The Arctic region is among the places on earth most profoundly impacted by recent climate changes. For example, according to the New York Times, each year Greenland loses 270 billion tons of ice as the planet warms, a rate that would contribute about two inches to sea level rise by the end of the century. Now Assistant Professor Colin Gleason of the Civil and Environmental Engineering Department at the University of Massachusetts Amherst has been awarded a five-year grant of $529,000 from the prestigious National Science Foundation Faculty Early Career Development (CAREER) Program to make a groundbreaking study of the Arctic hydrologic cycle by using a combination of field work, remote sensing, and computer modelling.
“The Arctic is undergoing rapid changes as this sensitive region responds to altered energy and water transport at the global scale,” observes Gleason. “Arctic rivers are a bellwether of this change, as the mass discharge through these rivers represents the sum effect of all hydrologic processes in a basin, thus cataloging changes in those processes.”
Gleason’s CAREER project will couple the recent explosion in big-data remote sensing with classic fluvial geomorphology to estimate discharge for every Arctic river reach wider than 150 meters while building on Gleason’s extensive body of past research. This process-based understanding of Arctic water will allow scientists to assess the changing Arctic as a whole with greater detail and clarity than ever before and help scientists to better measure a changing Arctic’s effects on the earth as a whole.
As background for Gleason’s research, he explains that the Arctic is changing precipitously as we speak, with alarming impacts on the earth in general. Glaciers and ice sheets in the Arctic are retreating and releasing long-stored freshwater into the global hydrologic cycle, flora and fauna are having to adapt rapidly to changes in their environment, and thawing permafrost is releasing more and more greenhouse gasses into the global carbon cycle.
The increased water discharge is primarily conveyed via rivers, which play a major role in transporting water from the continents to the oceans both in the Arctic and elsewhere. New estimates of river discharge are critically needed to ensure that accurate modelling and assessment of the Arctic hydrologic cycle can continue.
However, says Gleason, logistical difficulties and shifting international priorities have resulted in a steep decline in the gauge network that provides open-source monitoring of these rivers, and likewise the unique geomorphology of Arctic rivers is relatively understudied.
As Gleason explains, “This CAREER proposal seeks to advance understanding of the Arctic hydrologic system from the river up. I will bring UMass undergraduates from both the Geosciences and Engineering departments north of the Arctic Circle to conduct field studies they have designed themselves to better understand Arctic rivers. My graduate students and I will then build on this knowledge to more effectively estimate river discharge from remotely sensed data, leveraging the recent explosion in massively multitemporal satellite data.”
Gleason adds that “This project is ambitious: I hope to achieve an understanding of Arctic hydrology never before possible. UMass undergrads and graduate students will ultimately determine the success of this project. They will receive state of the art training in Arctic field sciences, funding to travel to the Arctic, and training in experiment design and data analysis all while fully participating in the scientific process.”
This geomorphology-based discharge accounting is unprecedented, and datasets and publications resulting from this CAREER award will provide much needed insight to the Arctic hydrologic system.
Gleason’s research group concentrates on the role that rivers play in the global water budget, particularly as climate change alters our hydrologic cycle and we venture into an uncertain hydrologic future. This interest manifests primarily in studies related to Arctic hydrology and ungauged river basins. His research employs a diverse range of methodologies, including intensive field work, algorithm development, remote sensing, and hydrologic and hydraulic modelling.
The CAREER research represents a continuation of Gleason’s extensive field studies on the Greenland ice sheet. He went to Greenland in 2011, 2012, 2013, and 2015 to perform various tasks on several different research teams producing many lasting impacts. For example, in 2012, Gleason was the medical lead for a five-day ice camp as part of a team of four researchers who made supraglacial stream measurements atop the ice from a base camp and from extensive helicopter travel. Additionally, he was part of the team that established a tundra camp for several weeks and make proglacial hydrologic measurements.
All of these research activities and more have led Gleason to invent a revolutionary set of geomorphic relationships known as “at-many-stations hydraulic geometry” (AMHG), showing that the empirical parameters of at-a-station hydraulic geometry (AHG) are functionally related along a river. This conclusion seemingly refutes previous decades of research defining AHG as spatially independent and site specific.
In that context, Gleason currently serves as a member of the prestigious NASA Surface Water and Ocean Topography (SWOT) mission Science Team. SWOT encompasses a $1-billion mission shared among NASA, the French government space agency, the Centre National D'études Spatiales, and the space agencies of Canada and the United Kingdom. Using novel measurements from space, the SWOT team expects to measure river discharge in ungauged basins around the world, monitor volume changes in global reservoirs, and improve our understanding of sub-mesoscale ocean processes.
The SWOT research and all of Gleason’s invaluable field experience will be built into his pioneering CAREER research. As he says about his NSF research, “Our discharge estimates for ungauged basins will be among the first made across the pan-Arctic and will include explicit estimates of uncertainty for ease of use by other investigators. This project will also test hypotheses on permafrost controls on channel morphology, increasing basic knowledge on these little studied systems and allowing for new discharge estimation techniques to be designed specifically for the Arctic.”
Gleason concludes that “The discharge mapping resulting from this proposal will provide an estimate of freshwater resources in the Arctic of use to a wide range of citizens and scientists. All data and processes will be made freely available, and we will work exclusively with open-source data, platforms, and models. This project will integrate field observations, satellite imagery, morphology-driven discharge estimation, and hydrologic models, and should serve as a foundation for hydrologic studies of other regions around the globe.” (February 2018)