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Antarctic Ice Shelf collapse possibly triggered by ocean waves | In a new research, a team of scientists has discovered
that ocean waves originating along the Pacific coasts of North and South America impact Antarctic ice shelves and could play a role in their catastrophic collapse.
Peter Bromirski, a scientist at Scripps Institution of Oceanography at UC San
Diego and his collaborators carried out the research. According to Bromirski,
storm-driven ocean swells travel across the Pacific Ocean and break along the
coastlines of North and South America, where they are transformed into very long-period
ocean waves called "infragravity waves" that travel vast distances to Antarctica.
Bromirski, along with his colleagues, has proposed that the southbound travelling
infragravity waves "may be a key mechanical agent that contributes to the production
and/or expansion of the pre-existing crevasse fields on ice shelves," and that
the infragravity waves also may provide the trigger necessary to initiate the
collapse process. The researchers used seismic data collected on the Ross Ice
Shelf to identify signals generated by infragravity waves that originated along
the Northern California and British Columbia coasts, and modeled how much stress
an ice shelf suffers in response to infragravity wave impacts. Bromirski said
that only recently has technology advanced to allow scientists to deploy seismometers
for the extended periods on the ice shelf needed to capture such signals. The
study found that each of the Wilkins Ice Shelf breakup events in 2008 coincided
with the estimated arrival of infragravity waves. The researchers note that such
waves could affect ice shelf stability by opening crevasses, reducing ice integrity
through fracturing and initiating a collapse. "Infragravity waves may produce
ice-shelf fractures that enable abrupt disintegration of ice shelves that are
also affected by strong surface melting," according to the researchers. "Whether
increased infragravity wave frequency and energy induced by heightened storm intensity
associated with climate change ultimately contribute to or trigger ice shelf collapse
is an open question at this point," said Bromirski. "More data from Antarctica
are needed to make such a connection," he said. |
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