{"id":53534,"date":"2026-11-06T08:40:00","date_gmt":"2026-11-06T13:40:00","guid":{"rendered":"https:\/\/www.ecoticias.com\/en\/?p=53534"},"modified":"2026-10-31T09:57:17","modified_gmt":"2026-10-31T13:57:17","slug":"a-hole-almost-as-big-as-portugal-opened-in-antarctic-sea-ice-in-midwinter-something-satellites-had-never-seen-there-since-1979-and-what-kept-it-from-freezing-came-from-above-and-below","status":"publish","type":"post","link":"https:\/\/www.ecoticias.com\/en\/a-hole-almost-as-big-as-portugal-opened-in-antarctic-sea-ice-in-midwinter-something-satellites-had-never-seen-there-since-1979-and-what-kept-it-from-freezing-came-from-above-and-below\/53534\/","title":{"rendered":"A hole almost as big as Portugal opened in Antarctic sea ice in midwinter, something satellites had never seen there since 1979, and what kept it from freezing came from above and below"},"content":{"rendered":"\n

A hole in Antarctic sea ice covering 34,410 square miles (89,121 square kilometers) opened in Breid Bay, East Antarctica, in August 2024. Portugal is only a little bigger, and down there August is deep winter, when the pack should be growing. A study in Geophysical Research Letters<\/a> blames six atmospheric rivers in a row, plus warm water welling up from a deep layer of the Southern Ocean.<\/p>\n\n\n\n

Jeebanjyoti Swain of India’s National Centre for Polar and Ocean Research in Goa led the work. His group pulled daily ice maps from the National Snow and Ice Data Center. They added ship casts from a 2024-25 coastal expedition and readings from Argo float 7900893.<\/p>\n\n\n\n

In the paper, published on September 27, 2026, the authors say a winter opening like this “has never been observed in this region in the satellite era since 1979.” In a normal July and August, about 93 percent of that stretch of ocean is covered by ice.<\/p>\n\n\n\n

Nine days of open water<\/h2>\n\n\n\n

Scientists call a patch of open water inside floating sea ice<\/a> a polynya. Around Antarctica, most of them form along the coast, where offshore winds push ice away. Open-ocean polynyas far from shore are rare and have been seen mainly in the Weddell Sea.<\/p>\n\n\n\n

On August 4, 2024, the Breid Bay opening showed up as three patches of water. Together they covered 3,666 square miles (9,494 square kilometers). After shrinking the next day, the hole reached 29,592 square miles (76,643 square kilometers) on August 7 and peaked on August 8.<\/p>\n\n\n\n

By August 10 it was down to 3,376 square miles (8,744 square kilometers). It was gone by mid-August, once winter freezing resumed. The pack had been thinning for weeks, from about 96 percent cover in early July to under 25 percent by July 30.<\/p>\n\n\n\n

\"Study
Figure from the study: (a) satellite view of the opening on August 8, 2024, (b) seafloor depth around Breid Bay with expedition and Argo float positions, and (c) daily sea ice concentration from July 29 to August 13, 2024. (Image: Swain et al. \/ Geophysical Research Letters, CC BY 4.0)<\/figcaption><\/figure>\n\n\n\n

Six atmospheric rivers in a row<\/h2>\n\n\n\n

Atmospheric rivers are long, narrow bands of moist air, often called “rivers in the sky.” They carry water vapor out of warmer latitudes. In the United States, they are best known for the storms that soak California.<\/p>\n\n\n\n

Six of them reached the polynya area between July 6 and August 6, 2024. They came from the South Atlantic and from the coast of South America. On six days, the moisture they moved topped the 99th percentile of the 1979 to 2023 record.<\/p>\n\n\n\n

The strongest river arrived on July 26, carrying more than 600 kilograms of water vapor per meter per second at its core. Air over the area ran 17\u00b0C (31\u00b0F) warmer than normal that day. Northerly winds also set a record for the period.<\/p>\n\n\n\n

After the third river passed on July 17, an atmospheric heat wave sat over the bay until July 31. Ice losses peaked in that window. Between July 23 and July 30, the shortfall against average ice cover grew from 22 to 68 percentage points.<\/p>\n\n\n\n

Snow falling near the thaw point<\/h2>\n\n\n\n

Every river dumped heavy snow on the pack. During the strongest events, air temperatures stayed between 26.8\u00b0F and 31.8\u00b0F (\u22122.9\u00b0C and \u22120.1\u00b0C). The usual winter range there is about 5\u00b0F to 8\u00b0F (\u221215.2\u00b0C to \u221213.4\u00b0C).<\/p>\n\n\n\n

Snow on sea ice acts as insulation<\/a>, according to the National Snow and Ice Data Center. That layer “slows ice growth in the winter.” It keeps the frigid air from pulling heat out of the water below.<\/p>\n\n\n\n

Thick clouds added to the problem. Heat radiated back down from them was the largest single source of extra energy during most of the rivers, the authors found. Net heat flux anomalies reached about 97 watts per square meter.<\/p>\n\n\n\n

Ekman suction lifts warmer water<\/h2>\n\n\n\n

Underneath, the ocean was also working against the ice. Strong winds pulled surface water apart, a process called Ekman suction. Warmer water from a deeper layer, known as Upper Circumpolar Deep Water, rose to fill the gap.<\/p>\n\n\n\n

The polynya sat over a basin 9,800 to 13,100 feet (3,000 to 4,000 meters) deep, between the Astrid and Gunnerus ridges. From July 23 to August 14, a marine heat wave kept the upper ocean up to 1.1\u00b0F (0.6\u00b0C) warmer than normal. In the warmest zone, the mixed surface layer thinned by about 88 feet (26.8 meters).<\/p>\n\n\n\n

Measurements from ships and floats point the same way. A CTD probe records conductivity, temperature and depth. One cast at 67\u00b0S, 21\u00b0E, made during the International Antarctic Coastal Circumnavigation Expedition 2024-25, found a warm, salty layer under colder surface water.<\/p>\n\n\n\n

Southwest of the polynya, Argo float 7900893 saw the line between cold and warm water rise during July and August. Similar warm water under Antarctic ice<\/a> has been tracked beneath the Ross Ice Shelf.<\/p>\n\n\n\n

Breid Bay held through record lows<\/h2>\n\n\n\n

Antarctic sea ice has been shrinking since 2016, with record-low winter extents in 2017, 2022 and 2023. Even then, Breid Bay never opened up. Its July and August sea surface temperatures used to cluster near freezing, but in 2024 they passed the 99th percentile.<\/p>\n\n\n\n

The National Snow and Ice Data Center reports that low ice has continued, and that this year’s Antarctic peak, on September 14, 2026, was the third lowest in the satellite record<\/a>.<\/p>\n\n\n\n

Why should anyone outside Antarctica care? The UK’s DEFIANT project<\/a>, which supported the team’s collaboration with the British Antarctic Survey, says sea ice “protects the exposed edges of the ice shelves from waves.” Those shelves hold back glaciers, and faster glacier flow into the ocean<\/a> explains most polar ice loss since 1979.<\/p>\n\n\n\n

Along parts of the coast, local features such as grounded icebergs that pin sea ice in place<\/a> also shape the pack. The Breid Bay hole sat well offshore, between 65 and 68 degrees south. One opening there cannot speak for the whole continent.<\/p>\n\n\n\n

No odds yet on a repeat<\/h2>\n\n\n\n

Swain’s team rebuilt a single winter, 2024, and put no number on the chance of another. Warming is expected to strengthen atmospheric rivers, and the upper Southern Ocean has warmed since 2016. Given that, the authors write, polynyas “may become frequent in regions where sea-ice has historically remained stable.”<\/p>\n\n\n\n

They want high-resolution models that couple ocean, ice and atmosphere. Right now nobody can say whether the air or the water did more of the damage. Much of the weather picture also rests on reanalysis, a computer rebuild of past conditions, not on instruments on the ice.<\/p>\n\n\n\n

The full study was published in Geophysical Research Letters<\/a>.<\/p>\n\n\n\n

Image: NASA Worldview \/ GIBS (AMSR2 sea ice concentration)<\/p>\n","protected":false},"excerpt":{"rendered":"

A hole in Antarctic sea ice covering 34,410 square miles (89,121 square kilometers) opened in Breid Bay, East Antarctica, in … <\/p>\n

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