摘要
把天气预报问题提成初值问题的反问题，可以使用多时刻的历史资料去补充和完善数值预报模式。借助于几何直观可以对大气动力学方程组的极限解集进行全局定性分析，运用胞映射的概念和方法可以对大气系统的数值模式的整体特征进行全局分析和借助概率论的语言进行统计描述。还可以给出“气候”这个模糊概念的严格的数学定义及定量研究大气可预测性问题的途径。全局分析是研究气候不同于简单初值问题的另外一条道路。综述了这方面研究的最新进展。
The initial value problem weather prediction is a classical deterministic problem in classical physics,there are a lot of difficulties in the method of initial value problem to predict long range weather and short range climate.Three characteristics of atmospheric motion are very important:nonlinearity,being forced and dissipation. It is necessary to combine the dynamical and statistical methods.The prediction problem could be looked as the inverse problem of the initial value problem,i.e. an evolution problem,so the multiple time data in the past could be used to modify initial values and/or numerical prediction model.The inverse problems are divided into there kinds,there are corresponding solutions. After the inverse problem of the initial value problem is introduced,the global analysis to the atmospheric dynamical equations(ADE) are reviewed. The global analysis is another method of climate research different from the simple initial value problem. The global analysis is also called global asymptotic analysis.It is used to study the long range behavior of deterministic systems.It is unnecessary to solve the equations,the properties of ADE are researched by means of studying the equations themselves.With the aid of the direct geometric pictures(the concept of phase space is introduced),the qualitative global analysis to the limit solution set of ADE could be done.It is proved that ADE is a special operator equation in Hilbert Space.The properties of operators must be maintained when ADE is simplified or discretized.It is revealed that the nonlinear adaptation process of a system to external source,so the system could be described by a small number of degrees of freedom sustaining attractors because of dissipative process.Cell to cell mapping is a powerful tool to study nonlinear systems,by use of the concept and method of cell to cell mapping,the global analysis to the general characteristics of numerical model of atmospheric system could be done.The global analysis to round off errors and observational errors could be done.With the aid of the language of probability theory,the statistical description of the characteristics could be given.It is revealed that the indeterminacy of individual state and the determinacy of global state.The restrict mathematical definition of the vague concept of “CLIMATE”is:climate could be defined as probability distribution function of state variables in chaotic attractors determined by controlling variables,and it is proved that it exists chaotic state in climate system really.The approach of quantitative studies to the predictability of the atmosphere could be given,the predictability is the time before the state of a system arrive the probability distribution of chaotic attractors.
出处
《地球科学进展》
CAS
CSCD
1999年第2期133-139,共7页
Advances in Earth Science
关键词
大气动力学
数值天气预报
大气方程组
全局分析
Atmospheric dynamics
Digital weather forecast
Atmospheric equations
Multiple time data
Inverse problem
Global analysis
Statistical description
