Snowbird uses Earth's City Lights, Blue Marble and Blue Marble NG images from NASA Visible Earth. GLOBE images were obtained from the National Geophysical Data Center (NGDC). The Natural Earth image was created by Tom Patterson for the US National Park Service.
We would also like to acknowledge our collaborators at Science for Citizens with whom we have worked since early on.
The idea came from a UK snowfall mapping project developed by Ben Marsh.