Decadal climate variability in the subpolar North Atlantic
Date
1994
Authors
Wohlleben, Trudy Monique Heide
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The cyclic nature of observed decadal to interdecadal climate variability of the subpolar North Atlantic is re-examined in terms of six separate climate components of this air-sea-ice system: 1) sea surface temperature; 2) atmospheric sea level pressure; 3) sea surface salinity; 4) sea ice extent; 5) gulf stream transport of heat and salt into this region; and 6) deep water formation within this region (especially within the Labrador Sea).
Sea surface temperature anomalies concentrated in the Labrador Sea region are found to have an impact upon atmospheric sea level pressure anomalies over Greenland, which in turn are believed to influence the transport of freshwater (salinity anomalies ) and ice anomalies out of the Arctic Ocean, via the Fram Strait. Such sea surface salinity and ice anomalies are advected around the subpolar gyre into the Labrador Sea affecting convection and the formation of Labrador Sea Water. This has an impact upon the transport of Gulf Stream water into the subpolar gyre and thus, also has an effect upon sea surface temperatures in the region.
A decadal climate loop is therefore proposed as an internal source of decadal to interdecadal climate variability within the subpolar North Atlantic region. Through the lags associated with the correlations between the different climate components, observed horizontal advection timescales, and the use of Boolean Delay Equation models , the timescale for one cycle of this loop is determined to have a natural range extending from approximately 15 years to approximately 21 years.