Wednesday, February 25, 2015

Mapping Shrinking Glaciers

Alaska Ice: Documenting Glaciers on the Move is an Esri Story Map which uses satellite imagery and comparisons of modern & vintage photographs to document Alaska'a glaciers.

The main focus of the map is the U.S. Geological Survey's Repeat Photography initiative. USGS has been comparing modern photographs of Alaskan glaciers with historical photos, both with the same field of view. The photographs are compared to document and understand the changes to glaciers resulting from changing climate.

The Alaska Ice Story Map visits 14 glaciers in the U.S. state. Each glacier can be viewed on a satellite map and a modern and an historical photograph of each glacier is compared in the map sidebar. Of the 14 mapped Alaskan glaciers only two are still advancing.

Disappearing Glaciers is another Esri StoryMap, this one is designed to highlight the alarming speed at which glaciers are disappearing around the world.

The map looks at recent aerial imagery of six different glaciers. Polylines have been overlaid on each glacier aerial image to show the glacier's size through time, demonstrating how far each glacier has reduced over the years.

Timelapse - aerial imagery of the Mendenhall Glacier in 1991 & 2012

Another interesting way to examine the loss of glaciers is with Google Timelapse. Timelapse allows you to compare aerial imagery over time for any location on Earth. You can therefore enter the name of any glacier into Timelapse and observe the effects of global warming for yourself.

Timelapse provides links to the Medenhall Glacier and the Columbia Glacier but you can use the search box to locate any glacier. You can therefore use Timelapse to search for the six glaciers used in the Disappearing Glaciers map and observe the highlighted loss of each glacier for yourself, using the historical aerial imagery.

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