 |
| Titel |
Overflow transports in Denmark Strait and the Faroe Bank Channel derived from combined moored ADCP and PIES measurements during 2011-2014 |
| VerfasserIn |
Martin Moritz, Kerstin Jochumsen, Detlef Quadfasel |
| Konferenz |
EGU General Assembly 2015
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250109962
|
| Publikation (Nr.) |
 EGU/EGU2015-9917.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Denmark Strait (DS) and Faroe Bank Channel (FBC) are the major pathways of dense
water leaving the Arctic Mediterranean. The water formed in the Nordic Seas crosses the sills
of this passages and descends into the deep North Atlantic Ocean where it becomes part of
the North Atlantic Deep Water. Estimates of strength and variability of these overflows are
useful to observe temporal changes and understand mechanisms that may affect the Atlantic
Meridional Overturning Circulation.
The velocities in the overflows have been measured with Acoustic Doppler Current
Profilers (ADCPs) for almost two decades. For transport estimates the thickness
of the overflow plume is typically derived from the depth of maximum velocity
shear.
During 2011 and 2014 Pressure Inverted Echo Sounders (PIES) were added to the
mooring sites. The thickness of the plume of overflow water that is usually characterized to
be denser than ÏăÎ=27.8 kgm-3 can be estimated from hydrographic profiles that were
obtained from travel time measurements of the PIES.
The volume transports in DS, calculated from ADCPs only and in combination with the
plume thickness derived from PIES measurements, are compared. The mean difference
between both is about 3% of the total transport of 3 Sv. Nevertheless, daily estimates can
differ within the same magnitude, whereas the difference of monthly estimates reduces to
about 0.3 Sv.
The heat transport of the overflow relative to 0Ë C calculated from combined PIES and
ADCP measurements across the DS varies within the order of 10 TW.
Estimates of transports from hydraulic control theory were derived from PIES data
upstream of the sills in DS and FBC and compared to transport observations at the
sills.
Additionally, the variability within the vertical structure of the water column in DS and
FBC are analysed. |
|
|
|
|
|
|