A Clear View of Alaska—and Maybe Our Future
By Phil Plait
Alaska, it so happens, is pretty big. If you take Alaska and subtract Texas, the amount left over is still bigger than Texas.
Given that, plus the usual atmospheric conditions, it’s pretty rare to get a picture of the nearly the entire state free of clouds. But that’s just what NASA’s Terra satellite saw on Monday:
What an amazing shot! The snow-covered mountains in the southeast really stand out, and you can see a forest fire raging farther to the west. I know we’re seeing a huge swath of land, so the scale is huge—the picture shows an area about 1,500 kilometers (900 miles) across—but it’s still striking not to see any real signs of human activity here.
Or are we? The reason the state is cloudless is because of a huge high-pressure system squatting over the state. This has also brought record high temperatures to much of the state. This reminds me of the same sort of system that’s been plaguing Greenland and which caused record ice melting last year.
A new study just came out possibly linking that Greenland system to global warming. It’s not a direct link; that is, it’s not that things are warmer now so we got more melting. What may be happening is that the changing climate is affecting the pattern of the jet stream, causing warmer high-pressure systems to sit and stay in one place in what’s called a blocking pattern.
more
http://www.slate.com/blogs/bad_astronomy/2013/06/20/alaska_cloudless_view_from_space_shows_forests_fires_and_evidence_of_global.html
http://www.nasa.gov/multimedia/imagegallery/image_feature_2534.html
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