The Arctic Ocean's surface temperature and salinity vary seasonally as the ice cover melts and freezes; [5] its salinity is the lowest on average of the five major oceans, due to low evaporation, heavy fresh water inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities.

2020年2月18日 · Layers of frozen seawater cap the Arctic Ocean. This sea ice grows dramatically each winter, usually reaching its maximum in March. It melts just as dramatically each summer, reaching its minimum in September.

2023年8月28日 · But there are limits to the thickness of Arctic ice, due to the ocean’s ability to hold heat. A cold atmosphere will only freeze a very small amount of the water at the ocean’s surface, and the ice that freezes in winter often melts during summer.

2025年1月6日 · Average Arctic sea ice extent for December was the lowest in the satellite record, in considerable part due to delayed ice growth in Hudson Bay and low extent in the northern Barents Sea.

2024年9月24日 · The amount of frozen seawater in the Arctic fluctuates during the year as the ice thaws and regrows between seasons. Scientists chart these swings to construct a picture of how the Arctic responds over time to rising air and sea temperatures and longer melting seasons.

2021年12月28日 · Arctic sea ice is frozen seawater that forms in the Arctic Ocean. Nearly all of the Arctic Ocean freezes during the winter months and melts during the summer. This ice is critical to the ocean’s currents and various ecosystems.

2024年6月23日 · Historically, most of the surface of the Arctic Ocean remained ice-covered year round. Around this core of year-round ice was a fringe of seasonal ice that froze each winter and melted each summer.

2023年10月19日 · The Arctic Ocean freezes during winters because the temperature of the water gradually begins to fall and a deep layer of seawater begins to develop tiny ice-crystals called …

Sea ice is frozen ocean water. It forms, grows, and melts entirely in the ocean. By contrast, icebergs, glaciers, and ice shelves float in the ocean but originate on land. For most of the year, sea ice is typically covered with snow. A polar bear walks on brittle sea ice in the Arctic Ocean. — Credit: US Geological Survey. Why is sea ice important?

With no insulating ice cap to protect it, the Arctic Ocean’s blue surface absorbs more and more solar energy. This added energy further reduces the Arctic’s cooling impacts on the global climate.