Arctic sea level change over the past 2 decades from GRACE gradiometry and multi-mission satellite altimetry

The Arctic is still an extremely challenging region for theuse of remote sensing for sea level studies. Despite the availability of 20 years of altimetry, only very limited sea level observations exist in the interior of the Arctic Ocean. However, with Cryosat-2 SAR altimetry the situation is changing and through development of tailored retrackers dealing with presence of sea ice within the radar footprint, we can now develop sea surface height and its variation in most of the Arctic Ocean. We have processed 3 years of Cryosat-2 data quantified as either Lead or Ocean data within the Cryosat-2 SAR mask in the Arctic Ocean. By carefully reprocessing and reediting conventional altimetry from ERS-1/ERS-2 and Envisat, we have now been able to derive a multi-decadal time series using far more remote sensing data in the interior of the Arctic Ocean than ever before.Through recently acquired gradiometer observations from the ESA GOCE mission, we are now able to derive a mean dynamic topography of the Arctic Ocean with unprecedented accuracy to constrain the Arctic Ocean circulation controlling sea level variations in the Arctic. We present both a new estimation of the mean ocean circulation and new estimates of large scale sea level changes based on satellite data and perform an estimation of the fresh waterstorage increase over the last decade using temporal gravity changes from the GRACE satellite.