A New Estimation of Mean Sea Level in the Arctic Ocean from Satellite Altimetry
Résumé
Sea level monitoring in the Arctic Ocean can provide useful information in the context of a rapid change of several parts of the Arctic climate system. Satellite altimetry systems are affected by various problems at high latitudes. As a consequence, no precise and reliable mean sea level record is available yet from altimetry products. After identifying some of the issues that affect satellite altimetry in the Arctic Ocean region, we describe the tailored processing that has been applied to along-track mono-mission altimetry data. We generate a new dataset of weekly gridded sea level anomaly fields over the Arctic region for the period spanning from 1993 to 2009 based on multisatellite altimetry missions. We demonstrate the improvements achieved by this new dataset, among which a better data coverage. The grids are used to describe some features of mean sea level variability in the Arctic Ocean both at basin-wide and local scales. The regional trend estimated for the Arctic Ocean mean sea level over all latitudes from 66 degrees N to 82 degrees N is 3.6 mm/yr with an uncertainty of 1.3 mm/yr (90% confidence) and without any glacial isostatic adjustment (GIA) correction applied. The record displays large inter-annual variability, but no strong correlation with climate indices was found. Spatial patterns in sea level trends and variability over the Arctic region are also investigated.