Artic ice comparison 2008/2009/2013

The annual Arctic ice jamboree revs up each year in September and much (undue) attention is given to just one day of the year, which is taken to somehow indicate the current state of the Arctic ice sheet.

This is totally misleading and unscientific when daily data is available for most of the last 30 years.

Wind and other weather events can have a large influence on daily estimates of ice cover as well as the timing of several pseudo periodic variations which can push the single day minimum either up or down depending on where they fall w.r.t. the equinox, potentially giving a very misleading impression of how the ice coverage is varying from one year to the next.

Here, short-term weather events have been filtered out to reveal the annual pattern for each year. This allows better comparison of 2013 progression with previous years.

The closest similarity to 2013 so far appears to be 2008 and 2009. The (weather-free) minima for those years were 3.23 and 3.67 million km sqr respectively.

An interactive version of the graph is available where each year can be toggled on and off by clicking of the years in the legend. A mouse click on the image gives cursor read-out of ice area and date.