Freshwater runoff from the Beaufort Sea could change global climate patterns

LOS ALAMOS, NM, February 24, 2021 – The Beaufort Sea, the largest freshwater reservoir in the Arctic Ocean, has increased its freshwater content by 40 percent over the past two decades, adding global climate patterns under threat. The rapid release of this freshwater into the Atlantic Ocean has destroyed the delicate climate balance that governs the global climate.

“The diffusion of freshwater of this magnitude into the subpolar Atlantic could affect a critical circulation pattern, known as the Meridional Overturning Circulation, which has a major impact on the northern hemisphere climate,” said Wilbert Weijer, author of Los Alamos National Laboratory on the project.

A joint modeling study with Los Alamos researchers and colleagues from the University of Washington and NOAA delves into the mechanics surrounding this view. The team first studied a previous dissolution event that occurred between 1983 and 1995, and using meaningful color detectors and numerical modeling, the researchers simulated the rotation of the ocean and followed the distribution of the freshwater.

“People have spent a lot of time researching why Beaufort Sea freshwater has become so high in the last few decades,” said lead author Jiaxu Zhang, who began work during her western alliance. at the Los Alamos National Laboratory in the Center for Freelance Studies. She is now at the UW Collaborative Institute for the Study of Climate, Ocean and Ecosystem. “But they rarely worry about where to go. freshwater, which we believe is a much more important problem. “

The study was the most detailed and solemn of its kind, yielding numerical insights into salinity reduction in specific areas of the ocean as well as the pathways for freshwater release. The unexpected test showed that most freshwater reaches the Atlantic Ocean (Labrador Sea) through a narrow set of corridors between Canada and Greenland, known as the Canadian Isles.

The traditional view was usually to consider the transport of meltwater in the form of sea ice through the Fram Strait (a corridor between Greenland and Svalbard). The freshwater distribution was found to significantly reduce the salts in the Labrador Sea – an update of 0.2 units of practical salinity (psu) on the west shelves and 0.4 psu locally in the Current Labrador.

However, the model distribution was based on freshwater volumes in the past, from the 1990s. Now, that size is much larger, more than 23,300 cubic kilometers, due to an unusual circulation pattern known as the Beaufort Gyre and unprecedented sea ice erosion. If this very freshwater body is released into the Atlantic Ocean, the effects could also be significant. The impact is still unknown. “Our study of the previous release event offers a picture of the potential future impacts of a larger spread,” Weijer said.

The model used in the study was also partially developed at Los Alamos. This is the Earth Energy Exascale System Model Model 0 (E3SMv0), which includes the LANL Parallel Ocean Program (POP) and its powerful marine ice model, CICE.

“This work is a fine example of Los Alamos’ innovative ocean modeling methods; and also demonstrates the laboratory’s leadership in high-speed climate science through projects such as the High-Latitude Application and Test Earth Systems Modules (HiLAT-RASM), “Weijer said.

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The paper: “Labrador marine renewal linked to Beaufort Gyre freshwater distribution.” Nature Communication. Jiaxu Zhang, Wilbert Weijer, Michael Steele, Wei Cheng, Tarun Verma, and Milena Veneziani. DOI 10.1038 / s41467-021-21470-3

The funding: This research was funded by the U.S. DOE Office of Science, the LDRD LANL award, the CNLS postdoc fellowship award, and the NOAA.

Los Alamos National Laboratory, a multidisciplinary research institute engaged in strategic science for national security, is managed by Triad, a public service-based national security science organization owned by all three members. founders: Battelle Memorial Institute (Battelle), the Texas A&M University System (TAMUS), and the University of California (UC) Governors for the Department of Energy’s National Nuclear Security Administration.

Los Alamos strengthens national security by ensuring the safety and reliability of the U.S. nuclear stock source, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, the environment , infrastructure, health, and global security concerns.

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