椒江沿海大风特征分析及精细化预报方法研究

Research on characteristic analysis and forecast method of gales in the Jiaojiang coastal area

利用大陈气象站、椒江口和一江山自动站的观测资料及美国国家环境预报中心分辨率为1°×1°的逐6 h再分析数据和欧洲中期天气预报中心的EC细网格(分辨率为0.25°×0.25°)模式资料,分析了椒江沿海大风月际、年际变化特征及影响因子,构建预报模态,提炼沿海大风预报思路,并对EC细网格模式大风预报进行检验。结果表明:冬季冷空气大风为椒江沿海大风的主要类型;气压梯度和高空环流形势是冷空气大风的两大影响因素;当椒江沿海存在负变压中心,极有可能在未来24~36 h出现变压大风;气旋北大风可划分为北槽南涡型和低涡切变型,气旋南大风可划分为东亚大槽型和沿海高压型;针对冷空气偏北大风和气旋偏北大风,EC细网格模式具有一定的可参考性,与实况极大风速相比,绝大多数情况下的预报风速偏小。

This paper analyzes the monthly and annual variation characteristics of gales in the Jiaojiang coastal area,studies its influencing factors and forecasting modes,and tests the EC fine-grid model gales forecasting product,based on the observational data from Dachen meteorological station,Jiaojiangkou and Yijiangshan automatic weather stations,the 6-hour reanalysis data at 1°×1°resolution from National Centers for Environmental Prediction,the EC fine-grid model data at 0.25°×0.25°resolution from European Centre for Medium-range Weather Forecasts.The results show that cold air gales in winter is the majority of gales in the Jiaojiang coastal area.The pressure gradient and atmospheric circulation situation are two main influencing factors of cold air gales.A negative barotropic center over the Jiaojiang coastal area very likely leads to barotropic gale in the following 24~36 hours.Gales at the north side of cyclones can be divided into north trough south vortex type and low vortex shear type,while gales at the south side of cyclones can be divided into East Asia great trough type and coastal high type.The EC fine-grid model product has a certain degree of reference value on forecasting the northerly gales of cold air and cyclones.Compared to the observed maximum wind speed,the predicted wind speed is smaller in most cases.