iiinova — where your digital self keeps evolving

Evgenii Salganik @salganik.bsky.social · 24/08/2026

Sea-ice density varies seasonally, but is still often treated as constant or ice-age dependent. Using hydrostatically weighed Arctic sea-ice cores, we develop a year-round parameterization based on temperature and thickness, plus snow/freeboard variants for remote sensing. doi.org/10.22541/ess...

000

Evgenii Salganik @salganik.bsky.social · 30/04/2026

During MOSAiC, one spring biological sample was named “Ridgey McRidgeFace” — and it made it into the final paper (doi.org/10.1038/s43247-026-03364-8). RMRF was a young ridge of thin first-year ice sampled in late March. The real challenge? Explaining what RMRF actually stands for.

Snow freeboard maps from 10 May 2020 showing the Ridgey McRidgeFace (RMRF) ridge. From the larger Central Observatory (CO) area near RV Polarstern (left) to a detailed view of the ridge (right), including coring sites sampled in late April and early May.

010

Evgenii Salganik @salganik.bsky.social · 13/04/2026

Our graphic shows Arctic sea-ice ridges aren’t just rubble—they’re biomass hotspots. In summer, they can hold up to ~80–100% of ice-algal biomass despite covering much less area. Their complex structure creates diverse microhabitats for microbial life. doi.org/10.1038/s432... 🎨 Frida Cnossen

0113

Evgenii Salganik @salganik.bsky.social · 09/04/2026

There are many colorblind-friendly, perceptually uniform colormaps (e.g., cmocean, @fabiocrameri.ch), yet many papers at @agu.org still use rainbow variants. Not just aesthetics — they can create artificial structures (see plot). Better options exist.

Two contour plots of continuous temperature measurements in sea ice, snow, air, and seawater (Hammer et al., 2026; doi:10.1029/2025JC022738), shown using a rainbow-style colormap.

021

Evgenii Salganik @salganik.bsky.social · 04/03/2026

My hypothesis is that averaging the heights of many triangles with different widths but similar peak heights would produce a cusped mean profile.

000

Evgenii Salganik @salganik.bsky.social · 04/03/2026

Some papers follow me into my nightmares. This study about the shape of pressure ridges claims that most of them are cusped (like an arrow tip). Not only is this counterintuitive, but when I checked the dataset used in the study, most ridges appeared to be either trapezoidal or irregular.

110

Evgenii Salganik @salganik.bsky.social · 29/12/2025

Can a portable device measure the full thickness of sea-ice pressure ridges? New preprint led by Polona Itkin @oceanseaicenpi.bsky.social tests ground-based electromagnetic induction (GEM) across all seasons. doi.org/10.5194/egus...

010

Evgenii Salganik @salganik.bsky.social · 04/12/2025

A blog post from Megan Lenss about our new paper on Antarctic sea-ice algae: ic3.uit.no/news/hidden-...

010

Evgenii Salganik @salganik.bsky.social · 19/11/2025

New nice preprint led by Dmitry Divine (@oceanseaicenpi.bsky.social) on #Arctic sea ice ridge volume in the Fram Strait, derived from moored sonar observations from 2012–2019: doi.org/10.5194/egus...

010

Evgenii Salganik @salganik.bsky.social · 29/09/2025

A new thesis about the inclusion of air bubbles into the mushy layer model of sea ice by Joseph Fishlock from the University of Oxford @ox.ac.uk: ora.ox.ac.uk/objects/uuid...

000

Evgenii Salganik @salganik.bsky.social · 12/09/2025

Back from the CONTRASTS expedition (July–Sept)! We studied 3 types of Arctic sea ice, revisiting each site 4 times. I wrote a short overview here: en.wikipedia.org/wiki/CONTRAS...

en.wikipedia.org

CONTRASTS Expedition - Wikipedia

082

Reposted by Evgenii Salganik

Alfred Wegener Institute @awi.de · 08/09/2025

Unique concept for observing Arctic sea ice successfully implemented: AWI scientists were able to study different types of sea ice in parallel during the Polarstern expedition “CONTRASTS.” 🧊 www.awi.de/en/about-us/... Photo: Evgenii Salganik

093

Evgenii Salganik @salganik.bsky.social · 28/06/2025

It also features exciting sea ice draft data from mooring observations in the northwestern Barents Sea (2018–2021):

000

Evgenii Salganik @salganik.bsky.social · 28/06/2025

The Nansen Legacy data paper also includes ice and snow thickness measurements from both on-ice and helicopter-borne electromagnetic surveys:

100

Evgenii Salganik @salganik.bsky.social · 28/06/2025

Sea ice density data from Nansen Legacy show seasonality and temperature dependence very similar to the MOSAiC observations we recently analyzed: doi.org/10.5194/tc-19-1259-2025

100

Evgenii Salganik @salganik.bsky.social · 28/06/2025

Great to see a data paper from the Nansen Legacy cruises (2018–2022), led by Dmitry Divine (@oceanseaicenpi.bsky.social), including sea ice density measurements that clearly show strong seasonality: doi.org/10.1002/gdj3.70001

120

Evgenii Salganik @salganik.bsky.social · 28/06/2025

Sea ice density data from Nansen Legacy show seasonality and temperature dependence very similar to the MOSAiC observations we recently analyzed: doi.org/10.5194/tc-1...

000

Evgenii Salganik @salganik.bsky.social · 06/06/2025

An example of how data from ROV-based multibeam sonar was used to quantify ridge-enhanced melt rates can be found here: doi.org/10.5194/tc-1...

000

Evgenii Salganik @salganik.bsky.social · 06/06/2025

The study includes an overview of >80 surveys including measurements of ice draft from sonar, solar irradiance and radiance (see below), hyperspectral images, physical, chemical (pH, nitrate, oxygen), and bio-optical (fluorometry, ultra-violet and visible absorbance spectroscopy) water properties.

100

Evgenii Salganik @salganik.bsky.social · 06/06/2025

Our new data paper about under-ice observations from a remotely operated vehicle (ROV) during MOSAiC led by Philipp Anhaus from @awi.de: www.nature.com/articles/s41...

172

Evgenii Salganik @salganik.bsky.social · 08/05/2025

A new study led by Niels Fuchs uses hydrological models to predict the locations of melt ponds: doi.org/10.1029/2025GL115033

021

Reposted by Evgenii Salganik

Marylou Athanase @marylouathanase.bsky.social · 31/03/2025

Our new study is out: The Arctic Beaufort Gyre is projected to weaken or vanish in most CMIP6 models under future climate change. The gyre would thus stop storing freshwater in its centre, with possibly large impacts on the Arctic and beyond. Read: agupubs.onlinelibrary.wiley.com/doi/full/10....

agupubs.onlinelibrary.wiley.com

The Arctic Beaufort Gyre in CMIP6 Models: Present and Future

CMIP6 models generally simulate a too strong, large, and northward-extending Beaufort Gyre (BG) during the historical period Among the least unrealistic models, most simulations project a decline...

13821

Evgenii Salganik @salganik.bsky.social · 29/03/2025

Ice Mass Balance (IMB) buoys are unique in their ability to distinguish between ice surface and bottom melt, which relates to the way solar energy is distributed. Models still do a poor job of capturing this. You can find the updated Wiki article here: en.wikipedia.org/wiki/Ice_mass_balance_buoy

Temporal evolution of temperature from Ice Mass Balance Buoy with identified interfaces of air, melt pond, first-year ice, seawater, and meltwater layer.

021

Evgenii Salganik @salganik.bsky.social · 28/03/2025

And if you are interested in longer observations of snow thickness from drifting stations in 1937–1991, I can recommend a wonderful PhD thesis by @robbiemallett.bsky.social: discovery.ucl.ac.uk/id/eprint/10161766

110

Evgenii Salganik @salganik.bsky.social · 28/03/2025

Huge thanks to Don Perovich, Chris Polashenski, Cameron Planck, and others for leading and maintaining CRREL, Dartmouth @dartmouthears.bsky.social, and Cryosphere Innovation www.cryosphereinnovation.com ice mass balance buoy programs.

cryosphereinnovation.com

Sea Ice Data Repository | View and Download

Download up-to-date results from the world's largest repository of seasonal sea ice thickness data.

121

Evgenii Salganik @salganik.bsky.social · 28/03/2025

And if you are working with the data from the MOSAiC expedition, here are an additional 24 Digital Thermistor Chain (DTC) datasets led by Mario Hoppmann from @awi.de and processed by me: doi.org/10.1594/PANGAEA.964023

Map showing the location of digital thermistor chains (DTCs) within MOSAiC Central Observatory (CO) ice floe.

100

Evgenii Salganik @salganik.bsky.social · 28/03/2025

A similar but even larger dataset with 96 SIMBA ice mass balance buoys was published by Andreas Preußer @ando-puru.bsky.social for both Arctic and Antarctic ice during 2012–2023: doi.org/10.1594/PANGAEA.973193

110

Evgenii Salganik @salganik.bsky.social · 28/03/2025

If you are into Arctic sea ice thermodynamics, here is our new dataset of 82 CRREL ice mass balance buoys deployed in 1997–2024 with estimates of snow and ice thickness and their interface evolution: doi.org/10.5281/zenodo.15096485

Two panels show the temporal evolution of snow (top) and sea ice (bottom) thickness from various ice mass balance buoys listed in the legend (right).

1219

Evgenii Salganik @salganik.bsky.social · 21/03/2025

The raw discrete data of sea ice physical properties, isotopes, and nutrients is available for first-year ice doi.org/10.1594/PANGAEA.959830, second-year ice doi.org/10.1594/PANGAEA.971385 for October 2019-July 2020, and doi.org/10.1594/PANGAEA.971266 for August-September 2020.

000

Evgenii Salganik @salganik.bsky.social · 21/03/2025

If you are into modeling of sea ice physical properties (salinity, brine volume, or density), we combined coring datasets to have a seasonal evolution for first- and second-year level ice: doi.org/10.5281/zeno... The coring datasets have many more parameters, including isotopes and nutrients.

242

Evgenii Salganik @salganik.bsky.social · 18/03/2025

Finally, I wanted to thank my co-authors Odile Crabeck @universitedeliege.bsky.social, Niels Fuchs @cenunihh.bsky.social, Nils Hutter @awi.de @geomarkiel.bsky.social, Philipp Anhaus @dlr-spaceagency.bsky.social, and Jack Christopher Landy (UiT), and Norwegian Polar Institute, where I made the study

030

Evgenii Salganik @salganik.bsky.social · 18/03/2025

What about historical observations? We measure sea ice density since 1927 by Malmgren. Seasonal evolution is complicated due to differences in melt onset timing in the Arctic Ocean. But the same data looks much tidier when plotted against ice temperature, with MOSAiC values fitting previous values:

The left panel shows seasonal evolution of historical and MOSAiC density measurements of first-year ice. The right panels hows the same data plotted against ice temperature.

120

Evgenii Salganik @salganik.bsky.social · 18/03/2025

The densities were similar from all used methods. This means that weighing is the most affordable and accurate way with minor errors from brine loss. Here we show that ice is typically not in hydrostatic balance on scales of 10 meters, which leads to artificially large spreads of density estimates:

The left panels show spatial variability of the total freeboard. The central panels show estimates of ice density assuming hydrostatic balance. The right panels show a histogram of ice density estimates from hydrostatic balance (grey) and from weighing (blue dots).

120

Evgenii Salganik @salganik.bsky.social · 18/03/2025

But why does ice get lighter upon warming? We linked the increase in air volume to two factors: (1) internal melt, which creates voids, enlarges bubbles, and nucleates new bubbles, and (2) the replacement of liquid brine by air in drained inclusions. Air occupies much more than 10% of brine:

120

Evgenii Salganik @salganik.bsky.social · 18/03/2025

When do these density changes happen? When it is getting warmer (d), its air volume fraction increases (h). The strongest changes were observed in first-year ice, but weaker effects were also observed in second-year ice and pressure ridges (g). So, after all, air bubbles matter even for altimetry:

120

Evgenii Salganik @salganik.bsky.social · 18/03/2025

Colors matter too. Here are measurements of snow freeboard (fb) from an airborne laser scanner, snow thickness (sn) from transects, and ice draft (d) from underwater sonar with a colormap from @fabiocrameri.ch. Ice just doesn't want to go down.

230

Evgenii Salganik @salganik.bsky.social · 18/03/2025

Scale matters. We also observed a similar increasing ice freeboard at 1 km² CO2 ice floe and at 40 km² coverage of airborne laser scanner (ALS full) surveys. Ice type matters too, and a less pronounced effect was observed for ridges due to their three times faster melt.

The left panel shows the evolution of snow and ice freeboard for CO2 ice floe for different ice types. The middle panel shows similar data for the coverage of the airborne laser scanner. The right panel shows a comparison of accumulated ice melt measurements from coring and from remotely operated vehicle (ROV) sonar surveys.

130

Evgenii Salganik @salganik.bsky.social · 18/03/2025

The snow and ice freeboard was measured by coring and by a combination of laser scanner snow freeboard and snow thickness from automatic probe surveys along the floe. The evolution of ice draft was measured by coring, by sonar on a remotely operated vehicle (ROV), and by temperature buoys (IMB):

120

Evgenii Salganik @salganik.bsky.social · 18/03/2025

The sampling was done in May–July 2020 in Fram Strait. Ice coring included weighing of ice cores. The freeboard of the whole ice floe was measured by laser scanner, while a smaller (purple) area also had draft measurements from underwater sonar. Ice floe included first- and second-year ice:

The left panel shows the location of coring sampling from May to July 2020 in the Fram Strait. The right panel shows an optical image of the surveyed ice floe with locations of first- and second-year ice, coring sites, and area sampled by sonar mounted on a remotely operated vehicle (ROV).

130

Evgenii Salganik @salganik.bsky.social · 18/03/2025

Thanks, Robbie! I would expect that this effect may last during a month of melt, but not for the whole melt season. It should be weaker for second-year ice. And, for radar altimetry, it depends on penetration of surface scattering layer and temporal evolution of its thickness. Lots of questions :)

110

Evgenii Salganik @salganik.bsky.social · 18/03/2025

In summer we typically track sea ice melt, assuming its height above the waterline decreases. In our new study, we show that sea ice freeboard may increase during the advanced melt in June and July due to the rapid decrease of ice density. Read more: doi.org/10.5194/tc-19-1259-2025

Upper panel shows temporal decrease of ice density in June and July estmated using (1 ) ice weighing, (2) thickness coring, and (3) co-located freeboard and draft measurements from underwater sonar and airborne laser scanner.

Lower panel shows spatiotemporal variability of first-year ice density during the melt season.

2123

Evgenii Salganik @salganik.bsky.social · 28/02/2025

Thanks, Andy! Happy to see you around Bonn. And have fun at DLR:)

000

Evgenii Salganik @salganik.bsky.social · 28/02/2025

Last day at the Norwegian Polar Institute. Thanks for the good memories.

140

Evgenii Salganik @salganik.bsky.social · 28/02/2025

Yesterday, you showed Zack's beautiful work to your colleague; today, he no longer works at NOAA. Huge support. We all live in an evolving dystopia.

031

Evgenii Salganik @salganik.bsky.social · 19/02/2025

Shocking. It is hard to overestimate the importance of all the wonderful research and observations from NOAA @climate.noaa.gov and other US-based agencies. Huge support to Zack and others who are affected.

093

Reposted by Evgenii Salganik

Oceans & Sea Ice NPI @oceanseaicenpi.bsky.social · 14/02/2025

Fate of #Arctic sea ice melt | In a new study led by @madm-ice.bsky.social, we followed the #MOSAiC ice floe and calculated the budget of freshwater sources and sinks from snow and ice melt in summer 2020. Read more: doi.org/10.5194/tc-19-619-2025

A researcher (Madison Smith) walking on sea ice covered by melt ponds. Photo by Evgenii Salganik.

052

Evgenii Salganik @salganik.bsky.social · 04/02/2025

Impressive airborne measurements of ice ridge spacing led by Thomas Krumpen:

042

Evgenii Salganik @salganik.bsky.social · 24/01/2025

Academic journals may need stricter guidelines for introductions. Broad overviews with ambiguous claims and irrelevant references are way too common. Worse, unjustified citations of colleagues and co-authors further devalue citations, as if they can get less valuable than now.

000

Evgenii Salganik @salganik.bsky.social · 20/01/2025

If only they could have asked the author. The sea-ice density part is not much better. Half-based on a 1978 study published in Russian and not publicly available.

110

Evgenii Salganik @salganik.bsky.social · 17/01/2025

The only problem with Fabio's color maps is that they are so beautiful it is hard to choose one.

120