall are improved, with main distribution correction lying on the right of cyclone track and correlating with SST dropping area. Upward heat flux is decreased by SST reduction induced by air-sea interaction, the laten heat flux decrease is more sensitive to the SST reduction.