Calving cycle of the Brunt Ice Shelf, Antarctica, driven by changes in ice shelf geometry
Despite the potentially detrimental impact of large-scale
calving events on the geometry and ice flow of the Antarctic Ice Sheet,
little is known about the processes that drive rift formation prior to
calving, or what controls the timing of these events. The Brunt Ice Shelf in
East Antarctica presents a rare natural laboratory to study these processes,
following the recent formation of two rifts, each now exceeding 50 km in
length. Here we use 2 decades of in situ and remote sensing observations,
together with numerical modelling, to reveal how slow changes in ice shelf
geometry over time caused build-up of mechanical tension far upstream of the
ice front, and culminated in rift formation and a significant speed-up of
the ice shelf. These internal feedbacks, whereby ice shelves generate the
very conditions that lead to their own (partial) disintegration, are
currently missing from ice flow models, which severely limits their ability
to accurately predict future sea level rise.
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