Temporal and Spatial Changes in the Dominance of the Wind-driven and Density-driven processes in the South Atlantic MOC

Shenfu Dong (CIMAS, Univ. of Miami and NOAA/AOML, United States)

CoAuthors

Gustavo Goni (NOAA/AOML, USA)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Science Keynotes Session

Presentation type: Type Keynote/invited

Satellite altimetry and in situ data are used to estimate the meridional overturning circulation (MOC) and meridional heat transport (MHT) in the South Atlantic since 1993 in the region between 20°S and 35°S. Analysis of the 24-year time series of MOC and MHT indicates that the interannual variations in the MOC at different latitudes are statistically correlated, with MOC at 35°S leading that at 20°S by about 20 months. Results also show that the dominance of the geostrophic (density-driven) and Ekman (wind-driven) transports on the interannual variations in the MOC and MHT varies with time and latitude. The time series indicate that at 20°S the Ekman component plays a larger role than the density-driven component. On the other hand, at 35°S the geostrophic component dominates over most of study period, except during 2007-2012 when the Ekman component dominates. Further analysis shows that, consistent with results in other regions, the oceanic heat convergence drives the heat content changes in the study region on interannual time scale, which in turn forces heat fluxes into the atmosphere. The MHT at both 20°S and 35°S appear to contribute equally to the heat convergence in the region. An important key result obtained is that the MOC exhibits positive anomalies since 2013.
Time series of the MOC and MHT in the South Atlantic can be found at: http://www.aoml.noaa.gov/phod/samoc_altimetry/data_all.php.
 

Keynote/invited presentation show times:

RoomStart DateEnd Date
Symphony Ballroom IV Mon, Oct 23 2017,14:25 Mon, Oct 23 2017,14:50
Shenfu Dong
CIMAS, Univ. of Miami and NOAA/AOML
United States
shenfu.dong@noaa.gov