气候系统的非平稳行为和预测理论

到目前为止,有关非平稳复杂系统及其在气候预测中的应用研究(它有着比混沌系统更为复杂的行为)是一个较少被人理解并有重大科学意义的前瞻性研究课题。在大气运动中,气候正是一个典型的非平稳系统,但是现有的气候预测理论,包括统计预测理论和非线性预测理论,几乎都无一例外地建立在平稳性假定的基础之上,这有悖于气候过程的基本性质,因此它有可能是导致气候预测水平低下的重要的理论原因。另外,近10年来,气候过程具有层次结构已经成为许多科学家的共识,但是如何发展和完善这一理论,使之成为一个完整的体系,人们似乎还没找到合适的途径。事实上,气候系统的多层次结构(它与通常的多尺度结构是两个完全不同的概念)正是产生非平稳行为的原因,而气候系统的非平稳特性正是层次结构的集中表现。在这样的思想指导下,文中系统地讨论了非平稳气候的一些基本问题和相应的预测理论,并为之搭起了一个初步的理论框架。

ON NONSTATIONARY BEHAVIORS AND PREDICTION THEORY OF CLIMATE SYSTEMS

The nonstationary behaviors of complex system and their applications to the climate prediction are a significant and forward-looking field of research.Up to now,they are not yet known and understood very well.In reality,climate is just a normal nonstationary system.However,almost all the current theories for climate prediction,including the ones in statistics and nonlinear science,are based on assumption that the process is stationary which is contrary to the nature of the climate process.Probably,this contradictory is an important cause resulting climate prediction at a lower level. In addition,in recent odd ten years,it has been a commonly cognition that the climate process possesses hierarchy structure for more and more scientists,but yet they seem not to find an appropriate way for improving this concept and developing a perfect theory system.In fact,the hierarchy structure of climate system is just the cause to produce nonstationary behaviors,while the nonstationary behaviors of climate process is just the most important expression of the hierarchy structure.Under this consideration,this paper has systematically discussed some basic problems in the nonsationary climate system and built a preliminary theoretical frame to predict such a system.