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These articles provide answers to frequently asked questions related to Earth's frozen realms. Questions range from general background information and detailed science processes to the data gathered and archived at the National Snow and Ice Data Center (NSIDC) and its data management programs including NOAA@NSIDC, the NASA NSIDC Distributed Active Archive Center (DAAC), and the Exchange for Local Observations and Knowledge of the Arctic (ELOKA). If you have a question that is not answered here, please contact NSIDC User Services.
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NSIDC archives satellite data for polar sea ice dating back to November 1978. The sharpest declines have occurred in the summer and fall, including the time of year when sea ice reaches its annual minimum in September. Although Arctic sea ice extent has not declined as much during winter months, it has still shown a steadily decreasing trend. Arctic sea ice extent now exhibits long-term declines in all months, including the coldest, darkest months of the year.
Although area and extent may sound synonymous, they are different measurements, rendering different numbers, even from the same satellite observations. Sea ice area is the total region covered by ice. Extent is the total region with at least 15 percent sea ice cover. NSIDC usually reports extent, which gives higher values than area.
About 70 percent of the planet’s freshwater is locked up in ice sheets: massive ice bodies spanning more than 50,000 square kilometers (20,000 square miles). Our planet has two ice sheets, one covering roughly 80 percent of Greenland and the other
By Agnieszka Gautier A glacial lake is a body of water that originates from a glacier. It typically forms at the foot of a glacier, but may form on, in, or under it. As Earth’s climate warms, the world’s glaciers are shrinking, increasing freshwater
On the landmasses surrounding the Arctic Ocean, tundra typically thrives. Tundra landscapes consist of low-profile, cold-adapted plants that eke out their tiny lives in short, cool summers. Since the early 1980s, though, satellites and ground-based
Besides occurring on the opposite side of the globe, Antarctic sea ice differs from Arctic sea ice in a couple of respects. First, the Arctic is an ocean basin largely surrounded by land whereas the Antarctic is a continent surrounded by ocean, and