Normalized US hurricane damage estimates using area of total destruction, 1900−2018

We present an approach to normalize hurricane damage, where damage is framed in terms of an equivalent area of total destruction. This has some advantages over customary normalization schemes, and we demonstrate that our record has reduced variance and correlates marginally better with wind speeds and pressure. That is, it allows us to better address climatic trends. We find that hurricanes are indeed becoming more damaging. The frequency of the very most damaging hurricanes has increased 3 times per century.

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Normalized US hurricane damage estimates using area of total destruction, 1900−2018, Aslak Grinsted, Peter Ditlevsen and Jens Hesselbjerg Christensen, Proceedings of the National Academy of Sciences. doi:10.1073/pnas.1912277116 Share

Surface velocity of the Northeast Greenland Ice Stream (NEGIS)

The Northeast Greenland Ice Stream (NEGIS) extends around 600 km from its onset in the interior of Greenland to the coast. Several maps of surface velocity and topography in Greenland exist, but accuracy is limited due to the lack of validation data. Here we present results from a 5-year GPS survey in an interior section of NEGIS. We use the data to assess a list of satellite-derived ice velocity and surface elevation products and discuss the implications for the ice stream flow in the area.

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Hvidberg, C. S., Grinsted, A., Dahl-Jensen, D., Khan, S. A., Kusk, A., Andersen, J. K., Neckel, N., Solgaard, A., Karlsson, N. B., Kjær, H. A., and Vallelonga, P., Surface velocity of the Northeast Greenland Ice Stream (NEGIS), assessment of interior velocities derived from satellite data by GPS, The Cryosphere, 14, 3487–3502, doi:10.5194/tc-14-3487-2020, 2020. Share

Hagen Bræ, A Surging Glacier in North Greenland — 35 Years of Observations

Improved ice velocity measurements with Sentinel-1 TOPS interferometry.

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Solgaard, A. M., Simonsen, S. B., Grinsted, A., Mottram, R., Karlsson, N. B., Hansen, K., ... & Sørensen, L. S. (2020). Hagen Bræ A Surging Glacier in North Greenland—35 Years of Observations. Geophysical Research Letters, 47(6), e2019GL085802. Share

Improved ice velocity measurements with Sentinel-1 TOPS interferometry

Improved ice velocity measurements with Sentinel-1 TOPS interferometry.

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Andersen, J. K., Kusk, A., Boncori, J. P. M., Hvidberg, C. S., & Grinsted, A. (2020). Improved ice velocity measurements with Sentinel-1 TOPS interferometry. Remote Sensing, 12(12), 2014. Share

East Greenland ice core dust record reveals timing of Greenland ice sheet advance and retreat

Grains of dust in an ice core illustrate how fast a landscape is covered with ice after an ice age sets in.

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Simonsen, M.F., Baccolo, G., Blunier, T. et al. East Greenland ice core dust record reveals timing of Greenland ice sheet advance and retreat. Nat Commun 10, 4494 (2019). doi:10.1038/s41467-019-12546-2 Share

Sea-level change in the Dutch Wadden Sea

A thorough report on the sea-level change in the Dutch Wadden Sea.

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Vermeersen, B. L. A., Slangen, A. B. A., Gerkema, T., Baart, F., Cohen, K. M., Dangendorf, S., Duran-Matute, M., Frederikse, T., Grinsted, A., Hijma, M. P., Jevrejeva, S., Kiden, P., Kleinherenbrink, M., Meijles, E. W., Palmer, M. D., Rietbroek, R., Riva, R. E. M., Schulz, E., Slobbe, D. C., ... van der Wegen, M. (2018). Sea-level change in the Dutch Wadden Sea. Netherlands journal of geosciences-Geologie en mijnbouw, 97(3), 79-127. doi:10.1017/njg.2018.7 Share

Influence of temperature fluctuations on equilibrium ice sheet volume.

Weather variability has a profound impact on the mass balance of ice sheets, and the equilibrium volume of ice sheets. We illustrate this in a simple ice sheet model and find that the equilibrium ice volume is ~1 m SLE smaller when the simple model is forced with fluctuating temperatures as opposed to a stable climate.

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Mikkelsen, T. B., Grinsted, A., and Ditlevsen, P., Influence of temperature fluctuations on equilibrium ice sheet volume, The Cryosphere, 12, 39–47, doi:10.5194/tc-12-39-2018, 2018. Share

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