New analysis integrating data from satellites, river meters and hydrological models shows that rivers in the Arctic are emitting more water than previously thought.
UNIVERSITY OF MASSACHUSETTS AMHERST
CREDIT: DONGMEI FENG, ET AL.
AMHERST, Mass. A civil and environmental engineering researcher at the University of Massachusetts Amherst has, for the first time, assimilated satellite information into in situ river measurements and hydrological models to calculate river discharges throughout the world. set of 35 years across the Arctic Region. The study found that, with unprecedented precision, the acceleration of water pouring into the Arctic Ocean could be three times higher than previously thought.
Publicly available research, recently published in Nature Communications, is the result of three years of intensive work by research associate professor Dongmei Feng, first and corresponding author on the paper. This unprecedented study assimilates the discharge estimate of 9.18 million rivers made from 155,710 orbital satellite images into hydrological model simulations of 486,493 Arctic rivers obtained between 1984-2018. The project and paper are called RADR (Remote Sensing Arctic Discharge Response Analysis) and are funded by NASA and National Science Foundation programs for early researchers.
“We have reconstructed river discharge information across the Arctic region. Feng said. “They only used some measured data and only for some, but not all, rivers to calculate how much water is pouring into the Arctic Ocean.”
“This is a new, publicly available daily record of flows across the Global North,” said Colin Gleason, professor of civil and environmental engineering and principal investigator of the study. “No one has ever tried to do it at this scale: teach models of what satellites see every day in half a million rivers from millions of satellite observations. It’s a very complex data assimilation process that merges models and data.”
River discharge integrates all hydrological processes of the upstream basin and determines the carrying capacity of the river. This is considered the most important measurement needed to understand a river, but the availability of this information is limited due to the lack of reliable, comprehensive and publicly available data, Feng said.
Physical measurement of rivers – the “gold standard” for gathering information on discharges – is expensive and labor-intensive to install and maintain as the meters require a lot of physical recalibration. times per year. In addition, the rough terrain around some rivers can make the gauge installation very difficult. This makes it more realistic for studies in this area to focus on larger rivers that empty into the Arctic Ocean, so many smaller rivers are not measured at all. In addition, some countries do not make their measurement information publicly available. That leaves hydrologists and environmental scientists in the dark about a large number of rivers, says Feng.
“This is a big contribution to our work, because we can provide river discharge information everywhere, especially for Eurasia,” says Feng. “Satellite is like a gauge in space. If we don’t have a meter in place on the rivers, we can use satellites to improve the data we have now.”
Traditional studies have had to rely on limited gauge information or on simulations based on a representative river sample. Feng’s work focuses on all the Arctic rivers that eventually empty into the Arctic Ocean, the Bering Strait, and the Hudson, James, and Ungava Bays. It does not include the Greenland Ice.
One of RADR’s key findings is that the river discharge acceleration in the Arctic over the past 35 years has been 1.2 to 3.3 times larger than previously estimated.
“This is the new reality that we have actually experienced, not a prediction of what might happen. RADR looks into the past and shows that 17% more water than previously thought has entered the Arctic Ocean,” Gleason said of RADR’s findings.
However, the increase in water flow was not uniform.
“We see huge differences between regions,” says Feng. “Some places show an increase, but others show a decrease. We also found that North America and Eurasia exhibit different patterns”.
“For example, Mongolia is actually getting drier, as are parts of the inland Mackenzie River,” says Gleason.
As more satellites launch, the data provided by RADR will only become more accurate. “We were able to improve it further, because we built this method and with this framework we can easily assimilate more satellite data and with more data,” says Feng. more, we can definitely improve more.” “This is an exciting and also promising direction.”
Feng is expanding access to the system in the hope that people who study other aspects of the Arctic, such as climate change, will use it to get new calculations on factors such as river sediments, precipitation and carbon emissions.
“I’m really glad that not only are we doing this, but we’re making it public and just putting it out there and anyone can download and use it,” Gleason said. “I hope this will become the standard global dataset for anyone studying the Arctic in any of the natural sciences.”
“This is a really huge amount of information that we can use for a lot of applications, like water resource management, hydropower or other infrastructure affected by rivers,” says Feng. . “We were also able to significantly improve the accuracy of global river discharge simulations.”
But the work has implications far beyond the North Pole, she added.
“Because we display satellites that can help us improve the accuracy of [measurements of] river discharge, we can use it to improve data on river discharge around the world,” she said.
The RADR framework “is a vector-based product, so it looks like a river network, and it’s going to be widely available in terms of flow across half a million rivers that are literally as narrow as 3 meters,” Gleason said. .
Now that RADR has shown that previous predictions of river discharge were incorrect, models using the new results will have to be generated.
“Now that we know this about the past, how does that change our predictions for the future? That’s where we’re going to move on,” Gleason said. “Climate change, ecology, pollution and sediment – those are the big things that will change dramatically.”
The article, “Recent Changes to Arctic River Discharge”, can be found at doi 10.1038 / s41467-021-27228-1
JOURNEYS
Nature Communications
DOI
doi 10.1038 / s41467-021-27228-1
RESEARCH SUBJECTS
Do not apply
ARTICLE TITLE
Recent changes to Arctic river discharge
ARTICLE PUBLICATION DATE
November 25, 2021
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