Freshwater discharge from the Greenland ice sheet has a direct and immediate effect on global sea level, has the potential to impact global climate by perturbing nearby sensitive regions of oceanic deep-water formation, and is an important but as yet poorly quantified part of the pan-Arctic water balance.

The investigators will synthesize a range of extant data sets using numerous methods. Remote sensing and atmospheric modeling calibrated by surface data accurately reveal a spatially resolved history of surface melting on Greenland over decades, and coastal weather stations extend observations to more than a century. Sophisticated transfer techniques, including nonlinear approaches, will be used to downscale from these instrumental data to specific ice-core records of melt, learning how the widespread signal is archived. The derived transfer functions, the centuries-long ice-core records, and the century-length coastal-station records then will allow upscaling to determine meltwater variability over longer times than now available. Remotely sensed changes in ice shelves/tongues and outlet-glacier flow speeds will be combined with the contemporaneous histories of surface melting, and analyzed using diagnostic ice-flow modeling incorporating longitudinal stresses to learn how meltwater variability and ice shelf changes force ice-flow variability. If successful diagnosis is achieved, then the longer melt history from the ice-cores can be used to estimate the ice-flow variability over the same interval; the relations between ice-flow and melt changes also can be used prognostically in assessing future changes in the ice sheet affecting freshwater fluxes.

Project Location

Dates

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Members

Principal Investigator

Dr. Richard Alley
Pennsylvania State University

Principal Investigator

Dr. Jason Box
The Ohio State University

Principal Investigator

Dr. Sarah Das
Woods Hole Oceanographic Institution (WHOI)

Principal Investigator

Dr. Ian Joughin
University of Washington

Principal Investigator

Martin Truffer
University of Alaska Fairbanks

Co-Principal Investigator

Dr. Byron Parizek
Pennsylvania State University

Co-Principal Investigator

Dr. David Reusch
New Mexico Tech

Keywords

synthesis of arctic system science i