Spatial correlations of interdecadal variation in global surface temperatures

We have analyzed spatial correlation patterns of interdecadal global surface temperature variability from an empirical perspective. Using multi-taper coherence estimates from 140-yr records, we find that correlations between hemispheres are significant at ≳95% confidence for non-randomness for most of the frequency band 0.06 <f <0.24 cyc/yr. Coherence estimates of pairs of 100-yr grid-point temperature data series near 5-yr period reveal teleconnection patterns consistent with known patterns of ENSO variability. Significant correlated variability is observed near 15 year period, with the dominant tele-connection pattern largely confined to the Northern Hemisphere. Peak-to-peak ΔT ≈0.5°, with simultaneous warming and cooling of discrete patches on the earth's surface. A global average of this pattern would largely cancel.