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
Tweaking AGC can cause a precipitous drop in signal level when the signal drops below detector amplification sensitivity.
@R Gates, what pipeline is this you are sure there is “warming” in? Where is this “warming”? Nobody can find it yet, and it has been a “travesty” that we cannot for a long while now. Are you sure it exists? Is it possibly just a convenient way to explain the lack of current warming, just as aerosols are being used for?
Lotsa questions. Few answers…..
Don’t these data sites file minority reports?
Seems they are now climbing out of one hole just to fall into another.
I’m sort of wondering about how do they calibrate the satellites to real ice? I.e., have they had anybody actually go out there and check to make sure there is open water where the satellites say there should be? My doubts stem from the rather stark difference between the ice area given by Alaskan weather service and the AMSRE satellites — see links below. This difference has persisted for several years in the late summer period, and emails to both providers produced very emphatic assertions that their view of ice limit is the accurate one.
http://pafc.arh.noaa.gov/ice.php?img=fullice
http://www.iup.uni-bremen.de:8084/amsr/arctic_AMSRE_nic.png
R. Gates
everyone knows that these days all them old farts have their own set of removable snappers.
If you are suggesting that toothless retired people living in homes drives sea ice levels, I have a satellite to sell you.
“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!).”
Did we have satellites during the Climate Optimum? More likely the least amount recorded since we started worrying about warm weather. Prior to then the average person had enough common sense to recognize that except for a narrow band in the tropics, the earth is too cold for human survival without fire. There was actually a time when people dreamed of an ice free arctic and how it would revolutionize global trade and commerce. Now the mice that inhabit this planet can only see it as yet another thing to fear.
A new climate worry. Nuclear subs under the Arctic are responsible for melting 40,000,000,000 tonnes of arctic ice.
http://www.sciencefile.org/SciFile/forum/The-h-Bar/168449-Nuclear-power-plants-beneath-the-Arctic-ocean
Perhaps some of the mice are less timid than others?
Russia says high ice melt opens Arctic trade routes
http://news.yahoo.com/russia-says-high-ice-melt-opens-arctic-trade-214152102.html
MOSCOW (Reuters) – Arctic ice cover receded to near record lows this summer, opening elusive northern trade routes from Asia to the West, Russia’s climate research agency said on Wednesday.
After the third hottest year on record since 1936 in the Arctic last year, ice cover has melted as much as 56 percent more than average across northern shipping routes, making navigation in the perilous waters “very easy,” it said.
“Since the beginning of August icebreaker-free sailing is open on almost all the routes,” the climate monitoring agency said on its website http://www.meteoinfo.ru.
It added that the mild conditions would last through September on shipping lanes that are tens of thousands of kilometers shorter than southern alternatives.
With retreating ice opening new strategic trade routes, Russia hopes to make Arctic passage a competitor to the Suez Canal, profiting from taxes and the lease of its unique nuclear icebreaker fleet to escort cargo ships along its Siberian coast.
http://www.redorbit.com/news/science/2091224/arctic_sea_ice_may_be_melting_slower_than_thought/index.html?source=r_science
Arctic Sea Ice May Be Melting Slower Than Thought
“Our studies show that there have been large fluctuations in the amount of summer sea ice during the last 10,000 years,” Svend Funder, team leader of the study, said in a press release.
“During the so-called Holocene Climate Optimum, from approximately 8000 to 5000 years ago, when the temperatures were somewhat warmer than today, there was significantly less sea ice in the Arctic Ocean, probably less than 50% of the summer 2007 coverage, which was absolutely lowest on record.”
That looks just like an upside down Hockey Stick.
Does anyone know the whereabouts of Mikey Mann and does he have access to this data ?
Looks like a CME caused satellite problem.
As an aside, the Artic has been naturally near ice free prior to 20th century. I am sure no one got excited when that occurred. Hardly anyone noticed it.
John
We all better hope it is a glitch…
REPLY: You forgot to add, Best, D
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?
It’s an honest question, since I really do have to wonder how this system works that could make it the case that “errors” are one sided. Perhaps in such cases the appropriate term would be “bias”, as the technical definition of “error” usual refers to situations were the inaccuracies go up or down. A bias is inaccuracy in a particular direction.
Of course, sense these incidents seem to be a result of sensor defects, perhaps someone can figure out a way to engineer sensors less prone to failure? I assume someone is probably working on this.
“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?
The Goracle has come true…… /sarc
Negative sign failure mode?
Oh how convenient….just turn the sensor off once in a while, and hope nobody notices.
But TWO sudden drops at opposite ends of the earth at the same exact time? Major anomalies, no less. What are the odds of that happening? This is a screaming example of let’s see the raw data before it gets “adjusted”.
It could be a manipulated sensor data Al Gore ithm !
ttca;
I think this is more along the lines of sensor failure, or dropout. CME victims.
Lol…right after you pointed out that sea ice extent had taken a left…uh…right turn. Are you sure it’s not just another convenient “data adjustment”?
R. Gates says:
August 7, 2011 at 2:51 pm
I am not aware of Putin claiming to be pumping hot crude under the Arctic Ice, so exactly when & where did this pipeline stuff come into being?
Let’s hope it’s only a glitch in instrumentation, not the sign of a larger scale data alteration fraud scheme suddenly gone out of control…
It’s either a CME blast that did it, or the Aliens abducted another sensor mistaking it for a lifeform.
I’ll go with the CME.
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?
=================================================================
It doesn’t happen, underestimating is build in to the day to day….
……keep in mind, CryoSat-2 is only one year old, and just produced it’s first data a few weeks ago.
CS-2 is tuned to Envasat, which is tuned to Jason 1 – 2, which are all tuned to the computer climate models when they deviate from what the computer climate models say they should say……
“The primary instruments aboard CryoSat-2 are SIRAL-2,[18] the SAR/Interferometric Radar Altimeters;[12] which uses radar to determine and monitor the spacecraft’s altitude in order to measure the elevation of the ice.”
“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.”
Gareth Phillips says: “…sorry to her about the rowers, have they fallen out with each other and started rowing?…
Oar-able pun, simply oar-able, Gareth.
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.
GogogoStopSTOP says:
August 7, 2011 at 3:25 pm
I used to be suspicious of this ice data. Now I don’t believe it at all. It’s the attitude of the people on the analysis end that disturbs me. ‘Doesn’t deserve to blog about(!)’ What a inarticulate, unprofessional thing to say. From our “friends” in the government!
We used to have, what, almost 6,000 temperature collection points throughout the world? Now we have 1,200, 1,300? And all the one’s that were dropped were in cooler places, all the one’s kept were in predominately urban areas, airports, parking lots.
####
there are 77,000 stations in GHCN daily supplying a wide variety of parameters
Not all of these are temperature stations of course, but 10s of thousands are.
From the change log
Effective January 24, 2011, the number of GHCN-Daily stations will
increase by 325 to a total 76671 with the addition of new U.S. Cooperative
Observer and CoCoRaHS stations.
1. Data from approximately 17000 Australian stations will be added on
20 September 2010. These data, supplied by the Australian Bureau
of Meteorology, replace any previous data for Australian stations
and will be updated monthly. The new total number of stations in
GHCN Daily is 75239.
Recently I downloaded 7676 stations from Environment canada.
Dont mistake GHCN for all the data.
Here is the funny thing. If you look at global coverage from UHA or RSS you see the whole planet and you can look at the trend since 1979. Now, pick 200 surface stations at random from around the world.
Pick stations not at airports, pick stations at rural locations. calculate the average. Guess what?
It’s substantially the same as UHA or RSS and CRU and GISS.