Daily Glacier

dailyglacier is a twitter-bot that tweets images of a random glacier every day. This page is used to display additional metadata and maps from the bot. .cocoen { box-sizing: border-box; cursor: pointer; line-height: 0; margin: 0; overflow: hidden; padding: 0; position: relative; -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none } .cocoen * { box-sizing: inherit } .cocoen ::after, .cocoen ::before { box-sizing: inherit } .cocoenimg, .cocoenpictureimg { display: block; width: 100% } .

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A workflow for video presentations

Video presentations are a powerful way of getting your science across to a wider audience. I recently published a scientific study on some very large Jökulhlaup in East Greenland. I wanted to have a video with the press release, but as our go to guy was on vacation I had to do it myself.

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Migrating to Hugo

This site is now created using a static site generator called hugo. I host it on netlify, and the source files are hosted on github. This is a nice setup for academics. So thumbs up from me.

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Periodic outburst floods from an ice-dammed lake in East Greenland

We report evidence of four cycles of outburst floods from Catalina Lake, an ice-dammed lake in East Greenland, identified in satellite imagery between 1966–2016. The lake measures 20–25 km2, and lake level drops 130–150 m in each event, corresponding to a water volume of 2.6–3.4 Gt, and a release of potential energy of 1016 J, among the largest outburst floods reported in historical times. The drainage cycle has shortened systematically, and the lake filling rate has increased over each cycle, suggesting that the drainage pattern is changing due to climate warming with possible implications for environmental conditions in Scoresbysund fjord.

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Grinsted, Hvidberg, Campos, Dahl-Jensen (2017), Periodic outburst floods from an ice-dammed lake in East Greenland, Scientific Reports, 7, doi:10.1038/s41598-017-07960-9 Share

The response of the Zachariae and 79N glaciers in Northeast Greenland to seasonal surface melt

The seasonal response to surface melting of the Northeast Greenland Ice Stream outlets, Zachariae and 79N, is investigated using new highly temporally resolved surface velocity maps for 2016 combined with numerical modelling. The seasonal speed-up at 79N of 0.15km/yr is suggested to be driven by a decrease in effective basal pressure induced by surface melting, whereas for Zachariae its 0.11km/yr seasonal speed-up correlates equally well with the break-up of its large ice mélange.

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Rathmann, N. M., Hvidberg, C. S., Solgaard, A. M., Grinsted, A., Gudmundsson, G. H., Langen, P. L., Nielsen, K. P. and Kusk, A. (2017), Highly temporally resolved response to seasonal surface melt of the Zachariae and 79N outlet glaciers in Northeast Greenland. Geophys. Res. Lett.. Accepted Author Manuscript. doi:10.1002/2017GL074368 Share

Coastal sea level rise with warming above 2°C

Two degrees of global warming above the preindustrial level is widely suggested as an appropriate threshold beyond which climate change risks become unacceptably high. This “2°C” threshold is likely to be reached between 2040 and 2050 for both Representative Concentration Pathway (RCP) 8.5 and 4.5. Resulting sea level rises will not be globally uniform, due to ocean dynamical processes and changes in gravity associated with water mass redistribution. Here we provide probabilistic sea level rise projections for the global coastline with warming above the 2°C goal.

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Jevrejeva, Jackson, Riva, Grinsted, Moore (2016) Coastal sea level rise with warming above 2°C, PNAS, doi:10.1073/pnas.1605312113 Share

EastGRIP 16, the song

This summer I’ve been doing fieldwork at Eastgrip, doing a GPS survey of a stake strain network, and mapping the surroundings with a fixed wing drone. But I also found some time to compose a track in the evenings. Here it is:

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Working offline and caching in matlab

I am working with satellite imagery in Matlab. This is way too much data for me to keep on my laptop, and so I keep it on a server somewhere. But this has the major drawback that I cannot as easily work on the data when I am out of office. 

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Picking a password manager

It is difficult to pick a password manager. After many considerations I eventually decided on a keepass2 database. It is a difficult decision because you have to place quite a lot of trust in the solution.

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Migrating from Google Sites to WordPress

I recently migrated from google sites to wordpress. There is lots to like about google sites (high uptime, zero maintenance), and I have been quite happy there.

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An existential threat to coastal nations

We may be committing ourselves to an eventual complete deglaciation of Earth in a business-as-usual scenario (ECP8.5). The sea level rise from a complete deglaciation would wipe my own country, Denmark, off the map.

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Plausible upper limit of WAIS ice loss

Ritz et al. (2015) have a recent model study of potential sea level rise from Antarctic marine ice sheet instability.

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