Nonlinear Forced Change and Nonergodicity: The Case of ENSO-Indian Monsoon and Global Precipitation Teleconnections

We study the forced response of teleconnection between El Niño–Southern Oscillation (ENSO) and Indian summer monsoon (IM) in Max Planck Institute Grand Ensemble, a set Earth system ensemble simulations under historical Representative Concentration Pathway (RCP) forcing. The teleconnection, or characteristic it, is defined as time dependence correlation coefficient evaluated over ensemble. consider temporal variability spatial averages that with respect to dominant modes sense Maximal Covariance Analysis, Canonical Correlation Analysis Empirical Orthogonal Function analysis across A further representation we define here takes point view predictability spatiotemporal monsoon. find strengthening ENSO-IM robustly consistently featured various representations, whether sea surface temperature (SST) level pressure (SLP) used characterize ENSO, both period RCP8.5 forcing scenario. It found be associated dominantly principal mode ENSO variability. Concerning representations involve an autonomous characterisation Pacific, terms linear regression model, main contributor coefficient, which can outcompete even declining when it represented by SLP. also change typically nonlinear 1) formally rejecting hypothesis ergodicity holds, i.e., expected values coefficients equal ensemble-wise itself, showing 2) trivial contributions changes means standard deviations are insignificant here. provide, test statistics, global maps degree nonlinearity/nonergodicity local precipitation ENSO.