台风“威马逊”(1409)和“海鸥”(1415)影响广西风雨特征及预报偏差的比较分析

Comparative analysis of wind and rain characteristics and forecast deviations of typhoon“Rammasun”(1409)and“Kalmaegi”(1415)affecting Guangxi

基于观测资料、数值模式产品及主观预报,对2014年超强台风“威马逊”和强台风“海鸥”影响广西的风雨特征及预报偏差进行对比分析。结果表明:(1)“威马逊”深入广西内陆,高层辐散更强,副高西脊点偏东,低层急流南北宽度更广且风速更大,台风强度更强,这是“威马逊”强降雨范围更广,小时雨强更强的可能原因。(2)主客观预报台风路径及强度随预报时效增加误差明显增大且差别较明显。ECMWF、广西遗传神经网络与中央台分别对台风路径、台风强度预报有很好的参考价值。(3)主客观均能报出强降水的形态但强度偏弱,预报误差随时效增加而增大且存在明显的空漏报。大暴雨量级预报评分ECMWF_HR明显高于广西主观,暴雨量级预报评分总体是广西主观优于ECMWF_HR。(4)ECMWF_HR没有准确预报副高西进南扩过程;副高预报的偏东偏北,是导致台风和急流中心偏南偏弱的可能原因。(5)ECMWF_HR预报850hPa水汽通量及其散度与实况在形态上基本一致,但位置偏西偏南,强度偏弱,这与预报副高偏东及台风偏西偏弱相关,应该引起今后业务预报关注。

Based on the observation data,numerical model products and subjective forecasts,this paper maked a comparative analysis of wind and rain characteristics and forecast deviation of super typhoon“Rammasun”and strong typhoon“Kalmaegi”affecting Guangxi in 2014.The results show that:(1)“Rammasun”penetrated deep inland of Guangxi with a stronger typhoon intensity,accompanied by stronger upper-level divergence,more eastward west ridge of subtropical high,and stronger low-level jet which was wider in north-south width.These was the possible reasons for the wider range and stronger hourly rainfall of“Rammasun”.(2)The errors of subjective and objective forecasting of typhoon track and intensity increased significantly and differ more significantly with the increasing forecast time.The ECMWF model,Guangxi genetic neural network model and the forecast of Central Meteorological Observatory had good reference values for typhoon track and typhoon intensity forecasts,respectively.(3)Both subjective and objective forecasts could report the pattern of heavy rainfall,but with a weak rainfall intensity.The prediction error increased with the increase of time lapse and there are obvious omissions.The heavy rain forecast score of ECMWF_HR was obviously higher than Guangxi subjective forecasting,and the torrential rain forecast score of Guangxi subjective forecasting was better than that in ECMWF_HR.(4)ECMWF_HR did not accurately predict the westward and southward expansion of the subtropical high.The easterly and northerly forecast of subtropical high was the possible reason for the southward and weaker center of typhoon and jet center.(5)The water vapor flux and its divergence at 850 hPa predicted by ECMWF_HR were basically consistent with the actual situation in terms of morphology,but the position was to the west and south,and the intensity was weak,which was related to the easterly position of the subtropical high and the westerly position of the weaker typhoon,what should be paid attention to in future operational forecasting.