利用EOF作相空间拓展与有限区域大气系统混沌吸引子维数的确定

DETERMINATION OF ATMOSPHERIC CHAOTIC ATTKACTOR DIMENSION IN LIMITED AREA BYE EOF PHASE SPACE CONTINUATION

提出用自然正交函数分解的方法来开拓相空间，从而研究有限区域上大气系统的混沌性质。与利用时间滞后作漂移来开拓相空间方法相比较，前者充分保证了相空间各基矢量的正交性，弥补了后者只能对单点资料进行计算的不足。文中利用欧洲中期数值天气预报中心１９８０～１９８６年北半球亚洲地区的５００ｈＰａ位势高度场逐日格点资料进行了ＥＯＦ分解并计算得到了该地区大气系统的分维数为Ｄ＝６．２。从而表明，为支撑该地区大气系统的混沌吸引子至少应取７维系统或以７个变量才能作出描述。

Atmospheric chaotic properties over a linuted area are investigated in terms of theEOF approach. Compared to the phase spacecont inuat ion based on time lag drifting,orihogonality of basic vectors in the space is fully, guaranteed by the EOF technique whichovercomes the problem of the drifting continuation that can be done of single- station data only;This paper presents the EOF decomposition and computation of 1980～1986 ECMWF dailygridded data of Asian 500hPa height with the atmospheric fractual dimensionality D=6.2,suggesting that the chaotic attractor behind the atmospheric system should have a 7D system,i.e , seven variables to describe the system.