From Dr. Roger Pielke Senior, one more paper saying what we’ve been reporting on since 2007 – Arctic sea ice extent is a significant function of wind and currents, not just temperature.
In 2007, when I was but a wee blogger, I wrote:
A science blogger named Tamino, in a post he made here, challenged me to “explain it or shut up” related to the loss of northern hemisphere Arctic ice this season which he claimed was …” undeniable, that it’s not natural variation” in contrast to the southern hemisphere Antarctic setting a new record for ice extent. While I suspect that sea ice is not his specialty, nor is it mine, I will bring some things to the attention of my readers available from literature.
Just last Monday, NASA was quietly issuing a press release explaining why Arctic sea ice loss was so great this year. (h/t Douglas Hoyt).
Full story: Arctic Sea ice loss – “it’s the wind” says NASA
In fact, in 2009, in further factual explanation for Tamino’s demand that I “explain it or shut up”, I did another post that showed a movie of wind pushing the ice out of the Arctic. See Watching the 2007 historic low sea ice flow out of the Arctic Sea What is interesting about this video is that you can watch sea ice being flushed out of the Arctic sea and pushed along Greenland’s east coast, where it then finds its way into warmer waters and melts.
Fast forward to today, now we have a peer reviewed paper on the issue. And, guess what, in this new paper they quantify it with a nice graph. It seems wind driven export of sea ice has been on the rise.
Dr. Roger Pielke Sr. writes:
New Paper “Recent Wind Driven High Sea Ice Export In The Fram Strait Contributes To Arctic Sea Ice Decline” By Smedsrud Et Al 2011
In response to the post
Peter Williamson alerted us to a related paper that highlights the major role of regional circulation patterns on climate (this time for the Arctic). The paper is
Smedsrud, L. H., Sirevaag, A., Kloster, K., Sorteberg, A., and Sandven, S.: Recent wind driven high sea ice export in the Fram Strait contributes to Arctic sea ice decline, The Cryosphere Discuss., 5, 1311-1334, doi:10.5194/tcd-5-1311-2011, 2011
Arctic sea ice area decrease has been visible for two decades, and continues at a steady rate. Apart from melting, the southward drift through Fram Strait is the main loss. We present high resolution sea ice drift across 79° N from 2004 to 2010. The ice drift is based on radar satellite data and correspond well with variability in local geostrophic wind. The underlying current contributes with a constant southward speed close to 5 cm s−1, and drives about 33 % of the ice export. We use geostrophic winds derived from reanalysis data to calculate the Fram Strait ice area export back to 1957, finding that the sea ice area export recently is about 25 % larger than during the 1960′s. The increase in ice export occurred mostly during winter and is directly connected to higher southward ice drift velocities, due to stronger geostrophic winds. The increase in ice drift is large enough to counteract a decrease in ice concentration of the exported sea ice. Using storm tracking we link changes in geostrophic winds to more intense Nordic Sea low pressure systems. Annual sea ice export likely has a significant influence on the summer sea ice variability and we find low values in the 60′s, the late 80′s and 90′s, and particularly high values during 2005–2008. The study highlight the possible role of variability in ice export as an explanatory factor for understanding the dramatic loss of Arctic sea ice the last decades.
The full paper is open access, and available here (PDF)
Another issue that should be looked at is the historic ice breaker traffic through this area. Has increased ice breaker traffic broken up the ice and made it easier to flow (be blown) south?
Nothing new here!
Marcel Leroux already explained this back then.
Looks like acknowledging credits is a tough entreprise in science even in our camp…
Ron Dean says:
June 21, 2011 at 3:57 pm
I read this post on Dr. Pielke’s blog with some interest. While I found the “it’s the wind” argument compelling, without comparing it to historic data, the wind argument itself really proved nothing. Since wind driven ice loss could have been the case also when ice was at recent decadal maximums, it could have been other factors responsible for the “record” declines. One needs to compare wind driven losses for the past and the present in order to get a handle on whether this is a factor in declines, or whether it is just a constant that does not change what causes minimums and maximums.
This paper gives credence to the theory that the minimums may be a result of wind, and not temperature (atmospheric or water). Very good read.
______
That wind and ice export through the Fram Strait change over time (and may have increased during the period in question) is hardly something new and has been studied for quite some time, but the notion that wind and ice export explains ALL the sea ice changes in the Arctic seems to be a favorite among skeptics. There is just one slight problem with this idea…and that has to do with the fact that permafrost is melting as well, and it’s really hard for the wind to get underground to melt that permafrost. And the melting of permafrost makes sense if you believe the data that shows a gradual arctic warming of both air and water over the past few decades. If you believe the data, then you can easily see how the permafrost could be melting, and the sea ice declining, and it all would not preclude the data that shows wind and ice export through the Fram strait could also be increasing. All these events could have a related cause such that their simultaneous existence makes sense. But no matter your perspective on AGW and the long-term sea ice decline, at least understand that many factors are at work in the dynamics of causing this decline, and while export of ice and wind explains part of it, it is only part, and widely misses the mark of explaining the many changes going on in the Arctic.
“I am a bit startled at the idea that this wind theory is a new revelation.”
It isn’t. But anyone could make that mistake from reading the top post. Anthony’s post gives the impression that scientists studying the cryosphere haven’t considered the possibility that winds influence sea ice extent. But that’s nonsense. The following quote is from NSIDC’s introductory page on sea ice
http://nsidc.org/sotc/sea_ice.html
The influence of wind on sea ice extent is also discussed on other pages, including NSIDC’s FAQ section, and you can read about it in numerous publications.
“So its taken us 200 years to catch up with the on the spot observations of our ancestors”
No, but it does take time to unlace misrepresentations of scientific understanding.
The lead author of the paper cited above, and one of the co-authors, projected in 2008 that the Arctic would be 95% ice free in summer by about 2050.
http://folk.uib.no/ngfls/mypapers/Smedsrud08.pdf
I wonder if their new paper would amend that projection.
Anthony, anyone interested.
Listen. Very good website
http://www.kingworldnews.com/kingworldnews/Broadcast/Entries/2011/6/23_William_Houston_.html
regards