After all of the news about a minimum record ice extent last month, this is interesting. As we know when water loses its ice cover, it allows a lot of heat to radiate into space as LWIR. many predictied that as a result of the extra open ocean surface, we see a very fast refreeze in the Arctic. It appears they were right. In fact, this is the fastest monthly scale refreeze rate in the NSIDC satellite record going back to 1979.
Here’s JAXA data plotted to show what has happened:
From the blog sunshine hours, here’s an analysis using NSIDC data:
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Today is day 291 in the Arctic. The minimum in 2012 was on day 260 – 31 days ago.
If you calculate the percentage of ice gained (the refreeze) 31 days after minimum, then 2012 is the fastest refreeze ever!
Arctic Sea Ice Extent has increased by 43.8% since the minimum was reached.
Extents are in millions of sq km.
(And note I am using NSIDC data here and their algorithm is making the refreeze appear slow compared to NORSEX)
| Year | Minimum_Extent | Extent Day | Extent_Change | Extent_Change_Pct |
| 1979 | 6.89236 | 295 | 2.55691 | 27.1 |
| 1980 | 7.52476 | 280 | 0.95144 | 11.2 |
| 1981 | 6.88784 | 284 | 1.71672 | 20 |
| 1982 | 7.15423 | 287 | 2.41499 | 25.2 |
| 1983 | 7.19145 | 282 | 1.70096 | 19.1 |
| 1984 | 6.39916 | 291 | 2.08442 | 24.6 |
| 1985 | 6.4799 | 281 | 1.50769 | 18.9 |
| 1986 | 7.12351 | 280 | 1.8491 | 20.6 |
| 1987 | 6.89159 | 276 | 1.37713 | 16.7 |
| 1988 | 7.04905 | 286 | 1.76783 | 20.1 |
| 1989 | 6.88931 | 296 | 2.70935 | 28.2 |
| 1990 | 6.0191 | 295 | 3.46791 | 36.6 |
| 1991 | 6.26027 | 290 | 2.69726 | 30.1 |
| 1992 | 7.16324 | 282 | 1.67903 | 19 |
| 1993 | 6.15699 | 280 | 1.85199 | 23.1 |
| 1994 | 6.92645 | 279 | 1.1014 | 13.7 |
| 1995 | 5.98945 | 283 | 0.5189 | 8 |
| 1996 | 7.15283 | 285 | 1.77882 | 19.9 |
| 1997 | 6.61353 | 277 | 0.65032 | 9 |
| 1998 | 6.29922 | 291 | 2.35169 | 27.2 |
| 1999 | 5.68009 | 286 | 2.68723 | 32.1 |
| 2000 | 5.9442 | 286 | 2.32372 | 28.1 |
| 2001 | 6.56774 | 293 | 1.95252 | 22.9 |
| 2002 | 5.62456 | 287 | 2.41992 | 30.1 |
| 2003 | 5.97198 | 291 | 2.10126 | 26 |
| 2004 | 5.77608 | 294 | 2.37329 | 29.1 |
| 2005 | 5.31832 | 296 | 3.09221 | 36.8 |
| 2006 | 5.74877 | 288 | 1.72446 | 23.1 |
| 2007 | 4.1607 | 288 | 1.39556 | 25.1 |
| 2008 | 4.55469 | 293 | 3.33615 | 42.3 |
| 2009 | 5.05488 | 286 | 1.45951 | 22.4 |
| 2010 | 4.59918 | 293 | 2.88065 | 38.5 |
| 2011 | 4.30207 | 282 | 1.35023 | 23.9 |
| 2012 | 3.36855 | 291 | 2.62409 | 43.8 |
Source: sunshine hours
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Here’s the NORSEX plot and NSIDC plot compared:
See all the data on the WUWT Sea Ice Reference Page
In other news. I’ve been in touch with Bill Chapman at UUIC/Crysophere Today to point out this bug:
It turns out to be an accidental issue, and he says:
“I was using the script to generate a plot for a publication that wanted a U.S.-centric view and it looks like I forgot to put things back to the way they were originally.
I’ll have it fixed by tomorrows update.”
Stuff happens, no worries.
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nah?, what did I tell you. It is just going to get colder and colder.
It will take another 4 years before we have “bottomed out”.
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
stop worrying about the carbon. Start getting worried about the cold.
What I find weird is that this seems inconsistent with the anomaly graphs. To see where I’m coming from, a few weeks ago a new “low” was reached. At that time it didn’t trigger a new maximum anomaly, because although lower than any other low, the departure from the “norm” wasn’t bigger than other anomalies that can occur any time of the year.
Now if refreezing has occurred at the fastest rate ever, I find it difficult to see how the anomaly could have increased in size, to the extent that weeks later, it reached a new record.
If the the hypothisis of lack of heat gained from summer sun in the arctic is correct then arctic sea ice could recover quickly if the conditions were right during summer and we could see the Arctic sea ice expanding like it is in the Antarctic.
It appears the current rate of recovery is greater than for any other year that has been at this extent or less. And I think too that the recent arctic wind storms gave us all a lesson in how multi-year ice is formed (by compaction) and was lost on us.
Very Cool Gentlemen….thank you all.
Tesla
If you look at the open ice-free km/day water in the Arctic Ocean, that is the water each day that can evaporate, 2012’s total was actually slightly lower than in 2011 due to the abnormally high extent of ice earlier in this season. As far as evaporation goes in 2012, it was roughly the same as in 2011, though just slightly below, same for 2007. The other years has less area/day than those three years. Seems there is a top forming.
It’s funny how physics tend to even things out when all factors are considered.
Big ice melt = large volume of fresh water added
large volume of fresh water present = faster freezing
Did I read the start of this post correctly “As we know when water loses its ice cover, it allows a lot of heat to radiate into space as LWIR”. The implications of this statement are PROFOUND. Water has an emissivity of around 1 in the thermal IR range (same as LWIR). The statement implies that ice radiates far less LWIR than does water which mans its emissivity in the LWIR much lower than 1. But the entire claim of positive feedback in the arctic is based on the supposition that ice is very reflective in the visible hence absorbs little of the incoming solar energy but has a LWIR emissivity of close to 1. Thus with ice, little energy absorption plus high emission hence cooling. Without ice same emission but more absorption hence warming.
But if ice is a poor emitter of LWIR then the case for positive feedback collapses. The presence of ice reduces both absorption and emission. In fact, since the amount of solar energy at the poles is quite low and effectively zero for 6 months of the year whereas LWIR emission occurs year round a better case could be made for it being negative feedback.
There is considerable evidence to suggest that ice is a poor LWIR emitter and I have argued that in the past. Here may be further evidence. I THINK THIS IS IMPORTANT FOLKS.
This stupid site can put a +ve spin even on diabolically bad news. Want a good laugh (or cry) read this one.
Sea Ice News Volume 3 Number 15 – Arctic refreeze fastest ever
No mention of the inconvenient truth that the ice cover is still only a little above ½ of long term average. Wont it be wonderful when it all melts in summer and we can slap ourselves on the back about the infinite % increase in cover as it freezes in autumn.
As long as the autumn freezing % keeps increasing there surly cant be a problem.
How devoid of intellectual rigor can a blog be and not be called brain-dead?
Could someone please plot a graph of the average radius of arctic sea ice extent over time.
The formula is to divide the area by pi then take the square root of that value, then plot that value.
I am curious what such a graph would look like, as I have a hunch that the closer you get to the pole, the harder it is in an exponential fashion to melt the ice. The warmists seem to be calculating a linear trend when predicting the no ice condition even though the area of concern sits on a sphere.
Confucios say Mann in heatwave talk a lot of hot air!
Hee hee. The high rate of change is just a simple mathematical consequence of the very extreme depth of the fall in ice extent in the first place.
Someone in warmists land has been reading Anthony’s mind apparently, because they predicted that this trend argument will be a favorite one, once the peak had passed. I now count two uses of the “record trend” argument.
This is a really positive thing, the sea ice increase attemp[ts to return the sea ice to its balance.
@Hammer That could very well be important, more research might do good though, because there could be many reasons that are not intuitive with such a small knowledge of the particular system.
Would not the more relevant measurement be the annual integrated ice extent (the area under the graph each year?) Seems to me that there would be a different energy ranking sequence if each year was summed day by day. Spread over a year, the minimum extent date and area seem to depend on several variables, some of which act in light and some in darkness, some months away from where the minimum extent happens. It’s not area that is the primary focus, it’s energy. including that difficult wind energy component & direction over a year.
The Cryosphere today graph would indicate the sea ice area anomaly is getting larger. This means that while as a percentage the ice growth may be quick, in real terms it is not as quick as the long term mean.
Ice and water have basically the same emissivity (very near to 1) between 4 and 11 µm.
Beyond 11µm where is a bit more than a half of the total radiated energy for temperatures near freezing point, the emissivity of ice drops below the one of water – water decreases slowly towards 0.98 as the wavelength increases while ice quite brutally drops towards 0.94.
So yes ice emissivity is is below water (for the wavelengths above 11µm) but the difference is not SO huge – about 4 %.
And as it bears only on half of the energy, the ice radiates roughly 2% less than water.
Now even if this is not a big number, it can not be neglected as it represents some 6 W/m² less emission for the ice.
See https://www.comp.glam.ac.uk/pages/staff/pplassma/MedImaging/PROJECTS/IR/CAMTEST/Icewater.htm
Interesting but not ground breaking news.
How fast is Antarctic sea ice melting now? I would guess not very fast.
Wouldn’t the graphs be more convincing if you could get a hockey stick out of them?
” As we know when water loses its ice cover, it allows a lot of heat to radiate into space as LWIR”
Can anyone explain to me why open water should radiate more than ice ? The emissivity of ice and snow is very close unity in the infrared, making it a near perfect blackbody. It also increases the Earth’s albedo by reflecting incoming sunlight. So the implication that open water would have a greater cooling effect that ice cover is not obvious. Can anyone provide evidence or logic for that statement?
Thanks MB
… and, one summer when the Arctic has melted out completely (in only a few years or decades from now), the instant the first ice crystals form during the autumn refreeze, then the recovery will be INFINITY PERCENT IN A MILLISECOND.
Berk.
John Marshall:
At October 19, 2012 at 2:13 am you say of the rapid Arctic refreeze
But it is disappointing news.
I had hoped for an ice-free Arctic ocean with all the resulting benefits for trade and shipping.
And nobody has managed to tell me of any problems likely to derive from an ice-free Arctic ocean (although some people who know nothing about polar bears think the bears would not like it).
The rapid refreeze implies we may not get the benefits of an ice-free Arctic ocean. It is a matter for regret.
Richard
TomVonk says:
October 19, 2012 at 2:07 am
Thanks Tom, I didn’t see your post at the time, you seem to have answered most of my question – nice link too. Do you or anyone happen to know what the albedo of water is? Especially at oblique incidence angles experienced by the Arctic Ocean?
Tom Vonk at 2.07 am. Hi Tom, I accept that ice probably has high emissivity but the same may not be the case for snow. Most diffuse scattering comes about from repeated rapid changes in refractive index in this case air to ice to air to ice etc. This also occurs of course in a cloud but In a cloud the water droplets are around 2 microns so visible light is scattered (wavelength 0.4 to 0.7 microns) while thermal IR simply diffracts around the droplets (wavelength 8 to 50 microns). This is why red light (and IR even better) penetrates a fog better than blue light. I am sure you know that already. But in the case of snow the ice crystals are far larger. Large enough to scatter even thermal IR which means I at least would predict that snow would be very reflective both in the visible and in the IR. If it is highly reflective (ie: absorptivity is low) then more or less by definition emissivity must be similarly low since emissivity must equal absorptivity.
Thus very clean ice ie: black ice would have high emissivity but ice which has a crazed surface or is covered with snow might well have a very low IR emissivity. All the photos I have seen of sea ice shows it as intensely white, meaning that the surface is strongly scattering. A smooth clean ice surface does not look intensely white.
Don’t you think that arctic sea ice is toast and it’s just a matter of a short time before the arctic is ice free? Pointing out a record refreeze isn’t going to save sea ice. Sea ice insulates the heat in an ocean, so it’s keeping heat from escaping into space during the early part of the ice formation season. That first year ice isn’t going to survive a melt. Don’t confuse insulation with insolation! Parts of that arctic aren’t getting sunlight, so why would someone bring up albedo, which isn’t important when sunlight isn’t direct, like in the summer? Anyone who has made an honest effort to study arctic sea ice knows it’s toast, so what’s with the games?
I can’t be bothered to go over there but do please let them know that the bolded phrase is a lie of unprecedented proportions. 😉
http://dx.doi.org/10.1016/j.quascirev.2010.08.016
http://adsabs.harvard.edu/abs/2007AGUFMPP11A0203F 😉