Arctic Field Projects



Project Title: Drainage efficiency of the Greenland supraglacial river network (Award# NNX14AH93G)

PI: Smith, Laurence C (laurence_smith@brown.edu)
Phone: (401) 863.5153 
Institute/Department: Brown University, Earth, Environmental and Planetary Sciences 
IPY Project?
Funding Agency: US\Federal\NASA
Program Manager: Dr. Thomas Wagner (thomas.wagner@nasa.gov)
Discipline(s): | Cryosphere |

Project Web Site(s):

Science Summary:
The production, transport, and export of meltwater from the surface of the Greenland Ice Sheet (GrIS) is critically important to our understanding of global sea level rise, yet remains one of the least-studied hydrologic systems on Earth. To date, efforts to measure GrIS contributions to global sea level rise have prioritized solid/dynamical ice losses, gravity anomalies from the Gravity Recovery and Climate Experiment (GRACE) mission, and calculations of surface mass balance from automated weather stations and/or climate modeling. None of these explicitly considers the fast transport of meltwater through supraglacial river networks, despite their ubiquity across much of the ablation zone and being a primary mechanism by which surface meltwater is routed to the englacial and proglacial parts of the ice sheet. This currently poor state of knowledge about supraglacial rivers impairs understanding of GrIS contributions to global sea level rise for at least four reasons. First, there is a recognized positive feedback between the penetration of surface meltwater to the bed and ice sliding velocity, thus impacting ice dynamics. Second, there is a growing appreciation in the Greenland science community that meltwater runoff contributes as much if not more mass loss to the global ocean than does solid/dynamical ice loss. Third, the intensity and areal extent of meltwater production on the GrIS surface are projected to increase. Fourth, virtually nothing is known about the hydraulics of GrIS supraglacial rivers, so numerical modeling of meltwater fluxes flowing over and into the ice sheet cannot be done with confidence. To address this knowledge gap, the researchers seek to answer five science questions: 1) To what extent does ice surface topography dominate the movement of water across the ice sheet? 2) Are fluxes of supraglacial meltwater into the GrIS subsurface uniformly distributed or do some parts of the ice sheet receive greater concentrations of meltwater than others? 3) Do supraglacial river flows attain supercritical velocities? 4) Was a 100% efficient surface water drainage pattern observed following the extreme July 2012 melt event unusual or typical for the ice sheet? 5) How efficiently is GrIS surface meltwater transported off the ice sheet surface and out to the global ocean? To answer these questions, the project will build upon new remote sensing capabilities developed in previous NASA Cryospheric Sciences grant NNX11AQ38G (ending 2014). It will use archived and scheduled high-resolution visible/NIR imagery and stereo digital elevation models from WorldView-1/2, QuickBird, and Geoeye-1 satellites, and cold-season IceBridge Digital Mapping System (DMS) camera imagery, to study supraglacial river drainage pattern and flow efficiency for a ~15,000 km2 area of the ablation zone in western Greenland. Remotely sensed estimates of river flow direction, velocity and flux (discharge) will be calibrated/validated using a dataset of in situ hydraulic measurements from two field campaigns in the ablation zone. The operation and maintenance of four previously established terrestrial river gaging sites near Kangerlussuaq will be continued. Finally, all of these remotely sensed and field datasets will be incorporated into a GIS-based hydrologic modeling framework to enable a first "snow-to-sea" simulation of GrIS meltwater runoff that explicitly includes principles of open-channel flow through supraglacial river drainage networks.

Logistics Summary:
This project will continue hydrological and supraglacial river studies in the vicinity of Kangerlussuaq begun under NASA grant "NASASmith". Beginning in 2015 through 2018 field teams will travel to Kangerlussuaq, Greenland for field work. In 2015, researchers will make three trips to Kangerlussuaq, in February, April and July. Three researchers will travel via commercial air to Kangerlussuaq in February, each staying for about 10 days. Based from the KISS, the team will collect water samples from the Watson River, accessing sites via snowmachine and ATV. They also may visit a camera installation nearby if able. A team of two will return in April to install instruments on the Watson River bridge, basing out of KISS for ~2 nights. In July, a team of eight will return for approximately two weeks, traveling to Greenland via the Air National Guard. July work is establishing 2 different ice camps in the area of the Watson River (WQ) and Isortoq River (IQ) Watersheds on the ice cap. In 2016, researchers will return to Greenland twice: in March and again in June, when they will remain for work through August. In March, two researchers will travel to Kangerlussuaq via the ANG to service the proglacial river instrumentation on the Watson River bridge and complete lidar surveys of the Watson River channel. Several days later, they will depart. Then, in June, five researchers will return to Kanger, establish a small tent camp, and work around Pt 660, returning to Kangerlussuaq occasionally for resupply. Three of the five will depart after about two weeks. At the end of June, eight additional scientists will join the remaining team of two, and this group will continue work at Pt 660 while preparing for the put in of the Smith ice camp, located out on the ice sheet margin. A six-person team will deploy to the Smith ice camp in early July and work there for about 2 weeks. When work is complete, eight people will depart Greenland; the remaining three will continue working out by Pt 660 for about another month. In 2017, researchers will return to Greenland in July. Four researchers will travel via the ANG to establish a small tent camp and continue work at Pt 660. Five additional researchers will travel via combination of ANG and commercial travel deploying to the Smith ice camp and work there for about 1 week. Nine people will depart Greenland at the beginning of August via a combination of ANG and commercial travel. Researchers will return to Greenland in 2018. One researcher will travel commercially to Kangerlussuaq to make advance preparations for the rest of the team’s arrival. Three additional researchers will arrive via ANG on 13 July to establish a small tent camp and continue work at Pt 660.

Via an interagency funds transfer NASA>NSF, CPS will provide Air National Guard coordination for passengers and cargo, KISS user days in Kangerlussuaq, rental trucks, freezer and warehouse space, and camp/communications/safety gear. UNAVCO will provide GPS equipment. The PI will arrange and pay for all other logistics from the grant.
SeasonField SiteDate InDate Out#People
2015Greenland - Kangerlussuaq02 / 06 / 2015 07 / 27 / 201510
2015Greenland - Smith Ice Camp 207 / 17 / 2015 07 / 24 / 20159
2016Greenland - Kangerlussuaq03 / 08 / 2016 08 / 19 / 201611
2016Greenland - Point 66006 / 01 / 2016 08 / 19 / 20166
2016Greenland - Smith Ice Camp 207 / 04 / 2016 07 / 14 / 20167
2017Greenland - Kangerlussuaq06 / 21 / 2017 08 / 05 / 20179
2017Greenland - Point 66007 / 21 / 2017 07 / 28 / 20174
2017Greenland - Smith Ice Camp 207 / 22 / 2017 07 / 29 / 20179
2018Greenland - Kangerlussuaq07 / 04 / 2018 08 / 30 / 20186
2018Greenland - Point 66007 / 06 / 2018 07 / 22 / 20185
 


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