[J01-3] Monitoring of the cryosphere III

[J01-3-02] Sea level rise from the Greenland and Antarctica ice sheet melt from combined CryoSat and GRACE inversion

^○Rene Forsberg, Sabastian Simonsen, Valentina Barletta (DTU Space, Lyngby, Denmark)

The combination of space-based remote sensing data, especially gravity field changes from GRACE and elevation changes from CryoSat, may yield time series of Greenland and Antarctica mass balance with both high temporal and spatial resolution, highlighting the varying individual mass loss behaviour of major glaciers systems, while still keeping a “correct" overall ice sheet wide mass loss. Although GIA-related errors continue to be large in Antarctica, the temporal changes in mass balance are well determined, and show significant acceleration both over the Antarctic Peninsula and the Pine Island/Thwaites glacier systems. For Greenland the large yearly melt event of 2012 followed by extraordinary cool summers have meant that the Greenland ice sheet mass loss have been slightly decreasing during the CryoSat period 2010-16, with large variations between individual glaciers and ice streams.

In the presentation we outline change results from CryoSat and GRACE 2010-2016, for both Greenland and Antarctica, using models of firn compaction and density as auxillary data. We estimate an overall mass balance of Greenland around -265 GT/yr and for Antarctica -145 GT/yr, representing nearly a doubling of Antarctica mass loss since 2002, while Greenland show only relatively small overall accelerations, with large regional melt region variations. From the ice sheet melt data, we find a current global sea level rise component of 1.1 mm/yr, or about 1/3 of the currently observed global sea level rise. Sea level rise from the melting ice sheets is far from constant across the globe due to associated gravity field and loading changes, and we show estimates of the current regional “fingerprinting" of the sea level rise signal.