东印度洋天气和风暴潮预报系统的初步评估

Preliminary assessment of a real-time forecasting system for atmosphere and storm surge in eastern Indian Ocean

东印度洋天气和风暴潮实时预报系统(EPMEF_EIO)由区域大气模式和区域风暴潮模型组成,每天实时运行4次.大气初边场来自美国国家环境预报中心(NCEP)的全球预测系统(GFS),通过区域嵌套得到印度洋-东印度洋-斯里兰卡区域的3 d预报结果.大气模式的10 m预报风场驱动风暴潮模式,得到东印度洋-斯里兰卡区域的潮汐和风暴潮3 d预报结果.通过与中国科学院南海海洋研究所斯里兰卡站气象塔观测数据、最优台风路径数据和科伦坡水位站数据对比,发现模式预报气温和相对湿度的日变化较观测值偏小,气温总体RMSE为1.26℃,相关系数为0.8,相对湿度的总体RMSE为7.0%,相关系数为0.7;模式预报风速以整体偏大为主,总体RMSE为2.3 m/s,相关系数为0.65;模式预报风向能把握主要的变化趋势,RMSE在20°~32°之间,相关系数约0.65;模式24、48和72 h路径预报平均误差分别为110.5、166.4和181.0 km.此外,模式水位预报的RMSE为0.035 m,占最大振幅约5%,与观测的相关系数达到0.996.这说明了模式可以用于预报潮汐和风暴潮过程.

A real-time regional forecasting system for the Eastern Indian Ocean(EIO),called the Experimental Platform of Marine Environment Forecasting for EIO(EPMEF_EIO),is introduced in this paper.EPMEF_EIO consists of a regional atmosphere model and a regional storm surge model,and performs a real-time run four times a day.Output from the Global Forecast System(GFS)from the National Centers for Environmental Prediction(NCEP)is used as the initial and boundary conditions of two nested domains of the atmosphere model,which can exert a constraint on the development of small-and meso-scale atmospheric perturbations through dynamical downscaling.Then the system outputs the 3 day forecast of 72 km,24 km,8 km for Indian Ocean-EIO-Sri Lanka.The forecasted winds at 10 m height from the atmosphere model are used to drive the storm surge model,obtaining the 1/12°-1/36°results for EIO-Sri Lanka.By comparing observation data from the Sri Lanka Station Meteorological Tower of the South China Sea Institute of Oceanology,Chinese Academy of Sciences,TC best track data,and data from the Colombo tide gauge station,it is found that the daily variations of the model forecasted temperature and relative humidity are smaller than the observations;the overall root mean square error(RMSE)of the air temperature is 1.26℃,and the coefficient is 0.8;the overall RMSE of relative humidity is 7.0,and the correlation coefficient is 0.7.The model forecasted wind speed is mostly larger than the observation,with an overall RMSE of 2.3 m/s and a correlation coefficient of 0.65.The forecasted wind direction of the model can grasp the main trend of variation,with an overall RMSE of between 20°-32°and a correlation coefficient of about 0.65.The average error of model track forecast is 110.5 km,166.4 km,and 181.0 km at 24 hour,48 hour,and 72 hour,respectively.In addition,the overall RMSE of the model water level forecast is 0.035 m,accounting for about 5%of the maximum amplitude,and the correlation coefficient with the observation reaches 0.996.This shows that the model has the ability to simultaneously forecast tidal and storm surge processes.EPMEF_EIO,established primarily for research purposes with the potential to be implemented into operations,provides valuable information to the operational forecasters of local marine/meteorological agencies or international TC forecast centers.