CoAuthors

Tilo Schöne (GFZ, Helmholtz-Centre Potsdam, Germany)

Regional sea level changes in the North Atlantic are studied for the period 2003 to 2013 on spatial scales greater than 500 km. The focus is on the relation between the total sea level and its steric and mass equivalent components. The data bases are: monthly gridded sea levels from the Jason-1/Jason-2 satellite altimeters processed by the GFZ's Altimeter Data System as well as gridded steric sea levels from Argo floats and mass equivalent sea level from the GRACE mission. In the analyzed period the sea level has decreased in the Northern Subtropical Gyre and increased in the Tropics. While the steric component is dominant in the Northern Subtropical Gyre the mass component seems to be crucial in the Tropics. Typical spatio-temporal patterns are studied using Empirical Orthogonal Functions. For the anomaly series (annual signal subtracted) of the total and the steric sea level the dominant mode is connected to the North Atlantic Tripole. This pattern indicates changes in the strength of the upper layer Gulf Stream and North Atlantic Current and has typical temporal scales of several years. The analysis indicates that these currents were weaker than normal during 2010 and 2011. In addition, there is evidence for a relation to concurrent changes of the meridional mass transports in the Subtropical Gyre.