Regional distribution of steric and mass contributions to sea level changes
Résumé
The contributing factors to regional sea level variability have been explored for the period 2004-2008 based on altimetry observations, hydrographic data and GRACE measurements. The regional averaged annual cycle of the mass contribution to sea level is shown to be highly unsteady. When compared with steric-corrected altimetry, both signals are coherent, though in some regions the coherence analysis is limited by the use of interpolated hydrographic data and in the equatorial regions it is limited by the low signal-to-noise ratio of GRACE data. The closure of regional sea level budgets depends mainly on the GIA correction chosen. A reconstructed global sea level field (with the atmospheric signal eliminated) spanning the second half of the 20th century together with historical hydrographic observations are used to infer the regional mass contribution to sea level rise for the last decades. Results indicate that mass addition from continental ice is the major contributor to regional mean sea level rise for the last decades. In addition, the spatial patterns of mass rates of change point at Greenland as the main source of fresh water input.