Thursday, September 21, 2017

Equinox Ice GIF

The autumnal equinox is tomorrow. The dark season will begin in the arctic, although it has been pretty close to dark there for about a month. Late last week (on 13 September) the extent of Arctic sea ice reached what is likely to stand as its minimum extent for 2017 (4.64 million square kilometers, 1.79 million square miles).

It will be a couple weeks before the sea ice starts rapidly building towards its spring maximum. Likewise it will be a couple weeks before the Antarctic sea ice starts rapidly melting.

There are all sorts of numbers that can be teased out of polar sea ice measurements that can help illustrate the warming of the planet. How late the sea ice minimum is reached is a great number; it has been getting a little later. Of course the extent of the minimum is great; the minimum has dropped dramatically in recent years. I’ve decided to take the Arctic sea ice extent around the equinox and compare them. I decided to use pictures to do this.

Here is an animated GIF made with sea ice extent pictures downloaded from the National Snow and Ice Data Center. It is made from 38 images that span the equinoxs from 1979 to 2016; the picture for 2017 is not ready yet. Feel free to use the GIF if you want. Please credit NSDIC for the data if you do.

Arctic sea ice extent for autumnal equinox years 1979-2016.  Data downloaded from National Snow and Ice Data Center.

Hope you enjoy the animation, and happy equinox!

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