GRAPES_TYM模式对2012-2013年登陆华南TC的降水预报能力评估及降水释用方法初探

摘要

The precipitation forecast of tropical cyclone(TC)landing in South China during 2012-2013 from the pattern matching capability,the average precipitation and extreme precipitation by GRAPES_TYM model was synthetically assessed.And on this basis that the interpretation methods of precipitation forecast for TC influencing Hainan Island were established and tested.The results show that the comprehensive evaluation index of ETS score and spatial correlation coefficient between the observed and forecasted precipitation by GRAPES_TYM model for TC landing in South China was 0.31,and the value depended on the deviation of TC path prediction by the model.The comprehensive assessment index of average precipitation forecast was 0.76.Thereinto,the error index showed that the forecasted median of average precipitation within the influence of TC was less than 3.6 mm of the observation,and the forecasted values of average precipitation in rain belts with different distances from the centre of TC were smaller than the observation,the forecasted precipitation in outer rain belt was better than that in inner rain belt.To the extreme precipitation assessment,the threshold of extreme precipitation within 100 km distance from the centre of TC was closed to the observation,while that in the rest of rain belts was smaller than the observation.As for Hainan Island,the interpretation method of TC precipitation predicted by GRAPES_TYM model was consistent of TC path correction,rain belts translation and topographic correction,and the corrected TS scores of moderate rain,heavy rain and rainstorm by the interpretation method of TC during 2012-2013 improved significantly,especially for rainstorm,increased by 9.9％compared with that before the correction.%利用GRAPES_TYM模式对2012-2013年登陆华南的TC降水预报从模式匹配能力、平均降水量评估和极端降水量评估3方面进行综合评估.在此基础上,以海南岛为例,探讨该模式TC降水预报的释用方法,并进行释用检验.结果表明:与实况相比,GRAPES_TYM模式对登陆华南的TC降水预报的ETS评分和空间相关系数的综合评估指数为0.31,分值的高低依赖于模式对TC路径预报的偏差;平均降水量预报的综合评估指数为0.76,其中平均降水量预报误差指数反映了在TC影响范围内预报的格点降水量中位数比实况偏小3.6 mm,距离TC中心不同雨带的平均降水量预报均比实况偏小,且模式对外雨带的降水预报优于内雨带;对于极端降水量预报的评估,发现除了距离TC中心100 km以内的极端降水阈值较接近实况,其余雨带预报的极端降水阈值均比实况偏小.就海南岛而言,GRAPES_TYM模式TC降水预报释用方法由TC路径订正、雨带平移和地形订正3部分组成,经2012-2013年TC降水预报的释用分析,发现订正后的降水预报TS评分在中雨、大雨和暴雨量级都有明显提升,其中暴雨TS评分升幅最明显,较订正前提高了9.9％.