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Left: acquired from July 3 to July 4. Whitish-yellow color parts indicate areas with heavy rain or sea ice, light blue color areas are with little water vapor in the atmosphere or thin clouds, the dark blue color sections are areas with more water vapor in the atmosphere or thicker clouds, and the black color parts are areas that were not observed.
Right: same day. Here white indicates areas covered by ocean ice, blue is sea areas, gray is land, and black areas were not observed.-> continue reading
When I missed some weeks of the melting season - occupied with lower latitude stuff - I usually check two things first: Neven's Sea Ice Blog and the composite images from the Canadian Ice Service. The former because of the comprehensive biweekly ASI overviews and the latter because of the mostly cloudfree and high resolution quality.
These false colour composites image highlight colour differences between sea ice and cloud. As a result, sea ice and snow appear light blue and clouds appear white (and purple over water) and are created every Wednesday using the preceding week’s images.-> continue reading
Envisat's radar images reveal a high fragmentation of the sea ice. It seems the algorithms using microwave echo to generate concentration maps are not optimized for the current state of the 'ice pack'.
While ESA's satellite operates with a resolution of 30mx30m, the pixel size of the AMSR-E instrument is factor 200 lower. Compare out for example the North of the Laptev Sea.
Also interesting is how the different microwave echo approaches depend on the resolution to calculate sea ice extent.
The NSDIC prefers a low resolution instrument for historical reasons and sees the extent of 2011 currently ...-> continue reading