|Title||PIs||CoPI(s)||Other Project Members||Start Date||End Date||Abstract||Programs||Funding Agency||Implementation Categories||Keywords||Region||Grant/Project Funding Amount||Project Identifer(s)||Project Web Link||Weblink to data and/or metadata||Outreach/Education Description|
|Collaborative Research: IPY: Dynamic Controls on Tidewater Glacier Retreat|
W. Tad Pfeffer (email@example.com)
Intellectual merit: The Principal Investigators will study both ongoing and historical changes in dynamics at the rapidly retreating Columbia Glacier, in south central Alaska. Tidewater glaciers (TWGs) like Columbia Glacier terminate in the ocean and merit special attention because they exhibit some of the largest and strongly non-linear dynamic volume changes of all glaciers worldwide. In addition, most ice sheet mass loss occurs at marine-ending outlet glaciers that display dynamic instabilities very similar to TWG. Yet, the response of these glaciers to climate forcing remains very poorly understood. They will continue an unmatched 30-year record of observations at Columbia Glacier and to study the similarities between it and the rapidly retreating Greenland outlet glaciers. Project goals are aimed at a predictive capability for future TWG volume changes, which are a dominant constituent of global sea level rise. A variety of measurements including vertical aerial photogrammetry (and subsequent feature-tracking), terrestrial time-lapse photogrammetry, airborne radar, GPS surveying, and meteorological monitoring will provide robust constraints for both inverse and forward modeling of the stress and flow fields. The need for a better understanding of the interaction between climate forcing, glacier dynamics and ice volume change is widely recognized and has led to recommendations for better glacier observations in the the IPCC 2007 Summary for Policymakers, the SEARCH Implementation Plan, the IPY E.U. initiative GLACIODYN, and the NSF call for an Arctic Observing Network. Both the SEARCH Implementation Plan and GLACIODYN list Columbia Glacier specifically as a key glaciological site. This study strongly aligned with the goals of GLACIODYN, and has been endorsed by the steering committee.
Broader impacts: Because of their large numbers, small glaciers still dominate the cryosphere's contribution to global sea level rise. The largest uncertainties in this contribution are from TWG where volume changes are controlled by unmeasured and poorly understood dynamical processes. Rapid freshwater inputs of glaciers and ice sheets directly affect ocean currents, and catastrophic retreats have affected global climate, as evidenced through Heinrich Events. Regional and local changes from rapid volume change at TWGs affect fjord geometry and circulation while exposing new landmass, which causes large changes in terrestrial ecosystems including some of the strongest observed isostatic rebound signals. This study will create new partnerships through collaborations with European colleagues interested in advancing terrestrial photogrammetric methodology, and through a forward modeling collaboration with A. Vieli. The activity is a collaboration between researchers from the Universities of Colorado and Washington, and has a strong educational component, involving undergraduates, and two graduate students. Outreach will occur through channels offered by INSTAAR and National Snow and Ice Data Center (NSIDC), local outreach activities conducted by the Principal Investigators in Valdez, Alaska and University of Washington. Data will be provided to the GLACIODYN outreach coordinator, who will use Virtual Globe technology for project visualization. Results will appear in peer reviewed journals, presentations at national and international meetings, and small workshops focusing on software and algorithm development, and will be archived at NSIDC and UNAVCO.
|Arctic Observing Network||National Science Foundation|
Climatology / Meteorology
|A synthesis of rapid meltwater and ice discharge changes: large forcings from the ice with impacts on global sea level and North Atlantic freshwater budgets|
Richard Alley (firstname.lastname@example.org)
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.
|Synthesis of Arctic System Science||National Science Foundation||Understanding Change|