| 全球数值模式中的台风初始化Ⅰ:方案设计 |
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| 引用本文： | 瞿安祥,麻素红,LIU Qingfu,李娟,胡江凯.全球数值模式中的台风初始化Ⅰ:方案设计[J].气象学报,2009,67(5). |
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| 作者姓名： | 瞿安祥 麻素红 LIU Qingfu 李娟 胡江凯 |
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| 作者单位： | 1. 国家气象中心,北京,100081
2. National Centers for Environmental Prediction/Environmental Modeling Center, Camp Springs, MD, USA |
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| 基金项目： | 国家重点基础研究发展规划(973计划)，国家气象中心课题 |
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| 摘 要： | 由于缺少大量有效的观测资料,台风初始化对数值天气预报业务模式而言,仍然是一个悬而末决的难题.中国国家气象中心自从1996年将台风数值预报系统投入业务运行以来,一直使用经验的人造bogus涡旋台风初始化技术.实际上,不同时期的台风有着不同的环流结构,即使同一个台风在不同的生命期也具有不同的结构特征,而这些结构特征的差异并不能依靠现有的bogus涡旋技术体现出来,这种主观方法的统一性与台风在时空上的差异性形成了强烈的反差.最近,基于国家气象中心全球资料分析同化-预报循环系统,设计和发展了一套新的台风初始化业务方案,它主要由初始涡旋形成、涡旋重定位和涡旋调整3部分过程组成.相比于业务中使用的人造bogus涡旋台风初始化方案,新方案在很大程度上减少了人为因素对台风涡旋结构的影响,而更多地是依靠数值模式自身的动力和物理过程来协调约束产生三维空间的涡旋结构.应用新方案,文中对生成于西北太平洋的2006年0605号台风格美(Kaemi)进行了数值试验,初步分析表明,新方案在实现台风涡旋环流结构的初始化方面效果较好,同时,对台风格美多个时次的预报结果也显示,相比于业务使用的bogus方案而言,新方案对台风路径平均预报误差有了大幅度的降低.
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| 关 键 词： | 台风初始化 涡旋形成 涡旋重定位 涡旋调整 |
The initialization of tropical cyclones in the NMC global model Part Ⅰ : Scheme design |
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| QU Anxiang,MA Suhong,LIU Qingfu,LI Juan,HU Jiangkai.The initialization of tropical cyclones in the NMC global model Part Ⅰ : Scheme design[J].Acta Meteorologica Sinica,2009,67(5). |
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| Authors: | QU Anxiang MA Suhong LIU Qingfu LI Juan HU Jiangkai |
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| Abstract: | Due to lack of valid observational data over the tropical oceans, TC (tropical cyclone) initialization for numerical models is one of major difficulties in accurate TC track forecasting. Since TC numerical prediction model at National Meteorological Center of China (NMC/China) was put into operation in 1996, it has always been applied an empirical and statistical method which imposes a scale- selective sophisticated filtering to remove shallow vortex from the initial field and inserts bogus vortex into it, constructed by a few observed parameters such as central pressure, position, and maximum sustained wind. In fact, TC structure varies from one form to another for different TCs and even the same TC in different time of life, which is not directly related to these observed parameters. The spatial and temporal variability of TC structure are not represented by bogus vortex with a few observed parameters. Recently, a new TC initialization scheme based on NMC global analysis-forecast cycle has been developed successfully. The new scheme is com-posed of three procedures: vortex formation, vortex relocation, and vortex modification. Specifically, an appropriate vortex (generat-ed by global model forecast) is inserted into background field when TC occurs at first time (it is called vortex formation). In the next forecast time, there must be a little weak and misplaced vortex in the background (6-h forecast at first time), what all we need to do is to move the vortex to correct position and modify it close to observed parameters by relative dynamic formula (it is called vortex re-location and modification). It can be seen that initial vortex of the new scheme is mostly formed with the integration of the global model and is compatible with the dynamics and physics of the global model. Using the new scheme of TC initialization, a series of ex-perimental forecasts were performed for TC Kaemi (0605) that occurred in the western North Pacific in 2006. From study it is found that the new scheme can produce the reasonable and realistic vortex in the initial field and produced much more accurate TC track pre-diction compared with operational bogus one. It indicates that mean track forecast biases can be reduced effectively by new TC initial-ization scheme. |
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| Keywords: | TC initialization vortex formation vortex relocation vortex modification |
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