This week was a true roller coaster ride with Arctic Sea Ice. It is best summed up by looking at the JAXA graph for extent, shown below:
Below, see the area of interest magnified.
I’ve added the 5 million square kilometer line for reference.
The roller coaster ride actually looked for a day like it might cross the 2009 line, but soon turned down again, ending this week at 5,142,813. Here’s the recent JAXA data
08,28,2010,5342656 08,29,2010,5352500 08,30,2010,5348281 08,31,2010,5329375 09,01,2010,5332344 09,02,2010,5304219 09,03,2010,5245625 09,04,2010,5192188 09,05,2010,5142813
Source: http://www.ijis.iarc.uaf.edu/seaice/extent/plot.csv
JAXA sea ice area has dropped to 2008 levels:
JAXA AMSR-E Sea Ice Area – click to enlarge
Sea ice concentration from JAXA:
While JAXA shows extent now lower than 2009, DMI and NANSEN plots show it to be about even. The differences in observing sensor/platform AMSRE -vs-SSMI and methodologies at agencies are in play.
Above: Danish Meteorological Institute Arctic Sea Ice Extent – 30% or greater. Note that while this graph shows 30% concentration at the cutoff point, it is valuable to compare.
Above: NANSEN Artic ROOS- Sea ice extent 15% or greater – click for larger image
The differences appear to be in the low end of concentration, the 15% to 30% range. It suggests that the brief gains we saw may be wind related, blowing floating ice around, compacting it when winds are strong versus allowing expansion when winds are weak.
Temperature, after holding near freezing, now appears headed sharply downward.
Above: Danish Meteorological Institute – Mean Temperature above 80°N
Some light refreezing may take place before the end of September, which could minimize the ability of wind to sharply change extent like we saw recently.
With all these variables in play, choosing a winner will be as much a game of luck as of skill. Based on what we’ve seen, it seems probable that it will come from the middle of the pack between 2008 and 2009.
From SEARCH:
The estimates from the scientific community range from 4.0 to 5.6 million square kilometers, with 8 of the contributors suggesting a September minimum below 5.0 million square kilometers, 3 contributors suggesting a minimum of 5.0 million square kilometers, and 5 contributors suggesting a September minimum above 5.0 million square kilometers. Two contributors forecast a September minimum below that of 2007 at 4.0 million square kilometers and 3 contributors suggest a return to the long term downward linear trend for September sea ice loss (5.5 to 5.6 million square kilometers). None of the contributors indicate a return to the climatological sea ice extent of 6.7 million square kilometers.
Including all 18 contributions gives a September ice extent minimum of 4.8 +/- 0.77 million square kilometers, with a range of 2.5 to 5.6 million square kilometers.
Individual responses were based on a range of methods: statistical, numerical models, comparison with previous observations and rates of ice loss, or composites of several approaches.
latitude:
“I agree
If you don’t look at the extremes, and only look at May, June, July and Nov, Dec, Jan,”
you realize that the ice is threshholded by geography in certain months. That is there is max extent to which it can grow. so you have to take care to account for that.
Tom in Texas says:
September 6, 2010 at 2:55 pm
I would also like to plot the DD data myself.
DMI does not have it’s numerical data available, but you might ask them.
What you see is a result of careful image processing to stack all years up.
It took tedious work to get the 2008, 2009 and 2010 graphics to blink correctly with 1958-2007, because DMI has altered their timeline ticks and legend, which stretches the later years up and includes part of the next year.
NeilT says:
September 6, 2010 at 1:48 am:
Mike, you are completely missing the point.
As usual.
Yes the sea ice will return every winter even after there is none in summer. However the impact of a summer absorbing sunlight instead of reflecting it, on the warming of this planet, will return many millions of us to dust much, much sooner than would normally be the case. [Don’t you care!]
Neil, your “sensitivity” to all those Humans is what impresses me. So tell me what you have done in your personal life to lower your own personal CO2 “footprint”?
While the Indians and Chinese are massively increasing theirs.
latitude:
“The middle is where you would look for a trend not effected by weather.”
depends.
Read this to understand why measures by area and extent are not the best thing to look at because of geography constraints, So just be wary of potentially rash statements about ‘where’ one looks and how one looks.
In general I think discussions about the ice are a trap for both sides. slippery stuff and subject to many issues unrelated to the warmth increase we will see from GW.
http://tamino.wordpress.com/2010/08/22/on-ice-with-a-twist/#more-2989
my advice is to practice good scepticism. If your opponent claims he can predict the ice, steer clear of any kind of competition with him. If you best him its only by luck. when the best science gets it hugely wrong ( in some years) its best just to sit back and let them be wrong again. Some however insist on following CAGW types in a run for the ice. The state of the ice says little about the truth of AGW one way or the other. Same with the hockey stick. So, its best just to engage in a critical exercise. That’s just a suggest. But people will continue to think there is something to be ‘won’ by trying to do ice science better than best. Not much hope for them.
I do know that Mosh. Arctic ice has to float some where.
Wind, clouds, currents, etc all things you might consider “weather” effects the highs and lows.
Growth or melt does not seem to effect it. Even when it’s had a growing year, back to the set point in May. When it’s had a melting year, back to the set point in Dec.
Each time, no matter how high or how low, it strikes that middle point around May and again in Dec. Almost so close each time that it could just be within the margin of error.
It has not done that.
Thanks Mosh
Smokey:
“If CO2 was the cause of melting ice, Antarctica would also be melting. It’s not.”
As far as I can tell the theory makes no definitive statement about ice in the Antarctic. increasing C02 causes warming.
For example in 2004 this was the state of the art:
“Forecasts of Antarctic sea ice variation are very much in demand, not only because of the potential importance of sea ice in global climate, but also for the practical purpose of exploring the Antarctic continent. However, such forecasts are not presently feasible with any state-of-the-art GCMs, since the complex ice-air-sea interaction processes are still not well understood and by no means well simulated by these models. The alternative is then to apply statistical methods to Antarctic sea ice prediction. The linear Markov model described here represents one of the first attempts in this previously untravelled territory. ”
It would be interesting to se what the theory predicts now. BUT you cannot falisify a theory that makes no claim about antarctic ice, by appealing to antarctic ice. that’s just a logic fail. Its like this. No GCM can predict the temperature in my shoes. None attempt this. Pointing out that my shoes are cooler than mean or full of ice, therefore says nothing about the models or the theory they embody.
Look there is plenty to criticize about the predictions that the models DO make.
But perhaps this IS an open question. What do the models predict about ice down south? Note of course that they can get this wrong and still be right about other things. In fact, by its very nature a GCM is likely to make all sorts of predictions that will be “wrong.” and it will still be right about others. Which means of course that the whole is not fully understood ( never will be) but that’s hardly a convincing argument to reject those predictions that are right. Our dilemma is this: will it continue to be right in the future about things it was right about in the past?” tougher question. But you only get to ask the toughest questions by accepting some of the truth.
Steven Mosher says:
September 6, 2010 at 3:35 pm
As far as I can tell the theory makes no definitive statement about ice in the Antarctic. increasing C02 causes warming.
It doesn’t have to. The theory is that the Earth is warming because of a trace gas. The Earth does not consist of a single hemisphere, where the proof of Global Warming is found in the Arctic. Smokey is right to question on the basis of the entire Earth.
I question the validity of a theory that uses a single hemisphere to make its case.
As far as I can tell, that case has not been made, and there is no need to continue taking seriously that which is not proven beyond the Null Hypothesis.
Re: Steven Mosher on September 6, 2010 at 3:19 pm
Great. Just great. The site lost one of its two headliner acts who went off to run his own blog, while the other had to take a brief break. The Wikio rankings dropped, #2 spot being lost to a ranting “godless liberal.” And now the “lukewarm” Goddard replacement is directing traffic to Tamino’s site, where he is (luke?)warmly received for his views.
Forget CAGW, we have enough signs of IMPENDING DOOM!!!
Espen says:
September 6, 2010 at 5:40 am
NeilT I don’t think your argument about reflectivity is valid until the sea ice melts already in June.
++++++++++++
Espen I agree with this perspective. Darker water is a great deal more effective at radiating heat than white ice. Why is more not made of the temperature of the Arctic ocean then? If the absence of ice creates a much warmer ocean, supposedly, does the darker ocean cool much more rapidly than one covered with a sheet of ice? Sunshine reflects very efficiently off water at a low incident angle. That is how you get sunburned under an umbrella. The light ice/dark water theory seems a little thin at the edges. At the Autumnal equinox the nocturnal heat loss from the surface is surely an order of magnitude greater than the gain during the day. Even when it is covered in ice there is a large net loss of heat from the polar regions.
An old ice-coated igloo is much warmer than a new one. Ice floating sheets insulate the ocean underneath from the much colder wintry air.
There’s something that’s bothering me. R Gates provided the link to the following graph that shows arctic extent anomalies back to 1953:
http://nsidc.org/sotc/images/mean_anomaly_1953-2009.png
It clearly shows an almost straightline downward trend since 1969, which would imply that CO2 is not the major factor in that trend (there’s no real change in the rate, despite increasing levels of CO2).
But what interested me was the earlier part of the graph. We know from photographic evidence that the ice at the North Pole was very thin in 1958/1959:
http://wattsupwiththat.com/2009/04/26/ice-at-the-north-pole-in-1958-not-so-thick/
But that graph shows that arctic sea ice extent anomaly well above what it currently is, and I believe that ice at the North Pole at the moment is still too thick for a submarine to surface.
This inconsistency has me wondering how the sea ice extent anomaly for the 1950s and 1960s was calculated? The NSIDC web site has the following:
http://nsidc.org/arcticseaicenews/faq.html#presatellite
That lead me to the page where the original graph was located:
http://nsidc.org/sotc/sea_ice.html
And the caption on that graph says:
So the graph is two data sets joined together. The first data set, 1953-1978, shows very little in the way of trend. The 1979-current section (which I would trust as being more accurate, given the consistency in how it is measured) shows an immediate drop followed by a downward trend.
My conclusion from this is that the first half of the graph is probably measuring differently to the second, and may not show the same trend as the satellite data. If we had satellite data from the 1950s and 1960s, I suspect it wouldn’t match what the graph shows… especially during the times when we had submarines surfacing at the North Pole. Thus, that graph does not provide any evidence of a change in sea ice extent anomaly behaviour because the change shown is too close to when the change in data set takes place.
Today 2010 has 2009 beat leaving the Goddard Minimum way far behind.
Let’s look at the standings.
2003 Min.: 6,041,250: Busted 8/14/10
2004 Min.: 5,784,688: Busted 8/19/10
2006 Min.: 5,781,719: Busted 8/19/10
2002 Min: 5,646,875: Busted 8/22/10
Goddard Min: 5,500,000: Busted 8/26/10
2005 Min: 5,315,156: Busted 9/2/10
2009 Min:5,249,844: Busted 9/2/10
2008 Min:4,707,813: ???
This puts 2010 in the top three lowest sea ice extents in the JAXA record and there is still time on the clock.
FYI, Steve,
Maybe you shouldn’t brag about being accurate until the last bullet is shot.
Espen says: “NeilT I don’t think your argument about reflectivity is valid until the sea ice melts already in June. Now the arctic sun is already very low in the sky, at those angles even open water will reflect most of the weak sunlight.”
True. The reflectance of open water overlaps that of ice. Zenith angle is the most important factor. Other factors include wind, age and dust content of the ice, clouds, and sea water plankton content.
latitude,
From the NSDIC data, May shows a statistically significant downward trend (R^2 of .497) of 32,000 per year since 1979.
June shows an even more statistically significant downward trend (R^2 of .784) of 42,000 per year since 1979.
November shows a downward trend of 50,000 per year with an R^2 value of .670.
December shows a downward trend of 43,000 per year with an R^2 value of .776.
So measuring in the middle of the seasons shows a consistently downward trend in sea ice since 1979.
Gail Combs says:
September 6, 2010 at 12:13 pm
Thank you, Gail. I appreciate the help.
David Gould says:
September 6, 2010 at 6:03 pm
From the NSDIC data
=====================
David, ask three different snow and ice measurement thingys, and you will get four different answers.
Thanks for putting all that together, but I was really just asking about the graphs that Anthony put up, and why people were looking at the extreme high and lows, when it’s obvious those are weather, and not looking at the May and Dec set points, when it’s obvious that if more ice is created, it melts faster and ends up at that same set-point, if less ice is created, it melts slower and ends up at that same set-point and the opposite happens six months later, when if less ice melts it grows back slower to reach the same set-point, and if more ice melts it grows back faster to reach that same set-point.
(I’m competing for the longest run-on sentence 😉
Is that all we have to talk about? Data? Where is the mechanism folks? So far the discussion is about data with little in the way of information. No matter what the trend is doing, trend alone does not illuminate mechanism. For those of you who say the Sun caused this or that, please tell us how. And I mean in scientific and mathematical terms. For those of you who say that CO2 is whut dun it, please explain. For those of you who say warmer waters is whut dun it, please explain where and how you think these warmer waters came to be in the Arctic. If you say it was weather, explain the weather systems that produced the data. Otherwise this thread is devoid of scientific discussion.
jorgekafkazar says September 6, 2010 at 5:18 pm
Do you know of any papers that have specifically looked into this aspect and tied it to area about the pole? I’m interested in what seems to happen around the 6th and 11th of September from the 15% JAXA record. Of course that’s very short and noisy and it’s far to easy to imagine patterns in anything if you stare at it long enough.
Jeff P says:
September 6, 2010 at 5:12 pm
Correction note for you Jeff P: that should be Sept 3 for going below 2009.
-Scott
Pamela Gray says:
September 6, 2010 at 6:48 pm
Is that all we have to talk about? Data? Where is the mechanism folks? So far the discussion is about data with little in the way of information. No matter what the trend is doing, trend alone does not illuminate mechanism. For those of you who say the Sun caused this or that, please tell us how. And I mean in scientific and mathematical terms. For those of you who say that CO2 is whut dun it, please explain.
==============================
He won’t produce it because he can’t.
R Gates, sensing that he was completely out of his league…for the thousandth time…and as usual…slipped away like an eel out of the net.
Chris
Norfolk, VA, USA
David Gould says:
September 6, 2010 at 6:03 pm
So measuring in the middle of the seasons shows a consistently downward trend in sea ice since 1979.
======================================
So??
And when you combine that with the anti-death-spiral of the southern hemisphere ice…you get…..nothing.
Big ******* deal.
Moving on.
Chris
Norfolk, VA, USA
jorgekafkazar says September 6, 2010 at 5:18 pm
I forgot to mention … other interesting dates are May 6th and Nov 18th.
Graeme W says:
September 6, 2010 at 5:08 pm
So the graph is two data sets joined together. The first data set, 1953-1978, shows very little in the way of trend. The 1979-current section (which I would trust as being more accurate, given the consistency in how it is measured) shows an immediate drop followed by a downward trend.
===================================
Excellent sleuthwork, Graeme.
Two data sets joined together. Cut and paste. Cut and paste.
Where have we seen this before? “Hockeystick Syndrome”?
[Though admittedly not as bad on this one.]
Chris
Norfolk, VA, USA
Latitude, I’m not sure what point you are trying to make. Are you suggesting that it is only the mid-point that matters? So, a maximum of 50 million square kilometers and a minimum of 0 square kilometers is the same as a maximum of 15 million square kilometers and a minimum of 5 million square kilometers?
Your conclusion is most definitely incorrect. There does tend to be a convergence in spring and fall. This is due to the seasonal change in solar radiation as well as geography (the ice growth/melt moving out of and into the Arctic Ocean proper).
There are statistically significant declines of Arctic sea ice extent in all months and the annual average.
Walt Meier
NSIDC
Mechanism: CO2 warms and warmer conditions melt more ice than cooler conditions.
Seems pretty simple to me.
And before you say, ‘There’s been no warming in the Arctic,’ have a look at the UAH data here:
http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
The warming trend in the Arctic is 3 to 4 times the warming for the globe, with the Arctic ocean – where the ice is – warming even faster than that.