Incessant mountain rain, snow and melting glaciers in a comparatively small region of land that hugs the southern Alaska coast and empties fresh water into the Gulf of Alaska would create the sixth largest coastal river in the world if it emerged as a single stream, a recent study shows.
Since it's broken into literally thousands of small drainages pouring off mountains that rise quickly from sea level over a short distance, the totality of this runoff has received less attention, scientists say. But research that's more precise than ever before is making clear the magnitude and importance of the runoff, which can affect everything from marine life to global sea level.
The collective fresh water discharge of this region is more than four times greater than the mighty Yukon River of Alaska and Canada, and half again as much as the Mississippi River, which drains all or part of 31 states and a land mass more than six times as large.
"Freshwater runoff of this magnitude can influence marine biology, nearshore oceanographic studies of temperature and salinity, ocean currents, sea level and other issues," said David Hill, lead author of the research and an associate professor in the College of Engineering at Oregon State University.
"This is an area of considerable interest, with its many retreating glaciers," Hill added, "and with this data as a baseline we'll now be able to better monitor how it changes in the future."
The findings were reported in the Journal of Geophysical Research: Oceans, by Hill and Anthony Arendt at the University of Alaska-Fairbanks. It was supported by the North Pacific Research Board.
This is one of the first studies to accurately document the amount of water being contributed by melting glaciers, which add about 57 cubic kilometers of water a year to the estimated 792 cubic kilometers produced by annual precipitation in this region. The combination of glacial melt and precipitation produce an amount of water that's larger than many of the world's great rivers, such as the Ganges, Nile, Volga, Niger, Columbia, Danube or Yellow River.
"By combining satellite technology with on-the-ground hydraulic measurements and modeling, we're able to develop much more precise information over a wider area than ever before possible," Hill said.
The data were acquired as an average of precipitation, glacial melting and runoff over a six-year period, from 2003 to 2009. Knocked down in many places by steep mountains, the extraordinary precipitation that sets the stage for this runoff averages about 6 feet per year for the entire area, Hill said, and more than 30 feet in some areas.
The study does not predict future trends in runoff, Hill said. Global warming is expected in the future, but precipitation predictions are more variable. Glacial melt is also a variable. A warmer climate would at first be expected to speed the retreat of existing glaciers, but the amount of water produced at some point may decrease as the glaciers dwindle or disappear.
Additional precision in this study was provided by NASA's Gravity Recovery and Climate Experiment, or GRACE satellites, which can make detailed measurements of gravity and, as one result, estimate the mass of glaciers they are flying over. As the glacial mass decreases over time, the amount of melted water that was produced can be calculated.
The close agreement of land-based measurements also help confirm the accuracy of those made from space, a point that will be important for better global understanding of water stored in a high-altitude environment.
Some of the processes at work are vividly illustrated at Glacier Bay National Park, where some of the most rapidly retreating glaciers in the world are visited each year by hundreds of thousands of tourists, many on cruise ships.
David Hill | EurekAlert!
Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
15.11.2018 | Faculty of Science - University of Copenhagen
The unintended consequences of dams and reservoirs
14.11.2018 | Uppsala University
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences