The Arctic Temperatures and Multidecadal Oscillation in recent research
Posted by Jeff Condon on September 25, 2009
A guest post by Dr. Arnd Bernaerts on the subject of Arctic warming. Dr. Bernaerts was one of a couple of people who responded to my offer to put up work by those who are not skeptics or who don’t share my viewpoint. Of course nobody knows what I think, so any good post has to have a shot. He’s done a short referenced piece here on warming in the Arctic.
The West Spitsbergen Current (WSC) is getting more attention, but only with regard to recent years. For modern science the Arctic warming 90 years ago is still a non issue, although one could learn so much from it. For example: Piechura et al.(2009) discuss the influence of a warmer WSC on the sea ice conditions north of Svalbard with the main conclusion, that it is primarily the heat transport to the Arctic Ocean (AO) by ocean currents, the West Spitsbergen Current (WSC) in particular, that is playing a significant role in the process of Arctic warming. Actually their investigation focused on the short warming period from 2004-2006.
>>NOTE: The graphic “Svalbard Luft” indicates a warming from 1980 until 2006, and decreasing annual temperature mean since 2007<<
Other researcher concluded already earlier that “the Atlantic inflow is the primary source of heat to the Arctic Ocean (2007), respectively that the fluxes from the North Atlantic through Fram Strait affect the heat budget in the Arctic Ocean (2003). Although Chylek et al.(2009) acknowledge that the warming early last Century proceeded at a significantly faster rate than the current after app.1970, the previous warming is ignored.
This applies particularly to Chylek et al which suggest that the Atlantic Ocean thermohaline circulation is linked to the Arctic temperature variability on a multi-decadal time scale, based on the assumption that the Arctic had been warming from 1910 to 2008 interrupted by a significant cooling period from 1940 to 1970, and that the changes are highly correlated with the Atlantic Multi-decadal Oscillation (AMO). One can only wonder that they come up with a start of the warming in 1910 when the IPCC (2007:WGI) sets the date in the year 1925, and the IPCC-Report (1990, p. 228) mentions 1920, which is also confirmed by Polyakov et al.(2003).
>>NOTE: The graphic “Arctic-Winter” indicates the hot-spots in the 1920s, at Spitsbergen , +3,4°C, and West-Greenland, +3°C<<
A little historical research would have lead the researchers to the fact that the warming started in winter 1918/19 (HERE). By such a variety of dates more efforts may be needed to come up with convincing timing before talking about “multi-decadal” AMO. Even more questionable is the ignorance of previous IPCC conclusions. The first IPCC report (1990:228) states that “Stronger westerlies over the Atlantic, do not, therefore, account for the Arctic warming of the 1920s and 1930s on their own: in fact they preceded it by 20 years”. If that is now regarded as wrong it needs to be said and explained.
More attention to the early Arctic warming that occurred 90 years ago, which had been subject to the last Hot Topic (26th June 2009), would have provided more insight in the functioning of the Arctic during the last decades, than one can learn from the papers mentioned.
___Svalbard Temp-Graphic; Source: NASA/Giss (download: Sept.2009).
___Arctic Winter Temp-Deviation, Source: Scherhag 1936.
 Piechura, Jan, Walczowski, W.; 2009, Warming of the West Spitsbergen Current and sea ice north of Svalbard , Oceanologia 2009, no. 51(2), pp 147-164; viewed 20 Sept. 2009, http://www.iopan.gda.pl/oceanologia/51_2.html#A1
 Cokelet, E. D., N. Tervalon, and J. G. Bellingham (2008), Hydrography of the West Spitsbergen Current, Svalbard Branch: Autumn 2001, J. Geophys. Res., 113, C01006, doi:10.1029/2007JC004150.
 Fahrbach, E., A. Beszczynska-Möller , E. Hansen , J. Meincke , S. G. Rohardt , U. Schauer ,A. Wisotzki (2003?), How to measure oceanic fluxes from the North Atlantic through Fram Straits? Poster, visited on 20 September 2009: http://acsys.npolar.no/meetings/final/abstracts/posters/Session_2/poster_s2_039.pdf
 Chylek, P., C. K. Folland, G. Lesins, M. K. Dubey, and M. Wang (2009), Arctic air temperature change amplification and the Atlantic Multidecadal Oscillation, Geophys. Res. Lett., 36, L14801, doi:10.1029/ 2009GL038777.