汪冬冬,方艳莹,申华羽,涂小萍,吕劲文,钱峥

• 1:宁波市气象服务中心
• 2:宁波市气象灾害预警中心
• 3:宁波市气象台

摘要(Abstract)：

【目的】为了解浙江省梅雨期的降水日变化特征以及气象业务模式对降水的预报能力。【方法】利用2008—2019年期间浙江地面雨量站小时数据和ERA-Interim再分析资料进行分析，同时评估ECMWF在浙江地区梅雨期的预报水平。【结果】结果表明：(1)梅雨期间浙江平均日降水量自西向东递减，浙西地区从05:00—18:00一直维持强降水的特征，平均最大日降水量超过20 mm。(2)浙中、浙北、浙东降水呈双峰型特征，主要降水时段在03:00—11:00和13:00—20:00。浙东北和浙南降水呈单峰型特征，浙东北降水峰值主要在03:00—10:00,但浙南降水峰值主要在14:00—21:00。除浙南外，梅雨期间浙江大部地区夜间至早晨强降水持续时间比午后至傍晚更长。(3)夜间至早晨强降水与低空急流(LLJ)在夜间逐渐加强密切相关。因为夜间至早晨期间，非地转风逐渐加强，使得LLJ增强，而增强的LLJ为浙江地区带来大量暖湿气流，提供不稳定能量，增强辐合上升运动，进而造成早晨降水峰值。午后热力条件可能是午后至傍晚强降水的主要原因。(4)ECMWF基本可以预报出浙江梅雨期间的降水趋势，但夜间至早晨(02:00—11:00)的降水趋势预报优于午后至傍晚(14:00—20:00)。【结论】总体上，ECMWF在夜间至早晨期间更倾向低估强降水，高估弱降水。模式对夜间至早晨的降水预报相对不够稳定，均方根误差大于午后至傍晚。随着预报时间的延长，模式预报能力降低。

关键词(KeyWords)： 梅雨;降水日变化;浙江;低空急流;ECMWF;评估;降雨;气候变化

Abstract:

Keywords:

基金项目(Foundation): 宁波市公益性计划重点项目(2022S181);; 宁波市自然科学基金项目(202003N4192,202003N4193);; 浙江省气象局预报员专项项目(2021YBY05);; 浙江省“海洋与港航气象”创新团队资助

作者(Author): 汪冬冬,方艳莹,申华羽,涂小萍,吕劲文,钱峥

DOI: 10.13928/j.cnki.wrahe.2023.07.004

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