The essay below is a result of some collaboration between Jeff Condon and myself. I’ve been wondering for quite some time if there was any trend difference between the truly “arctic” sea ice inside the Arctic Circle and the ice in the Hudson bay and other more southerly sea areas that really aren’t part of the Arctic, but that are included in sea ice measurements. I had noted in a previous post that “Dr. Walt Meier of NSIDC in an email exchange said that he agrees that the orange boundaries (in the graphic at left) are “somewhat arbitrary” and has agreed to explore a “what if” question for me.” Unfortunately, Dr. Meier hasn’t gotten around to it, but Jeff Condon, who recently did an impressive record-long sea ice video from raw NSIDC data had the time to run my request. One thing I noted, is in the graph he produced “Arctic Circle Sea Ice Area Anomaly“, that the variability was high until 1998, then variability was muted with a downturn, and then went highly variable again in 2007. Curious. Thanks Jeff! – Anthony
Comparison of Northern Hemisphere Perennial and Seasonal Sea Ice
Guest post by Jeff Condon
We have been looking at sea ice trends below the arctic circle at the request of Anthony Watts. It is a curiosity of his that he’s been asking Walt Meier of the NSIDC to consider for some time. I am a fan of the NSIDC because their data access is excellent and they answer questions very quickly and reasonably. This post is from the daily sea ice data as presented by the NSIDC on their FTP site. It is several gigabytes so if you are serious, fileZilla is a good free software to facilitate download.
From the video’s produced, it is apparent that a lot of noisy data exists at the extreme lower edge of detection. This data results in sea ice being detected in isolated squares of warm latitudes with no chance of having actual sea ice. The effect is visible in this video showing both poles through the history of satellite ice data.
You can see the great lakes around Michigan sparkle year round with sea ice detection noise yet we know that the beaches in July and August are 90F and and the only ice you will find would be in someones drink. So the false detection at the low end of the microwave sensor range is a known factor. Plotting the sea ice area outside of the circle above, we can see that the sea ice never quite hits zero. It gets pretty close though.
It is interesting that the minimum value has a shift at about 1998. Fluctuations in the minimums don’t seem to have much trend so I assumed the effect is instrument related. There are a number of different instruments on different satellites which have been combined to create this trend.
There is a statistically significant trend in the sea ice outside of the arctic circle. This ice is completely melting as expected every year so the trend we see is a result of reduced formation. I’m curious now what percentage of this new formation is in the open sea vs landlocked lakes but that will be a subject for a future post.
The Arctic trend shown next is comprised of everything above the arctic circle.
The trend is also significantly negative.
For confirmation of the above, these results differ very little from the UIUC cryosphere page. UIUC does infill the pole hole with estimated data whereas I simply leave it out. The pole hole is the region around the pole where the satellite instruments do not reach. This region changed size early in the record leaving some difficult choices as to how to handle the newly available data. I simply used the large mask throughout the record when creating trends. My trend may be slightly more negative than theirs due to the difference but the fractional differences are very small.
The purpose behind some of this work was to determine what percentage of the above trend is seasonal ice unrelated to polar cap melt. Taking 152000km^2/decade of seasonal ice out of the 518000km^2 total, that amounts to 29% of the melt trend is due to ice which, in the last 34 years, is completely seasonal in nature. Arctic circle ice also melts every year so it is a mix of seasonal and perennial (multi-year) ice. The ratio of the seasonal ice 152000 to the mixed seasonal/multiyear ice 366000 is 41% – not sure what use that is but it is interesting to consider that the multi-year ice loss is quite a bit less than these graphs show.
This next graph requires some interpretation. It is a ratio of the seasonal ice area outside the Arctic circle to the ice inside the Arctic circle.
In looking at this plot, I read it by observing the annual peaks only. There is a visibly evident trend in the peak values each year. This means that the peak seasonal ice is decreasing at a higher rate than the perennial Arctic peak ice. This seems to be a confirmation of gradual warming processes controlling the peak amount as we would expect the southerly ice to show the effects first. One problem with this graph is that it reads near zero during the time of greatest melting so we really only have good information at the peaks.
More work needs to be done. The next thing I want to do is look at landlocked ice to see if there are trends in satellite detection ability. After that, I have some new ideas to isolate whether the 2007 and 2010 arctic minimums were localized effects caused by ocean currents or if they were larger in scope.
My focus on this now is because the data is interesting and extensive and I haven’t seen much work done on regional effects in blogland. I am very much skeptical that we should be worried about any of this. If you add up all the sea ice in the world, we have a heck of a lot of it at any given time. About 19million Km^2 on average. If you take the global anomaly and offset it by the average amount, it gives a good idea what the sea ice death spiral is working out to be.
This data was compiled from the daily Ease grid files presented by the NSIDC. Code for this post his here. ice code Save it and change the extension to R as WordPress won’t allow upload of text or R files. It is written in several sections: functions, Northern hemisphere ice, Southern hemisphere ice, plotting calls etc. Authors of the various parts include RomanM, RyanO, Nic, Steve McIntyre and myself. Nearly all of their work has been modified so many times by me they may not recognize it but still deserve credit for the good parts. Any errors are my own.
As WUWT’s own Willis Eschenbach often says: “Citation please!” 🙂 🙂 🙂
Concerns? Definitely so.
“Most of the scientific world arguing forcefully?”
Uhhh … absent a citation, perhaps it is rational to be skeptical of this recollection?
A physicist says:
February 6, 2012 at 5:57 pm
From Wikipedia, not the most reliable but the easiest to find
Research
Current research into Lake Vostok involves attempting to drill through the ice into the lake. Doing so is controversial, due to concern that the lake could become contaminated.
Ice cores
Researchers working at Vostok Station produced one of the world’s longest ice cores in 1998. A joint Russian, French, and United States team drilled and analyzed the core, which is 3,623 meters (11,886 ft) long. Ice samples from cores drilled close to the top of the lake have been assessed to be as old as 420,000 years, suggesting that the lake was sealed under the ice cap 15 million years ago. Drilling of the core was deliberately halted roughly 100 meters (300 ft)[39] above the suspected boundary where the ice sheet and the liquid waters of the lake are thought to meet. This was to prevent contamination of the lake from the 60 ton column of freon and kerosene Russian scientists filled the borehole with to prevent it from collapsing and freezing over.[13]
From this core, specifically from ice that is thought to have formed from lake water freezing onto the base of the ice sheet, extremophile microbes were found, suggesting that the lake water supports life. Scientists suggested that the lake could possess a unique habitat for ancient bacteria with an isolated microbial gene pool containing characteristics developed perhaps 500,000 years ago.[40]
In November 2010, when the team allegedly came up with new, ecologically-safe methods of probing the lake without contamination, the scientists submitted a final environmental evaluation of the project to the Antarctic Treaty System’s environmental protection committee and were given the go-ahead to sample the ancient waters. In January 2011 the head of the Russian Antarctic Expedition, Valery Lukin, announced that his team had only 50 meters of ice left to drill in order to reach the water.[1] The researchers then switched to a new thermal drill head with a “clean” silicone oil fluid to drill the rest of the way.[41] Instead of drilling all the way into the water, they would stop just above it, when a sensor on the thermal drill detects free water. At that point, the drill will be stopped and extracted from the bore hole, thereby lowering the pressure beneath it and drawing water into the hole and left for quite some time to freeze, creating a plug of frozen ice in the bottom of the hole.[42] Finally, next summer, the team would drill down again to take a sample of that ice and analyze it.[1][43] Drilling stopped on 5 February 2011 at a depth of 3,720 meters (12,200 ft) so that the research team could make it off the ice and onto the last flight before the beginning of the Antarctic winter season. The drilling team left by aircraft on 6 February 2011.[44] The Russians resumed drilling into the lake in January 2012, and on 6 February 2012 announced that they had reached the upper surface of the water.[5]
A physicist says:
As WUWT’s own Willis Eschenbach often says: “Citation please!”
Well, this only puts you in the same camp with a “reformed cowboy who never inhaled.”
I am all for WUWT but don’t have anything in common with the foul-mouthed Mr. Eschenbach.
He is not “WUWT’s own,” he is his own, and full of it.