From The California Institute of Technology
6.18.24
Lori Dajose
(626) 395‑1217
ldajose@caltech.edu
The loss of volume of ice shelves in this region of West Antarctica has increased rapidly in recent decades. Credit: Andrew Thompson
Measurements of temperature and salinity being collected from the R/V Nathaniel B. Palmer in the Bellingshausen Sea, Southern Ocean.
Deployment of an autonomous ocean vehicle, called a glider, in the Bellingshausen Sea, Southern Ocean. The gliders measure the temperature, salinity and concentration of dissolved gases in the ocean. These can then be used to monitor how the ocean carries heat towards Antarctic floating ice shelves.
Credit: Andrew Thompson
Due to warming caused by climate change, the Antarctic ice shelves are melting at an accelerated rate. Most of the melt comes from below the ice shelves, a result of warm water flowing underneath them. However, the process does not stop there—as the meltwater enters the ocean, it is carried around the coast of Antarctica by ocean currents, modifying melt rates at ice shelves farther downstream. Mapping these meltwater pathways is needed to better understand and predict melting and resulting sea level rise.
“We used to think about ice shelves as isolated systems, but we now understand that multiple ice shelves are connected by currents along the Antarctic coast,” says Caltech’s Andy Thompson, John S. and Sherry Chen Professor of Environmental Science and Engineering. “What happens in one ice shelf changes the processes at another. To accurately predict changes, we have to understand the domino effect they have on one another.”
For over a decade, researchers in Thompson’s laboratory have studied the Antarctic seas using a combination of techniques. A new study led by senior research scientist Mar Flexas examines data collected by an underwater autonomous vehicle as well as seals equipped with sensors on their heads. Through these data, the team discovered a new current that meltwater follows through a region known as the Bellingshausen Sea, on the side of Antarctica nearest to South America.
“The Bellingshausen Sea is not a well-studied region, but it’s the first place where warm water from the Atlantic and Pacific oceans reaches the ice shelves,” says Thompson, who is also the director of the Ronald and Maxine Linde Center for Global Environmental Science and executive officer for environmental science. “As it melts the ice shelves, the water becomes cooler and fresher, decreasing its capacity to melt.”
A decades-long collaboration of researchers from several institutions equips seals with small sensors that measure oceanic properties as the animals travel and dive through the seas in search of food. The program is called Marine Mammals Exploring the Oceans Pole to Pole (MEOP) and the data collected are publicly available to researchers.
Combining this data with that from the Thompson lab’s undersea ocean gliders, Flexas and her team collected information on properties like ocean temperature, salinity, oxygen content, and the concentration of particles in the water throughout the Bellingshausen and Amundsen seas.
The team identified two distinct meltwater pathways that originate from different ice shelves. One follows the coast and can increase melting at downstream ice shelves by trapping warm waters at depth, while the other path returns to the open ocean. Interestingly, the seal data revealed a previously unknown trough, or canyon, in the seafloor, which the team dubbed, appropriately enough, Seal Trough. Underwater topographic features like Seal Trough influence the flow of currents similarly to how canyons on dry land guide the flow of rivers.
The research is an important step toward understanding how melting at individual ice shelves influences the larger Antarctic circulation and ice shelf melting around the entire continent. As the oceans continue to warm due to climate change, an improved understanding of processes near the Antarctic coast is needed to predict future rates of global sea level rise.
The research is described in a paper that appears in the journal JGR Oceans. In addition to Flexas and Thompson, Caltech undergraduate Megan Robertson is a co-author. Additional co-authors are Kevin Speer of Florida State University, and Peter Sheehan and Karen Heywood of University of East Anglia. Funding was provided by the National Science Foundation, NASA, the Internal Research and Technology Development program at JPL-Caltech, and the European Research Council.
See the full article here .
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The California Institute of Technology is a private research university in Pasadena, California. The university is known for its strength in science and engineering, and is one among a small group of institutes of technology in the United States which is primarily devoted to the instruction of pure and applied sciences.
The California Institute of Technology was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began attracting influential scientists such as George Ellery Hale, Arthur Amos Noyes, and Robert Andrews Millikan in the early 20th century. The vocational and preparatory schools were disbanded and spun off in 1910 and the college assumed its present name in 1920. In 1934, The California Institute of Technology was elected to the Association of American Universities, and the antecedents of National Aeronautics and Space Administration ‘s Jet Propulsion Laboratory, which The California Institute of Technology continues to manage and operate, were established between 1936 and 1943 under Theodore von Kármán.
The California Institute of Technology has six academic divisions with strong emphasis on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. First-year students are required to live on campus, and 95% of undergraduates remain in the on-campus House System at The California Institute of Technology. Although The California Institute of Technology has a strong tradition of practical jokes and pranks, student life is governed by an honor code which allows faculty to assign take-home examinations. The The California Institute of Technology Beavers compete in 13 intercollegiate sports in the NCAA Division III’s Southern California Intercollegiate Athletic Conference (SCIAC).
There are many Nobel laureates who have been affiliated with The California Institute of Technology, including alumni and faculty members (Linus Pauling being the only individual in history to win two unshared prizes). In addition, Fields Medalists and Turing Award winners have been affiliated with The California Institute of Technology. Crafoord Laureates and non-emeritus faculty members (as well as many emeritus faculty members) who have been elected to one of the United States National Academies. There are or have been Chief Scientists of the U.S. Air Force and numerous United States National Medal of Science or Technology winners. Many faculty members are associated with the Howard Hughes Medical Institute as well as National Aeronautics and Space Administration. According to a Pomona College study, The California Institute of Technology ranked very highly in the U.S. for the percentage of its graduates who go on to earn a PhD.
Research
The California Institute of Technology is classified among “R1: Doctoral Universities – Very High Research Activity”. Caltech was elected to The Association of American Universities in 1934 and remains a research university with “very high” research activity, primarily in STEM fields. The largest federal agencies contributing to research are National Aeronautics and Space Administration; National Science Foundation; Department of Health and Human Services; Department of Defense, and Department of Energy.
The California Institute of Technology has over 739,000 square feet (68,700 m^2) dedicated to research: 330,000 square feet (30,700 m^2) to physical sciences, 163,000 square feet (15,100 m^2) to engineering, and 160,000 square feet (14,900 m^2) to biological sciences.
In addition to managing NASA-JPL/Caltech , The California Institute of Technology also operates the Caltech Palomar Observatory; The Owens Valley Radio Observatory along with the New Jersey Institute of Technology; the Caltech Submillimeter Observatory; the W. M. Keck Observatory at the Maunakea Observatory along with the University of California; the Laser Interferometer Gravitational-Wave Observatory at Livingston, Louisiana and Hanford, Washington along with the Massachusetts Institute of Technology; and Kerckhoff Marine Laboratory in Corona del Mar, California. The Institute launched the Kavli Nanoscience Institute at The California Institute of Technology in 2006; the Keck Institute for Space Studies in 2008; and is also the current home for the Einstein Papers Project. The Spitzer Science Center, part of the Infrared Processing and Analysis Center located on The California Institute of Technology campus, is the data analysis and community support center for NASA’s Spitzer Infrared Space Telescope [no longer in service] .
The California Institute of Technology partnered with University of California-Los Angeles to establish a Joint Center for Translational Medicine (UCLA-Caltech JCTM), which conducts experimental research into clinical applications, including the diagnosis and treatment of diseases such as cancer.
The California Institute of Technology operates several Total Carbon Column Observing Network stations as part of an international collaborative effort of measuring greenhouse gases globally. One station is on campus.
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