Tag Archives: Polar Portal

Sea Ice Data Tampering At DMI?

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Not a lot of people know that our headline for today (apart from the terminating question mark) has been shamelessly plagiarised from Paul Homewood’s latest Arctic article. This will give you a flavour of Paul’s purple prose:

Electroverse have uncovered some blatant data tampering by DMI:

“It would appear that the Danish Meteorological Institute (DMI) may have taken a leaf out of NASA’s ‘data-fudging 101‘.

Sometime between late-Nov and early-Dec this year, the DMI’s Arctic Sea Ice Volume chart experienced a mysterious ‘vanishing’ of ice — this is revealed by a direct comparison of the Nov 18th and the Dec 8th charts below.”

I am able to corroborate their findings. In September I took this screenshot of DMI sea ice thickness. Note that the black line for this year was close to the 2018 line, and above 2017 for Sep 20th:

But the new version shows this year well below those two years:

There is no other way to describe this than blatant fraud. The changes do not appear to have been even documented, and the old data is not archived, being simply “replaced”. These should surely be very basic scientific requirements.

Neither does there appear to have been any public announcement by DMI about the fact or the justifications for what amounts to a significant change.

What this episode means is that DMI can no longer be trusted to produce honest, reliable data. It also raises the question of whether similar tampering has been carried out in previous years, without anybody being aware. After all, it is only by pure accident that it has been spotted this time.

Even fewer people know that my helpful explanatory comment is currently invisible to Paul’s band of merry (mostly) men:

Should anyone contrive to click on the invisible link this what they would see just below the DMI’s recent Tweet:

Quite predictably Tony Heller has also jumped on the self same bandwagon, claiming in an article entitled “Rapidly Disappearing Arctic Ice” that:

On December 4, DMI showed Arctic sea ice volume above the 2004-2013 average:

Quite predictably, the data disappeared for three days, and now that it has returned, DMI has massively reduced the amount of sea ice in the Arctic. Much of the thick ice off the coast of Siberia has disappeared:

Presumably their data tampering has freed the Russian ships trapped in the ice.

In normal circumstances I would of course point out the error of his ways to Tony via Twitter. However:

Here is the DMI’s explanation for the recent change in their Arctic sea ice thickness/volume visualisations, as shown on their “Polar Portal” web site:

New graphics December 7, 2021

We have improved the DMI operational ocean and sea-ice model HYCOM-CICE with higher horizontal resolution and updated HYCOM and CICE code. In particular, the sea ice code has been greatly improved with meltponds, sea-ice salinity, improved thermodynamics and much more. The freshwater discharge from Greenland has also been greatly improved using freshwater product from GEUS, which especially improves the coastal ocean currents and thus the ice transport nearshore Greenland. The model has been running continuously since September 1990. Therefore, we have by December 07, 2021 updated the graphics of sea-ice thickness and volume using the new and improved data on Polarportal and ocean.dmi.dk.

The improved model setup has led to higher variability as well as less abrupt melting during the melt season, which gives a shift of approximately half a month for the time of minimum ice volume. The trend between the years is almost unchanged. Thereby, a year with a large sea-ice volume in the old setup also has a large volume in the new setup, and similar for years with low sea-ice volume.

I always thought that “skeptical” folk didn’t much care for the output of “climate models” but I guess I must have been mistaken?

[Edit – December 13th]

Needless to say my comment at NALOPKT is still invisible this evening. However credit where credit is due. Tony Heller has at least not censored my comments on his blog. Earlier today Watts Up With That referred to both the Heller and Homewood DMIGate2 articles. Do you suppose the following helpful comment of mine will ever see the light of day at WUWT?

Watch this space for more #DMIGate2 news as and when we receive it!

Greenland 2016 Melt Starts A Month Early

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According to the Danish Arctic research institutions’ Polar Portal this year there’s been an “Unusually Early Greenland Melt“. The article by Ruth Mottram points out that:

An early melt event over the Greenland ice sheet occurred this week, smashing by a month the previous records of more than 10% of the ice sheet melting.

Greenland-Melt-2016-04-11

Based on observation-initialized weather model runs by DMI, almost 12% of the Greenland ice sheet had more than 1mm of melt on Monday 11th April, following an early start to melting the previous day. Scientists at DMI were at first incredulous due to the early date. “We had to check that our models were still working properly” said Peter Langen, a climate scientist at DMI. “Fortunately we could see from the PROMICE.dk stations on the ice sheet that it had been well above melting, even above 10 °C. This helped to explain the results”. The former top 3 earliest dates for a melt area larger than 10% were previously all in May (5th May 2010, 8th May 1990, 8th May 2006).

Just in case you think the DMI’s models really aren’t working properly, take a look at this satellite image of South West Greenland today:

NASA Worldview “true-color” image of South West Greenland on April 12th 2016, derived from the MODIS sensor on the Terra satellite
NASA Worldview “true-color” image of South West Greenland on April 12th 2016, derived from the MODIS sensor on the Terra satellite

Then head over to NASA Worldview and flip back to last year using the controls at the bottom left:

SWGreenland-Terra-2015-04-12

Can you spot the difference? According to the Polar Portal once again:

Around the coast of Greenland where DMI has climate records dating back to 1873, Greenland came close to setting a record temperature for the whole of Greenland in April. Kangerlussuaq measured a daily maximum of 17.8°C, the previous record is 18.0°C and the DMI observation station at the Summit of Greenland set a new “warm” April record of -6.6°C. “Everything is melting” observed Nuuk resident Aqqaluk Petersen.

The melt was driven by warm air advected from the SW bringing rain along the coast, similar to an extreme melt event in 2012 when 95% of the surface of the ice sheet had melt, a situation that has been reported in detail by GEUS and DMI scientists (Fausto et al., 2016).

[Edit – April 15th 2016]

It has been brought to my attention that the cloud cover in the first image above makes it difficult to see the melting ice sheet. By way of explanation, at this time of year you can use images derived from the MODIS instrument on the Aqua and Terra satellites and the VIIRS instrument on the Suomi satellite to watch the snow cover retreat across Alaska, Canada, Siberia and indeed Greenland.

There is less snow on the ground in SW Greenland than “normal” this year, and hence lower albedo. This implies there will also be less snow on the ice sheet itself, which is hence more vulnerable to “early melt”. In order to get visual confirmation of melt ponds on the ice clear blue skies are needed. You can see hints of “blue ice” through the gaps in the cloud on my first image above. To bring out the “blue ice” try following the link above to NASA Worldview and then experiment with the controls on the left. If you select “Corrected Reflectance (Bands 7-2-1) you should be able to produce an image that looks like this:

NASA Worldview “false-color” image of South West Greenland on April 12th 2016, derived from the MODIS sensor on the Terra satellite
NASA Worldview “false-color” image of South West Greenland on April 12th 2016, derived from the MODIS sensor on the Terra satellite

For a closer look between the clouds here’s a “natural colour” image from Landsat 8:

A “natural color” image of South West Greenland on April 12th 2016, from the Landsat 8 satellite
A “natural color” image of South West Greenland on April 12th 2016, from the Landsat 8 satellite