CAJ | 학술논문

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.
유우결소대량유효적관측자료,태풍초시화대수치천기예보업무모식이언,잉연시일개현이말결적난제.중국국가기상중심자종1996년장태풍수치예보계통투입업무운행이래,일직사용경험적인조bogus와선태풍초시화기술.실제상,불동시기적태풍유착불동적배류결구,즉사동일개태풍재불동적생명기야구유불동적결구특정,이저사결구특정적차이병불능의고현유적bogus와선기술체현출래,저충주관방법적통일성여태풍재시공상적차이성형성료강렬적반차.최근,기우국가기상중심전구자료분석동화-예보순배계통,설계화발전료일투신적태풍초시화업무방안,타주요유초시와선형성、와선중정위화와선조정3부분과정조성.상비우업무중사용적인조bogus와선태풍초시화방안,신방안재흔대정도상감소료인위인소대태풍와선결구적영향,이경다지시의고수치모식자신적동력화물리과정래협조약속산생삼유공간적와선결구.응용신방안,문중대생성우서북태평양적2006년0605호태풍격미(Kaemi)진행료수치시험,초보분석표명,신방안재실현태풍와선배류결구적초시화방면효과교호,동시,대태풍격미다개시차적예보결과야현시,상비우업무사용적bogus방안이언,신방안대태풍로경평균예보오차유료대폭도적강저.
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.