Abstract: Some studies holded that the firsteig envector field of the time series of or iginal observations fields usually shows a striking similarity to the time-averaged field. How ever, this paper pointed out that there are intrinsic differ ences between the two statistical fields of the time series of original observ ations fields. Their similarity depends on the structure in the phase space of the time series of original observations fields. The relative intensity of the time-averaged(climatic) field and temporal anomalies fiel dset plays an import ant role in their similarity.