As many readers have noted, one of the Arctic sea ice extent plots on our WUWT sea ice page took a Serreze style nosedive today:
Source: http://ocean.dmi.dk/arctic/plots/icecover/icecover_current.png
According to DMI (Danish Meteorological Institute), this is the source of the data:
The ice extent values are calculated from the ice type data from the Ocean and Sea Ice, Satellite Application Facility (OSISAF), where areas with ice concentration higher than 30% are classified as ice.
And when I backtrace from OSISAF to find what satellite/sensor they used, this is what they say:
Data used: SSM/I (DMSP F15), ECMWF forecast for atmospheric correction
The glitch is reminiscent of the Feb 2009 failure of an SSMI sensor used by NSIDC.
That failure showed up on NSIDC’s plot, and when I pointed it out with a blog post NSIDC responded that it “isn’t worth blogging about“.
Click for larger image
A couple of days later they were forced by the failure of the sensor to take their data offline, so apparently it was worth blogging about after all.
They wrote in the press release at the time:
Last year, F13 started showing large amounts of missing data. The sensor was almost 13 years old, and no longer provided complete daily data to allow us to track total daily sea ice extent. As a result, we switched to the DMSP F15 sensor for our near-real-time analysis.
And as noted above, DMI uses SSM/I (DMSP F15), the same as NSIDC. Is this glitch worth blogging about? I think so since NSIDC was unaware last time that a problem had developed until we pointed it out for them.
This looks like the beginning of the problem on August 6th, as seen at the OSI SAF page:
Source: http://saf.met.no/p/ice/nh/conc/imgs/OSI_HL_SAF_201108061200_pal.jpg
The day before on August 5th:
Source: http://saf.met.no/p/ice/nh/conc/imgs/OSI_HL_SAF_201108051200_pal.jpg
It may be related to the three Coronal Mass Ejections, (CME) that hit Earth about that time. From Spaceweather.com
Earth’s magnetic field is still reverberating from a CME strike on August 5th that sparked one of the strongest geomagnetic storms in years. Registering 8 on the 0 to 9 “K-index” scale of magnetic disturbances, the storm at maximum sparked auroras across Europe and in many northern-tier US states.
It is possible the satellite operator shut down the bird for protection, but nobody got the memo. There’s no mention of data outages on NSIDC’s page or at CT or other ice product websites that I’ve found. Or, the sensor data might be so corrupt as to be unusable, or the sensor has been fried by the CME.
So, like before, I’ll send NSIDC’s Dr. Walt Meier a courtesy note on this one and see what he says. NSIDC’s plot averages over 5 days, IIRC, so it won’t show up for a few days and they have time to correct it if in fact it is the satellite sensor data again.
This may be a sensor issue, or it may be an algorithm issue. Since other plots aren’t showing it, we know it doesn’t represent a real loss of ice, just loss of data.
Curiously though, I’ve noted another glitch half a world away:
Source: http://www.iup.uni-bremen.de:8084/amsr/ice_ext_s.png
Which looks to be unrelated, since it is the AMSR-E sensor on a different satellite.
Must be the day for glitches in sea ice.
Meanwhile, Row to the Pole‘s progress is slowing to a crawl:
Must be a sea ice glitch of a different kind.
UPDATE:
Dr.Walt Meier of NSIDC responds:
Hi Anthony,
This is quite clearly a data issue. We don’t work with the F15 satellite
anymore – we’ve been using the sensor on the newer F17 satellite, so I
can’t say if it is a a sensor problem or a processing issue at DMI. I
could be the CME, though it doesn’t seem to have affected the F17
sensor. From the image, it looks to be a missing swath of data, perhaps
from CME, perhaps from some other issue. A missing swath is not
particularly unexpected. Sometimes the data can be recovered later and
added in, sometimes not. The AMSR-E issue in the Antarctic also appears
to be due to one or more missing swaths of data on Aug. 5:
In our images, as you point out, we do a 5-day averaging to remove the
noise, often errors due to ephemeral weather effects, from the
timeseries. This avoids the day-to-day ups and downs that can be
misleading and provides a more representative overall trajectory (though
we do get occasional wiggles from the preliminary data used in the 5-day
data that is later replaced).
For the timeseries plot, we also interpolate over missing data (such as
a missing swath) using data for that region from the day before and
(when it becomes available) the day after. However, there doesn’t appear
to be any missing swaths in our F17 data over the last several days.
Info on the sensor we use and the interpolation are explained on our
website here:
http://nsidc.org/arcticseaicenews/disclaimer1.html
You’re welcome to print the above, though if you do, I would appreciate
if you would also add the following links, where we addressed the sensor
issue and made corrections to the near-real-time data.
And also here, where I discussed some the issues dealing with
near-real-time data from satellite sensors:
http://wattsupwiththat.com/2009/03/01/nsidcs-walt-meier-responds-on-the-sensor-issue/
These may be useful for new readers or to refresh other readers’
memories, such as some of the readers who posted in the comments section.
walt
——————————————-
Walt Meier, Research Scientist
National Snow and Ice Data Center
University of Colorado
UCB 449, Boulder, CO 80309
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Athelstan. says:
August 7, 2011 at 4:51 pm
“Anthony, why are you allowing this ‘toothless’ post-normal student, to let fly with this sort of very cheap incivility?”
R Gates is to be ignored. He likes to come here with nothing but Gatesisms and to poke around with barbs and needles. After a while you just don’t read what he types.
Quality — It’s job # 832! We’ll get to it eventually. Maybe
Steve Mosher said:
Hmm. Why would anyone think near surface temperatures should match satellite?
TheTempestSpark says: August 7, 2011 at 1:25 pm
WOW, There was three recent coronal mass ejections that hit earth around this time.
the K Index chart for the 6th August shows a very high Geophysical hit for Earth from the recent CMEs Could this be a result of solar activity effecting the satellites?
The magnetosphere has been buffeted over the last couple days, the action starts 32 seconds in:
Fred in Canuckistan wrote:
That looks just like an upside down Hockey Stick.
Only if you’re in the Northern hemisphere… 😉
“A careful analysis of satellite radar altimetry echoes can distinguish between those backscattered from the open ocean, new ice or multi-year ice. The difference between the elevation of the echoes from snow/sea ice and open water gives the elevation of the ice above the ocean; the ice thickness can computed from this.[4] The technique has a limited vertical resolution – perhaps 0.5m – …………….
……………………..and is easily confused by the presence of even small amounts of open water.”
In their response to my question about the differences between their ice estimates and those based on radar data, the Alaskan weather service said they based their analysis on satellite pictures. Could somebody who has access to the data (Anthony?) compare radar-based ice estimates with pictures?
DR.
DR says:
August 7, 2011 at 7:12 pm
Steve Mosher said:
It’s substantially the same as UHA or RSS and CRU and GISS.
Hmm. Why would anyone think near surface temperatures should match satellite?
###########
trend matches. The absolute numbers are of course different.
Look at it this way. If you saw the air above the surface (2m) trend up by 1C per decade, what would you expect for LTL? more trend? less trend? or about the same?
Now if the surface measurements were wildly corrupted and you saw 2C at the surface and 1C aloft, then you’d have a nice clue that measurements at the surface were biased.
But that’s not what we see. We see a trend at the surface and we see substantially the same trend aloft. That similarity gives us some measure of confidence that the surface measurements, on the whole, are substantially correct. Or you can look at it this way. There are now 5000 canadian stations sitting on my computer. WAYYY more than GHCN has for canada.
When I calculate the average for canada using 5000 stations do you think it will be
1. Higher than GHCN
2. Lower than GHCN
3. About the same.
“timetochooseagain says:
August 7, 2011 at 4:20 pm
Is it just me, or does it look like sensor “errors” are of only a particular sign? That is, underestimating extent. Can anyone give an example of a failed sensor producing erroneously high extent values at some point?”
But did you mean “high” values or values that do NOT support CAGW?
See the following:
http://boballab.wordpress.com/2010/08/12/lake-michigan-temp-july-4th-2010-489-2f/
“Lake Michigan Temp July 4th 2010: 489.2°F ?”
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
Steve Mosher,
Aside from the missing “hot spot” debate, shouldn’t the satellite data show more warming than the near surface during the same period due to moist convection amplifying the warming with height? It seems like basic physics to me.
I’m just sayin’
Hey Mr. Gates, what was 15% ice extent on this date in1956, 1935 or 1750?
Anthony says “REPLY: Problem is, Serreze is hardly “reserved”. More like “activist hippie”. You should see some of the things he says in historychannel.com documentaries. – Anthony”
Wow, for a guy living in the Peoples Republic of Chico that is some kind of funny. Just imagine how far out Dr S has to be when you are surrounded daily with aging activist hippies that comprise ‘normal’ in the neighborhood.
Look, sometimes Viagra fails.
.
(62 comments and no one had cracked a joke like that? It was just sitting there, waiting)
August 4, 2011, 9.3 CME
http://www.youtube.com/watch?v=KvXqL7RmcN0
Steven Hoffer says:
August 7, 2011 at 3:38 pm
R. Gates
If you are suggesting that toothless retired people living in homes drives sea ice levels, I have a satellite to sell you.
___
Currently CO2 is more of a driver of climate change than methane.
Athelstan. says:
August 7, 2011 at 4:51 pm
“With the warming still in the pipeline, we’ll have a virtually ice free summer arctic by the time most of you are gumming your oatmeal at the retirement home.”
Anthony, why are you allowing this ‘toothless’ post-normal student, to let fly with this sort of very cheap incivility?
____
Don’t know from whence you come to cast your barbs in my direction, but I suspect I may not like you very much.
Grant says:
August 7, 2011 at 8:43 pm
Hey Mr. Gates, what was 15% ice extent on this date in1956, 1935 or 1750?
_____
You can be 99.9% certain it was more than it is on this date…especially as the NE and NW passages are virtually once more open, and they certainly were not on any of those dates.
James Allison says:
August 7, 2011 at 6:22 pm
Athelstan. says:
August 7, 2011 at 4:51 pm
I like reading Mr R Gates’s comments. He appears to have extensive knowledge of the Arctic and short term weather patterns and so I appreciate his views. That his view happens to be from the other side of the climate fence should not be held against him. And the poking fun comments are part of what makes Anthony’s site so good to visit.
____
Thank you James…perhaps its my Norwegian and Swedish heritage. I know enough about the Arctic to absolutely bore most my friends to death with it, so I’ve agreed to not talk about it anymore around them. WUWT and other sites help me keep my promise and give me an outlet. I’ve got the Humboldt Glacier (the widest tidewater glacier in the world by the way, and yes, it’s losing mass) as a background on my computer…what a nerd!
R. Gates says:
August 7, 2011 at 2:51 pm
By the time the September low comes around, we’ll end up with the least amount of sea ice on record by area and volume (or at least since the Holocene Climate Optimum!). With the warming still in the pipeline, we’ll have a virtually ice free summer arctic by the time most of you are gumming your oatmeal at the retirement home.
=====================
Only in your make-believe cartoon, milk-toast, smooth-handed, never-swung-a-hammer-before cyber world, GATES!
You can not prove or even BEGIN to predict ANY of the above….right down from the oatmeal (where will you be???) to the “least amount of sea ice on record”.
PROVE IT!
Arwww…I thought so. You can’t prove anything.
Time to press the REJECT button.
Next?????
Chris
Norfolk, VA, USA
First, kudos to Walt Meier for his willingness to discuss the issues. Next,
Ric Werme says:
August 7, 2011 at 1:58 pm
Fallacy of the excluded middle. You left out
5) Someone at NSIDC actually takes a quick glance at the data, and finds the error before Anthony does. How much time did it take you to spot the problem, Ric? One second? Two? You seem to think that taking two seconds to glance at a chart is somehow impossible during regular working hours … but since that’s what we’re paying them for, why can’t they do it? Most everyone on the planet finishes their jobs during their work hours, and I doubt greatly that the NSIDC folks are that overworked. Take a few minutes off from issuing alarmist predictions and actually look at the data … is that too much to ask?
6) Someone writes a bozo simple computer program that checks the data to see if it’s gone off the rails, and if so, it holds the data release up until someone can look at it when they get back. Duh …
Personally, I’ll go for 6). The code needed is trivially simple, and if NSIDC were a business they’d have done it the first time Anthony found an error. Businesses have to correct their errors or they go out of business. NSIDC just repeats their errors, as there is no penalty for mistakes. So no, 3) is not acceptable.
w.
Werner Brozek-I was referring to sea ice, so your comment is kinda not remotely relevant! It’s okay though. Wow, now that’s a high temperature! Perhaps it was a fluke and they were meaning to report in the Rankine scale 😉 Oh wait, then it would be below freezing which doesn’t make sense either. Hm…
steven mosher-“Look at it this way. If you saw the air above the surface (2m) trend up by 1C per decade, what would you expect for LTL? more trend? less trend? or about the same?”
I think it is reasonable a priori to expect that the lower troposphere should have a trend of the same sign. Quantitatively what one expects has to be determined either through some kind of “physics model” as you like to call them, or some kind of comparison of how the series relate to one another in ways independent of their long term trend, making the (seemingly reasonable assumption) that the same physics that applies to the fluctuations should apply to the long term trends. From the former approach, we get the answer that the “amplification” of TLT relative to the surface should be a factor of about 1.2, while from the latter, I get substantial the same answer:
http://devoidofnulls.wordpress.com/2011/07/16/relating_lower_tropospheric_temperature_variations_to_the_surfac/
In other words, yes, it looks like there should be more warming aloft than at the surface. Funny thing is, the trends are “about the same” (and actually, for UAH at least, a little less). So when you say:
“That similarity gives us some measure of confidence that the surface measurements, on the whole, are substantially correct.”
You are, in fact, incorrect. While not as troubling as a complete lack of trend in the TLT data would be, the fact that the trend is not greater, means that the satellite data does not give anyone who actually understands these data additional confidence that the surface data are “substantially correct.” Note I am being generous: I am not saying that the TLT trend being only about the same as the surface raises questions about the accuracy of the surface data, only saying that they do not eliminate or lessen concerns about the surface data. The satellites are not confirmatory evidence of the surface data in any meaningful sense.
Something wrong with my understanding here. (as usual 🙂 ) During an ice age the Arctic Ocean must be free of ice so as to provide sufficient water vapour to allow the snow accumulation to build up towards New York.
DR says:
August 7, 2011 at 8:39 pm
Steve Mosher,
Aside from the missing “hot spot” debate, shouldn’t the satellite data show more warming than the near surface during the same period due to moist convection amplifying the warming with height? It seems like basic physics to me.
I’m just sayin’
#######
Of course, thats why, if you read my words when I talk about the trend, I say it should be roughly similar. But If you want to talk about Santer et al we can. And further, remember, we are talking about the trend. So, if the surface warms by .45C over 40 years, what is your expectation for warming aloft?
R. Gates says:
August 7, 2011 at 10:27 pm
Thanks, R. Gates. Could you please cite your sources for the claim that the NE and NW passages were not “virtually open” in 1750?
Also, what does “virtually open” mean? Because to me it means that the passages are open in a virtual world, say a climate model. For you it clearly means something else, but what? Perhaps you mean that satellite images show an opening for at least one day or something like that … but if so, how can you compare that satellite data to pre-satellite years?
Finally, could you list for us the number of vessels that made the NorthWest Passage this year? I can’t find any indication that anyone made the passage (or is even trying) this year, and as of August 7th the NWP was not open … and (as far as I know), zero passages this year is the same number of boats that made the passage in 1935, 1956, and 1750. If the NWP is “virtually open” now, so far it’s only virtual boats that have made it this year.
I also note that Amundsen made the first traversal of the NW Passage in 1902, when the world was colder than now. I note that the Coast Guard Cutter Storis made the passage in 1957 … was the NWP “virtually more open” or “virtually less open” in 1957 than it is now? Victory Adventure Cruises (perhaps buoyed by your optimism) was taking reservations for their NWP trip … which was supposed to complete the passage by the 30th of this month. Near as I can tell, it never even started the trip, I can find no further mention of the voyage.
So is that what you meant by “virtually open”? It’s kinda sorta open, but only virtual boats can make the passage?
w.
Didn’t I tell you they forgot to “adjust” it?