ERA5 Modes of Interannual Variability

Basic fields for each of these variables include a monthly mean climatology and standard deviation, corresponding anomalies spanning 40 or more years of data, empirical orthogonal functions (EOFs), principal component (PC) time series, percent variance explained by each EOF, and an estimate of the standard error of the percent variance explained.

Dominant modes of variability include El Nino Southern Oscillation (ENSO) in sea surface temperature, and the Antarctic Oscillation (AO) and North Atlantic Oscillation (NAO) in surface pressure. Separate analyses are performed for the entire globe, northern hemisphere only, and southern hemisphere only. There is sufficient information to further explore lagged correlations, teleconnections, and more advanced statistical techniques.