from the Neven ice blog, at http://neven1.typepad.com/

A couple of days ago a paper was published in the journal Revista de Climatología by Diablobanquisa, a Spanish blogger who regularly writes about Arctic sea ice on his blog. In this paper Diablobanquisa, together with his co-author, presents a new time series of September Arctic sea ice extent, including data for the Siberian sector. I think the work looks very solid and gives us an improved view of pre-satellite Arctic sea ice.

Abstract

Since 1979 satellite-borne passive microwave sensors have provided a continuous and consistent record of Arctic sea ice extent. This record shows a significant downward trend, particularly at September, when Arctic sea ice reaches its annual minimum. Records before 1979 exist, but are not consistent with the satellite record and have limited reliability, specially before 1953. We present a new time series of September Arctic sea ice extent from 1935 to 2014 that includes data for the Siberian sector (AARI operational charts) not used previously in the Arctic wide existing time series (Walsh, HadISST). The new record has been adjusted to be consistent with satellite data. The trend for 1935-2014 is -3.5% decade, while the trend for the satellite era is -13.3% decade. However, the trends since 1935 until early 1980s are positive and statistically significant. The trends turn negative in the 1990s, reaching statistical significance from 2006 onwards. The lowest annual minimum in the pre-satellite era is higher than any annual minimum after 2001.

Diablobanquisa September Arctic sea ice extent: 1935-2015

http://neven1.typepad.com/.a/6a0133f03a1e37970b01b7c809c471970b-800wi

Here is the NSIDC September Arctic Sea Ice Extent 1979 – 2015, for comparison

Click Here

http://nsidc.org/arcticseaicenews/files/2015/10/monthly_ice_09_NH-350×270.png

Maps
Median September Arctic sea ice extent for the lowest decade of the pre-satellite era (1935-1944, left) and for the lowest decade of the satellite era (2005-2014, right)

Click Here

http://neven1.typepad.com/.a/6a0133f03a1e37970b01bb08ae82ac970d-800wi

To read Diablobanquisa’s original article, for more graphs and full methodology employed, (in Spanish),

click here

https://diablobanquisa.wordpress.com/2016/01/14/extension-hielo-marino-artico-1935-2014/