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.
It is an outrage that Gore has used sea ice variability in an effort to convince people that the “ice caps are melting.” I have an entire chapter on the ice caps in my book, an excerpt of which is here:
Old ice cannot accumulate at the North Pole, because the pack ice is in a constantly-moving train, on its way east and south toward the North Atlantic, where it eventually melts out. Calling the Arctic sea ice an “ice cap” during an interglacial is somewhat misleading. Unlike the “hard
hat” of land-bound glaciers in Antarctica, the Arctic sea ice is like a knit garment that is rapidly stitched together on its edges each fall and slowly pulled across the Arctic basin toward the relatively warm waters off southern Greenland. When the transited ice completes this trip,
the southernmost portion of it melts, principally in late summer. It can and does take some parts of the fabric as long as a few decades to make the trip, but, again, it is a highly variable amalgam of ice, some brand new and some older, that sits atop the Arctic Ocean each winter.
More here:
http://amzn.to/yLN0Zm
Good work. the video is sensational in the true sense of the word. Well done.
I would be interested to see the scientists who frequent realclimate, make a similar study, and what their conclusions would be. One could Hope those conslusions would not be Foregone ones.
I have always thought that they played around with the borders of if each NH ice section baltic etc, to fit the AGW agenda. You see that cannot be done with Antarctica because its one mass and voila! its not melting etc.
It is important to note several important relationships about the “geography” of the Arctic sea extents.
Current CAGW “theory” holds that Arctic sea ice is steadily and disastrously declining (even though total Antarctic + Arctic sea ice is steady), and that this decline is caused by increasing Arctic temperatures (“measured” supposedly in the interior of Russia-Siberia and Canada and extrapolated by NASA-GISS-Hansen over the Arctic by as far as 1200 km, and despite actual DMI Arctic measurements at 80 North showing average summertime temperatures at that latitude have been declining since 1958), and that such a decline in sea ice extents causes a catastrophic positive feedback of increasing ocean albedo and thus increasing heat absorption by the planet.
Despite these assumptions, these are a few relevant facts concerning Arctic sea ice, albedo, and reflectivity of light (warmth received from the sun) at low elevation angles. Note! All (well, almost all) of NASA-GISS-Hansen’s assumptions about sea ice impact are correct – but only if their sea ice feedback occurs down low at near the equator (between the tropics of Cancer and Capricorn)
Not at the actual location of sea ice up at the North Pole.
Let us look at a real view of what would happen if (suddenly and for no assumed purpose) all of the Arctic sea ice vanished one year. Would any positive feedback actually affecting the next year’s sea ice extent occur?
1. Today’s Arctic sea ice extents include vast areas of sea ice that melt regularly every summer. The minimum is reached in mid-September at just at 4.5 million sq km. The maximum sea ice extent is limited by the actual Canadian/Alaskan/Siberian and north Russian coasts surrounding the Arctic Ocean, Hudson Bay, Labrador/Greenland/Newfoundland estuaries and gulfs and channels. It is actually almost impossible to greatly increase northern sea ice “much” past the maximums of what is there now.
So sea ice maximums can’t expand much past where they are now – barring a full Ice Age. At which time the sea AREA itself greatly decreases because of land-based ice/glaciers mass increases -> sea level decreases – sea ice extents reduce, so the sea ice is more than replaced by land ice reflectivity.
2. Land ice is a greatly different story. But northern land ice – the summertime coverage of land ice extents is NOT the point of issue right now. Currently only the very small northern coast of Greenland is permanently covered by land ice – the rest of the north Arctic coasts are all barren wastelands of marsh and tundra during the summer. So what the Arctic land area summer time albedo is now – is what their summertime albedo will be in the future. Regardless of how far the Arctic sea extents are reduced in any year. To repeat – if all of the summer land ice is melting now, then, all of the future land ice in this scenario has also already melted when the sea ice vanishes.
No impact on global temperatures the current year, nor any in the next year.
3. At its summertime minimum, Arctic sea ice minimums are about 4.5 million km^2. This corresponds to a global “spherical cap” ranging from 79.2 latitude to the pole. In real life, the actual summertime minimums are actually nearly circular, but are slightly skewed to the side of the pole, but this is a very good approximation.
We are left then with the summer ice suddenly vanishing from the region of 80 north to 90 north. Since the minimum sea ice extent now happens in Sept, it is only possible that the vanished sea ice will disappear in Sept as well.
Temperatures by mid-October decrease rapidly to less than -20 C. Arctic air temperatures (now) in early September are at only +2.5 to +3 C. We MUST assume that the sea ice will begin re-freezing by mid-October.
If sea ice extents vanish in Sept, but are at their maximum in February- March (as now), then the minimum ice will be less in August than now, and such reduction must be accounted for, but in September – the critical month of 0.0 sea ice, ONLY the Sept sun conditions apply to the perceived “positive feedback” nightmare feared by the CAGW extremists.
So, let us focus on the potential “added” solar exposure of the Arctic Ocean north of 80 north latitude during the 2 weeks before, and 2 weeks after, the equinox – assuming, as above, that all of the ice vanished.
4. In Sept, the earth’s tilt with respect to the sun is 0.0 at the equinox (Sept 21-22 most years), and so there is NO “24 hours of summer sunlight”that can be asorbed. Sunlight (before and after the minimum at Sept 22) will be “only” 12 hours per day.
5. But available sunlight is even less. The maximum elevation angle of the sun is at local solar noon. At all other times of the day, the sun is lower in the sky, and passes through longer and longer lengths of the atmosphere to reach your eye (the surface of the ocean/land it might heat.)
At the equinoxes, at 90 north latitude, the sun’s maximum angle is no longer the 23.5 degrees angle of mid-summer (itself very small!) but 0.0 No sunlight is present at noon to heat the (now exposed) ocean surface.
At 80 north in mid-Sept, the lowest point of the region of interest (highest possible sun exposure) the sun is only 10 degrees above the horizon at noon. Sin of 10 degrees is .17, so only 17 percent of the rays (measured at top of atmosphere at the equator is the “disk earth model” so favored by the CGAW theory) can heat the newly-exposed ocean surface. And that percent declines quickly every minute before and after local solar noon.
6. Atmospheric masses. The sun ray’s at the pole at Sept 22 are trying to penetrate 806 km thick “atmosphere – assuming a 50 km high stratosphere. 16 atmospheric masses. At 80 north, there is “only” 273 km of atmosphere to absorb the rays: 5.5 atmospheric masses. Even down low at 70 north, the sun must penetrate 145 km (3 air masses) before it can hit the earth/land/ocean surface.
4.
The units for the slopes for three of the graphs appears to be wrong. On the y-axis, km^2 was plotted, but the slope units were in Deg C for the rise. (The “Decade” part was OK.)
It appears to be a degree of correlation between the extent of the Arctic’s summer see ice coverage and the tropical hurricanes
http://www.vukcevic.talktalk.net/AHA.htm
with about 15years delay . If link can be confirmed it would be a significant step towards further understanding of the climate change events.
“The purpose behind some of this work was to determine what percentage of the above trend is seasonal ice unrelated to polar cap melt.”
Why hasn’t this already been done by the “Professional” climate scientists?
Jeff may well prove that it is “worse then we thought” when it comes to the Arctic ice melt trend. But, I have to suspect that if it were, the alarmists would have already been adding into their scare tactics?
The 1998-2007 period is very interesting. It appears that there was a different weather regime existing in the Arctic that more consistently melted the ice and caused large net losses. Does anyone know of any studies that look at the differences in pressure, cloudiness, jet streams etc. for this period compared to before and after??
This is a wonderful post, Jeff and Anthony!
(the ice-area before climate change)
(the approximate year ice-melting began to accelerate)
(the rate of Hansen-style melting acceleration)
I wonder whether you (as yet) have fitted the data of your final figure (“Global Sea Ice Anomaly Offset by Average Global Ice”) to James Hansen’s acceleration function, per Hansen’s recent article Paleoclimate Implications for Human-Made Climate Change (an article that was much-discussed here on WUWT).
For fun, I did a by-eye fit of your data to the following three-parameter Hansen-type function (which generically describes the consequences of accelerating ice-mass loss):
These by-eye curve-fitting results were robustly in the following range:
When we plot these numbers, we discover that a Hansen-style acceleration fit to the Condon/Watts sea-ice data robustly predicts total loss of planetary sea-ice by the end of the 20th century.
This excellent agreement of skeptical-style curve-fitting with Hansen-style theory-driven prediction was very surprising and impressive (to me)!
For the general public, a key question is whether Hansen’s Seven Key Predictions of Warmism come true.
If these seven key “Warmist” predictions prove correct, then not only will the “Warmists” have (rightly) have won the day, but (far more importantly) the sobering severity of our planet’s climate-change challenge will be apparent to everyone, skeptic and nonskeptic alike.
Jeff and Anthony, that is why I urge you to be skeptical regarding the above calculation, and therefore, to verify for yourselves the predictions that are associated to a Hansen-style acceleration fit to your data.
Layman’s question….when the sun is at very low angles as mentioned above (RACookPE1978), won’t most of the light/energy simply reflect off the water?
“Jeff Id”… is that Jeff Condon’s “nom de plume” ?
A Farewell to Old Sea Ice
http://youtu.be/Co68_tod0dQ
Arctic Ice Flushing as seen by Satelitte AMSR-E 89GHz-V 6.25km from 20071001 through 20080318
http://youtu.be/gxxR3Q0AgQA
RACookPE1978 says:
February 5, 2012 at 8:26 am
Excellent post. Thanks. Once again, Hansen and crew report only half the equation.
I find it weird that you have missed what’s going on in Europe the last couple of weeks. More than 100 dead only in Ukraine.
Visually, it appears that there are periods of stability followed by a drop to a lower regime. For example in your Arctic Circle chart it appears relatively flat from 1995 to 2000 then drops until 2005 before stabilizing. The below the Arctic shows something similar from about 1995 until just before 2005. When the two are combined the flat periods aren’t as obvious. There seem to be others in the graphs as well.
As the Arctic ice extent winter max is largely constrained by the geography of the region, would it not be reasonable to assume that the negative trend would be steeper if that constraint did not exist?
RACookPE1978 says:
February 5, 2012 at 8:26 am
6. Atmospheric masses. The sun ray’s at the pole at Sept 22 are trying to penetrate 806 km thick “atmosphere – assuming a 50 km high stratosphere. 16 atmospheric masses. At 80 north, there is “only” 273 km of atmosphere to absorb the rays: 5.5 atmospheric masses. Even down low at 70 north, the sun must penetrate 145 km (3 air masses) before it can hit the earth/land/ocean surface.
—————————————————————————————————
Very good RACook. but as a sarc:
Hansen could take that thick atmosphere and run with it….
He claims the thick atmosphere and CO2 on Venus is what causes the runaway warming there.
Since the pole’s sunlight, at that time of year, must travel though such a thick atmosphere and multiples more of CO2, that, by the Venus example, is what is causing the warming and melting at the North Pole… See? sarc.
By that theory, the Arctic will be the first water to boil away… Polar Bear Tea anyone?
I wanted to add:
One can warp and misuse these theories (like Hansen’s) to extremes to suit one’s purposes and mislead and misdirect everyone like a magician…
Until the facts, real science, and reality “get in the way”, that is…
Cringeworthy article in the Independent yesterday from one of the usual suspects …
http://www.independent.co.uk/news/science/science-behind-the-big-freeze-is-climate-change-bringing-the-arctic-to-europe-6358928.html
So what happened to cause the shift in 1998?
akehig says:
February 5, 2012 at 9:34 am
Layman’s question…when the sun is at very low angles as mentioned above (RACookPE1978), won’t most of the light/energy simply reflect off the water?
The answer is … Yes.
But it depends on the amount of cloud cover assumed, and types of cloud cover, and altitude of the cloud cover. (See Herman and Curry, 1984; Warren, 1982; Curry and Ebert, 1992; Curry and Schramm 1994; Schramm Holland and Curry, 1997; Curry and Schramm, 2001 for examples of the assumptions and measurements – for what little actual data covering how few weeks there is actually collected that far north.)
You are probably familiar with the following, but to repeat for others’ benefit. Emissivity is the ratio of what (thermal) energy is actually emitted from an “average” surface compared to a perfect black body surface at the same temperature. Albedo is – thermally speaking – the opposite: the ratio of what an average body reflects compared to what it shined on that surface. Both are significantly variable with respect to wavelength of the radiation (Snyder, 2005 goes into excruciating detail if you’re interested in wavelength effects.)
Therefore, the amount of energy released from any given Arctic surface (ice, snow-covered ice, or open water) does NOT depend on solar angle, time of day, day of year, nor degree of ice coverage – only on the surface material. Radiation will be emitted from an open water surface all 24 hours per day.
Snow albedo does change with angle of incidence of the sun’s rays. (Warren, 1982) but it is more strongly affected by what type of what type of snow fell, how it was blown, how compact the snow is, how long the snow has been laid down, melt rate, sublimation rate, wavelength measured etc. (Basically, no climate scientist that I’ve read varies the assumed snow albedo with solar angle.) The Arctic snow – to be present at all) MUST be on top of the ice fields over the ocean, and we assuming that the ice in Sept has all melted, therefore, there is no snow to reflect potential energy reaching the surface at all.
The earth’s albedo doesn’t change at all with angle of the sun: The albedo of forest, tundra, open ground and grasslands (not mud or ponds or tidal flats!), croplands do change with the season (time of year = type of coverage and amount of snow assumed) but not with angle of the sun’s rays. Conceivably, you could claim that bare deserts will change since the rocks reflect energy differently, but actual rocks are not flat and have a coarse surface. Sand is crystalline, and is “infinitely” rough at the length of light/heat waves. No known rock, sand, deserts nor forests are present at 80 north latitudes, so these variations are of “academic” interest only for this problem. 8<)
That leaves water. Assume calm water: If there are storms (significant waves) then there are clouds present, and there is no direct sunlight. (Indirect sunlight is also either greatly diminished under cloud cover, or absent almost entirely – and we can cover that indirect radiation later.) Also, if there are waves present, then the "rise" of wave shadows the trough between that wave and the next = no solar radiation at all in the trough at all.
ALL water surfaces no how rough emit thermal radiation constantly, so the presence (or absence) of waves does NOT slow the rate of cooling of the Arctic water at ANY time of day or night.
All exposed water surfaces allow evaporation at a greater rate than that of snow, ice-covered water, or snow-covered-ice-covered water. The rougher the water (higher the waves) the greater the amount of evaporation into the low humidity air common at 80+ north. So, the presence of any ice at all removes approximately 80 Watts/meter of "insulation". Adding ice reduces cooling and increases heat retention in water above 80 north.
Albedo and the open ocean water? Not so.
And the impact of your observation is significant. Wikipedia is actually pretty thoroughly on this subject: See http://en.wikipedia.org/wiki/Albedo Solar light (heat) is commonly approximated using the average of the polarized and unpolarized light waves, or the middle line of 3 in the graphic at that page. Note that the "angle" described is angle FROM VERTICAL of the calm water's surface. In the Arctic, you have to use (90-normal angle) to understand the effect of the low sunlight incident to a sq km of ocean.
At solar elevation angles above 40 degrees, almost ALL inbound solar radiation is absorbed. But this value of water is the ONLY albedo used by so-called "climate" scientists
in their classes for lectures, tests, and summaries! Even Curry uses only a single value of for the "ocean" albedo in her arctic research papers. The albedo changes significantly at low angles: at 30 elevation angle, albedo is still 0.07: 93% is absorbed.
At 0 solar elevation angle, 100% is reflected. None is absorbed.
At 2-3 degrees, only 20% is absorbed. Albedo = .80
At 6-7 degrees, 50% is absorbed, 50% is reflected from the water.
This period of 0 to 7 degrees elevation corresponds to the light available between 6:00 and 10:00 am; and between 14:00 pm local solar time to 18:00 pm. Between 18:00 pm and 06:00 am, there is no sunshine at all.
At 10 degrees elevation angle, 35% is reflected, 64% is absorbed.
At 20 degrees elevation angle – only relevant in the early days of Sept near noon! – 15 percent is reflected, and 85% is absorbed.
Therefore, during the 4 weeks that sea ice is at a minimum each year, at no time of the day is more than 35% of the maximum available solar heat ever absorbed by the water. Through most of the daylight hours when the sun IS shining, less than 20% is absorbed. Further, the amount of time that this heat is available, is NOT "24 hours of every day" but only 2-4 hours per day!
True, for almost all of the rest of the summer months, the sun's angle is higher than 10 degrees, and so open water can absorb direct sunlight. But … for those months, the ice coverage now is still present, and so whether or not open water exists in Sept in irrelevant to what the sun's angle is in mid-summer. The ice will (or will not) melt between its maximum in March and its minimum in Sept regardless of whether or not there is open water present.
Isn’t Mark “Death Spiral” Serreze with NSIDC? Wonder what he thinks of this analysis.
If the surface of the Earth was covered in a perfect layer of artificial insulation that blocked incoming solar radiation and trapped in outgoing core heat from below ground, what would happen?
The internal heat generated from within the planet would eventually heat and melt the surface of Earth, under the insulation, to become a relatively uniform molten ball of magma. It would have nothing to do with either the sun or CO2.
This might be part of the problem on Venus. The atmosphere could be so thick that it is trapping the escape of the core heat of the planet. If Venus also has stronger forces acting to generate more internal heat such as: stronger gravitational forces from the sun, more radioactive decay elements, etc, then this would amplify the intensity and wattage of the core heat.
Mars has more CO2 by both quantity of molecules and percent of volume in its atmosphere than Earth does. Runaway warming is not a problem there, so CO2 as a villain for warming there doesn’t exist.
I suspect that Venus’ high surface temperature is greatly fueled internally by the core heat being trapped by the thickness of the atmosphere. There was never a runaway greenhouse there from CO2… it was always hot!
I believe that the partial melting of ice on planet Earth is being caused by something other than CO2 alone. Keep looking.
How much snow and ice will make the AGW crowd happy ?