SST对台风过程影响的敏感性试验——以“杰拉华”为例

Sensitive study on the effect of SST on typhoon process: the case of typhoon“Jelawat”

针对台风"杰拉华"过程,使用中尺度大气模式(WRF),采用不同时间分辨率的TRMM/TMI海表面温度观测资料作为大气模式底边界条件,设计数值试验,研究不同时间分辨率SST对台风模拟的影响;同时,通过分析HadISST1资料得到东中国海近50 a SST变化趋势,根据计算得到的SST(海表温度)变化趋势重构SST,并以重构的SST作为模式底边界条件,通过定量分析水文要素的变化,研究台风"杰拉华"过程对重构SST的响应情况。数值试验结果表明:SST时间精度的提高对台风"杰拉华"的路径后报误差减小贡献较小,但台风强度精度有明显提高。在根据SST长期变化趋势改变SST条件后,海平面气压显著降低,海面10 m风速、潜热通量、波浪能密度明显加大,有较明显增幅。

Using TRMM/TMI sea surface temperature(SST)data with different temporal resolution as bottom boundary condition,the Weather Research and Forecasting Model(WRF)is employed to investigate the impacts of SST temporal resolution on the simulation of typhoon"Jelawat".The variation trend of SST over the past 50 years in the East China Sea is deduced using HadISST1 data,based on which SST can be reconstructed.The reconstructed SST is used as the WRF bottom boundary condition to study the response of typhoon"Jelawat"by analyzing the variation of hydrological variables.The results of numerical experiment show that the increase of SST temporal resolution doesn't notably decrease the track error in"Jelawat"hindcast,whereas its accuracy of intensity is significantly increased.Taking the long-term SST trend into consideration,typhoon'Jelawat'is prominently strengthened.