Nonlinear Characteristics Of The Precipitation Anomaly Over China And The Nonlinear Association Between Summer Precipitation Of China And East-Asian Summer Monsoon

According to the Spring (March to May), Summer (June to August), Autumn (September toNovember) and Winter (December to February), the precipitation of China were separated into 4seasons. Then the nonlinear Characteristics of the precipitation anomaly over china during thelast five decades were investigated by applying a feed-forward neural-network based nonlinearprincipal component analysis (NLPCA) method to the rainfall anomaly data for individual season.The composite and case analysises were used to investigate the the general circulation anamolyof the Northern Hemisphere thoroughly according to the two different space distribution patternsof Summer precipitation. Whereafter, a nonlinear projection of the East-Asian Summer monsoononto the Summer precipitation over China was performed by applying a nonlinear canonicalcorrelation analysis method (NLCCA), discussing the linear response and the nonlinear responseof Summer precipitation to the East-Asian Summer monsoon. The results show:1. In the 50 years, the precipitation anomaly of each season over Cina has a certain extentnonlinearity. And the nonlinearity appears the seasonal dependence that the nonlinearity ofAutumn and Winter is weaker than Spring's and Summer's.2. The precipitation space distribution pattern of each season according to the leadingNLPCA mode assimilation manifests obvious asymmetry corresponds to the maximum andminimum nonlinear principal component value. And the leading NLPCA mode assimilation ismore realistic to the original precipitation anomaly data than that of the leading PCA modeassimilation.3. When the nonlinear principal component (i.e. u) of the Summer precipitation anamolyof the leading NLPCA mode take biggish and lesser value respectively, the corresponding generalcirculation anamoly of the Northern Hemisphere manifest distinct dissimilarity. While theSummer precipitation anamoly appears "- +" pattern (biggish values of u), the pressure ridgenear Baikal is strengthened and that of Okhotsk is weakened, whereas, when the Summerprecipitation anamoly appears "- + -" pattern (lesser values of u), the pressure ridge nearBaikal and Okhotsk are both strengthened; moreover, the two dissimilar space distributionpatterns of Summer precipitation are closely relevant to the the Longitudinal Oscillation of SouthAsia High,the position of the Western Pacific Ocean substropical high and the headstream of warm-wet vapor.4. The relationship between Summer precipitation and East-Asian Summer monsoon revealsobvious nonlinearity. According to the strongest and the weakest Summer monsoon, the Summerprecipitation anamolies of China appear obvious dissimilarity in intensity and pattern. TheSummer precipitation response to the East-Asian Summer monsoon can be separated into a linearcomponent and a nonlinear component, and nonlinearity is a bit more important.