When Satellites go Boink

April 13, 2016


A friend dropped me a note the other day, asking what was going on with Arctic ice, which just set a new record for the lowest maximum extent on the modern record.
Quick look at the National Snow and Ice Data Center’s graph showed a peculiar spike.


..Which looked spurious, given what we know about current temperature conditions in the Arctic.  Several other indicators looked funky, as well.


A few inquiries revealed that, yes, the satellite was bonkers. Today this from NSIDC:

NSIDC has suspended daily sea ice extent updates until further notice, due to issues with the satellite data used to produce these images. The vertically polarized 37 GHz channel (37V) of the Special Sensor Microwave Imager and Sounder (SSMIS) on the Defense Meteorological Satellite Program (DMSP) F-17 satellite that provides passive microwave brightness temperatures is providing spurious data. The 37V channel is one of the inputs to the sea ice retrieval algorithms, so this is resulting in erroneous estimates of sea ice concentration and extent. The problem was initially seen in data for April 5 and all data since then are unreliable, so we have chosen to remove all of April from NSIDC’s archive.

It is unknown at this time if or when the problem with F-17 can be fixed. In the event that the sensor has permanently failed, NSIDC is working to transition to either the DMSP F-18 or possibly the JAXA Advanced Microwave Scanning Radiometer 2 (AMSR2) on the Global Change Observation Mission – Water (GCOM-W) satellite. Transitioning to a different satellite will require a careful calibration against the F-17 data to ensure consistency over the long-term time series. While this transition is of high priority, NSIDC has no firm timeline on when it will be able to resume providing the sea ice time series. For background information on the challenges of using data in near-real-time, see the ASINA FAQ, “Do your data undergo quality control?

UPDATE: Japanese sat probably closer to reality.


13 Responses to “When Satellites go Boink”

  1. pendantry Says:

    O.o … cue the denial crowd crowing about ‘data manipulation’ (sic).

    • markle2k Says:

      I was wondering if we were about to hear about some big cyclone in the Arctic pushing ice out and inflating the extent (15% coverage, remember). The JAXA data shows a growth of ~60k km^2 between the 10th and the 12th with almost all of it (83%) in the last day.

  2. skeptictmac57 Says:

    Look at the quick response by these scientists in an effort to get the data right (adjustments?) . Contrast that to the foot dragging by deniers when their favorite data set erroneously biases the data toward cooling.
    That’s the difference between the intellectually honest approach to science, and the ideological one.

  3. dumboldguy Says:

    Lets play the conspiracy game for a bit. What with all the grim news about unprecedented Greenland ice melt, record Arctic sea ice decline, and ever-accelerating Antarctic glacier flow, the powers that be have had a convenient “failure” that will allow them to “black out” some of the bad news for a while. It will be “move along, folks, we have nothing to show you so you folks in FL and NC and VA and NJ shouldn’t worry about that water rising over your shoes”.

    (I will drop my conspiracy thoughts and agree with skepticman if and when the “adjustments” are made and the data flows again—-I have never liked the term “until further notice”).

  4. grindupbaker Says:

    Less sea ice departing the Arctic Ocean and north Atlantic slows the thermohaline circulation.

    • dumboldguy Says:

      And is that any more relevant to a satellite failure than the fact that cold slows the circulation in my feet and makes them numb? If so, how?

    • grindupbaker Says:

      “thermohaline” got me focussed/obsessed with salinity but since Arctic Ocean is less saline than Atlantic it would be a retarding component. There can be a horizontal force simply by going down hill but it would not sustain a current. Mostly the cooling that’s causing the pressure difference I’m thinking, with some local salinity increase. I see that a paper North Atlantic deep water formation by Bennet, Wally Broecker, Hansen has a part at page 47 about sea ice but it’s only about overturning in situ, to drive a current the sea ice has to depart and melt elsewhere to remove the 12 psu(?0 freshish water. I suppose the bottom line is that sea ice is a negligible factor.

  5. shelama Says:

    As long as we’re doing Calvin & Hobbes and the subject is Arctic ice…. http://assets.amuniversal.com/2cc64e90debb01317193005056a9545d

  6. […] recent weeks, one of the important satellite monitors of arctic sea ice, a critical control on global weather and climate, (see elsewhere on this page) […]

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