For most of the year, ice blankets the waterways of the northern Canadian Arctic Archipelago. But during the brief summer melt season, the stark white and gray landscape transforms into a colorful, dynamic environment. On a particularly striking day in 2022, sediment plumes and fractured sea ice traced swirling eddies in a branch of the Nansen Sound fjord system.
一年中的大部分时间，加拿大北部北极群岛的水道都被冰覆盖。但在短暂的夏季融化季节，纯白和灰色的景观变成了色彩缤纷、充满活力的环境。 2022 年一个特别引人注目的一天，沉积物羽流和破裂的海冰在南森峡湾系统的一个分支中留下了漩涡的痕迹。
These satellite images show a section of Cañon Fiord, located about 115 kilometers (70 miles) southeast of the Eureka research station on west-central Ellesmere Island. Waters from the fjord flow into Greely Fiord, which connects to Nansen Sound and ultimately the Arctic Ocean. The images were acquired by the OLI (Operational Land Imager) on Landsat 8 on August 9, 2022.
这些卫星图像显示了卡农峡湾的一部分，位于埃尔斯米尔岛中西部尤里卡研究站东南约 115 公里（70 英里）处。峡湾的水流入格里利峡湾，与南森海峡相连，最终汇入北冰洋。这些图像由 Landsat 8 上的 OLI（操作陆地成像仪）于 2022 年 8 月 9 日采集。
Igor Dmitrenko, a physical oceanographer at the Centre for Earth Observation Science at the University of Manitoba, has studied eddies in the fjord system and notes that the water’s turbidity, a measure of its cloudiness, remains low during the ice-covered season. Freshwater runoff—and the sediment it carries—drops sharply this time of year, and the formation of 2-meter-thick sea ice shields the surface from wind, suppressing mixing that would otherwise resuspend particles.
曼尼托巴大学地球观测科学中心的物理海洋学家伊戈尔·德米特连科（Igor Dmitrenko）研究了峡湾系统中的涡流，并指出，在冰雪覆盖的季节，水的浊度（衡量其浑浊程度的指标）仍然很低。每年这个时候，淡水径流及其携带的沉积物急剧下降，2米厚的海冰的形成可以保护表面免受风的影响，抑制混合，否则会使颗粒重新悬浮。
Summer presents a contrasting scenario. The detailed image below (top) shows that the sea ice in this part of the fjord has broken up, free to drift with the currents and wind. Note that some of the pieces are likely icebergs that have broken off from nearby outlet glaciers. The second detailed image shows a similar scenario; however, in this case, it is sediment suspended in the water that is tracing the flow.
夏季则呈现出截然不同的景象。下面（上）的详细图像显示，峡湾这一部分的海冰已经破裂，随水流和风自由漂移。请注意，其中一些碎片可能是从附近的出口冰川脱落的冰山。第二张详细图像显示了类似的场景；然而，在这种情况下，追踪水流的是悬浮在水中的沉积物。
Alex Gardner and Chad Greene, glaciologists at NASA’s Jet Propulsion Laboratory, pointed out that the sediment plume is mostly glacial flour —rock that has been pulverized by a glacier. Surface meltwater that gets under the glacier ultimately flushes the glacial flour into the fjord, making the water appear turquoise. Glacial flour is a critical source of nutrients, specifically iron. Soluble iron is a vital nutrient in marine ecosystems because most phytoplankton —the foundation of marine food webs—depend on it to grow.
美国宇航局喷气推进实验室的冰川学家亚历克斯·加德纳和查德·格林指出，沉积物羽流主要是冰川粉，即被冰川粉碎的岩石。进入冰川下方的地表融水最终将冰川粉冲入峡湾，使水呈现出绿松石色。冰川面粉是营养物质的重要来源，特别是铁。可溶性铁是海洋生态系统中的重要营养素，因为大多数浮游植物（海洋食物网的基础）依赖它生长。
The glacial ice visible in these scenes comes from the Agassiz Ice Cap, one of five major ice caps on Ellesmere Island. Using data from NASA’s ICESat and the DLR-NASA GRACE missions, scientists have shown that glaciers in the Canadian Arctic Archipelago began shrinking rapidly in the mid-2000s and that the trend has persisted .
这些场景中可见的冰川来自阿加西冰盖，这是埃尔斯米尔岛的五个主要冰盖之一。科学家利用 NASA ICESat 和 DLR-NASA GRACE 任务的数据表明，加拿大北极群岛的冰川在 2000 年代中期开始迅速萎缩，并且这种趋势一直持续存在。
NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey . Story by Kathryn Hansen.
NASA 地球观测站图像由 Lauren Dauphin 使用美国地质调查局的陆地卫星数据拍摄。凯瑟琳·汉森的故事。