Arctic Field Projects

Project Title: Collaborative Research: Refreezing in the firn of the Greenland ice sheet: Spatiotemporal variability and implications for ice sheet mass balance (Award# 1604058)

PI: Rennermalm, Asa K (
Phone: (732 ) 445.4731 
Institute/Department: Rutgers University, Department of Geography 
IPY Project?
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ANS
Program Manager: Dr. Cynthia Suchman (
Discipline(s): | Cryosphere\Firn Studies | Cryosphere\Greenland Ice Sheet | Cryosphere\Hydrology | Cryosphere\Meltwater |

Project Web Site(s):

Science Summary:
A substantial fraction of meltwater of the Greenland ice sheet is retained in firn (liquid or refrozen) rather than running off into the ocean. Unusually thick, near-surface, ice lenses have recently been discovered in the firn and are thought to be the result of exceptionally large recent melt events. This suggests that the larger volumes of meltwater produced in recent years may have been prevented from percolating into deeper firn layers, as has typically been observed in the past, and have instead run off immediately. As a result, a qualitatively different and new ’state’ of the firn has to be taken into account when attempting to quantify the mass balance of the ice sheet, and estimates based on our current state of knowledge are probably subject to larger uncertainty than previously thought. Refreezing, as the mechanism which creates impenetrable ice lenses, emerges as a crucial process in the redistribution of surface runoff and therefore in the determination of surface mass balance (SMB) of the Greenland ice sheet. To quantify this impact on the current and future SMB, this project will combine detailed field observations in the Kangerlussuaq section of the Greenland ice sheet with numerical modeling of the relevant components of the climate system. Project goals are: 1) to investigate the changes and quantify the spatio-temporal variability of the firn by analyzing shallow firn cores and subsurface data at selected sites covering a wide range of elevations and climatic conditions, and compare these new observations to similar data from past decades and remotely sensed observations of firn structures; 2) to quantify the role of refreezing on the SMB with the help of a regional climate model and a high-resolution distributed energy balance model, both of which include a sub-surface snow/firn model; 3) to perform simulations of the spatio-temporal evolution of the SMB with an improved representation of refreezing process under different emission scenarios through the year 2100.

Logistics Summary:
This collaboration between Rennermalm (1604058, Rutgers), Hock (1603815, UAF), and Tedesco (1603331, LDEO) will investigate an important part of Greenland’s cryo-hydrological system, namely the role of firn in producing, transmitting, and retaining meltwater. The project will combine detailed field observations of firn meltwater processes and a state-of-the art model to better constrain the role of firn meltwater in the Greenland ice sheet cryo-hydrologic systems. This will be performed over three years (2017, 2018, and 2019); each year includes field research on the ice sheet near Kangerlussuaq, Greenland: In year 2017 and 2018, the fieldwork will take place in spring before the melt season. In 2019, the fieldwork will take place at the end of the melting season to retrieve sensors and remove installations. The total deployment time is 3-4 weeks each year. In each year of field work, one week will be at spent at Kangerlussuaq and 2-4 weeks working on the ice sheet. The annual deployment will be via LC-130 flights to Camp Raven. From there a field team of 4-8 will travel via snow machines to four field sites. One field site will be established at DYE-2 near Camp Raven, the three other sites are within 100 km from Raven (Site J, KAN U and EKT). At each field site, a camp will be established and various instruments will be installed and measurements will be made. In April 2018 six team members, including the PI, will travel via NY Air National Guard (ANG) to Kangerlussuaq and prepare science equipment and field gear for a late April deployment to the field. The team will use an ANG LC-130 to travel to Raven/Dye 2 where they will establish camp for approximately one week. While camped at Dye 2 the team will test and fine-tune science instruments, collect firn data, and prepare for an 80km snowmachine traverse to KAN-U and EKT. At KAN-U/EKT, the field team will set up a camp to work out of for approximately two weeks. While at the site, the team will gather and analyze firn cores, use snowmachines to gather GPR data, and conduct maintenance on an existing weather station. At the conclusion of these activities, the team will traverse back to Raven/Dye 2, depart the field on an LC-130 to Kangerlussuaq where they will continue on to the US via the ANG. In April 2019 five team members, including a CPS-provided mechanic, will travel via NY Air National Guard (ANG) to Kangerlussuaq and prepare science equipment and field gear for a late April deployment to the field. The team will use an ANG LC-130 to travel to Raven/Dye 2 where they will overnight prior to traversing to Core 4. From Core 4 the group will take day trips to drill firn cores at Core 3, Kan-U, Core 7, and Site J over a nine-day period. The group will then traverse to EKT and spend several days drilling firn cores and servicing an existing AWS. The team will return to Raven, service an AWS, drill firn cores and use snow machines to gather GPR data. All firn cores will be processed in the field. In late-May the team will depart the field on an LC-130 to Kangerlussuaq where they will continue on to the US via the ANG. Also in 2019, PGC and CRREL will provide remote sensing and analysis with the goal of identifying possible crevasses along the route. In September two team members will return to Kangerlussuaq to retrieve and return their equipment. The team will return in late-August 2019 to retrograde field instrumentation utilizing twin otter daytrips from Kangerlussuaq. The instruments will winter-over in Kanger and will be returned to the home institution via ANG in the spring of 2020.

CPS will provide Air National Guard (ANG) coordination for passengers and cargo, dedicated LC-130 missions to Raven/Dye2, KISS user days, rental truck in Kangerlussuaq, snow machines, fuel, an Arctic Field Training course, communications and field/safety equipment. IDP will provide a hand auger and Sidewinder power drive and UNAVCO will provide a GPS base station. In 2019, CPS will also hire a mechanic to support the traverse. In 2020, CPS will provide ANG cargo transport for the equipment from Kanger to US. All other logistics will be arranged and paid for by the PIs.
SeasonField SiteDate InDate Out#People
2017Greenland - DYE-204 / 24 / 2017 05 / 21 / 20176
2017Greenland - EKT04 / 24 / 2017 05 / 21 / 20176
2017Greenland - Kangerlussuaq04 / 18 / 2017 06 / 11 / 20177
2017Greenland - Raven04 / 24 / 2017 05 / 21 / 20176
2017Greenland - Site J04 / 24 / 2017 05 / 21 / 20176
2018Greenland - DYE-205 / 03 / 2018 05 / 15 / 20186
2018Greenland - Kangerlussuaq04 / 19 / 2018 05 / 25 / 20186
2018Greenland - KAN-U04 / 26 / 2018 05 / 02 / 20186
2018Greenland - Raven04 / 25 / 2018 05 / 20 / 20186
2019Greenland - Core_305 / 01 / 2019 05 / 01 / 20195
2019Greenland - Core_404 / 30 / 2019 05 / 11 / 20195
2019Greenland - Core_705 / 01 / 2019 05 / 01 / 20195
2019Greenland - Core_805 / 13 / 2019 05 / 13 / 20195
2019Greenland - DYE-205 / 25 / 2019 05 / 25 / 20195
2019Greenland - EKT05 / 12 / 2019 05 / 21 / 20195
2019Greenland - Kangerlussuaq04 / 23 / 2019 09 / 10 / 20195
2019Greenland - KAN-U05 / 01 / 2019 05 / 01 / 20195
2019Greenland - Raven04 / 29 / 2019 06 / 01 / 20194
2019Greenland - Site J05 / 01 / 2019 05 / 01 / 20195
2020Greenland - Kangerlussuaq0

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