Research

New satellite tools track river flows throughout the Lower Mekong Basin

Gabe Allen — Wed, 15 Apr 2026 12:00:00 +0000

New satellite tools track river flows throughout the Lower Mekong Basin Gabe Allen Wed, 04/15/2026 - 06:00

Gabe Allen

Robert Brakenridge is a Senior Research Associate at the Institute of Arctic and Alpine Research (INSTAAR).

After the Mekong River descends from the highlands in China, it flows into Cambodia, Laos, Thailand and Vietnam providing freshwater for farming, fishing, hydropower and transportation. 52 million people rely on the lower Mekong River Basin for their livelihoods, according to the Mekong River Commission.

In the past decade, the Lower Mekong’s flows have dwindled, putting pressure on downstream communities. Until recently, a lack of information on the river’s hydrology has hindered efforts to understand these changes.

A new paper from an international group of researchers, including INSTAAR scientist Robert Brakenridge, takes aim at this knowledge gap. They present a suite of tools capable of precisely monitoring river flows.

The author's techniques rely on satellite-mounted sensors that map “passive microwave radiation” across the Earth’s surface.

“You’re listening to the radiation actually emitted by the Earth,” Brakenridge said. “It turns out that water bodies are much lower emitters than land bodies… we use that difference as a way to track water changes.”

The researchers also pulled data from an extensive network of physical river monitoring stations in the Lower Mekong to double-check the satellite observations and calibrate their model. The alignment was excellent. The satellite-powered data proved accurate even during periods of drought and flood — river stages that often prove challenging for remote sensing.

“These sensors have very precise dynamic range,” Brakenridge said. “Basically you can use each pixel as a gauging station.”

Left: A boat used to measure river discharge is moored at the hydrologic station in Tan Chau, Mekong Delta, Vietnam. Right: The impeller component of a boat-mounted current meter rests on the shop floor. These meters contributed to the in situ data that the authors used to validate their satellite results. (Anna Podkowa)

Trouble on the Mekong

The new investigation is more than just a proof of concept. It also uncovered a nuanced understanding of how the Lower Mekong Basin is changing in the 21st century.

In 2015 and 2016, the Lower Mekong Basin experienced a severe drought. Millions of farmers lost autumn and winter rice harvests and salt water leached upstream into the Mekong River Delta. According to the new investigation, river flows have yet to recover from this historic drought.

The Lower Mekong’s slow recovery after drought may be due, in part, to an increase in damming upstream. Huaneng Power International, a Chinese electricity company, completed two large dams on the upper Mekong in 2010 and 2012 respectively. In addition, two new water diversion projects are planned for the near future in Cambodia and Thailand.

The analysis reveals that the new Chinese dams likely decreased annual flows on the Lower Mekong overall. As the river struggles to recover from the 2015-2016 drought, the diversion projects in the lower basin could further exacerbate the issue.

While new construction proliferates on the Mekong, climate change is causing precipitation to become more erratic in the region. As such, it is hard to parse out which factor — climate change or human infrastructure — is the driving force behind recent water shortages.

Brakenridge is careful to hedge on this point. There are conflicting results in the literature, and more research is needed to resolve the issue.

“It becomes very political very fast,” he said. “Our conclusions are pretty conservative. They mainly describe the observations we made.”

A new wavelength

A map of the Lower Mekong Basin shows "satellite gauging reaches" — focus sites of Brakenridge and his collaborator's recent investigation. (Courtesy)

While the new investigation stops short of naming a leading culprit of the Mekong’s dwindling water supply, it does suggest a way forward. The results show the power of passive microwave radiation to monitor the river into the past, present, and future.

Brakenridge has honed these techniques for decades. In the early 2000s, he was one of the first to demonstrate the ability of “Ka band” radiation for river monitoring. In recent years, he has joined a new generation of researchers leveraging “L band” radiation data from NASA’s Soil Moisture Active Passive mission, colloquially known as SMAP, for the same purpose.

“With the L band microwave you see through the vegetation much better,” he said. “So if you’re looking at a floodplain with a forest canopy, it doesn’t matter so much.”

The new investigation employs both types of radiation.

“The two seem to counterbalance each other,” he explained.

Though L band data is only available for the past decade, Ka records extend to the late 1990s and other passive microwave records extend back to the late 1970s. By combining all three, the scientists compiled a record of river flows spanning nearly half a century, adding weight to the trends they observed.

Planned NASA missions will also extend L band data into the future — at least to the 2040s. Brakenridge hopes that one day water managers may use this data to monitor the river in near real time. But for this to happen, NASA or another entity would need to build a system to translate and transmit data to end-users on a daily basis.

“All that needs to happen now is a daily refresh of the data that’s already being gathered,” Brakenridge said. “It may sound easy, but it’s not yet clear who might have the capacity to take on such a role. It could be an in-country agency, or an international organization such as the Mekong River Commission.”

For now, data from the new investigation is already being put to good use. Several years ago, Brakenridge attended a meeting of the Mekong River Commission in Laos and shared preliminary data from the project. Now that it’s completed, the researchers have shared their results with the commission.

“The short term goal is to improve their technical capabilities,” Brakenridge said. “Long-term, they may be able to avoid bad outcomes and be more prosperous and water-resilient overall.”

An investigation by INSTAAR scientist Robert Brakenridge and collaborators unveils a new method for monitoring water throughout the most important river basin in Southeast Asia.

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A new map of ecological hotspots makes waves in Antarctica

Gabe Allen — Tue, 07 Apr 2026 20:52:15 +0000

A new map of ecological hotspots makes waves in Antarctica Gabe Allen Tue, 04/07/2026 - 14:52

Gabe Allen

The ocean surrounding Antarctica is one of the most austere habitats on Earth. But, amidst the frozen, windswept landscape, an incredible diversity of life thrives. Each spring, phytoplankton harness the energy of the southern sun and, in turn, give rise to other microorganisms, fish and marine predators like penguins and seals.

Cassandra Brooks (left) and Zephyr Sylvester present at the 44th annual meeting of the Commission for the Conservation of Antarctic Marine Living Resources in October 2025. The researchers shared a new mapping tool with an audience of global leaders. (Courtesy, Cassandra Brooks)

In a new paper, a team of scientists led by The National Science Foundation Center for Atmospheric Research’s Alice DuVivier and INSTAAR’s Cassandra Brooks have designed a tool capable of mapping the relative importance of specific areas to the overall Antarctic ecosystem. The tool, called the Antarctic Ecosystem Value Index, captures life throughout the food web — from phytoplankton to penguins.

Even before the paper was published, their findings were already making waves. Last fall, Brooks and postdoctoral scholar Zephyr Sylvester traveled to Australia to present the Antarctic Ecosystem Value to the international governing body in charge of creating Marine Protected Areas in Antarctica.

“They are the ones that actually make the decisions about what to protect,” Brooks said. “They’re required to make decisions based on the best available science with the whole ecosystem in mind, so they really are our target audience.”

The researchers didn’t stop with policy makers. In partnership with ocean and climate communication nonprofit OnlyOne, the team developed a public-facing web campaign where users can explore ecosystem values via an interactive map. John Weller, a photographer, filmmaker and senior fellow at OnlyOne, also produced a 5-minute documentary about the project.

“We wanted to be able to show these areas we could consider protecting through stories,” Brooks said.

Oases in the ice

The ocean surrounding Antarctica is dominated by sea ice. It forms sprawling plains, towering walls and buckling glaciers. Every so often though, natural forces create a stretch of open water. These breaks in the ice are known as polynyas, and they are oases for marine life. The sunlight allows phytoplankton to get a head start each spring, and marine animals flock to the areas in search of food.

Orca Whales gather at a polynya in the Ross Sea. (John B. Weller)

In the new paper, Brooks and her collaborators confirmed a theory that scientists have long suspected — polynyas play an outsized role in the Antarctic ecosystem. According to the Antarctic Ecosystem Value Index, they are 31 to 72 percent more important than surrounding areas.

“People are always saying that polynyas are really important,” Brooks said. “But, as far as I know, we are the first ones to quantify what that actually means.”

To arrive at these values, the researchers combined ecological models that predict productivity at every level of the food web. Specifically, they focused on phytoplankton, krill, bottom-feeding fish and penguins — each group being key to the functioning of the ecosystem.

The next step was to project these values through time. Antarctica is warming nearly twice as fast as the global average, a reality that will permanently alter marine ecosystems. If the researchers could predict ecological value in the future, it could reveal which areas will remain important candidates for conservation.

To accomplish this, DuVivier combined the Antarctic Ecological Value with computer-simulated Earth system models. The results were clear, despite future losses in sea ice, polynyas will remain vital ecological hotspots at least to the end of the century. Protecting these areas now could safeguard Antarctic ecosystems for years to come.

“With careful management of protected areas, policy makers can ensure we conserve Antarctic biodiversity ,” DuVivier said. “You give the ecosystem the best chance at adapting to change.”

Cassandra Brooks captures photos of Emperor Penguins in the Ross Sea. (Christina Riesslman)

Safeguarding the future

Aside from global warming, the largest human impacts on marine ecosystems in Antarctica are commercial fishing and tourism. But, according to the scientists, more informed conservation can help, not just ecosystems, but industry too. For instance, placing restrictions on the right areas can help commercial vessels get a good catch for years to come.

“It can be a really good fisheries management tool,” DuVivier said.

There are limitations to the data, for instance it does not capture the effect of short-term events like marine heat waves. But, it’s the best tool yet for weighing potential impacts of conservation around the continent. And, though Antarctica is distant from the rest of the world, it is critical to the functioning of global earth systems. It stores the majority of the world’s freshwater, drives global ocean circulation and regulates our climate, storing disproportionate amounts of carbon and heat.

“What happens in Antarctica does not stay in Antarctica,” Brooks said. “By safeguarding Antarctica, we actually help safeguard our own future.”

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

Cassandra Brooks, Zephyr Sylvester and Alice DuVivier have published a new tool for evaluating ecological value in the Antarctic ocean. Now they are launching a campaign in support of Antarctic ecosystems.

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A pair of emperor penguins stand near the ice edge at a polynya in the Ross Sea in Antarctica. The new paper predicts a sharp decline in emperor penguin populations across the continent by the end of the century, while Adélie penguin populations will remain relatively stable. (John B. Weller)

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How do you measure snow from space? First, climb a mountain (New York Times)

Gabe Allen — Tue, 24 Mar 2026 14:59:08 +0000

How do you measure snow from space? First, climb a mountain (New York Times) Gabe Allen Tue, 03/24/2026 - 08:59

New York Times journalists followed the mountain hydrology lab on recent a winter excursion to Niwot Ridge. The researchers were measuring snow on the landscape in real time in order to calibrate data from an overhead satellite.

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Why pristine mountain lakes are suddenly turning green (Scientific American)

Gabe Allen — Tue, 17 Mar 2026 21:14:20 +0000

Why pristine mountain lakes are suddenly turning green (Scientific American) Gabe Allen Tue, 03/17/2026 - 15:14

Journalist Cody Cottier tells the story of the Oleksy lab's summer expedition to an alpine lake in the San Juan range. The scientists are investigating the source of a mysterious algal bloom that was first spotted by a ranger in 2021.

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Garrett Boudinot and the Many Paths to Entrepreneurship (Leeds School of Business)

Gabe Allen — Thu, 12 Mar 2026 22:30:34 +0000

Garrett Boudinot and the Many Paths to Entrepreneurship (Leeds School of Business) Gabe Allen Thu, 03/12/2026 - 16:30

A recent alum of INSTAAR's organic chemistry lab is the founder of a new climate tech startup called Vycarb. The company amplifies natural processes in the ocean to remove carbon dioxide from the atmosphere.

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What Colorado’s mountain lakes can tell scientists about climate change (Aspen Times)

Gabe Allen — Wed, 11 Mar 2026 22:40:22 +0000

What Colorado’s mountain lakes can tell scientists about climate change (Aspen Times) Gabe Allen Wed, 03/11/2026 - 16:40

Mountain lakes are the "canary in the coal mine" for how ecosystems are responding to climate change. That's according to the Mountain Liminology Lab's Mary Jade Farruggia, who was featured in an article from the Aspen Times this week.

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A new investigation will evaluate water filtration options in a community plagued by PFAS

Gabe Allen — Wed, 11 Mar 2026 12:00:00 +0000

A new investigation will evaluate water filtration options in a community plagued by PFAS Gabe Allen Wed, 03/11/2026 - 06:00

Gabe Allen

If you are a resident of Airway Heights interested in becoming a research participant, you can visit this link for more information.

INSTAAR fellow Riley Mulhern is launching a new study to evaluate the efficacy of home treatment options for PFAS in a contaminated area outside of Spokane, Washington. (courtesy photo)

INSTAAR fellow and �鶹��Ƶ professor Riley Mulhern first visited Airway Heights, Washington in January of last year. After the trip, he summed up the emotional state of the community in a one-word title to a post on his Substack: “Incensed.”

Mulhern has spent his career fighting for people's access to clean water, through both research and advocacy, and this community was in the midst of a water crisis.

A filtration system guards an Airway Heights home from contaminants. (courtesy photo)

In 2017, the city of Airway Heights found PFAS, a toxic family of industrial compounds also known as forever chemicals, in their municipal water. The contamination stemmed from firefighting foam used in training exercises at a nearby airforce base over decades. A 2022 report by federal agencies subsequently found that many residents of Airway Heights had elevated levels of PFAS in their blood — up to 56 times the national average.

Airway Heights municipal water has since been cleaned up, but many local residents own private wells. They are left to figure out how to test and filter the water that comes into their homes on their own, and many are concerned by a dearth of clear information about how to accomplish these tasks.

“One in seven Americans gets no protection from the federal Safe Drinking Water Act, we’re on our own,” said John Hancock, an Airway Heights local and president of West Plains Water Coalition, a community action group formed around the PFAS issue.

This problem is at the center of a new investigation, funded by the Water Quality Research Foundation and led by Mulhern. The study will evaluate commercially available water filtration systems’ efficacy against PFAS contamination.

“There’s a lot of confusing information online about what’s the best way to filter water, how well do these filters work, how are they certified, and so on,” Mulhern said. “So there’s a lot of value in providing third-party evidence of the real world performance of these products.”

First, Mulhern and his collaborators will test the water coming out of pre-existing home filtration systems in Airway Heights. Then, they will install filtration systems at the homes of a second cohort of participants, and monitor their water over two years.

Many filters are already certified by third-party assessors for efficacy against specific PFAS chemicals, such as PFOS and PFOA, which are currently regulated by the EPA. Yet, many more PFAS compounds are unregulated by federal drinking water standards or have not yet been included in third-party certification testing and have unknown health consequences. With this in mind, the new study will test for a broad range of PFAS and other fluorinated organic compounds which make up the larger “class” of chemicals to which PFAS belong.

“We are essentially trying to future-proof the public health recommendations we can make around household filter use,” Mulhern told the Water Quality Research Foundation. “Measuring the broader category of organic fluorine through household filters will provide increased confidence in these products for handling PFAS as a class, rather than just for specific types.”

When Mulhern first visited Airway Heights, he came as a volunteer. He spoke about water filtration options at a meeting organized by West Plains Water Coalition, drawing on his experiences working in North Carolina communities affected by PFAS. Now, he is happy to return with the necessary funding to offer more substantive support.

“We won the award because we have a strong foundation with the community already,” Mulhern said. “Even more important than that is that there is a community group that is so well organized and ready and willing to participate in research like this.”

A map illustrates data on water quality around Airway Heights, Washington. X's mark PFAS source sites, while orange dots mark private wells at risk. (courtesy photo)

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

INSTAAR fellow Riley Mulhern is launching a new study to evaluate the efficacy of home treatment options for PFAS in a contaminated area outside of Spokane, Washington.

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New minor spans disciplines in studying climate science (Colorado Arts & Sciences Magazine)

Gabe Allen — Wed, 25 Feb 2026 00:12:27 +0000

New minor spans disciplines in studying climate science (Colorado Arts & Sciences Magazine) Gabe Allen Tue, 02/24/2026 - 17:12

The interdisciplinary climate science minor, available in Fall 2026, will offer undergraduates a window into �鶹��Ƶ's world class climate research. INSTAAR fellows Bradley Markle and Robert Anderson make the case for the new program.

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Inaugural Sustainability Research Initiative Research Fellows unveiled (RIO)

Gabe Allen — Mon, 23 Feb 2026 18:42:15 +0000

Inaugural Sustainability Research Initiative Research Fellows unveiled (RIO) Gabe Allen Mon, 02/23/2026 - 11:42

INSTAAR fellows Keith Musselman and Irina Overeem have been named to the inaugural cohort of SRI fellows at �鶹��Ƶ. The fellows will form a year-long sustainability research incubator across academic disciplines.

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Tahoe avalanche: What causes snow slopes to collapse? A physicist and skier explains, with tips for surviving (The Conversation)

David J Lubinski — Thu, 19 Feb 2026 04:13:09 +0000

Tahoe avalanche: What causes snow slopes to collapse? A physicist and skier explains, with tips for surviving (The Conversation) David J Lubinski Wed, 02/18/2026 - 21:13

Nathalie Vriend updated an article for The Conversation that explains what happens in an avalanche, techniques for surviving one, and how they are impacted by climate change.

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Research

New satellite tools track river flows throughout the Lower Mekong Basin

Trouble on the Mekong

A new wavelength

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A new map of ecological hotspots makes waves in Antarctica

Oases in the ice

Safeguarding the future

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