It appears Arctic sea ice has bottomed out and is now on the growth rebound. The NANSEN Arctic ROOS website shows that in terms of area, sea ice appears to have turned the corner as of Sept 13th data. While that is just one data point, it turned the corner about this time last year, and the year before.
More data and graphs from NANSEN Arctic ROOS are available here.
Many WUWT readers have been watching JAXA’s sea ice extent graph closely, so have I. Typically JAXA updates the graph twice a day; once around the start of their business day (in Japan), and then a second update that contains the corrected data (after going through processing and QC) a few hours later. Tonight (9/14) about 11:30PM PST JAXA updated their Sept 14th AMSRE data with this new number:
5,269,531 km2
UPDATE: JAXA updated the number again and it now stands at 5,276,563 km2
That is a gain of almost 20,000 26,719 km2 from the Sept 13th value of 5, 249, 844 km2 which may very well turn out to be the minimum extent for 2009. Here is the Sept 14th chart and the data from JAXA:
Source: IARC-JAXA Sea Ice page
Here is the tabular Arctic Sea Ice Extent data for September 2009 with the minimum highlighted in blue. A CSV data file for Excel is available here.
| 9 | 1 | 2009 | 5423750 |
| 9 | 2 | 2009 | 5398281 |
| 9 | 3 | 2009 | 5379844 |
| 9 | 4 | 2009 | 5387969 |
| 9 | 5 | 2009 | 5363438 |
| 9 | 6 | 2009 | 5345156 |
| 9 | 7 | 2009 | 5328906 |
| 9 | 8 | 2009 | 5330469 |
| 9 | 9 | 2009 | 5315938 |
| 9 | 10 | 2009 | 5295313 |
| 9 | 11 | 2009 | 5278594 |
| 9 | 12 | 2009 | 5259375 |
| 9 | 13 | 2009 | 5249844 |
| 9 | 14 | 2009 | 5276563 |
For 2008 the value reached minimum on September 9th, rebounded slightly, shrank again, and then turned the corner and started rebound again on September 17th.
| 9 | 1 | 2008 | 4957656 |
| 9 | 2 | 2008 | 4924219 |
| 9 | 3 | 2008 | 4927031 |
| 9 | 4 | 2008 | 4868906 |
| 9 | 5 | 2008 | 4825625 |
| 9 | 6 | 2008 | 4808281 |
| 9 | 7 | 2008 | 4739844 |
| 9 | 8 | 2008 | 4715469 |
| 9 | 9 | 2008 | 4707813 |
| 9 | 10 | 2008 | 4729688 |
| 9 | 11 | 2008 | 4751563 |
| 9 | 12 | 2008 | 4745156 |
| 9 | 13 | 2008 | 4742344 |
| 9 | 14 | 2008 | 4747188 |
| 9 | 15 | 2008 | 4731875 |
| 9 | 16 | 2008 | 4726250 |
| 9 | 17 | 2008 | 4718594 |
| 9 | 18 | 2008 | 4736406 |
| 9 | 19 | 2008 | 4745000 |
| 9 | 20 | 2008 | 4752500 |
Of course it is entirely possible nature has other plans, but the appearance of a change in direction is there and the time is about right historically. If this holds it will put 2009 542,031 km2 above 2008’s Sept 9th low extent, making it the third lowest extent in the AMSRE data set and the second year of increasing ice extent since the historic low in 2007 of 4,267,656 km2
The signs are right, and Nature will let us know in the next few days if we have indeed turned the corner and will be headed upwards.
UPDATE: Commenter Dave points out that the DMI extent graph, shown below, does a better job of illustrating the uptick.
It may be the case that Beluga Fortitude and Beluga Fraternity are the first German merchant ships to transit the Northeast Passage but they are not the first German vessels to do so. The armed raider Komet passed through from West to East in August/September 1940 with, as in the present instance, assistance from Soviet icebreakers: not Soviet this time of course.
See http://en.wikipedia.org/wiki/German_auxiliary_cruiser_Komet
DaveE (18:30:32) :
MikeW (12:53:53) :
“To: George E. Smith (10:44:56)
I strongly doubt that the seawater freezing mechanics are quite as simple as you describe. Water becomes more dense as either salinity increases or temperature drops, so I would expect tiny convection currents to immediately set up underneath the ice, effectively transferring the increased salinity downward and bringing heat upward.”
Except you failed to not that water is at its most dense about +4ºC, that’s how we know the temperature at the ocean bed.
That’s only true for freshwater, saltwater has a maximum density at its freezing point (which depends on salinity).
“As the ocean temperature nears the freezing point, the water density increases and the water sinks. Warmer water that replaces it must also be cooled, so more than just the ocean surface needs to reach the freezing point. Once ice begins to grow, it acts as an insulator between the ocean and atmosphere. Heat from the ocean must be conducted, or pass through, the sea ice before being emitted to the atmosphere. Ice growth slows as the ice thickens because it takes longer for the water below the ice to reach the freezing point.”
From: http://nsidc.org/seaice/processes/thermodynamic_growth.html
“”” Phil. (09:32:41) :
DaveE (18:30:32) :
MikeW (12:53:53) :
“To: George E. Smith (10:44:56)
I strongly doubt that the seawater freezing mechanics are quite as simple as you describe. That’s only true for freshwater, saltwater has a maximum density at its freezing point (which depends on salinity).
>>> <<<
“As the ocean temperature nears the freezing point, the water density increases and the water sinks. Warmer water that replaces it must also be cooled, so more than just the ocean surface needs to reach the freezing point. Once ice begins to grow, it acts as an insulator between the ocean and atmosphere. Heat from the ocean must be conducted, or pass through, the sea ice before being emitted to the atmosphere. Ice growth slows as the ice thickens because it takes longer for the water below the ice to reach the freezing point.”
From: http://nsidc.org/seaice/processes/thermodynamic_growth.html """
I have no disagreement with ANY of that; BUT it seems to me to be not the point. It certainly relates to the process of ice thickening; but not to the more important point of surface coverage increasing.
The increase in surface coverage, must be mainly due to totally new ice forming on open water, and surface extansion at the perimeter of existing pieces of ice.
In other words, the processes that I have been alluding to, and offering as (possible) mechanisms, apply strictly to the interface between the very water surface, and the atmosphere, so there isn't any insulating ice layer in the regions where my postulated process is occurring.
The atmosphere at the surface must be cold enough to suck energy out of the water by conduction, as radiation would have to be a minor cooling process, nad it would be easier for new surface ice to form attached to the perimeter of an existing ice floe.
A colleague who spent a great deal of time in those waters courtesy of the US NAvy's underwater fleet, and subsequently as an oceanographer (Scripps educated) working for an oil exploration company; describes the process, as being one where large expanses of open water suddenly become very mushy; as he describes it open water could disappear in minutes; but then just as quickly the mush vanishes, only to reappear, and eventually persist.
This to me, would be the period, when the evicted salts, are resisting the freeze by lowering the interface freezing point.
So what he describes having watched happen on numerous occasions, is not like a front moving acroiss a surface, but a large area of surface suddenly change its phase. The period of instability before the freeze takes hold, he suggested was somewhat dependent on the degree of surface wave action; calmer water was less finicky about freezing.
But yes once the surface water is replaced by ice, and pushed above sea level by its buoyancy, then the impediments to thickening you mention would come into play. I was only talking about the appearance of ice out of nowhere, rather than mass increasing once ice is present.
George
So I just looked at Phil’s NSIDC link, and it is clear they are talking about the growth of existing ice; and not the nucleation of new ice, out of nowhere.
All that stuff about the density increasing, and the water sinking to be replaced by warmer; for sure all of that has to happen; but that all takes place BEFORE the freeze starts. But at some point you will have surface water temperatures of -1.8 deg C (their number) at which point water of that particular salinity can freeze RIGHT AT THE SURFACE, where it connects to the coolest thing around which is the atmosphere.
George
“”” DaveE (18:30:32) :
MikeW (12:53:53) :
To: George E. Smith (10:44:56)
I strongly doubt that the seawater freezing mechanics are quite as simple as you describe. Water becomes more dense as either salinity increases or temperature drops, so I would expect tiny convection currents to immediately set up underneath the ice, effectively transferring the increased salinity downward and bringing heat upward.
Except you failed to not that water is at its most dense about +4ºC, that’s how we know the temperature at the ocean bed.
This gives us a paradox…
Water above the bed must be both above and below ~4ºC
DaveE. “””
I would think that by now, readers of WUWT, would have thoroughly worked out of their system, this 4 deg C maximum density of pure H2O.
That results in the remarkable process of lake turn over; but it doesn’t happen in typical oceanic waters which never have a maximum density point short of their freezing temperature. I have a graph somewhere that someone referred me to, that shows water at about 2.47% salinity freezing at around -2.5 deg C which is its maximum density point also, so less than 2.47% gives a maximum density point, but typical oceanic water is supposed to be around 3.5%.
Now NSIDC says typically -1.8 C for sea ice formation, so there is some discrepancy on actual numbers; makes you wonder why such fundamental things weren’t thoroughly researched in the very early days of oceanography, so that the data was in every 8th grade science text book, instead of requiringf a PhD in Googling to locate behind some paywall.
George
One of my concerns is that we only have such data back to 1978. That’s a very short period of time over which to analyze the data against other potential influences of a natural origin, such as TSI & sunspot cycles/length, ocean oscillations, and so on.
Now NSIDC says typically -1.8 C for sea ice formation, so there is some discrepancy on actual numbers; makes you wonder why such fundamental things weren’t thoroughly researched in the very early days of oceanography, so that the data was in every 8th grade science text book, instead of requiringf a PhD in Googling to locate behind some paywall.
It can be found here for free George.
http://nsidc.org/seaice/intro.html
http://nsidc.org/seaice/processes/index.html
IJIS website Arctic Sea Ice chart: the red 2009 line now appears to be touching the green 2005 line:
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
It will be interesting to see if the red line passes through the “knot” at 8.8 x 10^6 km² on November 1st, or passes above it.
Measuring sea ice by satellite is like counting angels on ther head of a pin–
http://solarcycle24com.proboards.com/index.cgi?board=globalwarming&action=display&thread=346&page=114#30005
“States: Passive microwave underestimates sea ice concentrations by an average of 25% in summer (but the underestimate can be more than this) and 5-10% in winter. …. its mostly all in one direction.
(Met Office, Hadley Centre)”
http://ioc3.unesco.org/oopc/meetings/oopc-9/presentations/monPM/Rayner_OOPC9_pr.pdf
—
also–with the now slowed down Gulf stream
no longer delivering much heat to the arctic–
http://solarcycle24com.proboards.com/index.cgi?action=display&board=globalwarming&thread=772&page=5#29831
http://news.nationalgeographic.com/news/2009/09/090910-sea-levels-rise.html
17 mil square kil of winter sea ice
seems likely to occur but
will never be reported by warmers
on their morphing, falacious graphs.
Big glaciers and big bergs coming.