Research / Observation

Diomede Islands, Bering Strait, November 2024 and March 2025

Two radar acquisitions of the same 48 by 27 km window, 108 days apart, record the strait's transition from open water in November to fractured pack ice in March.

Satellite radar image of the Diomede Islands in the Bering Strait on 16 November 2024, surrounded by open water.

2024-11-16

The same area on 4 March 2025, with the islands surrounded by fractured pack ice.

2025-03-04

Diomede Islands, Bering Strait. 2024-11-16 and 2025-03-04. Contains modified Copernicus Sentinel data 2024, 2025.
Place
Diomede Islands, Bering Strait
Coordinates
65.7600, -168.9500
Acquired
2024-11-16 and 2025-03-04
Region
United States, Alaska
Satellite
Sentinel-1, radar
Source
Sentinel-1A interferometric wide swath, ground-range detected, VV polarisation
Catalog
Microsoft Planetary Computer STAC, collection sentinel-1-grd
Resolution
25 m ground sample distance
Scenes
Sentinel-1A IW GRDH VV, relative orbit 161 descending, 2024-11-16, Sentinel-1A IW GRDH VV, relative orbit 161 descending, 2025-03-04
Rights
Contains modified Copernicus Sentinel data 2024, 2025. Copernicus Sentinel data is free, full, and open. Rendering by Heimdall Research.
Credit
Contains modified Copernicus Sentinel data 2024, 2025.
Published
Locator map: Diomede Islands, Bering Strait marked on a globe.
Diomede Islands, Bering Strait. Made with Natural Earth.

Context

What this shows

Big Diomede and Little Diomede sit in the middle of the Bering Strait with the international date line between them. Radar sees through cloud and polar night, so the same pass can be compared across the season. In the November image the strait is open water, which returns almost no signal and appears dark. In the March image the islands are locked in pack ice: bright, fractured, and pushed against their northern shores.

This pair is the reference case for the Arctic Open-Water Window dataset, which counts open-water days at fixed gates in this strait.

Method

How the image was made

Two acquisitions from the same Sentinel-1 orbit, 108 days apart, warped to a common 25-meter grid and shown with one fixed brightness stretch so the two dates are directly comparable. Bright is rough or icy; dark is calm open water. No classification has been applied; this is the measured backscatter, contrast-stretched.

Prints

Prints

Every print carries the place, the date, and the source credit on the mat, as shown. Sizes and paper are quoted with the rights and source resolution confirmed.

Related

  1. Observation

    Ilulissat Icefjord and Disko Bay, Greenland, August 2024 to October 2025

    Thirty-eight Sentinel-1 passes at a twelve-day interval record the icefjord's discharge, the freeze and break-up of Disko Bay, and the seasonal advance and retreat of sea ice over fifteen months.

This observation

Prints and analysis

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