The Nonlinear Characteristics Of The Surface Air Temperature Over China And The Relationships Between SSTA Over Tropical Pacific And China SATA

Based on the monthly average temperature data of 160 stations by the Naional Climate Center and the Global sea Ice and Sea Surface Temperature (GISST) data sets of Hadley Center,nonlinear characteristics of the China four season temperature anomaly and the interdecadal dependence are determined with the techniques of NLPCA,also the spacious response pattern of China individual season temperature anomaly to the SSTA of tropical mid-east Pacific.In succession,the response pattern of China winter temperature anomaly to the SSTA of tropical mid-east Pacific was drawed by the NLCCA and comparison between the CCA and the NLCCA was made.Results show:1.The results of the first NLPCA mode show that:the nonlinearity is strong in spring (MAM) and summer (JJA),but is weaker in fall (SON) and winter (DJF),manifesting the seasonal dependence of the nonlinearity in the Chinese SAT.Through the comparison of the original SATA data and the two approximations,the 1D NLPCA approximation greatly displays the real space distribution of the SATA than does the 1D PCA approximation.2.According to the cold term and warm term of the interdecadal changes of the temperature, we separate the total data set into two subsets. The NLPCA was computed for the two datasets separately.The leading NLPCA mode from the two datasets have the similar results to the total dataset:the nonlinearity of the Spring is strongest,and the one of the Winter is weakest.From the interdecadal point of view,there was not a definit change of nonlinearity in Spring,Autumn,and Winter,changes in Summer is obvious,the nonlinearity in Summer has definitely enhanced in recent 23 years from 1980-2003. 3.From the result of first mode of CCA,the response of China seasonal temperature anomaly to the mid-east Pacific SSTA has a good linear characteristic.The China temperature anomaly pattern is totally opposite when the SSTA of mid-east Pacific is separately positive and negative.The temperature of most aera in China is higher than the averaged state in Spring,Summer and Winter when the SSTA of mid-east Pacific is positive,otherwise,the temperature is lower than the averaged state.The situation in Summer is opposite.4.The first NLCCA result of tropical SSTA and China Winter SATA show that:the response of China Winter SATA to tropical SSTA is not totally linear.There is somewhat nonlinear associations between them,the linear and nonlinear components account respectively for 84.6ï¼…and 15.4ï¼…of the variance in SAT anomaly data derived from the NN projection.,and the nonlinear response has almost 1/5 the variance of the linear respoinse and the 1/6 variance of the total response.5.The reason why the SATA in China is higher than the averaged state When the SSTA of the mid-east Pacific is higher than the averaged state is probabely that the East Asian Winter monsoon is usually weaker than the averaged state when the SSTA of the east Pacific is higher than the averaged.So it's not benefit for the cold air mass thansforn form the high latitude to low latitude and caused the highertemperature in most aera inChina.