All Climate Events

Interannual-decadal variability and predictability over the South Atlantic and southern Indian Oceans

Download as iCal file

Monday, 08 July 2019, 2:00

Monday, July 8, 2019. 2:00PM. Interannual-decadal variability and predictability over the South Atlantic and southern Indian Oceans. Yushi Morioka, Japan Agency for Marine Science Technology. Sponsored by NOAA GFDL. More information here

 

Interannual-decadal sea-surface temperature (SST) variability in the South Atlantic and southern Indian Oceans has great influences on regional rainfall variability over the southern Africa through modulation of moisture transport. The Interannual SST variability, so called “Subtropical Dipole” which is characterized by a meridional dipole pattern of SST anomalies in each basin, is induced by ocean mixed-layer thickness variability associated with subtropical high variability. A series of climate model experiments reveals that besides remote forcing such El-Nino Southern Oscillation (ENSO) and the Southern Annular Mode (SAM), sea-ice extent variability over the Weddell Sea has a potential to influence the atmospheric variability over the South Atlantic. On a decadal timescale, the SST variability over the South Atlantic tends to propagate eastward as quasi-stationary oceanic Rossby waves under the influence of the Antarctic Circumpolar Current (ACC) and induce the decadal SST variability over the southern Indian Ocean. Decadal reforecast experiments with different ocean initial conditions show that the decadal SST variability over the South Atlantic (southern Indian Ocean) is predictable when the model's SST, subsurface ocean temperature and salinity are initialized (only the model's SST is initialized).

Location  NOAA GFDL, Smagorinsky Seminar Room, Princeton University, Princeton, NJ.