Readers may recall that I brought an issue with NSIDC’s sea ice data to their attention back in February 09. The official response from Walt Meier then was “its not worth blogging about”. Shortly afterwards that tune changed when it was announced:
Not only was the glitch I pointed out part of the sensor failure real, there was also a long term drift in the sensor readings.
Cryosphere Today followed soon afterwards, pulling the plug on their data plot.
This image below is what prompted me to bug NSIDC about the issue, the downspike was highly atypical of the dataset.
The glitch seen above turned out to be a “catastrophic failure” of the SSMI sensor on the Defense Meteorological Program (DMSP) satellite that NSIDC (and many others, including Cryosphere Today) also use. Here’s a look at the problem in more detail that WUWT covered in June.
So today, I was advised in an email that I should have a look at the data from Danish Meteorological Institute (DMI), which also uses DMSP SSMI data to make their web graphic presentation. To quote Yogi Berra, it was “deja vu all over again”. Here’s the DMI image from today:
Note the downward glitch in the black 2009 line. Source: http://ocean.dmi.dk/arctic/icecover.uk.php
Now compare that to the AMSRE sensor data (on the AQUA satellite) from JAXA:
The sea ice extent value from JAXA is 6.5 million km2
The sea ice extent value from DMI is pf course much lower, around 4.4 million km2
That is due to DMI choosing to plot “where areas with ice concentration higher than 30% are classified as ice”, while NSIDC, CT, and JAXA plot an area with at least 15 % sea ice. So the absolute difference isn’t what concerns me, it’s that darn glitch again.
NSIDC and CT have taken steps to filter out such things in their own records. DMI obviously hasn’t. The fact that such abrupt downward glitches are still observable in the DMSP SSMI data makes me concerned for the integrity of the dataset. In May 2009, NANSEN also had problems with SSMI data.
Nansen Corrects Sea Ice Data – Sea Ice Extent Now Greater, Near Normal for Most of April/May
So the biggest names in sea ice data on the web, NSIDC, Cryrosphere Today, NANSEN, and now DMI, all of which use SSMI data, have had problems with it. The IARC-JAXA data has held steady.
This is why I prefer using the JAXA AMSRE data from the AQUA satellite to look at current and recent history sea ice events. The newer AMSRE sensor has not shown any such errors, drifts or glitches during its history.
It would seem to me that the time has come for these agencies to consider switching to the more reliable AMSRE/AQUA platform and splicing the older SSMI data set with appropriate considerations to make an accurate longer term record of sea ice since 1979.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
More hockey sticks, inverted or otherwise. They’ve lost one, what’s wrong with trying to fool the masses again?
How do we know that the ice sheet records of 1979 are correct? They can be just as faulty as the glitches from this year show.
It seems that from 18 september the problems are in the current gulf too:
in september i send an e-mail to noaa, and they respond:
” A new initialization was implemented today for the RTOFS-
Atlantic operations. This was needed to fix numerical problems near the
southern open boundary of the model domain. A significant
change with improvements in the overall ocean state is expected.
The product line remains the same as before.
Please note that this change today is independent of the already
planned upgrade of RTOFS-Atlantic production next month.
”
Now we are in the middle of october, and the problems seem to continue…
http://polar.ncep.noaa.gov/ofs/aofs_images/large/aofs_cur_nowcast_natl.png
Or is all ok?
Anthony, do you know something?
Simon from Italy
I have a simple question…please pardon my ignorance. Is this the same satellite/sensor that provides the Arctic temperature measurements displayed on the righthand bar up above (http://ocean.dmi.dk/arctic/meant80n.uk.php)? If so, could these sensor problems be behind the weird Arctic temperature readings as of late? Once again, sorry if this is a dumb question. I guess it’s possible that the data is correct, but the form of the curve looks different this year when compared to the last 10 years or so of data that I looked at.
Ooops, a little heavy on the homogenizing there, I’ll just type in some new numbers in the model and it will look more plausible. Sorry.
What do the maintenance and data quality people do? I assume as long as the trends agree with the grant money, nothing.
Robin Guenier (00:03:02) :
It’s interesting to compare the AP “North Pole summers ice-free in 10 years” story (given headline prominence by a reverting to type BBC this morning) with the 6 October NSIDC press release that reported that “Second-year ice made up 32 percent, compared to 21 percent in 2007 and 9 percent in 2008”.
NSIDC Scientist Walt Meier commented, “We’ve preserved a fair amount of first-year ice and second-year ice after this summer compared to the past couple of years. If this ice remains in the Arctic through the winter, it will thicken, which gives some hope of stabilizing the ice cover over the next few years”.
But the real kicker is that the older than 2yo ice has dropped from 52% to 19%, that’s a major change. The younger ice flows more easily, it’s flowing out of the Fram at a good clip now, hence the tongue of ice down the E Greenland coast, that is mainly 2+yo ice which will be gone next summer.
But, there again, perhaps we shouldn’t overlook the real polar ice authority: early this year, Al Gore warned us that “the entire north polar ice cap may be gone in five years”.
AndyW35 (00:40:19) :
“I quite like them using different sensors/satellites so we can spot the problems better!”
An excellent point IMHO. “Faulty” or not, at least there is more than one source for data. I believe the word is “weighting”?
Just a completely random and irrelevant thought: Perhaps arctic sensors and satellites appear to be sentient beings, and a Vogon is reading poetry to them, and they are self-destructing in an attempt to make the pain stop.
Now, back to our regularly scheduled program . . .
So the biggest names in sea ice data on the web, NSIDC, Cryrosphere Today, NANSEN, and now DMI, all of which use SSMI data, have had problems with it. The IARC-JAXA data has held steady.
This is why I prefer using the JAXA AMSRE data from the AQUA satellite to look at current and recent history sea ice events. The newer AMSRE sensor has not shown any such errors, drifts or glitches during its history.
Likewise, all though I also use CT because I prefer area over extent and that has a longer history. CT changed to AMSR_E anyway but have apparently done a splice for their comparison page (although I don’t use that often). NSIDC switched to the other SSMI satellite and appears to be OK since.
After ArcticROOS did their switch it looked too erratic to me so I haven’t used it in a long while.
I read with great mirth Steve H’s tale about losing his sail boat. I suspect he’s off on Lake Minnetonka, about 2 miles from where I live.
What he didn’t mention (I will) is that the smaller lakes and ponds now are having an ice layer on them. That is rather ODD for MN this early. Today it is rain and snow. I’m looking out at trees covered with GREEN leafs! Apparently the cold has come on us so fast, that it has “locked” the leafs on the trees, “frozen” them, as it would be, at the late summer early fall stage. Now for the kicker – – – this is being blamed on a deep jet stream pull, bringing down an ARCTIC AIR BLAST.
Maybe Catlin can come to Lake Minnetonka in January, and get some “Arctic expidition practice”. Nice thing is, by following the right route, they could pop off for a nice burger or “Bloody Mary”, in a warm business..when the going gets too rough. Well, copping out early should be no problem for them. (They’ve done it before.)
That downward trend has been corrected in the interesting form of an upward squiggle.
http://ocean.dmi.dk/arctic/icecover.uk.php
That downward trend has been corrected in the interesting form of an upward squiggle.
http://ocean.dmi.dk/arctic/icecover.uk.php
Sorry, forgot to add great post! Can’t wait to see your next post!
Janice (07:17:49) :
Perhaps arctic sensors and satellites appear to be sentient beings, and a Vogon is reading poetry to them, and they are self-destructing in an attempt to make the pain stop.
Not altogether unbelievable. Here is a sample of Vogon poetry:
“Oh freddled gruntbuggley, thy micturations are to me
As plurdled gabbleblotchits on a lurgid bee
Groop I implore thee, my foonting turlingdromes
And hooptiously drangle me with crinkly bindlewurdles, or I will rend thee in the gobberwarts with my blurglecruncheon, see if I don’t!
Apologies…
Pragmatic (10:00:59) –
Now you’ve done it. My CPU just tried to escape so it could throw itself off the balcony.
“”” Pragmatic (10:00:59) :
Janice (07:17:49) :
Perhaps arctic sensors and satellites appear to be sentient beings, and a Vogon is reading poetry to them, and they are self-destructing in an attempt to make the pain stop.
Not altogether unbelievable. Here is a sample of Vogon poetry:
“Oh freddled gruntbuggley, thy micturations are to me
As plurdled gabbleblotchits on a lurgid bee
Groop I implore thee, my foonting turlingdromes
And hooptiously drangle me with crinkly bindlewurdles, or I will rend thee in the gobberwarts with my blurglecruncheon, see if I don’t! “””
I’ve actually heard people who can talk like that for three hours straight; they do it all the time on “Coast to Coast AM” that evolved out of the Art Bell Radio show; now hosted by George Noory.
They rattle on about Harmonic Convergences, and other tripe; and they do it in such a way, that half the time, I can’t tell if George believes a word of it or not; same goes for some of his other hosts that do the program on the weekends.
Sometimes you even can read that stuff here on WUWT; and it even gets followed by other visitors.
George
George E. Smith, I hope you’re not quoting my favorite Vogon piece in order to mock it! I have oft longed again to experience crinkly bindlewurdles. And nobody, NOBODY can take away the breathtaking enjoyment of micturation.
Jari (19:46:24) :
DMI is Danish, not Dutch.
___________________________________
But Denmark is actually IN the Netherlands, right Jari? [Just kidding]
I’m currently working on downloading the data from ASMR-E. It’s in a nightmarish format from the NSIDC which forces you to download 50mb files for each day and separate the part you want out using an asinine data format invented for ‘data sharing’ it’s a nightmare.
On this upcoming Sunday the Air Force is planning to launch DMSP F18. The launch time is set for 9:12 am PDT. It will launch from Vandenberg AFB, CA and head south over the Pacific. Anyone on California’s central and southern coastal areas should have a good view. It appears that the weather will be very nice and visibility should be excellent.
The sea ice page of Spreen and Kaleschke at Uni-Hamburg has data from AMSR-E for area and extent for both poles. They only update once/month, though. Their ftp server is here: ftp://ftp-projects.zmaw.de/seaice/AMSR-E_ASI_IceConc/area-extent/
CodeTech (12:16:10) :
last time I saw THAT word was in Billy Bathgate. Ranks up there with “caprophagous”… which is my considered and erudite opinion of catastrophic warmers in general and RC commenters in particular.
http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2009252/crefl1_143.A2009252204500-2009252204959.250m.jpg
This a satellite shot
from the file–
http://rapidfire.sci.gsfc.nasa.gov/realtime/2009252/?multiple&resolutionlist
Lower and middle right shows
shattered scattered ice pieces
which can only be the result of intense
icebreaker activity–
warm water or air does not disrupt ice in this manner–
With minimal attention it
will be easy for you to differentiate
between the ice chunks and the cloud cover.
No update for http://arctic.atmos.uiuc.edu/cryosphere/ since Oct 11.