2007年国内台风模式路径预报效果评估

使用中央气象台提供的台风中心定位报文资料、国内台风业务预报部门提供的台风模式路径预报报文资料和台风所气候持续性方法路径预报报文资料等,对2007年中央气象台编号的热带气旋对国内5种台风业务数值预报模式的路径预报效果进行了检验评估,检验内容主要包括距离误差、技巧评分和稳定度指标等.结果表明:(1)国内各模式24h/48h预报平均距离误差最小值为122.8km/246.3km,最大值为180.7km/304.4km.各模式24h/48h预报最大误差为1429.7km/1003.7km, 最小误差为11.2km/10.1km.24h/48h预报平均距离误差为147km/267km.平均而言,导致路径预报误差最大的是0707号热带气旋帕布,误差在其登陆后尤为明显.(2)相对于上海台风研究所路径预报气候持续法做了各种数值预报方法的技巧评分:各模式24h/48h预报平均技巧评分为32%/43%,最高的技巧评分为48%/54%, 最低的技巧评分为3.17%/33.53%.其中4个模式的24h/48h技巧评分高于36%/33%.(3)检验了距离稳定度、方向稳定度、有效稳定度等指标,以全面评估各模式的路径预报性能.该评估结果在一定程度上反映了当前国内台风路径数值预报相对于常用气候统计方法的优越性,同时也表明,尽管国内台风数值预报模式对于热带气旋在海上时的路径预报有一定的稳定性,但对热带气旋登陆后转向过程的预报表现出了较大误差.因此,在模式开发的下一步工作中,除台风初始化之外,还应结合登陆台风的特点,对边界层和陆面过程参数化等作针对性的研究.

Verification on Typhoon Track Forecast by Operational Typhoon Numerical Models of China in 2007

Verification of typhoon track forecast in 2007 was conducted to understand the performance of five operational typhoon numerical models of China. The datasets include the typhoon center location data officially issued by CMA and the associated prediction of typhoon track provided by five typhoon operational forecast centers of China. The evaluation includes distance error, skill score and index of stability, etc. The result shows that: 1) the minimum (maximum) case-averaged 24h/48h distance error, the minimum(maximum) 24h/48h distance error for the best(worst) case prediction and 24h/48h model-averaged distance error are 122.8km/246.3km (180.7km/304.4km), 11.2km/10.1km (1429.7km/1003.7km) and 147km/267km, respectively. Pabuk (No. 0707 numbered by CMA) brought big difficulty to a majority of typhoon models; 2) the model-averaged skill score against the climatic-persistent statistical track prediction approach of Shanghai Typhoon Institute (STI) is 32%/43% for 24h/48h prediction; 3) stability indexes in terms of distance, direction of movement and availability are also presented to give an overall evaluation. Significant advantage of numerical model is identified against the traditional statistical method in typhoon track prediction. However, it is also recognized that most of the typhoon models witness deficiency in the case of landfall, particularly when typhoon making abrupt turning. This suggests that, in addition to vortex initialization, more attention should be paid on improving the physics parameterization of boundary layer and land surface in typhoon numerical model.