From NSIDC and the “worth blogging about” department
Sensor on F-17 experiencing difficulties, sea ice time series temporarily suspended
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?”
Here’s what the failure looks like:
Interestingly, the failure in 2009 and this one both came to the attention of NSIDC on a Monday morning.
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Thanks, Samuel. I’m on Win7, with the latest version of Firefox and Chrome. If I’m the only person with this problem, it’s not that important.
Speaking of fixing things someone needs to kick the ENSO meter as it must be stuck again.
The satellites have been a potential target of the climate con after all.
BTW, if you click on the below Nino 3.4 SST graph, you can get the current weekly Nino 3.4 temp anomaly, which is 1.15C (a drop of 0.1C from last week):
http://www.bom.gov.au/climate/enso/monitoring/nino3_4.png
Cheers!
Thank you! But doing that with the sea ice gives some really strange numbers! So it obviously does not work there.
Conspiracy theorizing dutifully showing up in the comments, it seems apt to mention an old article of mine, http://moregrumbinescience.blogspot.com/2011/07/how-large-conspiracy.html How large would the sea ice conspiracy have to be?
F-17 was launched November 2006, so these problems are showing as it approaches its 10th birthday. Given that the design life was 5 years, it’s doing awfully well for a geezer. The surprise is that it was still giving good data through to this month, and that it is still doing so on almost all its channels. Not that an elderly satellite is having some data quality issues.
Glitches, errors, sensor fall-off are OK as long as the down trend is maintained. Data for the last three months is suspect; how long does it take to realize the data is atypical? Didn’t the last failure occur during winter? Much too convenient for my taste.
Do the AMSR2 face also some problems now?
http://www.meereisportal.de/fileadmin/user_upload/redakteur/sea_ice_latest/extent_n.png
Data outage 1600 UTC on April 15th to 0740 UTC on the 16th. And apparently this graph doesn’t respond well to data voids.
The apparent source of the problem has been found, the attached is the announcement by NSIDC:
“Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations, Version 1
Notice (04/05/2016): Notice (04/19/2016): Daily sea ice concentration updates have improved. On 04/05/2016 a change in the solar panel position to shade the nitrogen tank on board the Defense Meteorological Satellite Program (DMSP) F-17 satellite was made. In doing so, the integrity of the vertically polarized 37 GHz channel (37V) of the Special Sensor Microwave Imager and Sounder (SSMIS) was compromised. This is a primary channel used in the sea ice processing. On 04/13/16 an additional change in the solar panel position was made.This change has improved the problems we were seeing in the 37V GHz channel. The affected daily files from 04/05 – 04/13 have been removed from distribution.”