MELBOURNE, Dec. 6 (Xinhua) -- A robotic float has completed the first oceanographic transect beneath East Antarctic ice shelves, measuring the temperature and salinity from parts of the ocean never sampled before, an Australian study revealed Saturday.
This provides insights into the vulnerability of the ice shelves and their potential contribution to sea level rise, said a media release from the Australian Antarctic Program Partnership (AAPP), a collaboration of Australia's leading Antarctic research institutions.
The Argo float, a robotic profiling instrument equipped with oceanographic sensors, spent two-and-a-half years drifting about 300 km beneath the Denman and Shackleton ice shelves, collecting nearly 200 ocean profiles, the release said.
"Our intrepid float drifted beneath the ice and spent eight months under the Denman and Shackleton ice shelves, collecting profiles from the seafloor to the base of the ice every five days," said oceanographer Steve Rintoul from the Commonwealth Scientific and Industrial Research Organization, Australia's national science agency, and the AAPP.
The data show the Shackleton ice shelf is not currently exposed to warm water capable of melting it from below, and therefore less vulnerable. But warm water is reaching the base of the Denman Glacier, which could contribute up to 1.5 meters to global sea level rise if destabilized.
The transfer of heat from the ocean to the ice depends on the ocean conditions in the 10-meter-thick "boundary layer" immediately below the ice shelf, according to the study published in Science Advances.
"A great advantage of floats is that they can measure the properties of the boundary layer that control the melt rate," Rintoul said, adding that float data will refine computer models of ice-ocean interactions, reducing the uncertainty in sea-level rise projections.
"Deploying more floats along the Antarctic continental shelf would transform our understanding of the vulnerability of ice shelves to changes in the ocean," he said. ■
