MULTI-DECADAL CHANGES IN ICE DYNAMICS FOR GREENLAND’S MARINE-TERMINATING PERIPHERAL GLACIERS AND ICE CAPS (Invited Presentation)

Although mass loss from the Greenland Ice Sheet has received a larger amount of attention over the last two decades, the nearly 600 marine-terminating glaciers peripheral to the ice sheet have also strongly contributed to ice mass loss from Greenland. ICESat data suggest that Greenland’s peripheral glaciers lost ~40 Gt/yr of mass from 2003-2009 and independent estimates of surface mass balance suggest ~36 Gt/yr was due to surface meltwater runoff. This study represents the first efforts to quantify the remaining mass loss term ­­– dynamic mass loss – using Landsat-derived surface velocity, width, and terminus position observations. We find that discharge increased from ~3 Gt/yr from 1985-1998 to ~5 Gt/yr from 1999-2018. Mass loss was primarily driven by synchronous acceleration of glaciers in SE Greenland in 1999. Gradual increases in discharge were also observed for glaciers in western and central east Greenland from the 1980s into the 2000s. Although a portion of the estimated mass loss signal may be due to changes in velocity coverage and accuracy associated with the launch of Landsat 7 in 1999, the acceleration is evident in glaciers with complete velocity records and is coincident with terminus retreat. The observed patterns in mass loss are similar to those documented for the Greenland Ice Sheet, but with an earlier onset of synchronous acceleration in the SE. These data suggest that the peripheral glaciers may respond faster to climate perturbations than their larger ice sheet counterparts, and more work should be done to explore relationships between climate perturbations, terminus position change, and dynamic acceleration of these glaciers to better understand their past and future response to climate change.