Interannual variability and lagged correlation during strong El Nino events in the Pacific Ocean

Abstract

Interannual climate variability in the Pacific Ocean is investigated using historical data for precipitation, sea-surface temperature (SST) and sea-surface height (SSH). Emphasis is placed on examining the regional correlation, teleconnection patterns and their time lags. Spatial and temporal relationships are examined using empirical orthogonal functions (EOFs), wavelet transform and cross correlation analyses. All the analyzed data derived from first modes of EOFs show interannual variability very similar to those of Nino indices. Associated time series from second modes of EOFs explaining strong El Nino episodes have a high correlation with those of first modes at a time lag of about 9 to 11 mo. Spatial distributions of the strong El Nino modes and the lagged correlations with Nino3 region show a possible teleconnection pattern of the eastward migration of the Pacific climate system.