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MM5-卫星数据变分同化方法及气象预报应用研究

Study on MM5-Variational Assimilation Methods of Satellite Data and the Application to Meteorological Forecasting

【作者】 谢红琴

【导师】 吴增茂;

【作者基本信息】 中国海洋大学 , 气象学, 2003, 博士

【摘要】 海洋气象研究中,特别是业务预报中使用各种非常规观测数据和各种迅速发展的大气数据同化方法,已经在全世界引起了越来越大的关注和重视。充分利用非常规资料,提高对非常规资料的同化能力已成为迫在眉睫的问题。“十·五”国家重点科技攻关项目“海洋环境预报与减灾技术”中把海洋气象数值预报及资料同化方法的研究列入重点内容。本论文的任务正是基于此背景,而开展对卫星气象数据同化方法及其应用的研究,寻求同MM5中尺度气象模式业务预报相结合的数据同化方法,为海洋环境预报服务。提高非常规资料的同化质量及应用水平关系到气象预报的未来,而非常规资料的同化利用也是未来数值天气预报的希望所在。很明显,本论文的研究具有重大的实用价值和现实意义。 本论文建立了基于Sasaki增广Lagrange算子算法并和MM5中尺度模式相结合的二维变分同化系统。地球同步卫星(Geostationary Meteorological Satellite(GMS-5))的红外和水汽轨迹风数据及来自NOAA极轨卫星的TOVS(TIROS Operational Vertical Sounder)温、湿数据作为观测资料,经过MM5模式的质量控制而最终进入该同化系统。使用该二维变分同化系统,对2002年发生的三个台风进行了同化卫星数据的数值模拟实验,并对模拟结果同三维观测松弛逼近等数据同化方法对台风路径影响做了比较分析。同时也对各同化方法同化不同卫星数据对台风的影响进行了比较分析。结果表明:所发展建立的二维变分同化系统发挥了应有的作用,也不同程度的改善了台风路径的数值模拟结果。选用现有不同卫星数据进行同化对台风路径的影响不同,但都在一定程度上改善了模拟的结果。虽然二维变分数据同化系统同化各卫星数据对台风模拟实验的结果,不如使用三维观测松弛逼近同化方法的效果好。但就所有的同化实验整体而言,台风路径误差在模式积分24时和48时分别减小约5%和10.5%,对单个台风路径误差可减少30%-50%。另外,即使只是使用很简单的同化方案,如卫星资料仅作为观测资料而被吸收到模式的初始场中,都会对模拟结果产生正面的影响。值得一提的是所发展建立的二维数据同化方法原理简单,计算快捷而稳定,而且易于应用到各种相关领域数据同化的研究中。 本论文接着改进和发展了由国家数值预报中心引进的,基于增量法和Delpha工作站平台的三维变分同化系统。所发展的三维变分同化系统以MICAPS(气象信息综合分析处理系统,由中国国家气象局和中国气象科学研究院共同研制)T213为背景场并同入D涯5模式相结合。该同化系统有同化GMS一5的红外和水汽轨迹风数据和TOVS温湿数据的能力并可在PC机的Linux系统下顺利运行。使用所改进的同ND涯5模式相结合的三维变分同化系统,对以台风为代表的天气现象进行了数值模拟实验,并检验了该同化系统的同化能力。对文中所用N伍15数值模式所产生的初始场和三维变分同化系统生成的初始场进行了比较和分析。分析比较初始风场、初始位势高度场、初始相对湿度场和台风周围分布的探空站的探空曲线后的结果表明:在三维变分同化后各模式物理量之间更加协调,更加符合实际观测。三维变分数据同化系统同化卫星数据后,所形成的初值场是合理和正确的。 在初始场形成的较详细地比较和分析的基础之上,最后本论文进行了三维变分数据同化系统同化卫星数据对台风影响的数值模拟实验结果的比较分析研究。在对三维变分实验与对应控制实验的风场、位势高度场、相对湿度场和几个探空站探空曲线的模拟结果,及对所模拟的台风路径和路径的偏差比较分析研究的基础上,得到如下结果:各模式物理量之间在三维变分数据同化后的分布,在动力上和物理上都更加协调和合理,更加符合实际观测。三维变分数据同化方法能明显减小台风路径的模拟偏差,即使模式积分48小时台风路径的偏差改善也多达50%。平均而言,同控制实验相比,台风路径偏差改善在模式积分24时为49%,48时达到了56%。对单个台风,路径误差的改善更大。对台风路径的预报来说,这是很令人鼓舞的消息。值得注意的是即使所模拟的台风是发生转向的台风,其路径的改善也是明显的。同时使用该三维变分同化系统,比较分析了使用三维变分同化方法仅同化常规观测数据的模拟结果和使用文中所用Nl五遭5模式同化方法进行数值模拟的结果,分析结果表明在其它条件相同的情况下,前一种实验的模拟效果远好于后一种实验,这也证实了变分方法的确比一般的客观分析方法优越。 本论文发展、改进和建立的二维和三维变分数据同化方法有很普遍的适用性。把二维变分和三维变分同化方法应用到类似M入15中尺度模式的模式系统中也具有比较现实的意义。这两种数据同化系统中增加新类型的数据是极其方便和快捷的;适用于海洋上发生的各种海洋天气现象的数值预报和模拟研究;而且就计算量和所需的计算时间而言,在数值业务预报所容忍的范围之内。在地方级气象台所能获取的卫星等非常规数据种类和数量都逐渐增加的前提和背景下,使用本论文所建立的基于入D涯5模式的三维变分数据同化系统,对科研投资有限而无法购买昂贵的高

【Abstract】 Greater and greater concern and attention in the whole world has focused on using all kinds of non-routinely observed data and data assimilation methods that have developed very quickly in marine atmospheric research, especially in operational forecast. It has become a very urgent problem to use asynoptic data and improve the capability to assimilate data. The research on marine atmospheric numerical forecast and data assimilation methods are very important parts in the project of "marine environmental forecasting and natural disasters reducing technology", which belongs to the national key scientific projects of tenth five-year. The study of the thesis is based on such background to carry out the satellite data assimilation methods connected with MM5 mesoscale meteorology model operational forecast, and to serve for the marine environmental forecast and prediction. It is very clearly that the study of the thesis has important practical value and realistic meaning.A two-dimensional variational (2DVar) data assimilation system connected with MM5 model is set up which based on the augmented Lagrangian algorithm of Sasaki. The Geostationary Meteorological satellite (GMS-5) derived wind data from infrared and water vapor images and TIROS Operational Vertical Sounder (TOYS) temperature and humidity data enter the assimilation system after the quality control of MM5 model. Then, the numerical simulation experiments with satellite assimilation are launched on three typhoons in 2002 using the 2DVar data assimilation system. The comparison analysis with other data assimilation methods, such as Nudging, is also going on the simulation results to typhoon track influence. The assimilation influence on typhoon track with different satellite data is also compared. The results show that the 2DVar assimilation scheme really takes effect and improves the numerical simulation results more or less. The typhoon track errors at model integral 24 hours and 48 hours reduce about 5% and 10.5%, respectively. Though numerical simulation experiments of typhoon processes using 2DVar data assimilation system is not so good as that of the Nudging method. In addition, even using very simple assimilation methods to assimilate satellite data, the positive influence will happen to the simulation results. The 2DVar assimilation scheme used here withsimple theory and numerical stability can be very easily applied to many relevant data assimilation fields.A three-dimensional variation (SDVar) system is successfully combined with MM5, which based on the original version of National numerical prediction center. The present version runs smoothly on a PC with Linux operation system rather than on Delpha workstation and using MICAPS (Meteorological Information Composite Analysis Processing system, by CNMC and CAMPS) T213 data as background. The 3DVar data assimilation system has the ability to assimilate GMS-5 cloud drifted winds and TOYS data. The numerical simulation experiments of typhoon processes are carried out using the 3DVar data assimilation system. After comparing the initial wind, geopential height, relative humidity and the sounding profiles of temperature and humidity at several sounding stations between the original MM5 assimilation scheme and the 3DVar assimilation system, some conclusions are drawn: the relationship among model variables becomes more harmony and more close to observations. The initial field formed by 3DVar system is right and reasonable. The study on the numerical simulation experiments to typhoon processes using 3DVar assimilation system also carries out. The conclusions are drawn after comparing the wind field, geopential height, relative humidity and several sounding profiles at sounding stations between control experiment and 3DVar data assimilation experiments. The results show that the model variables are more harmony in dynamic and physics to the experiments of 3DVAR assimilation. The simulated track errors obviously reduce using the 3DVar assimilation scheme, even to recurvature typhoon.The 2DVar a

  • 【分类号】P578
  • 【被引频次】3
  • 【下载频次】898
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