It looks as if we are about to see the turn in Arctic sea ice, and if so it will be earlier than last year. But right at that same time, JAXA has decided to switch horses mid-stream.
They say timing is everything, and this timing couldn’t be more wrong. You”d think they would have waited until after the minimum had been recorded, so that there would be no questions or issues with the timing. But for some reason, JAXA has decided that now is the opportune time, right when everyone is watching. An update on their Arctic Sea-Ice Monitor page dated September 6th shows that they are switching from Version 1 to Version 2, and revising 2012. Of course the revision is for less ice:
In Sep. 2012 the arctic sea ice extent renewed the smallest record in observation history, but as the result of the version 2 using AMSR2 data of 2012, minimum sea ice extent became 3.18×106km2 which was 0.3×106km2 smaller value than Version 1 result using WindSat.
Here is what they display, on the plus side, at least they are keeping version1 in place until September 30th:
I have overlaid the two graphs, and it looks like all of the sudden about 250,000 square kilometers of ice has disappeared.
Note: I don’t have issues with their methodology, which is to remove uncertainty/noise related to the land mask boundary, which is always a good thing. But, the timing is certainly odd.
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From their update page:
With the version upgrade of AMSR-E Level 1 brightness temperature data, geolocation errors were improved from ±10km to ±1km.
The Version2 sea ice extent was calculated after the analyzing the arctic sea ice concentration derived from the upgraded AMSR-E brightness temperature data.
In addition, the other satellite observational data (1980, 1990, 2000 and 2010′ s average of SMMR, SSM/I and WindSat) was used to calculate sea ice concentration after adjusting the brightness temperature of each sensor using AMSR-E as standard data, and the adjustment of the sea ice concentration threshold which counts the sea ice extent was applied to consist with the AMSR-E sea ice extent.
The modified processing point due to the improvement of the geometric precision of AMSR-E Level 1 brightness temperature data is shown on description below.
With version 1, sea ice can be falsely detected along coasts due to contamination of ocean pixels by the passive microwave emission of land (the false sea ice). To decrease this false sea ice, we applied the “land expanded mask” (See Fig.1).
By improvement in AMSR-E geometric precision and decreasing of the false sea ice, we stopped the land expanded mask in the processing of version2.
Compared to Version 1, Version 2 sea ice extent has increased.
For the purpose of eliminating the false sea ice near the coast, Land Expanded Mask consider horizontally and vertically adjacent pixels as land when the 3×3 box centered on the land pixel.
Version 1 used the land-ocean mask which is provided for SMMR and SSM/I, but for Version 2, due to the AMSR-E geometric precision improvement, we made new land-ocean mask which is adjusted for footprint size of the 18GHz band of AMSR-E (IFOV: 16×27km) and applied to the analysis of sea ice concentration.
Compared to Version 1, the sea ice extent of Version 2 has decreased.
![fig1-ii-1-SIC_AMSE_N_PS12_20030301_05diff_only-cncl[1]](http://wattsupwiththat.files.wordpress.com/2013/09/fig1-ii-1-sic_amse_n_ps12_20030301_05diff_only-cncl1.png?quality=75)
In version 2, the false sea ice near the coast has decreased by the geometric precision improvement of the AMSR-E. But the false sea ice still cannot be removed completely, so we applied the land filter which Cho (1996) proposes. When at least one of 3×3 pixels was inspect as land, as the considering that the central pixel is effected by land spill over and has increased in sea ice concentration, central pixel will be replaced with the minimum value within the 3×3 pixels.
By applying this land filter process, sea ice extent of Version 2 has decreased in the melting period compared to Version 1.
After the observation halt of AMSR-E, the sea ice extent was calculated by WindSat in Verion 1, but in version 2, it was replaced by AMSR2 since July 2012.
In Sep. 2012 the arctic sea ice extent renewed the smallest record in observation history, but as the result of the version 2 using AMSR2 data of 2012, minimum sea ice extent became 3.18×106km2 which was 0.3×106km2 smaller value than Version 1 result using WindSat.
Furthermore, there is no modification in ranking of the successive sea ice extent due to the latest upgrade.
![fig2-1-Sea_Ice_Extent_ver1[1]](http://wattsupwiththat.files.wordpress.com/2013/09/fig2-1-sea_ice_extent_ver11.png?quality=75)
![fig2-2-Sea_Ice_Extent_ver2[1]](http://wattsupwiththat.files.wordpress.com/2013/09/fig2-2-sea_ice_extent_ver21.png?quality=75)
Fig.4 Arctic Sea Ice Extent during the minimum period
(Left:Ver.1, Right:Ver.2) – click to enlarge
sunshinehours1 says:
September 6, 2013 at 1:59 pm
All the Jaxa differences are graphed here:
http://sunshinehours.wordpress.com/2013/09/06/jaxa-version-2-all-the-other-graphs-compared/
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WOW!!! These differences are unlikely to be a result of an unbiased algorithm. The algorithm has a much different effect the further back in time you go, suggesting that the algorithm is not constant over time in its effect. Reminds one of GISS adjusting the past to make it appear cooler.
http://www.ijis.iarc.uaf.edu/en/home/revision_v2.html
(ii) Modified Land-Ocean Mask
Version 1 used the land-ocean mask which is provided for SMMR and SSM/I, but for Version 2, due to the AMSR-E geometric precision improvement, we made new land-ocean mask which is adjusted for footprint size of the 18GHz band of AMSR-E (IFOV: 16×27km) and applied to the analysis of sea ice concentration.
Compared to Version 1, the sea ice extent of Version 2 has decreased.
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So they are using a different and incompatible land mask for version2.
AMSR-E was launched on May 4, 2002, on NASA’s Aqua spacecraft. So all the pre-2002 data and their 1980s and 1990s averages are incomparable with the new processing.
If you go and dig they clearly state that there is a reduction, so why are they still presenting the data in the same file with the old averages.
This is just inviting misinterpretation and false conclusions. Comparable to Jones’ incarnation of “Mike’s trick” where he graphed different data together using the same colour.
@ur momisugly Sunshine hours, your graphs have different vertical axes: for the 1980’s 0.4 of difference = 26 mm on the screen, for 2013, 0.4 = 31 mm of screen.
I reckon the turn has occurred and NH ice will now be normal or above for the next couple of 1000 years
“graphed ” should of course have been grafted. I frightened myself there, thinking I’d started using graph (a noun) as a verb.
Jones grafted different datasets together, applying a low pass filter after the graft to neatly blend the two together (Mike’s Nature trick TM). He then plotted the graph using the same colour, thus presenting the two as being the same thing.
Providing data in adjacent columns in the same file: initially decadal averages then individual years, implies that the they have at least been thoroughly cross-calibrated into a self-consistent time series.
This was previously the case for this same file but is no longer the case for v2.
That is a serious professional error at the least.
What they need to do is maintain v1 as long series and provide the better resolution v2 as 2002 onwards.
“JAXA V2 increased the difference between 2007 and 2012 by 200,000 sq km. V2 dropped 2007 by 200,000 sq km. V2 dropped 2012 by 400,000 sq km.”
http://sunshinehours.wordpress.com/2013/09/07/jaxa-version-2-increased-difference-between-2007-and-2012-by-200000-sq-km/
With the JAXA estimates of ice extent undergoing “adjustments”, it’s good to know that the National Ice Center is still on the job. NIC shows the smallest Arctic ice extent so far on Sept. 5, 2013 at 5.9 M sq. km., with the packed ice (8/10ths) portion at 4.7 M sq. kms. Since 2007, only 2009 and 2010 ran higher at that date.
Sleepalot I’ll fix the axis a little later today.
I’ve gone into this in some more detail on The Blackboard.
http://rankexploits.com/musings/2013/september-nsidc-prediction/#comment-119346
definitely looks rigged. There is not way the mask changes etc can be justly applied to the earlier instruments on which the decadal averages are built.
Another dataset gets rigged to prop up the failed hypothesis….
Ron C. says: “NIC shows the smallest Arctic ice extent so far on Sept. 5, 2013 at 5.9 M sq. km., with the packed ice (8/10ths) portion at 4.7 M sq. kms.”
Ron, I’ve seen you refer to NIC quite a bit but I can’t find a processed data “product” anywhere on NIC, just graphs and contour info.
Do you have a link to some usable data ? This looks like a good source.
@Greg
The main NIC products are the charts, and the numerical data are attached to them.
The Arctic Daily Ice Extent Archive shows graphs, and if you select a single year and month, the daily total ice extent number for each day will be displayed.
http://www.natice.noaa.gov/products/ice_extent_graphs/arctic_daily_ice_extent.html
To see a breakdown of that number you have to go to Products/Products on demand/Arctic Daily where detailed ice extent is shown in the two components: 8/10ths and Marginal Ice Zone. Unfortunately, to retrieve the numbers for any given day, you have to call up the chart for that day, using the Tools Box on the right side.
http://www.natice.noaa.gov/Products_On_Demand/pod.html
Perhaps researchers with credentials can access their database more conveniently, but I don’t qualify.
For those who want to know more about NIC ice charts:
“Arctic charts include information on sea ice concentration and edge position as well as (since about 1995)information on ice type. The charts are constructed by analysts using available in situ, remotely sensed, and model data sources. Data sources and methods of chart construction have evolved since 1972 resulting in inconsistencies in the data record; a
characteristic shared with most operational products. However the arctic-wide charts are the product of manual interpretation and data fusion, informed by the analyst’s expertise and by ancillary products such as climatologies and ice information shared by foreign operational ice services. They are therefore often more accurate, especially since the addition of synthetic aperture radar to data sources in the mid 1990s, than are the passive microwave derived sea ice data sets commonly used by researchers. This is especially true for ice edge location because of its operational importance. NIC provides charts free of charge on their Web site.”
“Often a wide marginal ice zone of 40% to 60% is not detected in passive microwave (this was noted anecdotally in earlier studies by the authors comparing passive microwave with ice chart and other analyses), and this appears to be the case here. Also, the NIC partial ice concentration for multiyear shows that thinner types are present in higher concentration near the edge, and passive microwave can fail to detect thinner, younger ice.”
ftp://sidads.colorado.edu/pub/ppp/conf_ppp/Fetterer/National_Ice_Center_Arctic_sea_ice_charts_and_climatologies_in_gridded_and_GIS_format.pdf
@ur momisugly Greg
I did a little more searching re your question, and found a source for a csv file.
http://nsidc.org/data/masie/index.html
It appears to provide ice extent numbers by region for the last 30 days. I don’t know where the archives are.
I didn’t read through this entire thread so this may have been said already. — I’m assuming the ice breaks up more in the summer and so could the new software be just discarding the broken up ice better?
Well what little I know about computer software, I always believed that computers do exactly what you tell them to do, except for occasional cosmetic rays going through your memory chips.
So I think it is incorrect to blame these differences on software; which after all merely tells the computer to do what you want it to do.
So if the results are different, then clearly it is the algorithms they changed, and not the software; in which case, they are no loger calculating what they previously were calculating, so when the change the algorithms, they should start the clock all aver again, as they clearly are calculating something different from what they used to calculate and plot.
Now I can see the software guys rewriting the computer code, to calculate the result more efficiently; but they should be able to do that anyhow, while still keeping the same algorithms they used to use.
So they need to come up with a new name for their graph, if they are using a different algorithm.
Global warming may be bad science, but the paranoia on this site is unbelievable. Like a pack of eighth-grade school girls. Or college profs after grants.
They’re being as transparent, the author agrees and the change is in the tenths of percent. Get on with some real topic.
richardscourtney says:
mogur2013:
“Your post [is] a very poor example of concern trolling.
I am sure you could have disguised your purpose much better if you had put more thought into your post before sending it.”
Okay, you think I am trolling, disguising my purpose, and didn’t put much thought into my post. I simply refer to your own post, “we know as certain fact that climate data are all frequently ‘adjusted’. The global temperature data change so often that it has reached the stage whereby if you don’t like the data today then don’t worry because it will be different next month. And the adjustments always alter the past to enhance the AGW-scare.”
These data changes are NOT ‘paranoia, conspiracy allegations, and general wing-flapping’: they are documented facts. And now we see large changes to Arctic sea ice data when Arctic sea ice loss is the final straw alarmists can cling to. Only a fool would not consider whether those changes are reasonable, justified and accurate.”
I agree that we should consider whether they are reasonable, justified and accurate, but where is your documentation that they aren’t? I don’t disagree with you, I simply question your commitment to unbiased truth. My post that you chose to tear apart wasn’t directed at you, only the general tone on this thread. And I was happy to just leave this site to pursue less biased opinions, but your personal attack on me justifies at least an attempt at rebuttal. I am sure your ‘onlookers’ overwhelmingly approve your trashing of my post, but of course, that merely reinforces it.
What happened to honest dialog? The best to you in your endeavors, and I sincerely hope that the ‘experts’ are wrong.
A phony ‘concern troller’,
Gary Seymour