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D

NSIDC is still "calibrating" for 2016. I looked for information there but found nothing. Thanks to you and DMI for writing up this chilling story.

AbbottisGone

What do you mean by still calibrating?

Is there some sort of official word on the matter?

The graphs went up,... Is this false?

Neven

Yes, there is an official word on the NSIDC website:

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.

A switch to AMSR2 wouldn't bee too great, because if everyone starts to rely on that and it goes boom too...

Of course, there will always be other (non-passive microwave) sensors to observe Arctic sea ice, but changes should be kept as small as possible.

Neven

Robertscribbler has a follow-up post: The Greenland Summer Melt Season Just Started in April

And Climate Central reports: Greenland's Melt Season Started Nearly Two Months Early

Neven

I've asked Ruth Mottram about the differences between the way DMI and NSIDC measure ice sheet melt as a percentage of total cover and here's her reply:

We have looked at the dates Marco mentioned and found they did not pass our (admittedly rather arbitrary) threshold of 10% of the ice sheet area melting though it came fairly close.

The 5th and 6th April 2012 both had about 9% of the area melting in our model, days either side had about 3% melt area.

To answer your question on the NSIDC and DMI Greenland melt products:

The two products are complimentary as the NSIDC method is essentially a satellite based estimate of where melt is occurring based on passive microwave scatter, whereas our SMB and melt estimates come from a model. The surface model is driven by a weather forecast model, which has observational data assimilated into it, but with no observations directly assimilated from the ice sheet surface. Nonetheless we are pretty confident it does a good job in describing the melt area as, when the NSIDC page is live, the two are often rather similar. The promice stations on the ice sheet also confirm that the HIRLAM/HIRHAM model performs pretty well in characterizing the ice sheet weather.

We hope to produce a paper showing this and documenting the model system soon.

Two further differences between the two products that may cause a divergence in results:

1) We use different ice masks, ours is based on a very thorough mapping of the ice sheet carried out by Michele Citterio and Andreas Ahlstrøm at GEUS, the NSIDC one is older and in most places has a larger ice sheet area. I think it may be based on an old USGS map of Greenland as our previous ice mask had some similar problems. This would probably mean that the NSIDC product shows a larger melt area than the model.

2) The resolution of the two data products is also different, our model is run at 5km, the NSIDC product calculates gridded brightness temperatures for grid cells of 25 x 25km. This means you may get a different percentage area of the ice sheet when comparing melt across grid cells.

I'm adding this answer to the blog post.

wayne

The ice horizon announced this heat wave well before it arrived.
It was marked by a prolonged, longer than all previous records, continuous lower horizon.

It also goes like this, the coldest atmosphere agglomeration has shrunk dramatically dragging straight North Cyclones usually dedicated to the UK and Ireland.

The coldest air never garnished enough depth on land and sea ice,
so summer will come early everywhere.

Bill Fothergill

Whilst on the Woods Hole site looking for some info on Sea Level Rise, I happened to notice the attached article discussing Greenland melt.

https://www.whoi.edu/oceanus/feature/scientists-find-trigger-that-cracks-lakes

As he is excellent at sniffing out such pieces, it is very possible that Colorado Bob has already mentioned this article in an earlier thread. (It's a toss-up these days which is worse - my memory or my eyesight.)

Colorado Bob

Bill Fothergill -

Thanks for the hat tip.

(It's a toss-up these days which is worse - my memory or my eyesight.)

Move over, you're not the Lone Ranger.

Insert smiley face here.

Colorado Bob

Bill Fothergill -

I read about this today in Antarctica. Cracks appear in the ice . Melt water drains down the cracks , it wedges the ice apart.
It's called "hydraulic fracking" .
Scientists Are Watching in Horror as Ice Collapses

http://news.nationalgeographic.com/2016/04/160412-ice-sheet-collapse-antarctica-sea-level-rise/

Colorado Bob

Scientists Are Watching in Horror as Ice Collapses

http://news.nationalgeographic.com/2016/04/160412-ice-sheet-collapse-antarctica-sea-level-rise/

Water weights 8.6 pounds per gallon. It's very heavy.

It moves the heat. It carries life. It's 70 percent of life.

Jeff Lemieux

This is the article on Antarctica that's troubling me today. From an insurance conference of all things. Don't know if this is well vetted or just some more offhand comments, but the hints that the latest fieldwork is from WAIS is particularly bad, but that the results won't be released for years, is a bit jarring.

http://www.insurancejournal.com/news/national/2016/04/12/405089.htm

Margaret Davidson, NOAA’s senior advisor for coastal inundation and resilience science and services, and Michael Angelina, executive director of the Academy of Risk Management and Insurance, offered their take on climate change data in a conference session titled “Environmental Intelligence: Quantifying the Risks of Climate Change.”

Davidson said recent data that has been collected but has yet to be made official indicates sea levels could rise by roughly 3 meters or 9 feet by 2050-2060, far higher and quicker than current projections. Until now most projections have warned of seal level rise of up to 4 feet by 2100.

These new findings will likely be released in the latest sets of reports on climate change due out in the next few years.

“The latest field data out of West Antarctic is kind of an OMG thing,” she said.

AbbottisGone

Going out on a limb I would expect that forecasts of 3m of sea level rise by 2060 would never be released!

If that is anywhere near the truth we are already in anarchy!!

Al Rodger

Jeff Lemieux,
I think you would describe Margaret Davidson as a technical/scientific civil servant rather than a scientist and her un-referenced statement is not well made.

I'm sure that if there were some "OMG" field data out of West Antarctica, even preliminary data, it would not remain secret in the manner described. So I would suggest that Davidson is referring to something in plain sight.
Perhaps she refewrs to Hanson et al (2016). That paper is based on a certain level of evidence but is more a discussion document rather than a focused piece of science. It does point to "West Antarctica and Wilkes Basin in East Antarctica (having) potential to cause rapid sea level rise" which sort of fits the bill although the paper does not provide the "roughly 3 meters by 2050-2060".

FrankD

Are the F-17 sensor issues behind the bizarro numbers Cryosphere Today have been posting recently? Areal variations of 700,000 sq km per day can't possibly be right.
(obviously there are some data quality assurance issues as well, but that's another story...)

Jim Hunt

Frank - In brief - Yes! For much more detail on that see:

Satellite Problems With Arctic Sea Ice Measurement

For a related story on "data quality assurance issues" in certain sections of the cryoblogosphere see also:

Global Sea Ice “Comeback” Conspiracy

As you point out "that can't possibly be right", but certain "experts" seemed not to notice:

You will note that we were not the only ones to swiftly conclude that Judy [Curry]’s assertion was lacking both veracity and verisimilitude!

Do you suppose we can now expect a “fulsome apology” from the other players in this tragi-comic farce, together with all their rebloggers, retweeters, plagiarisers and other assorted acolytes?

AbbottisGone

I like to imagine the good people of NSIDC let the false data go on for few more days to imply that a concession from the deniers was really required once they admitted their data had to be admitted faulty and thus pulled from the official record.

I like to imagine...

Jim Hunt

Fondly imagine if you so desire AiG, but no hint of an apology, fulsome or otherwise, has yet emerged via the virtual pens of Curry, Peiser, Watts et al.

http://GreatWhiteCon.info/2016/04/global-sea-ice-comeback-conspiracy/#comment-214267

Watts seem particularly keen to prevent any hint of the actual facts emerging within his soundproof "skeptical" echo chamber.

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