According to a University of Washington research report, modern-day computer simulations and historic observations from 100-year old ship logbooks have extended estimates of Arctic sea ice volume all the way back to 1901, says an article published in Futurity.
Gauging the Arctic Ice ThicknessThe Pan-Arctic Ice Ocean and Modeling System, or PIOMAS, is a leading tool for gauging the thickness of sea ice coverage in the Arctic Ocean. Until now, that system has gone back only as far as 1979, when...
http://mfame.guru/can-100-year-old-ship-logbooks-provide-insights-into-the-melting-arctic/