29 April, 2019 by Nicholas O'Flaherty
Open water bound by sea ice (a polynya) during the austral summer, in front of the Ross Ice Shelf, generates warm water. This transports heat into the cavity beneath the ice shelf, causing melt rates to nearly triple. The revealing new data comes from oceanographic moorings beneath the Ross Ice Shelf.
Marine physicists Drs Craig Stewart and Mike Williams from NIWA New Zealand, and a team from the UK, studied the north-western corner of the Ross Ice Shelf over several years to build up a record of how it is melting, and the key processes driving it.
“We’ve shown that the ocean is melting the north-western corner of the Ross Ice Shelf much faster than the rest of the shelf, and a lot of that melting is linked to summer heat from the top layer of the ocean,” Dr Stewart says.
The finding is significant because the stability of ice shelves is generally thought to be related to their exposure to warm deep ocean water. However, this research has shown that surface ocean heat also plays a crucial role.
Although the interactions between ice and ocean occurring hundreds of metres below the surface of ice shelves seem remote, they have a direct impact on long-term sea level.
More information here.