It’s here – as promised and right on schedule — the sea ice atlas put together by University of Alaska Fairbanks (UAF) now has ice concentration maps for Alaska going back to 1850 — and for every year up to 2013.
Several examples are included below: August 1850 vs August 1870, and April 1850 vs. April 1920 and April 2012.
For background, see my post announcing the site preview, which was then limited to 1953-2012 data, when it became available in late January.
The atlas provides ice maps from January 1850 to December 2013.
The maps chart polar bear habitat for the Southern Beaufort and Chukchi Sea subpopulations (including the Bering Sea), as well as the western portion of the Northern Beaufort Sea subpopulation region.
It’s worth a look — see for yourself how variable Alaska sea ice has been, season by season, since 1850 (e.g. August 1850 vs August 1870 above, and April 1850 vs April 1920 and April 2012 below, all screen-caps from the ice atlas). Remember that ice coverage is most important for polar bears for March through June.
Just keep in mind that all data prior to 1979 is not really comparable in detail or quality to satellite era data (1979-present) – see this pdf copy of the “Sources of sea ice data used in this Atlas.”
I’ve added a link to this site on my “other useful sites” list in the right column.
Some other relevant posts you might want to check out:
Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice August 29, 2013
Tracking polar bears in the Beaufort Sea: September map October 17, 2013 [and every other month until December 2013, posted early the following month]
How and why great news about Chukchi polar bears has been suppressed
September 8, 2013
Where were the appeals to feed starving polar bears in 1974? February 21, 2013