Arctic Field Projects

Project Title: Comprehensive Assessment of Ice Sheet Contributions to Sea Level Based on Integrated Remote Sensing Observations (Award# NNX10AR76G)

PI: Scambos, Theodore A (
Phone: (303) 492.1113 
Institute/Department: U of Colorado, Boulder, Cooperative Institute for Research in Environmental Sciences 
IPY Project?
Funding Agency: US\Federal\NASA
Program Manager: Dr. Thomas Wagner (
Discipline(s): | Cryosphere |

Project Web Site(s):

Science Summary:
A wide range of estimates have been made of the current Greenland and Antarctic ice sheet contributions to sea level using a number of different methods. Each method carries strengths and weaknesses that have led to discrepancies. It is essential that these differences be reconciled, and that the strengths of the different approaches be fully utilized, as they each provide important insights into different aspects of the ice sheet mass balance question. When properly exploited these different assessments can provide a more robust estimate of ice sheet sea level contributions than has ever been provided before, along with important new information on potential future ice sheet behavior. The project's researchers aim to understand and quantify key differences among ice sheet mass balance estimates, and to use that information to improve ice sheet mass balance assessments now and in the future. The primary focus will be to improve the analyses and interpretation of observations from the Gravity Recovery and Climate Experiment (GRACE) and the Ice Cloud and Land Elevation Satellite (ICESat) missions, which unlike most other approaches, observe the total integrated effects of the full set of mass balance components. Researchers will develop high resolution mascon solutions form the GRACE data for Greenland and Antarctica, building on what they have already done for Alaskan glaciers. They will then combine these results with a comprehensive set of results from ICESat, from airborne laser altimetry (including data acquired through IceBridge), and from surface mass balance (SMB) models to provide an integrated analysis of ice sheet mass balance and the factors that control it. Through this analysis, and by comparing results to published mass balance assessments derived by other means, the team will provide: (a) an integrated assessment of ice sheet contributions to sea level that is better understood and better constrained than any that have preceded it, (b) a quantitative assessment of the strengths and limitations of the various mass balance approaches (c) a detailed assessment of the spatial variability of density changes associated with observed elevation changes, and (d) a basis and strategy for improving future ice sheet mass balance results derived from ICESat-2 and DESDynI, which will not have the benefit of coincidence with GRACE or GRACE-2. The team's analyses of ice sheet changes will complement efforts by others, who presumably will examine issues related to ocean thermal expansion, terrestrial storage, the terrestrial reference frame and other geodetic aspects of sea level rise. The field effort will focus on component (c), and will be a survey of the percolation to saturation zones in Greenland for increased compaction of firn (affecting altimetry measurements of mass balance) and increased melt and melt runoff under recent warming conditions.

Logistics Summary:
Researchers on this NASA-funded project hope to correct one of the biggest error components of ice sheet altimetry mass balance products, namely, corrections for firn compaction. In late April/early May 2012, a field team member will travel to Greenland and conduct work based largely from a Danish program camp, KAN-U. These participants will travel to and from Greenland via commercial air, having placed some cargo in the Air National Guard logistics chain between Scotia and Kangerlussuaq. In April 2013, researchers will return to Greenland for the Surface Processes of the Lower Accumulation Zone (SPLAZ) project, a joint field campaign between CIRES and GEUS studying the rapid transformation of surface processes across Southern Greenland's accumulation zone. The team will make a snow machine traverse in two phases during ANG flight periods 1 and 2 in April and May. During the first phase, dubbed “Window 1,” (W1), six researchers and equipment will fly from Kangerlussuaq to Raven via ANG in the season’s first flight period. The team will traverse on snowmachines from Raven to KAN-U to maintain/install equipment, make GPR surveys, drill bore holes, and maintain a weather station at KAN-M nearby. They will camp en route. After completing work at KAN-U, researchers will visit Parca 6745 to drill bore holes and make GPR surveys for 2-3 days, returning to Raven at the end of W1, where they will await field team turnover during ANG flight period 2. For “Window 2,” (W2) two new researchers will fly to Raven via ANG during the season’s second flight period; four of the original personnel depart. The remaining four researchers will then traverse from Raven to KAN-U. As time allows, the team will make more GPR surveys around KAN-U, traverse toward the ice divide, and drill bore-holes along the way, surveying beneath a 2012/2013 NASA IceBridge flight line. The team will end the traverse at Raven and personnel will fly on a Twin Otter chartered for Konrad Steffen back to Kangerlussuaq, and return to the U.S. via commercial air. Science and CPS equipment will be sent from Raven to Kangerlussuaq on ANG training flights as space allows. In late June, one researcher on a separate GEUS grant will stop to visit instruments and take firn samples at the PARCA and KAN-U sites during a helicopter traverse. The helicopter will fuel at Raven where CPS will position two drums of fuel via LLC-130 in May. GEUS will purchase this fuel.

CPS will provide ANG coordination for project cargo between Scotia, NY and Kangerlussuaq for U.S. personnel and cargo; flights to and from Raven for personnel and cargo; KISS user days; camping, communications and safety gear; snow machines; and fuel and drums from CPS inventory. The NSF will recoup costs via an interagency funds transfer with NASA. The researchers will arrange all other logistics—including support related to the late June effort by PI Box—and pay for them from the science grant.
SeasonField SiteDate InDate Out#People
2012Greenland - Kangerlussuaq04 / 26 / 2012 05 / 07 / 20121
2012Greenland - KAN-U04 / 26 / 2012 05 / 07 / 20121
2013Greenland - Kangerlussuaq04 / 19 / 2013 05 / 27 / 20138
2013Greenland - KAN-U04 / 24 / 2013 05 / 20 / 20138
2013Greenland - Raven04 / 23 / 2013 05 / 23 / 20138

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