[Linear discriminate analysis on annual and seasonal characteristics of major cations' profiles of rainwater at Zhoushan rain-sampling spot].

Rainwater samples were collected at rain-sampling Spot of Zhoushan in 2002-2003. Major cation concentrations (H+, NH4+, K+, Na+, Ca2+, Mg2+) of rainwater sample were determined. The concentration variation range and character were depicted by robust statistic analysis. Linear discriminate analysis (LDA) was used to acquire a further knowledge on the annual and seasonal characteristics of research major cations. Distribution character of samples from sample spot was clearly depicted in the new CA1-CA2 ordinates generated by linear discriminate analysis, and the reasons that caused the outliers in samples were discussed.