 |
| Titel |
Southern Ocean Eddies as Weather Makers |
| VerfasserIn |
Ivy Frenger, David Byrne, Nicolas Gruber, Reto Knutti, Matthias Münnich, Lukas Papritz |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075144
|
|
|
|
|
|
| Zusammenfassung |
| Several hundred mesoscale eddies populate the Southern Ocean south of 30°S at any time,
however, little is known about their effect on the overlying atmosphere. As these eddies
feature sea surface temperature (SST) anomalies one can expect them to play a role in the
coupling of the atmosphere and the ocean. Here we show based on satellite observations of
about 600,000 eddies occurring between 1997 and 2010, that these ocean eddies significantly
alter near surface wind, cloud properties and rainfall by several percent. Relative to the
atmospheric variability, the magnitude of the anomalies related to ocean eddies
represents ±13-15 % (wind, cloud fraction), ±6-10 % (cloud water content) and
±2-6 % (rain). This impact on the atmosphere is striking given the fact that oceanic
eddies constitute non-stationary SST fronts of moderate size relative to the much
larger atmospheric low pressure systems which are constantly passing by at these
latitudes.
The spatial pattern of these changes is consistent with a mechanism labeled downward
momentum mechanism in which the SST anomalies related to eddies modify the stability and
thus turbulence of the atmospheric boundary layer. We will investigate the mechanisms and
impact of the atmospheric modifications associated with ocean eddies in a regional
high-resolution coupled atmosphere-ocean model (COSMO-ROMS) over the Southern
Ocean. |
|
|
|
|
|
|