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气象:2023,49(7):805-818
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台风灿都路径预报中的非绝热加热因子分析
吴胜蓝,漆梁波,邹兰军
(上海中心气象台,上海 200030)
Analysis of Diabatic Heating Factor in Track Forecast of Typhoon Chanthu
WU Shenglan,QI Liangbo,ZOU Lanjun
(Shanghai Central Meteorological Observatory, Shanghai 200030)
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投稿时间:2022-05-17    修订日期:2023-02-09
中文摘要: 依据欧洲中期天气预报中心集合预报系统(EC EPS)预报产品,采用位涡趋势诊断方法,对比分析了台风灿都路径预报差异较大的两个集合成员各物理因子的贡献。结果表明两个集合成员的台风中心均朝位涡趋势一波分量最大的位置移动,且大多数时刻水平平流项的贡献是最大的,其次是非绝热加热项,垂直平流项的贡献相对较小。两个成员路径分叉时刻的位涡趋势差异主要由非绝热加热项引起,而分叉之后位涡趋势仍主要由水平平流项(即引导气流)主导。在路径分歧时刻,两个集合成员预报的非对称对流活动也表现出不一样的分布,且都与诊断的非绝热加热项方向较为一致,即非对称对流结构和加热率的水平梯度在引导气流偏弱时对台风移动可能起到关键作用。非对称对流活动出现主要受水汽、潜在不稳定条件以及低层急流等环境因子的影响。分析表明,在近海台风路径预报中,尤其是引导气流偏弱的情况下,加强对非绝热加热过程(对流活动发展趋势及非对称结构)的分析,有助于做出更精准的路径预报。
Abstract:Based on the ECMWF ensemble prediction system (EC-EPS) and the potential vorticity tendency (PVT) diagnosis, this paper examines the contributions of physical factors to track forecast of Typhoon Chanthu (2114) by comparing two distinct ensemble members. It is found that the typhoon centers of two ensembles both move towards the area with the largest wave number one component (WN1) of PVT. The contribution of the horizontal advection term is dominant most of the time, followed by the diabatic heating term, and the contribution of the vertical advection term is relatively small. The PVT discrepancy of the two members at bifurcation time is mainly attributed to the diabatic heating term, while that after the bifurcation time is still dominated by the horizontal advection term (i.e., steering flow). The asymmetric convective activities of two ensemble members also show different distributions at bifurcation time, which is consistent with the direction of diabatic heating, that is, the asymmetric convective structure and the vertical gradient of diabatic heating may play a key role in the movement of typhoon when the steering flow is weak, which is largely affected by the environmental factors such as water vapor, potential instability, and low-level jet. This research emphasizes the impact of diabatic heating processes (including development and asymmetric structure of convective activities) in typhoon track forecast for more accurate prediction when steering flow is weak.
文章编号:     中图分类号:P456    文献标志码:
基金项目:长三角科技创新共同体领域项目(21002410200)、中国气象局复盘总结专项(FPZJ2023-043)共同资助
引用文本:
吴胜蓝,漆梁波,邹兰军,2023.台风灿都路径预报中的非绝热加热因子分析[J].气象,49(7):805-818.
WU Shenglan,QI Liangbo,ZOU Lanjun,2023.Analysis of Diabatic Heating Factor in Track Forecast of Typhoon Chanthu[J].Meteor Mon,49(7):805-818.