By Steven Goddard
The quest for the Holy Grail.
I have been looking for a reliable early predictor of September area/extent based on June ice data, and have found it – almost. Previously I established that current extent is a useless predictor, prior to August. The reasons for this are :
- Extent tells you nothing about thickness
- Many areas currently covered with ice, will normally have almost none in September (Hudson Bay, Barents Sea, etc.)
I eliminated the second issue by reducing the region of interest to the area shown in white below. That area corresponds approximately to the maximum extent of September ice in the 30 year NSIDC record.
Then I tried three different metrics to compare June 6 ice parameters vs. September extent and area, for the decade 2000-2009.
The first parameter was June 6 ice area. As expected, this correlated very poorly with September extent and area. The rsq value of June 6 ice area rankings vs September extent rankings is 0.02. The rsq value of June 6 ice area rankings vs September area rankings is 0.07.
The next parameter for comparison was June 6 ice volume (calculated from PIPS) vs September extent. This correlated much better. The rsq value of June 6 ice volume rankings vs September extent rankings is 0.22. The rsq value of June 6 ice volume rankings vs September area rankings is 0.37.
The final parameter for comparison was June 6 average ice thickness (calculated from PIPS) vs September extent. This correlated the best. The rsq value of June 6 average ice thickness rankings vs September extent rankings is 0.28. The rsq value of June 6 average ice thickness rankings vs September area rankings is an excellent 0.65.
So it appears that we have found a reliable predictor of September extent based on June ice thickness, which makes sense from a physical point of view. But it isn’t perfect! The graph and table below show the problem.
Average thickness on June 6, 2010 is 2.55 metres. The table below shows the June 6 rankings for the last 11 years. 2010 is in 7th place, behind 2006 and ahead of 2007, 2003, 2009 and 2008. Average thickness is more than half a metre thicker than 2008.
Date Average Thickness 6/6/2004 2.95 6/6/2005 2.87 6/6/2001 2.86 6/6/2000 2.84 6/6/2002 2.76 6/6/2006 2.68 6/6/2010 2.55 6/6/2007 2.54 6/6/2003 2.5 6/6/2009 2.17 6/6/2008 1.96
Everything in that table makes sense, except for 2007. Ice thickness in the central Arctic on June 6, 2007 was nearly identical to 2010 and the top year – 2003.
Conclusion : Based on current ice thickness, we should expect September extent/area to come in near the top of the JAXA rankings (near 2003 and 2006.) However, unusual weather conditions like those from the summer of 2007 could dramatically change this. There is no guarantee, because weather is very variable.
No doubt some people are wondering how this can be true, given that extent is currently lowest in the record. The reason (again) is that June extent has almost no correlation with September extent. Imagine an ice cube floating in water. It occupies a much smaller area of water than a ground up ice cube. But which one melts faster? The ground up ice cube will of course melt faster. Having a wide extent in June is not necessarily a good thing, unless the ice is also thick.
Sea surface temperatures continue to run cold in the Northern Pacific. They also are cooling down some in Atlantic.
http://weather.unisys.com/surface/sst_anom.html
Arctic temperatures have been running cold for the last week or so.
From: http://www.esrl.noaa.gov/psd/map/images/fnl/sfctmpmer_01a.fnl.anim.html
http://ocean.dmi.dk/arctic/meant80n.uk.php
There is no indication of melt in the ice off Barrow, with ongoing cold temperatures and the deepest snow of the winter.
http://seaice.alaska.edu/gi/observatories/barrow_sealevel/brw2010/BRW_MBS10_overview_complete.png
Ice continues to look very concentrated in the Arctic Basin, as seen in this enhanced satellite photo.
http://ice-map.appspot.com/?map=Arc&sat=ter&lvl=7&lat=67.940426&lon=-168.991006&yir=2010&day=149
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The disparity between ice indices continues to widen.DMI has 2010 ahead of 2007 and 2008. Other indices have 2010 lower. Given the analysis above, these numbers are relativelymeaningless this early in the summer.
The modified NSIDC graph below shows a comparison of 2010 ice extent vs. 2007. Areas in green have more ice than 2007. Areas in red have less ice.
The modified NSIDC map below shows ice loss since April 5, in red.
The modified NSIDC map shows changes in Arctic ice over the last week, using the same colour scheme.
The modified NSIDC image below shows the current anomaly. Areas in red have less ice than the 30 year mean, and areas in green have more ice.
Those of us betting on September recovery need to hold our nerve, but I think we’ll still win.
Excellent. If you want to play with multiple regressions, you might try the average Arctic temp as a second variable.
If you qualify r^2=0.65 as being excellent (for climatological studies) I might just accept it.
Back in my experimentalist days, anything less than 0.90 was more or less considered random chance. Granted that compared to the GCM, 0.65 is impressive.
Steve, just want to congradulate you on your continuing quest for the scientific answer. I am really enjoying watching your (and thanx to you mine) journey to better knowledge of this part of the system.
Thanx for sharing!
“Everything in that table makes sense, except for 2007. Ice thickness in the central Arctic on June 6, 2007 was nearly identical to 2010 and the top year – 2003.”
Exactly. Ice had already started recovering before the wind anomaly in 2007 pushed so much old ice out into the Atlantic. That event was very fortunate for the AGW crowd as it gave them a data point that could be spun that actually had nothing at all to do with temperatures. They could point and say “the Arctic is MELTING” when it wasn’t “melt” at all; at least not melting in the Arctic.
Dropping. Like. A. Rock.
http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent_L.png
http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Area.png
http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png
http://iup.physik.uni-bremen.de:8084/amsr/ice_ext_n.png
I’m curious why you convert ice extent, volume, and thickness measures into ranks, before taking correlations. I would think the raw metrics could give a clearer view of their possibly nonlinear relationships.
I see more variations from supposedly reputable sources on both thickness and extent of Arctic sea ice than I can track. The U.S. Navy seems to be saying it’s now thicker than ever while Goddard’s chart indicates it is thinner than in 2004. Al Gore (whom I exclude from the aforementioned “credible” sources) says the ice is almost all gone and British “pretend explorers” almost froze to death two years running while trying to climb over great mounds of the stuff between themselves and the North Pole while reporting that Gore was right.
The whole subject has degenerated into a Tower of Babel.
A bold and reasoned prediction, Sir! If only to stem an unwelcome return of 2007 portentous wailings, I truly hope you hit the target.
Steven,
As the german soldier character portrayed by Artie Johnson on Laugh In used to say “Verrrryyy Interesssting!”
My recollection is that persistent currents and/or winds drove large masses of old, thick ice out of the arctic polar region in 2007. What was the underlying root cause of those less common persistent currents/winds? Can they be predicted and subsequent minimum ice extents anticipated as well? Is it possible that a similar purge of arctic polar ice into the north Atlantic shipping lanes in 1912 contributed to the sinking of the Titanic?
Discussion of polar ice and global warming remind me of a favorite poem:
Fire And Ice, by Robert Frost.
Some say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.
Thanks again for your continued efforts and enlightening post series on polar ice variables!
Anu,
I take it from your comment that you didn’t read the article.
Frederick Michael
The interesting thing about 2007 is that temperatures north of 80N were below normal much of the spring and summer.
http://ocean.dmi.dk/arctic/plots/meanTarchive/meanT_2007.png
Certainly more useful than my usual recommendation to check back in September. 🙂
Nice to have something that we can attach numbers to.
Also note that “extent” can be more of a proxy for wind than for temperature. If the wind blows the ice up against one of the continental land masses (North America or Eurasia), then it can compact the extent to a considerable degree without much loss in ice volume. It is just thicker ice that covers a smaller area.
I am just not convinced of the value of Arctic “ice extent” as it seems to me to be more if a wind proxy than anything else. Antarctic ice extent would seem to me to be more of a temperature proxy than Arctic extent is.
>>Arctic temperatures have been running cold for the last week or so.<<
The Arctic temperature, especially North of 80 degrees North, will drop when the melting starting, all the heat is sucked out of the atmosphere… because of the heavy melting… the opposite happend when the ice starts freezing, heat energy is released to the atmisphere.
see http://ocean.dmi.dk/arctic/meant80n.php
Temperatures below average (high melting) and temperature above average (low melting) in the melting season (day 150-250)
Kind regards from Greenland
S.E. Hendriksen
Are you suggesting that the ice started melting at minus 8C two weeks ago?
It would be interesting to see how surrounding ocean temps and wind direction relate to past years as well. Perhaps that would explain 2007.
Anu says:
“Dropping. Like. A. Rock.”
You make Steve’s point. The current extent is on par with 2006–on target to be one of the highest minimums come September–and yet you are talking about the raw numbers. I hope you are still around then and wonder what your explanation is going to be.
Anu says: June 6, 2010 at 12:58 pm
“Dropping. Like. A. Rock.”
How about that Antarctic Sea Ice Area and Extent?
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png
http://nsidc.org/data/seaice_index/images/daily_images/S_stddev_timeseries.png
http://www.iup.uni-bremen.de:8084/amsr/ice_ext_s.png
And Global Sea Ice Area appears to be above average at the moment:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg
Claude Harvey says:
June 6, 2010 at 1:06 pm
I see more variations from supposedly reputable sources on both thickness and extent of Arctic sea ice than I can track. The U.S. Navy seems to be saying it’s now thicker than ever while Goddard’s chart indicates it is thinner than in 2004. Al Gore (whom I exclude from the aforementioned “credible” sources) says the ice is almost all gone and British “pretend explorers” almost froze to death two years running while trying to climb over great mounds of the stuff between themselves and the North Pole while reporting that Gore was right.
The whole subject has degenerated into a Tower of Babel.
You are exactly correct. That’s a great non-scientific conclusion! And that huge variance you speak of, if put into numbers and proper frame, can be used to prove scientifically there is no underlying true science on Arctic ice exists but from the Navy! Someone should have at it.
This wind energy that strews the current Arctic Ice introduces ‘heat’ to the region as the Sea Ice melts.
When winter comes, the water freezes, and the heat energy (originally from the excessive winds) escapes to space.
That would be the opposite of AGW, losing the energy to space and cooling the Earth.
I think Joe Bastardi sort of alluded to that in one of his videos on accuweather.com.
So, for Earth’s warmth sake, I do hope your prediction for a less than record melt holds.
AGW has it back-asswards.
I’m still looking to see if a La Nina is really happening. If so the Alaska area should melt slower than usual.
How about that Antarctic Sea Ice Area and Extent?
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png
What the Arctic will be doing next winter, if the hopscotch effect of the last few years holds.
@Steve Goddard
Steve… no of cause not, but when the seawater temperature is above -1.5 C it starts melting… you will see the same pattern for the last 50 years, from around day 150 it starts.
The sun radiation is strong now, even North of the 80th, and there is a lot of surface melting. On the Ice Cap the local Government cancelled all expeditions accross the Ice Cap for 2010, huge freshwater lakes and meltwater rivers (up to 100 meters width)
But nothing unusual…it happends every year…. but this May was about +5 C warmen than normal and finally…the temperature North of 80 degrees North is not messured, but calculated (interpolated) from very few (4-6) weather stations, North of the 80th.
The ‘Great Ice’ along the East-Coast and in Southern Greenland is similar to 2007, travelling South and melts
http://www.dmi.dk/dmi/en/gronland/iskort.htm
Anu said:
Anu said:
Dropping. Like. A. Rock.
http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent_L.png
http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Area.png
http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png
http://iup.physik.uni-bremen.de:8084/amsr/ice_ext_n.png
_____________
Thanks for the update Steve, and thanks to Anu for the other links.
And in the dropping like a rock category, I would also add:
http://psc.apl.washington.edu/ArcticSeaiceVolume/images/BPIOMASIceVolumeAnomalyCurrent.png
But of course, most of the AGW skeptics want to discount the PIOMAS model in favor of Steve’s PIPS 2.0 model (remember, both are models), even though the newer CICE based model includes projections for better ice dynamics that include the mass of ice contained in pressure ridges, etc. and up to 40% of the mass of sea ice can be contained in these ridges. PIOMAS includes that information.
I certainly can’t fault the process of Steve’s analysis, for the process seems sound enough, but I would fault the data being used. It’s clear from previous posts that I hold very little stock in the accuracy of PIPS 2.0, but I also have a problem with the Unisys temperature anomaly. Compare that chart with this one:
http://iridl.ldeo.columbia.edu/maproom/.Global/.Ocean_Temp/Weekly_Anomaly.html
And I think you’ll see a big difference…especially in the temperatures in the N. Atlantic, which have been running warm and continue to do so.
So, in general, if you believe Steve’s PIPS 2.0 model data, you’ll probably tend to believe his projection for the September low, and if you believe PIOMAS, and the other sources that I tend hold to, you might be pursuaded that we could see a September low approaching close to the 2007 level. I would like to point out that I first began making my projection that the September low would be lower than 2008 or 2009 back in March, when all the noise was being made about the “bump up” in sea ice extent as it made a run at getting almost back to normal. I knew this short bump up in ice at the end of the season would have to be thin, and would melt just as quickly, so I discounted it, and sure enough, we saw one of the most rapid early season melts on record as the sea ice extent went from one of the highest in th e past 8 years to the lowest in just over a month.
Steve is right…sea ice volume is the better predictor than extent, and September will tell the story…and at least we’ll know whose data to discard, and so it will be useful one way or another.