The Nonlinear Relationships Between ENSO And The Winter Atmospheric Circumfluence Anomalies Over Northern Hemisphere

Based on the sea surface temperature from December 1950 to March 2002 edited by HardlyClimate Prediction and Research Center of Britain Weather Bureau, monthly average analysisdata of SLP and monthly average 500hPa height analysis data by NCEP/NCAR, the nonlinearcorrelation analysis of Tropical Pacific SSTA and SLP anomalies over Northern Hemisphere inwinter, and of Tropical Pacific SSTA and 500hPa height anomalies over Northern Hemisphere inwinter, are determined with the techniques of NLCCA (Nonlinear Canonical CorrelationAnalysis), to reflect the nonlinear relationship between ENSO and the winter atmosphericcircumfluence anomalies over Northern Hemisphere. The result from EOF shows that, NAO isthe main teleconnection in Winter sea surface level. Among the atmospheric centers of action inthe sea surface level, Aleutian Low and Iceland Low are the activest ones. Among 5teleconnections in the troposphere, PNA and EU (or EUP) are the most important. The result ofCCA shows that, in El nino and La nina periods, the response of distribution of Winteratmospheric circulation and teleconnections to ENSO is almostly symmetric, proves the linearrelation between Winter atmospheric circulation anomalies and ENSO.The result of NLCCA shows that: (1) Winter atmospheric circumfluence anomalies overNorthern Hemisphere to ENSO is composed of linear part and nonlinear part, which possessesquadratic character. (2) The spatial pattern of relation between Winter atmospheric circumfluenceanomalies over Northern Hemisphere and ENSO shows that, compared with the linear relation,in the nonlinear relation special pattern, the NPO disappears,but the NAO appears in Winter seasurface level; the EU turns to its positive phase, the WP turns to its negative phase, the PNA andEA disappear. (3) The pattern of time of relation between Winter atmospheric circumfluenceanomalies over Northern Hemisphere and ENSO shows that, both of time patterns of linear andnonlinear relations are synchronous, but the PC1 of former is positive in La nina period, negativein El nino period; the PCl of latter is almostly positive in all periods, and its amplitude is smallerobviously. The difference between special patterns or time pattern of linear and nonlinear relations illustrates the linear and nonlinear relations between Winter atmospheric circumfluenceanomalies over Northern Hemisphere and ENSO again. (4) When strong La nina turns to strongEl nino, the NPO and NAO in Winter sea surface level disappear, positive phase of the WP andnegative phase of the WA in 500hPa height firld disappear too. When the sigh of ENSO varies,the changes of special pattern of Winter atmospheric circulation is asymmetric, illustrates thenonlinear responce of Winter atmospheric circumfluence anomalies over Northern Hemisphere toENSO forther.M-K method of climate mutation detection reflects that, the nonlinear response of Winteratmospheric circumfluence anomalies over Northern Hemisphere to ENSO is weaker, theweakening of nonlinear relation between Winter SLP anomalies and ENSO starts from 1978, andthe the weakening of nonlinear relation between Winter 500hPa height firld anomalies and ENSOstarts from 1983.