Science / project summary
The sudden increase in mass loss of the Greenland Ice Sheet (GIS) over the past two decades has spurred scientific scrutiny into the mechanisms causing these changes, and the varying regional response of the ice sheet. The majority of the increase in mass loss is due to the acceleration of marine-terminating outlet glaciers. Until recently, marine-terminating glaciers have been examined mostly from an ice-sheet perspective with little regard to the specific ocean processes that may control rates of calving and submarine melt. The outlet glaciers of central west Greenland exhibit temporal and spatial variability in their velocity response averaged over multiple years; in several cases, glaciers that are adjacent to one another exhibit very different dynamic responses. To address this growing need for better understanding of ice-ocean interactions, this research objective is to examine the forcing mechanisms on outlet glaciers in central west Greenland in order to understand their observed variability in speed (and mass loss) over time and space. The approach is holistic in that researchers will examine atmospheric, oceanic and geometric controls on outlet glaciers in order to elucidate the role that the oceans play in regulating Greenland mass loss. The methodology will be a combination of field and remote-sensing data, with particular emphasis on NASA’s IceBridge survey across this region, to determine how these glaciers (and their forcing mechanisms) have changed over time. The field program is aimed at measuring glacier and ocean properties in two adjacent fjords where outlet glaciers exhibit differing velocity changes. Finally, observations will be used in ice, ocean and coupled numerical models to determine the particular processes that control glacier variability for these two glaciers. Model efforts will then be used along with the remote-sensing database to upscale field observations to the entire region in order to test the validity of using remote-sensing observations (such as SST) to understand ice sheet variability and to determine which measurements (and at what resolution) need to be acquired to improve GIS mass balance predictions. The key impact of this work will be identifying the specific processes controlling GIS mass variability, measurements needed (field and/or remote-sensing) for improved mass balance prediction and improving estimates of mass loss from this sensitive region of Greenland.