Notes from the weather underground

https://www.wunderground.com/cat6/arctic-sea-ice-primed-phenomenal-melt-season

During the first week of every month, I post here the NSIDC Arctic sea ice extent graph comparing that month’s sea ice extent with previous years’ extents for that month. The general slope of the regression is always down, although there is a lot of noise in the data.

The following graph displays the ice VOLUME data for every month for all the years since the satellites have been measuring sea ice (1979). In essence, it puts all these monthly time series on one graphic, using a uniform set of axes, domain and range values. It is possible to simultaneously see how the ice is melting over the decades, superimposed on the natural fluctuation of the ice due to the seasons. For example all the maxima (April) are greater than any of the minima (September) which is exactly what you would expect. But the general trend for the last 40 years is down.

About 37% of the winter ice has gone, and about 75% of the summer ice.

https://s.w-x.co/wu/piomas-volume.png

BTW, the rest of the article at the Weather Underground (link at the top) makes some pretty interesting reading.