Well that's a nice message to receive on a Friday afternoon, I feel like I should pack up for the weekend now. Except of course, the wheels of #science keep turning...
Congratulations to @agrinsted who did the vast majority of the work on our first #PRECISE_NNF paper
EDIT: To add a link in case you want to spend a quiet half hour reading about the fracture properties of ice
Abstract. Ice fractures when subject to stress that exceeds the material failure strength. Previous studies have found that a von Mises failure criterion, which places a bound on the second invariant of the deviatoric stress tensor, is consistent with empirical data. Other studies have suggested that a scaling effect exists, such that larger sample specimens have a substantially lower failure strength, implying that estimating material strength from laboratory-scale experiments may be insufficient for glacier-scale modeling. In this paper, we analyze the stress conditions in crevasse onset regions to better understand the failure criterion and strength relevant for large-scale modeling. The local deviatoric stress is inferred using surface velocities and reanalysis temperatures, and crevasse onset regions are extracted from a remotely sensed crevasse density map. We project the stress state onto the failure plane spanned by Haigh–Westergaard coordinates, showing how failure depends on mode of stress. We find that existing crevasse data are consistent with a Schmidt–Ishlinsky failure criterion that places a bound on the absolute value of the maximal principal deviatoric stress, estimated to be 158±44 kPa. Although the traditional von Mises failure criterion also provides an adequate fit to the data with a von Mises strength of 265±73 kPa, it depends only on stress magnitude and is indifferent to the specific stress state, unlike Schmidt–Ishlinsky failure which has a larger shear failure strength compared to tensile strength. Implications for large-scale ice flow and fracture modeling are discussed.
Proud supervisor moment: my former PhD student and now #DMI colleague in #PRECISE_NNF project Nicolaj Hansen presenting his #Antarctic research to the Danish Meteorological Society #DAMSdk .
(I wrote about the PRECISE project here http://sternaparadisaea.net/2023/06/16/celebration-time-precise/)
Yesterday the Danish Meteorological Society had a talk and discussion on #AI in #weatherforecasting. It's a big area that DMI (cc @leifdenby ) is also investigating, + in #PRECISE_NNF project we're developing a #climate + #iceSheet variant. I missed this before but @voooos piece here is an excellent primer...
https://sciencemastodon.com/@voooos/111426572785565467
[email protected] - For background, here's our Science story from earlier this week explaining the explosive growth in weather AI: https://www.science.org/content/article/ai-churns-out-lightning-fast-forecasts-good-weather-agencies
For background, here's our Science story from earlier this week explaining the explosive growth in weather AI: https://www.science.org/content/article/ai-churns-out-lightning-fast-forecasts-good-weather-agencies
The good news keeps coming today...
Just heard this review paper I'm a coauthor on, led by the brilliant Ines Otosaka, with @icenowicki and Martin Howarth is out.
We review the use of #Satellites to measure the mass budget of #Greenland + #Antarctica - so perfect background reading for our new #PRECISE_NNF project too.
https://link.springer.com/article/10.1007/s10712-023-09795-8/metrics
Satellite data have revealed that the Greenland and Antarctic Ice Sheets are changing rapidly due to warming air and ocean temperatures. Crucially, Earth Observations can now be used to measure ice sheet mass balance at the continental scale, which can help reduce uncertainties in the ice sheets’ past, present, and future contributions to global mean sea level. The launch of satellite missions dedicated to the polar regions led to great progress towards a better assessment of the state of the ice sheets, which, in combination with ice sheet models, have furthered our understanding of the physical processes leading to changes in the ice sheets' properties. There is now a three-decade-long satellite record of Antarctica and Greenland mass changes, and new satellite missions are planned to both continue this record and further develop our observational capabilities, which is critical as the ice sheets remain the most uncertain component of future sea-level rise. In this paper, we review the mechanisms leading to ice sheets' mass changes and describe the state of the art of the satellite techniques used to monitor Greenland’s and Antarctica’s mass balance, providing an overview of the contributions of Earth Observations to our knowledge of these vast and remote regions.
Ruth Mottram
Ruth Mottram