September daily extents are now fully reported and the 2017 September monthly results can be compared with years of the previous decade. MASIE showed 2017 exceeded 4.8M km2 and SII was close behind, also reaching 4.8M for the month. The 11 year linear trend is more upward for MASIE, mainly due to 2008 and 2009 reported higher in SII. In either case, one can easily see the Arctic ice extents since 2007 have not declined and are now 500k km2 higher.
In August, 4.5M km2 was the median estimate of the September monthly average extent from the SIPN (Sea Ice Prediction Network) who use the reports from SII (Sea Ice Index), the NASA team satellite product from passive microwave sensors.
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