What does this mean?

The maps and bar graphs show the age of Arctic sea ice for each month of a chosen year. On the maps, ice that has survived four years or more appears in the darkest shade of blue, while sea ice that is under a year old appears in the lightest shade of green. This time series of maps by year helps show how ice changes and moves throughout the year.

The bar graphs show sea ice age as either millions of square kilometers or as a percentage of the total sea ice extent. On the graphs, ice is broken out into three categories to give a closer look at ice age. The bar graphs help highlight the changes in ice age through a seasonal cycle.Continue reading...