Many of our readers may have seen the recent string of news articles about the shrinking extent of Arctic Sea ice, but perhaps you have never analyzed the data for yourself. If that is the case, the US National Snow and Ice Data Center (NSIDC) has made a variety of data layers available that can be viewed with Google Earth on glaciers, snow, ice shelves and more. You can find the collection here.
The NSIDC Google Earth overlays are derived from multiple government satellites such as ASTER and MODIS as well as more than 10,000 photographs of glaciers dating back to the 1880s. The layers are downloaded in KMZ format and with a double-click, they open in Google Earth (assuming you have this freeware software installed). Once the layers are open, a new interface is added to the top left of Google Earth which lets you move forward and backward in time through the images. Clicking on the small clock icon with a play button will move you through the animation automatically. If you click on the settings icon (the wrench at the top right of the toolbar), then you can change the animation speed among a few other settings.
The September Sea Ice Extent file is definitely an eye-opener to the changes that are happening right now to our fragile arctic ecosystem.
Until my next edition of Free For All, happy hunting for free GIS data!
Brock Adam McCarty