Hilfe Wegweiser Datenschutzhinweis Impressum Kontakt





Water mass transformation and the North Atlantic Current in three multicentury climate model simulations


Lohmann,  Katja
Director’s Research Group OES, The Ocean in the Earth System, MPI for Meteorology, Max Planck Society;

Externe Ressourcen
Es sind keine Externen Ressourcen verfügbar
Volltexte (frei zugänglich)

(Verlagsversion), 5MB

Ergänzendes Material (frei zugänglich)
Es sind keine frei zugänglichen Ergänzenden Materialien verfügbar

Langehaug, H. R., Rhines, P. B., Eldevik, T., Mignot, J., & Lohmann, K. (2012). Water mass transformation and the North Atlantic Current in three multicentury climate model simulations. Journal of Geophysical Research-Oceans, 117: C11001. doi:10.1029/2012JC008021.

The warm and saline Subtropical Water carried by the North Atlantic Current undergoes substantial transformation on its way to higher latitudes, predominantly from oceanic heat loss to the atmosphere. The geographical distribution of the surface forced water mass transformation is assessed in multicentury climate simulations from three different climate models (BCM, IPSLCM4, and MPI-M ESM), with a particular focus on the eastern subpolar North Atlantic Ocean. A diagnosis, originally introduced by Walin (1982), estimates the surface water mass transformation from buoyancy forcing. While the depth structure of the Atlantic Meridional Overturning Circulation (AMOC) is similar in all models, their climatological heat and freshwater fluxes are very different. Consistently, the models differ in their mean pathways of the North Atlantic Current, location of upper ocean low salinity waters, as well as in sea ice cover. In the two models with an excessive sea ice extent in the Labrador Sea, most of the water mass transformation in the subpolar region occurs in the eastern part (east of 35 degrees W). The variability of the eastern water mass transformation on decadal time scales is related to the variable warm northward flow into the subpolar region, the upper branch of AMOC, where a strengthened flow leads an intensified transformation. This relationship seems to disappear with a weak connection between the Subtropical and Subpolar gyres.