By late summer it pulls back to the roughly circular Arctic basin.
Three drainage basins cover European Russia south of the Arctic basin.
Among other things, the online library displays years of ice imagery from six sites inside the Arctic Circle, including the Fram Strait, the main route for icebergs moving from the Arctic basin into the North Atlantic.
Dr. Untersteiner said the federal government had already adopted one of the report's recommendations — have reconnaissance satellites follow particular ice floes as they drift through the Arctic basin rather than just monitoring static sites.
The observation comes just weeks after an iceberg twice the size of Manhattan broke away from the Petermann glacier in northern Greenland and other scientists recorded a rapid loss of floating sea ice further north in the Arctic basin.
A new study, led by Son Nghiem at NASA's Jet Propulsion Laboratory and appearing this week in Geophysical Research Letters, used satellites and buoys to show that winds since 2000 had pushed huge amounts of thick old ice out of the Arctic basin past Greenland.
