Decadal variability of Sea Surface Temperature wavenumber-4 pattern in the Southern Hemisphere
Abstract
The Southern subtropical (20°S-55°S) sea surface temperature (SST) wavenumber-4 (W4) pattern exhibits a decadal variability as revealed in the wavelet and EOF analysis. Involved physical processes and its impact are discussed. It is found that the decadal variability of the SST W4 pattern is the decadal modulation of its interannual variability. The decadal modulation of the SST W4 pattern is mainly linked with the SST footprints from the South Pacific Meridional Mode (SPMM). The SST residuals of the SPMM create a favourable environment for the frequent occurrence of positive/negative type of the SST W4 pattern. Also, the SST W4 pattern has the potential to impact the rainfall variability over the Southern continents on a decadal scale. It modulates the local atmospheric circulation by enforcing the wind to go on/offshore and converging/diverging the moisture into/out of the landmass. As a result, specific humidity changes and alters the rainfall over Southern continents on a decadal scale.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMOS21B..03S