Global SST/SLP waves during the 20th century

A discrete number of global signals in covarying sea surface temperature (SST) and sea level pressure (SLP) dominated climate variability from 40degreesS to 60degreesN during the 20th Century. They are the quasi-biennial (similar to2.2-year period), interannual (3- to 7-year period band), quasi-decadal (similar to11-year period), and interdecadal (similar to17-year period) signals. A joint frequency-domain analysis of SST and SLP anomalies over the global ocean finds these signals composed of mixed global standing modes and traveling waves that are similar in pattern and evolution. On each period scale, the global traveling wave is composed of global zonal wavenumbers-1 and -2, directed eastward with a phase speed that takes 1 to 2 cycles to traverse the global ocean between 40degreesS and 20degreesN. The existence of these global traveling waves may enhance the predictability of regional climate variability.