 |
| Titel |
Time variability of the Southern Ocean gravest empirical mode |
| VerfasserIn |
Andrew Meijers, Nathan Bindoff, Steve Rintoul |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250044387
|
|
|
|
|
|
| Zusammenfassung |
| We examine the first order temporal trend in the Southern Ocean gravest empirical mode
(GEM) over the period 1992-2006 to observe the change in Antarctic Circumpolar Current
(ACC) density structure. Combining this trend with a time evolving satellite GEM (satGEM)
projection of the temperature and salinity fields resolves the change in Southern Ocean heat
and freshwater content into an adiabatic component driven by frontal movement, and a
diabatic part driven by fluxes of heat and freshwater. The southward trend of the
Antarctic Circumpolar Current (ACC) fronts drives a net adiabatic warming equivalent
to 0.056 ± 0.004 PW over most of the ACC and over all depths in the satGEM.
This is strongest at the SubAntarctic Front (SAF). The deep water masses tend to
freshen, while SubAntarctic Mode Water (SAMW) and Antarctic Intermediate
Water (AAIW) increase in salinity for a net trend of 0.009 ± 0.001 Sv. These heat
and freshwater trends are respectively significantly larger and smaller than those
estimated from in situ observations. The addition of a diabatic contribution rectifies
this and we show there is a cooling (-0.029 ± 0.006 PW) and strong freshening
(0.044 ± 0.002 Sv) over this period, so that the net heat and freshwater trends are
0.027 ± 0.004 PW (0.591 ± 0.093 Wm-2) and 0.053 ± 0.001 Sv (36.12 ± 0.68 mmy-1m-2). |
|
|
|
|
|
|