Tidewater glaciers: Melting underwater far faster than previously estimated?

July 25, 2019

A tidewater glacier in Alaska is melting underwater at rates upwards of two orders of magnitude greater than what is currently estimated, sonar surveys reveal. The study's results, based on direct measurements, suggest that some glaciers may be in "hotter water" than previously thought. Like vast frozen rivers, tidewater glaciers flow from the land and into the sea, forming a partially submerged ice-ocean boundary. However, unlike terrestrial glaciers, which are often sequestered to high-altitudes, tidewater glaciers can be far more dynamic and subject to ongoing changes driven by underwater melting and iceberg calving where the ocean meets the ice. While it is widely recognized that ice loss from these glaciers influences both the rate of sea level rise and potentially global ocean circulation - a primary driver of global climate - the understanding of the dynamics of tidewater glacier melt, particularly as a response to accelerated warming in high-latitude glacier environments, is largely predicated upon sparse data, indirect inferences and an unconstrained theoretical model of subsurface melting. To date, suggest the authors of this study, no direct measurements of submarine melting at tidewater glacier fronts have been made. To address this lack of direct observations, David Sutherland and colleagues conducted repeat multibeam sonar surveys of the submerged face of the LeConte Glacier in Southeast Alaska. Along with other ocean, ice and atmospheric measurements collected in August 2016 and May 2017, the sonar images were used to document and create a time-variable, three-dimensional record of changes in the glacier face that could be linked to melting and calving patterns. Sutherland et al. discovered seasonally increasing submarine melt across the glacier face and at rates far greater than theory-based predictions. Their results, they say, suggest a pressing need to reevaluate existing models of tidewater glacier ice loss.
-end-


American Association for the Advancement of Science

Related Glaciers Articles from Brightsurf:

Rock debris protects glaciers from climate change more than previously known
A new study which provides a global estimate of rock cover on the Earth's glaciers has revealed that the expanse of rock debris on glaciers, a factor that has been ignored in models of glacier melt and sea level rise, could be significant.

New 'law' to explain how glaciers flow over soft ground
Addressing a major source of uncertainty in glacier-flow models, researchers present a new slip law to describe glaciers sliding on soft, deformable material.

Melting glaciers will challenge some salmon populations and benefit others
A new Simon Fraser University-led study looking at the effects that glacier retreat will have on western North American Pacific salmon predicts that while some salmon populations may struggle, others may benefit.

How the ocean is gnawing away at glaciers
The Greenland Ice Sheet is melting faster today than it did only a few years ago.

Last remaining glaciers in the Pacific will soon melt away
The last remaining tropical glaciers between the Himalayas and the Andes will disappear in the next decade -- and possibly sooner -- due to climate change, a new study has found.

Drones help map Iceland's disappearing glaciers
Dr. Kieran Baxter from the University of Dundee has created composite images that compare views from 1980s aerial surveys to modern-day photos captured with the help of state-of-the-art technology.

Disappearing Peruvian glaciers
It is common knowledge that glaciers are melting in most areas across the globe.

New insight into glaciers regulating global silicon cycling
A new review of silicon cycling in glacial environments, led by scientists from the University of Bristol, highlights the potential importance of glaciers in exporting silicon to downstream ecosystems.

Tidewater glaciers: Melting underwater far faster than previously estimated?
A tidewater glacier in Alaska is melting underwater at rates upwards of two orders of magnitude greater than what is currently estimated, sonar surveys reveal.

Asia's glaciers provide buffer against drought
A new study to assess the contribution that Asia's high mountain glaciers make to relieving water stress in the region is published this week (May 29, 2019) in the journal Nature.

Read More: Glaciers News and Glaciers Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.