南海海域海表面温度对低空大气波导数值模拟的影响研究

Influence of sea surface temperature on numerical simulation of lower atmospheric duct over the South China Sea

为了研究海表面温度(sea surface temperature,SST)对低空大气波导数值模拟的影响,针对南海海域基于天气研究与预报(weather research and forecasting,WRF)模式开展了不同SST对低空大气波导数值模拟的影响研究.结果表明:精确的SST对低空大气波导数值模拟影响最大,其次是更新周期;美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,NOAA)提供的最优插值SST给出的大气波导模拟结果最好,正确率为68.2%,且波导底高平均误差和标准差最小,这是由于其模拟的相对湿度和气温变化较为准确,其次为气候预报再分析系统(climate forecast system reanalysis,CFSR)给出的SST方案较好;此外不同嵌套网格方式对大气波导数值模拟也有影响,在最优方案中子网格模拟的大气波导正确率和发生概率分别提高了11.8%和10.4%,虚报率降低了2.4%.该研究可为南海低空大气波导的精确预报提供技术支撑.

In order to study the influence of sea surface temperature(SST) on the numerical simulation of low atmospheric ducts, the influence of different SST on the numerical simulation of lower atmospheric ducts over the South China Sea(SCS) was studied based on WRF model. The results show that the simulation of lower atmospheric ducts events is affected greatly by SST accuracy and the update frequency. The experiment scheme of the SST provided by US National Oceanic and Atmospheric Administration(NOAA) has the best simulation results with the accuracy of68.2%, and its lowest mean error and standard deviation of duct-bottom heights are less than the other schemes,followed by climate forecast system reanalysis(CFSR) SST, which might be attributed to good numerical simulation of relative humidity and air temperature profiles. Besides those, nested grid pattern also affects the numerical simulation of atmospheric ducts. Using the best scheme, the duct characteristic parameters of the sub-grid simulation are more accurate, and the accuracy rate of the simulation and the duct probability increase by 11.8% and 10.4% respectively,with the false alarm rate decreased by 2.4%. This study provides technical support for accuracy numerical prediction of low atmospheric ducts over the South China Sea.