This visualization shows the weekly age of the sea ice between 1984 and 2019. The animation shows the seasonal variability of the ice, growing in the Arctic winter and melting in the summer. In addition, this also shows the changes from year to year by depicting the age of the sea ice in different colors. Younger sea ice, or first-year ice, is shown in a dark shade of blue while the ice that is over four years old is shown as white. A color scale identifies the age of the intermediary years. Note that data for the sea ice age is not available along the coastlines. The region where data is not available is shown in a dark lavender color. One significant change in the Arctic region in recent years has been the rapid decline in perennial sea ice. Perennial sea ice, also known as multi-year ice, is the portion of the sea ice that survives the summer melt season. Perennial ice may have a life-span of nine years or more and represents the thickest component of the sea ice; perennial ice can grow up to four meters thick. By contrast, first year ice that grows during a single winter is generally at most two meters thick. The graph displayed in the upper left corner quantifies the area covered by sea ice that is 4 or more years old in millions of square kilometers. This graph also includes a memory bar - the green line that indicates the maximum value seen thus far in the animation for the given week being displayed. For example, when viewing the sea ice age for the first week in September, the memory bar will display the maximum value seen for the first week of September in all prior years from the beginning of the animation (1984). In addition, a violet bar indicates the weekly average area covered by sea ice 4 years of age or older during the 20-year time period from 1984 through 2003. Visualizers: Cindy Starr (lead), Horace Mitchell For more information or to download this public domain video, go to svs.gsfc.nasa.gov/4750#27894

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