A global analysis of multi-mode sea surface temperature pattern

The variability of the air-sea system in the low-frequency time domain can be decomposed into several systematic climate modes, namely, the decadal variability (DV) mode, the El Niño Southern Oscillation (ENSO) mode, the annual cycle (AC) mode, the semiannual cycle (SC) mode and the intraseasonal variability (ISV) mode.The combination of these primary modes in the air-sea system orchestrates a complex climate system.The multi-mode low-frequency variability in SST is investigated based on 22 a SST records from 1982 through 2003.The variation of SST in the past two decades undergoes a different combination of these dominant climate modes over different regions, which leads to an interesting new classification of the global ocean based on the relative importance of these modes.The new classification can provide ideal locations for better monitoring of these low-frequency modes in the scientific proof sense.Moreover, two no-annual variation and 14 no-semiannual variation oceanic points, termed annual and semiannual amphidromes, have been well defined in the AC and SC phase maps.The formation of these nodal points is attributed to the couplings of climate modes in EOF analysis results.