The production and transport of meltwater (runoff) is an important hydrological process operating on parts of the Greenland Ice Sheet surface today and is projected to become more prevalent in the future. Runoff generated on the ice sheet surface typically passes through moulins to the bed thus influencing basal conditions, and/or emanates from the ice edge to the ocean thus contributing to global sea level rise. The physical process of surface water runoff on ice sheets therefore warrants study, both for basic scientific understanding and to enable better representation and parameterization of ice sheet surface runoff in ice-dynamics and surface mass balance (SMB) models. This research would use remote sensing, in situ measurements, established hydrological theory, and models to address three current knowledge gaps about GrIS surface runoff. The principal scientific goals are to learn what areas of the Greenland ice sheet receive inputs of surface runoff to the bed; to improve representation of surface runoff in ice sheet models; and to assess whether supraglacial drainage patterns that form on the ice sheet surface influence ice dynamics. Researchers will achieve these goals through testing of three scientific hypotheses and a four-part work plan. In brief, the work plan would: 1) Use 2016 Sentinel-2 visible/NIR satellite imagery to create a first pan-Greenland map of surface runoff drainage pattern; 2) Obtain in situ measurements of proglacial river discharge at sites optimal for validation of climate/SMB runoff models, including a new hydro-meteorological gauging station in Inglefield Land, a uniquely advantaged, little-studied area of NW Greenland; 3) Assess and refine climate/SMB model runoff products and calibrate a classic surface water routing parameterization for use with ice sheet models; and 4) Conduct sensitivity tests to determine the influence of routing supraglacial runoff to mapped moulins in the simulations of subglacial and ice flow models. By the conclusion of the project, researchers will deliver i) a first pan-Greenland map of supraglacial drainage pattern, surface catchments, and terminal moulins, revealing where and how much observable surface runoff penetrates the ice sheet; ii) validation of climate/SMB model runoff products using in situ proglacial discharge records; iii) improved representation of GrIS surface runoff in the MERRA-2 and ISSM models; iv) a sensitivity study of the influence (or lack thereof) of surface fluvial drainage patterns on ice dynamics. The investigative team consists of university academics and civil servants with previous experience in Greenland remote sensing, field work, and/or modeling. Four summer field assistantships would introduce graduate students to Greenland. New collaborations would be established with the Geological Survey of Denmark (GEUS) and the Greenland water survey (Asiaq), including supplying automated weather station data to the Danish Programme for Monitoring of the Greenland Ice Sheet (PROMICE) to fill a gap in NW Greenland AWS coverage.

Researchers on this project will construct a pan-Greenland map of GrIS surface drainage pattern (supraglacial rivers, surface catchment boundaries, and terminal moulins and lakes) from satellite remote sensing and obtain archived and new in situ measurements of proglacial discharge suitable for validation of climate/SMB models, including establishing a new hydro-meteorological discharge monitoring station in an area of NW Greenland (Inglefield Land), while maintaining existing measurements in the Kangerlussuaq area from 2019 to 2024. In 2019 two separate field efforts will take place in Greenland. In Kangerlussuaq, work was done to maintain existing proglacial discharge monitoring sites and sites near point 660. The work occurred in two staggered deployments in July and August. For the work at Inglefield Land, six researchers traveled to Thule via AMC and then on to Inglefield Land by helicopter. A new hydro-meteorological monitoring station was established to record oceangoing meltwater runoff from the Greenland ice sheet through proglacial rivers. The PI traveled to Thule for site selection and depart via Embassy flight to Kangerlussuaq prior to camp put-in. In October 2019, two researchers returned to Inglefield Land (again by AMC to Thule and then to the site via helicopter) to service the hydro-meteorological station solar panel. This was accomplished via a day trip from Thule. In 2020, the Pt. 660 and Kangerlussuaq area support was deferred due to COVID-19. Inglefield Land instrument maintenance and repairs were performed by ASIAQ Greenland Survey with no researchers traveling to Greenland due to travel restrictions related to COVID-19. In 2021, fieldwork was cancelled but while there was no researcher travel to Inglefield Land in 2021, automated instruments continued to function. In 2022, three team members were based at Thule Air Base (Thule AB) for four weeks working locally. One team member arrived at Thule mid-June for a day trip to Inglefield Land for instrumentation maintenance activities. In August, three team members traveled to Inglefield Land via Thule. No fieldwork took place at Pt. 660 in 2022. In May 2023, one team member will arrive Kangerlussuaq via commercial air to inventory gear for two days. Then in June 2023, one team member will arrive Kangerlussuaq via commercial air, and three team members will arrive Kangerlussuaq via Air National Guard. Researchers will spend 2.5 weeks camping in Kangerlussuaq area to continue Pt 660-based work maintaining existing proglacial discharge monitoring sites and experiments on the ice sheet. The ice sheet work is accomplished during day visits (no permits needed), and sites are 1-2 km from the end of the road and reached by foot. Three researchers will exit via Air National Guard while one researcher will depart via commercial flights. In June 2024, one team member will arrive Kangerlussuaq via commercial air to inventory gear. Three team members will arrive Kangerlussuaq via Air National Guard. Researchers will spend 2.5 weeks camping in Kangerlussuaq area to continue Pt 660-based work maintaining existing proglacial discharge monitoring sites and experiments on the ice sheet. The ice sheet work is accomplished during day visits (no permits needed), and sites are 1-2 km from the end of the road and reached by foot. Three researchers will exit via Air National Guard. One researcher will stay a few days longer to clear out storage, recycle, and arrange return shipments, before departing via commercial flights. In May 2025, Pituffik Space Base contractor staff stationed on base will support demobilization efforts of local Pituffik stations as well as Inglefield Land instrumentation via helicopter charters.

Battelle ARO will provide Air National Guard support for passengers and cargo. In Kangerlussuaq, Battelle ARO will provide lodging, storage, truck rental, and camping, field and communications equipment. NSF will recoup these funds via an interagency transfer with NASA. All other support will be arranged and paid for by the project.