数字滤波弱约束四维变分同化在台风初始化中的应用(I I):数字滤波权重选择
Application of digital filter weak constraint four-dimensional variational data assimilation on typho on initialization (I I):Digital filter weight chosen
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摘要: 数字滤波权重的选择是影响台风路径和强度预报的重要因素,某些个例中直接决定着台风数值模拟的成功与否,合适的数字滤波权重非常重要。本文利用2010年3个台风7个不同初始时刻个例,开展数字滤波弱约束四维变分同化(4D-Var)台风初始化试验,分析不同数字滤波权重对台风路径和强度预报的影响;基于上述台风路径和强度预报后验统计信息,以及台风中心区域800 km范围和整个模拟区域3 h平均地面气压倾向信息,提出一种bogus资料同化台风初始化中数字滤波权重优选方案,并进行理论解释说明;同时,指出bogus资料同化台风初始化中,常规数字滤波权重为1000更合理,明显有别于常规天气和暴雨天气权重设置。
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关键词:
- 数字滤波弱约束四维变分同化 /
- 数字滤波权重选择 /
- 台风初始化
Abstract: In Part I, the digital filter weak constraint four-dimensional variational (4D-Var) data assimilation is implemented with different digital filter weight settings through two typhoon cases. The results show that the influence of the digital filter weight on typhoon track and intensity prediction is large, and how to choose an appropriate digital filter weight is important. In this paper, seven different initial time typhoon cases in 2010 are selected to analyze the effects of different digital filter weight settings on typhoon track and intensity prediction. Based on the track and intensity prediction information of the seven cases, and the three-hour pressure tendency information for the whole domain and the area with 800 km radius from the typhoon center, a method of choosing digital filter weight is proposed for typhoon initialization with bogus data assimilation. Also, the ordinary digital filter weight setting is proposed, which is 1000 and obviously different from the operational and storm cases weight setting. -
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