sea ice Archives - Astrobiology

Left: Average ocean fraction, calculated assuming a seawater freezing point of −1.8°𝐶 for Cases 1 and 3 and 0°𝐶 for Case 2. White shows the ice, and blue ocean. Middle: The mean near-surface air temperatures. Shown within the black contours are the regions where these vary between above and below freezing over the course of a single Earth year. Right: The mean surface temperatures. Also shown within the black contours are the regions where these vary between above and below freezing over the course of a single Earth year: these regions are narrower than the air ‘perifreezing zone’.-- [astro-ph.EP]

Water/Hycean Worlds & Oceanography

Sea Ice As An Origin Of Life Location For Hycean And Ocean Worlds

by Keith CowingSeptember 9, 2026September 9, 2026

[astro-ph.EP] Water worlds with potential deep oceans are at the forefront of currently observable exoplanetary habitability.

Snowball Earth -- Grok via Astrobiology.com

Amplified Cooling Of Snowball Earth From A Salt-albedo Feedback

by Keith CowingSeptember 4, 2026September 4, 2026

[Climate of the Past] It is believed that the atmospheric circulation on Snowball Earth produced a net ablation zone exposing bare sea ice.

(a) Annual mean sea ice concentration and sea ice thickness at the end of the simulations. Red lines in TSI100 indicate the presentday winter sea ice edge (Hirahara et al., 2014), and the contour in TSI094 indicates the simulated annual mean sea ice thickness (unit: m). The red shades on the land grid indicate that the monthly minimum snow depth exceeds 1 cm. (b) Annual mean surface shortwave albedo. -- physics.geo-ph

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Habitable Zones, Icy Worlds, Status Report, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

Climate And Ocean Circulation Changes Toward A Modern Snowball Earth

by Keith CowingApril 2, 2026April 2, 2026

It has been hypothesized that the Earth may have experienced snowball events in the past, during which its surface became completely covered with ice. Previous studies used general circulation models […]

Overview maps illustrating Arctic Ocean bathymetry and source data for the compilation of IBCAO 5.0. (a) Bathymetry based on IBCAO 5.0. Two versions are available: one with under-ice topography of Greenland (shown), and another with the ice-sheet surface topography, both based on BedMachine Version 5 DMT180. The bold black line shows the Seabed 2030 Arctic region, for which a geographic DTM is produced and contributed to the global GEBCO DTM. The square region shown in brighter colours represents the more limited extent of the IBCAO DTM. White stars show the locations of detailed comparison between IBCAO 5.0 and 4.0 in Fig. 9. (b) Source data displayed based on the mapping method (MB = Multibeam; SB = Singlebeam). (c) Close-up of the East Siberian Sea depicting soundings from charts (in black) and digitised contours (in white). The nodes of the digitised contours, utilised in the gridding process, may be challenging to discern due to their sparse density. To enhance visibility, several contours are presented as polygons in white. (d) Close-up of North Greenland showing a part of the least mapped area of the Arctic Ocean. (e) Source data displayed as individual data sets using different colours. Note that the high resolution of the IBCAO 5.0 gridded products precludes displaying fine details in overview figures. For detailed information, readers are referred to the downloadable grids. -- PNAS via PubMed

Arctic / Antarctic / Alpine, Atmospheres, Climate, Weather, Away Teams & Field Reports, Exploration Gear & Tech, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Nomenclature, Systematics, Natural History, ROVs/Submersibles/Diving, Status Report, Water/Hycean Worlds & Oceanography

Ocean World Cartography: The International Bathymetric Chart of the Arctic Ocean Version 5.0

by Keith CowingJanuary 12, 2025January 11, 2025

Knowledge about seafloor depth, or bathymetry, is crucial for various marine activities, including scientific research, offshore industry, safety of navigation, and ocean exploration.

Close-up of a newly formed pressure ridge in the Arctic Ocean. -- Credit Alfred-Wegener-Institut / Andreas Preusser

Arctic / Antarctic / Alpine, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Cryobiology, Europa, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, Press Release, Water/Hycean Worlds & Oceanography

Ice World Update: Marked Decrease in Arctic Pressure Ridges

by Keith CowingJanuary 8, 2025January 8, 2025

In the Arctic, the old, multiyear ice is increasingly melting, dramatically reducing the frequency and size of pressure ridges. These ridges are created when ice floes press against each other […]

Earth's cryosphere - NASA

Arctic / Antarctic / Alpine, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Cryobiology, Gaia - Planetary Perspectives, Habitable Zones, Icy Worlds, Polar / Alpine Expeditions, Press Release, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

Preserving Our Home World’s Cryosphere: World Meteorological Organization

by Keith CowingJune 14, 2024June 14, 2024

Editor’s note: The Astrobiology community is all excited about two missions that wil; explore the ice worlds orbiting Jupiter with a focus of understanding their potential to host habitable – […]