Sea Ice

Why is it so hard to measure the sea ice extent? There's a number of factors. The Arctic Ocean is large, remote, and the weather is really nasty. All of that works against measuring the ice extent, even by satellite. But, take a look at this image and you can see another reason. Just how would you characterize the ice extent?

Source: NASA

This true-color image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite off the coast of Greenland on July 16, 2015.

As you can see, although the ice is broken up it is still very dense in some area, but not so dense in others.  And, if a storm or high winds comes through, all of this can change very rapidly. This makes measuring the extent a difficult process.

By the way, the extent for this year has now been measured to be less than the minimum extent for every year prior to 2007 and still falling.