Figure 3: Three first leading E-EOFs (Extended EOFs) of sea level anomalies from TP/ERS. Left panels show the spatial structures of the modes and the right panels the associated time series. We use a time window of one year with a one-month interval (time resolution is 10 days). This lead to a 3x12xN_{x}xN_{y}-dimensional "observation" vector, where Nx and Ny are the numbers of longitude and latitude grid points respectively (N_{x}=56, N_{y}=31). The variance maximization procedure for these extended vectors leads to the diagonalization and eigenvalue problem of the lagged-covariance matrix. Percentages of explained variance are indicated at the top of each panel. Multiplying the time series with the amplitude of the spatial structure yields the value in millimetres for sea level for the corresponding mode. Contour interval is 10 units. a) 1^{st} EOF (28.29%); b) 2^{nd} EOF (20.11%) and c) 3^{rd} and 4^{th} EOF (21.40%) |