Tag Archives: Extent

Facts About the Arctic in December 2021

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Christmas is coming. Santa’s secret summer swimming pool has frozen over. The time has come for a new monthly Arctic update.

The JAXA/ADS/ViSHOP web site is undergoing maintenance for a week, so let’s start the festive season with a look at high resolution AMSR2 area and extent:

After a brief hiatus in early November both metrics are once again tracking within, but near the upper bound of the last 10 years.

Next let’s take a look at the latest AWI CryoSat-2/SMOS thickness map:

together with the anomaly map from the Finnish Meteorological Institute:

Still thinner than usual in the so called “last ice area” north of Greenland and Ellesmere Island, and thicker than usual on the Siberian side of the Arctic, particularly in the Chukchi Sea.

Finally, for the moment at least, here’s the latest CryoSat-2/SMOS volume graph:

Unlike the previous metrics, this particular one is close to the middle of the pack.

[Edit – December 5th]

The National Snow and Ice Data Center issued their latest monthly Arctic Sea Ice News update earlier than usual this month:

Sea ice extent increased at a faster than average pace through November and by the end of the month, extent was just within the interdecile range. Extent was above average in the Bering Sea, but Hudson Bay remained unusually ice free through the month.

The November 2021 monthly average extent was 9.77 million square kilometers (3.77 million square miles), which ranked tenth lowest in the satellite record. The 2021 extent was 930,000 million square kilometers (359,000 million square miles) below the 1981 to 2010 long-term average. Extent was higher than average in the Bering Sea, but is extremely low in Hudson Bay.

Air temperatures at the 925 millibar level (about 2,500 feet above the surface) were well above average north of the Canadian Archipelago, by as much as 6 degrees Celsius. Conversely, temperatures over southwest Alaska and the eastern sector of the Bering Sea were as much as 6 degrees Celsius below average:

The sea level pressure pattern for November featured widespread low pressure over the Atlantic side of the Arctic and extending into the Barents and Kara Seas, paired with a moderately strong Beaufort Sea High. Strong low pressure over the Gulf of Alaska resulted in a circulation pattern in the eastern Bering Sea that brought cold air from the north. This pattern was favorable for sea ice growth, and can explain the above average ice extent in the region:

[Edit – December 7th]

Since the start of December high resolution AMSR2 extent has been flatlining:

Sea ice area has even declined slightly over the past few days:

Here too is an animation created by Uniquorn on the Arctic Sea Ice Forum using AWI ASMR2 data to reveal ice movement through the Nares Strait during December:

[Edit – December 9th]

The JAXA/ADS/ViSHOP web site is down again, so let’s take another look at high resolution AMSR2 area and extent:

It seems that the “brief hiatus” is over, and extent is now in a “statistical tie” with 2018/19 at 4th lowest for the date amongst recent year.

[Edit – December 13th]

The PIOMAS Arctic sea ice volume data for November 2021 has been released:

Average Arctic sea ice volume in November 2021 was 7,830 km3. This value is the 7th lowest on record for November,  about  1600 km3 above the  record set in 2016.   Monthly  ice volume was 61% below the maximum in 1979 and 45% below the mean value for 1979-2020. Average November 2021 ice volume was about one sigma above the 1979-2020 trend line. October saw relative rapid ice growth  for recent years bringing the mean ice thickness  (above 15 cm thickness) above the recent low values: 

The ice thickness anomaly map for November 2021 relative to 2011-2020 continues to show anomalies divided into positive and a negative halves with areas of positive anomalies increasing since the two prior months. Negative anomalies stretching from North of Greenland and along the Canadian Archipelago across the Eastern Arctic into the Barents Sea. Areas North of Greenland again feature very low ice thickness as in prior years (see our recent paper).  Positive anomalies are notable in the Beaufort and Chukchi seas due to advection of thicker older ice into the areas during the previous winter (See recent paper on this). The Alaskan summer has also been relatively cold contributing to unusually thick ice in this area:

CryoSat-2 ice thickness shows a similar picture sea ice thickness anomalies but with the maxima slightly displaced which maybe due to temporal sampling of the composite:

The JAXA web site is still down, so here’s another set of high resolution AMSR2 graphs:

[Edit – December 14th]

NOAA have just released their 2021 Arctic Report Card. Here’s the introductory video:

and here is the report itself:

[Edit – December 18th]

Ice hardened LNG tanker Vladimir Vize is about to enter the Vilkitsky Strait on the Northern Sea Route:

Meanwhile Science.org reports that “The Arctic is warming four times faster than the rest of the world“:

“Everybody knows [the Arctic] is a canary when it comes to climate change,” says Peter Jacobs, a climate scientist at NASA’s Goddard Space Flight Center, who presented the work on 13 December at a meeting of the American Geophysical Union. “Yet we’re misreporting it by a factor of two. Which is just bananas.”

Jacob’s co-authors include researchers who oversee several influential global temperature records, and they noted the faster Arctic warming as they prepared to release the global temperature average for 2020. NASA’s internal peer reviewer challenged the higher figure, suggesting the scientific literature didn’t support it. But the researchers have found the four times ratio holds in record sets from both NASA (3.9) and the United Kingdom’s Met Office (4.1), and they hope to soon include the Berkeley Earth record. (Their work also has company: In July, a team at the Finnish Meteorological Institute posted a preprint also arguing for the four times figure.)

The researchers found Arctic warming has been underestimated for a couple of reasons. One is climate scientists’ tendency to chop each hemisphere into thirds and label the area above 60°N as the “Arctic”—an area that would include, for example, most of Scandinavia. But the true definition of the Arctic is defined by Earth’s tilt. And, as has been known for centuries, the Arctic Circle is a line starting at 66.6°N. When researchers lump in the lower latitudes, “you’re diluting the amount of Arctic warming you’re getting,” Jacobs says. “That is not a trivial thing.”

The other difference is the choice of time periods over which the warming rate is calculated. Jacobs and his colleagues focused on the past 30 years, when a linear warming trend emerged for the Arctic. Analyses that look at longer term trends see less divergence between the Arctic and the world.

[Edit – December 23rd]

Here is the latest CryoSat-2/SMOS volume graph, now including some reanalysed data which seems to have come in slightly higher than the earlier “near real time” numbers:

Plus the AWI thickness map:

Further discussion of the divergence between volume and extent continues in the new New Year 2022 thread:

Facts About the Arctic in November 2021

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It’s not November until tomorrow, but Andy Lee Robinson has just published the 2021 edition of his long running “Arctic ice cube” video series, based on the PIOMAS volume data. Here it is for your edification:

You may also wish to keep tabs on our deep dive into CERES top of the atmosphere energy flux data. Here’s a sneak preview:

[Edit – November 3rd]

In stark contrast to other recent years, northern hemisphere snow cover is very low at the moment:

Continue reading Facts About the Arctic in November 2021 →

Facts About the Arctic in October 2021

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By way of a change we start this month’s look at all things Arctic with some sea ice statistical analysis. Anthony Watts’ Arctic porky pie production line has been speeding up recently, and I am not the only one who has noticed. As part of his takedown of the latest “skeptical” allegations against the United Kingdom Met Office Tamino has been looking at trends in Arctic sea ice extent over at his “Open Mind” blog:

First and foremost, the yearly minimum is only one day out of the year. We have sea ice extent data throughout the year, and what happens during the rest of the year counts. Instead of using the annual minimum, let’s use the annual average. To avoid losing the most recent data, I’ll compute the yearly average for October through the following September rather than the usual (but arbitrary) January through December. I’ll also omit October 1978 through September 1979 because that year is incomplete. I get this:

The annual averages show much less fluctuation than the annual minima, so we can estimate things like rates of change with greater precision. I find that there is statistical evidence that the rate changed over time. One model of such changes uses three straight-line segments with their changes chosen to best-fit the data, like this:

Continue reading Facts About the Arctic in October 2021 →

The 2021 Arctic Sea Ice Minimum Extent

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The results of the ARCUS Sea Ice Prediction Network August call have been released, and here is the outlook for the 2021 minimum September mean Arctic sea ice extent:

The median prediction for the mean sea ice extent during the month of September 2021 is 4.39 million km2. According to ARCUS:

As of 22 August 2021, the Arctic sea-ice extent was 5.58 (compared with 25 August 2020 value of 4.43) million square kilometers. Arctic sea-ice extent in 2021 remains well below the climatological median and has closely followed the 2012 values for much of the summer but has diverged to higher sea-ice extent starting in early August. The forecasts continue to support September 2021 mean sea-ice extent being well above the September 2020 value. July sea-ice retreat has been greatest in the Eurasian seas, particularly in the East Siberian Sea, making the 2021 ice edge well north of the long-term median edge in Eurasia. Sea ice retreated since the end of July along the northern coast of Alaska, although the ice edge is near its climatological position, which makes the Beaufort and Chukchi sea ice extent the largest at this time of year since 2006. A tongue of sea ice that has been present all summer continues to extend close to land in the Kara Sea, making the northeast passage likely to remain blocked for the first time in several years. Half the models which provide spatial data to the SIO predict that the tongue is likely to survive.

Now let’s take a look at a range of assorted extent measurements. Here’s the NSIDC’s 5 day average extent:

Continue reading The 2021 Arctic Sea Ice Minimum Extent →

Facts About the Arctic in August 2021

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Let’s first of all take a look at JAXA’s flavour of Arctic sea ice extent:

After reaching lowest extent for the date in early July, the weather in the Arctic Basin was stormy, cloudy and cool compared to other recent years until the last few days of the month:

Here’s the same period in 2020 for comparison purposes:

Consequently the rate of extent loss in the second half of July was significantly less than last year.

Next let’s take a look at AMSR2 concentration:

Continue reading Facts About the Arctic in August 2021 →

Facts About the Arctic in July 2021

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The JAXA ViSHOP web site was down for maintenance over the weekend. It is now back in action, to reveal Arctic sea ice extent at the lowest for the date in the AMSR2 record:

[Edit – July 6th]

High resolution AMSR2 area is also now lowest for the date:

as indeed is extent:

[Edit – July 13th]

According to the Canadian Meteorological Centre the current cyclone has bottomed out with a central mean surface level pressure of 971 hPa:

Continue reading Facts About the Arctic in July 2021 →

Facts About the Arctic in June 2021

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Let’s begin the month with a “true colour” image from the Terra satellite of the Laptev Sea and thereabouts:

The blueish tinge indicates the appearance of melt ponds almost everywhere over the land-fast ice currently covering the majority of the Laptev Sea.

Let’s also take a look at the high resolution AMSR2 metrics for the end of May 2021:

Thanks to the recent “brief hiatus” in areal decline, Arctic wide compaction is no longer in record territory:

Finally, for the moment at least, here is the Danish Meteorological Institute’s high Arctic temperature data in the form of a graph of freezing degree days:

For some reason the data file still doesn’t include data to the end of May, but things won’t change much by then. Over the winter as a whole only 2016/17 was significantly warmer.

Let the 2021 Arctic sea ice summer melting season officially begin!

[Edit – June 4th]

Perhaps unsurprisingly the GFS forecast from four days ago hasn’t quite worked out as predicted. The Arctic as a whole is certainly on the warm side, with a +2 C anomaly at this moment:

However the 966 hPa MSLP cyclone predicted for Monday is now forecast to be a mere 978 hPa:

With 3 days to go there is a reasonable chance of it verifying in the “New Arctic” of 2021. As you can see from the map above a large area of the Central Arctic has now lost its snow cover. This is confirmed by the Rutgers Snow Lab northern hemisphere data for May:

A new Sentinel 3 melt pond fraction product from the University of Bremen confirms that on the fast ice in the Laptev & East Siberian Seas snow cover has departed and melt ponds have arrived:

In other news Wipneus has released the latest PIOMAS gridded thickness and volume data on the Arctic Sea Ice Forum:

For some strange reason 2021 volume at the end of May is almost identical to 2012 and 2020! Plus of course there’s the modelled volume export from the Central Arctic via the Fram Strait:

[Edit – June 6th]

This “false colour” image reveals that there’s virtually no snow cover left on land, and this “false colour” image reveals that the land-fast ice in the East Siberian Sea is now awash with melt ponds:

[Edit – June 8th]

The forecast low pressure area appears to have bottomed out near the Severnaya Zemlya islands with a 978 hPa MSLP:

High resolution AMSR2 Arctic sea ice area is now 2nd lowest for the date after 2016:

Laptev sea ice area is still lowest for the data, and looks as though it will retain that position for a while:

[Edit – June 9th]

The effect of the recent heat and wind on the remaining sea ice in the Laptev Sea is now all too apparent:

It’s also evident in the DMI >80N temperature graph, which has now reached sea ice “melting point” ahead of the climatology:

Note that the blue line is actually above the “freezing point” of salty Arctic sea water.

[Edit – June 13th]

Fairly clear skies over the Laptev Sea and the western East Siberian Sea, revealing wall to wall melt ponds and the land-fast ice starting to break up near the coast as well as on the edge of the now open ocean:

Plus yesterday’s view of the Beaufort Sea, revealing fast ice breaking up in the western entrance to the McClure Strait:

[Edit – June 18th]

A clearish view of the Laptev Sea today, revealing assorted cracks in a variety of locations:

[Edit – June 20th]

The latest mid-month PIOMAS thickness/volume numbers have been released:

[Edit – June 23rd]

The skies over the Vilkitsky Strait have been cloudy for a few days. However a fairly clear view yesterday reveals that breakup is well under way in what is usually one the last areas along the Northern Sea Route to become navigable:

[Edit – June 26th]

The land-fast ice in the East Siberian Sea has started to disintegrate en masse:

Data from ice mass balance buoy 441910, currently located at 76.1 N, 151.1 W in the Beaufort Sea, reveals the onset of both surface and bottom melt:

Watch this space!

Steve Koonin’s Unsettled Arctic Science

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Regular readers of this blog will no doubt have realised that way up here in the Great White Con Ivory Towers we concluded many moons ago that Arctic sea ice is the “canary in the climate coal mine”.

Unlike some others we have already mentioned we were not the beneficiaries of a review copy of Steven E. Koonin’s new book, catchily entitled “Unsettled: What Climate Science Tells Us, What It Doesn’t, and Why It Matters”. Hence I was compelled to acquire my own review copy, and have just purchased the electronic version. I eagerly searched the virtual weighty tome for the term “Arctic sea ice”, and you may well be wondering what I discovered?

Nothing. Nada. Zilch. ничего такого. Nic.

I broadened my thus far vain search by removing the “Arctic” specifier, which revealed:

No mention of “sea ice” in the body of the book, merely a reference to the data underlying this graph of northern hemisphere snow cover:

I am forced to an unsettling conclusion. Evidently there are some areas of climate science that Dr. Koonin tells his eager readers nothing whatsoever about. It seems likely that he is also well aware that Arctic sea ice is the canary in the climate coal mine, which is why he has chosen to make no mention of it in his magnum opus.

Here is an informative video which will no doubt not appear in “Unsettled – The Movie”:

[Edit – May 8th]

Having now had time to read some of Steve Koonin’s “Unsettled Climate Science” at greater length I have discovered that it does contain one reference to Arctic sea ice, albeit using non-standard terminology. On page 40 of the Kindle version of the book I read:

Rising temperatures at the surface and in the ocean are not the only indicators of recent warming. The ice on the Arctic Ocean and in mountain glaciers has been in decline, and growing seasons have been lengthening slightly. Satellite observations show that the lower atmosphere is warming as well.

A paragraph I can broadly agree with, but I am compelled to ask why Dr. Koonin does not quantify the “decline of the ice on the Arctic Ocean” anywhere in the book? There are a wide variety of metrics used to quantify the “amount” of sea ice in the Arctic, but here is one readily available for download from the NASA web site. It is hard to believe that a scientist of Dr. Koonin’s experience, particularly one writing about climate change, has never previously come across a similar graph of Arctic sea ice extent:

Arctic sea ice reaches its minimum each September. September Arctic sea ice is now declining at a rate of 13.1 percent per decade, relative to the 1981 to 2010 average. This graph shows the average monthly Arctic sea ice extent each September since 1979, derived from satellite observations.

It seems safe to assume that Dr. Koonin has heard of NASA, since the organisation is mentioned several times in his list of references and once in the body of the book. However it seems that the United States’ National Snow and Ice Data Center (NSIDC for short) is not very visible on his personal radar screen, meriting only a single reference which is to snow rather than ice data.

Here is the NSIDC’s version of the NASA graph above, which includes a handy trend line:

Monthly September ice extent for 1979 to 2020 shows a decline of 13.1 percent per decade.

Nearby Steve has penned another paragraph I can broadly agree with. On page 36 he states:

The warming of the past forty years on large scales hasn’t been uniform over the globe. That’s evident in Figure 1.5, reproduced from the US government’s 2017 CSSR (Climate Science Special Report, described earlier). As you can see, the land is warming more rapidly than the ocean surface, and the high latitudes near the poles are warming faster than the lower latitudes near the equator.

Here is the figure 1.5 referred to above:

Surface temperature change (in °F) for the period 1986–2015 relative to 1901–1960. Changes are generally significant over most land and ocean areas. Changes are not significant in parts of the North Atlantic Ocean, the South Pacific Ocean, and the southeastern United States. There is insufficient data in the Arctic Ocean and Antarctica to compute long-term changes there.

Once again I am compelled to ask some questions. Why not include a map that uses more recent data than 2015? And why not quantify how much faster the “high latitudes near the poles are warming than the lower latitudes near the equator”?

NASA helpfully provide an interface to their data which allows anybody who can click a mouse to produce their own global surface temperature maps. Here is the up to date answer to the first question:

NASA have also produced another informative video, which I suspect will also never make it into “Unsettled – The Movie”:

Another US scientific agency that provides publicly accessible climate data is the National Oceanic and Atmospheric Administration (NOAA for short). The abbreviation is referred to several times in Steve Koonin’s book, but for some reason he never expands the acronym in full. Like NASA they also provide a means to produce your own maps and time series. Albeit with a somewhat more complex user interface, the Web-based Reanalysis Intercomparison Tool (WRIT for short) allows the user to differentiate between different regions of Planet Earth, and hence answer the second question above.

Please compare and contrast the “non polar” temperature time series with the “Arctic” one. Note the change of scale of the X axis, and also the units. Degrees Kelvin rather than degrees Fahrenheit which are seemingly preferred by Dr. Koonin:

To summarise, you don’t need to wait for Steve Koonin to write another book or for the US government to produce another CSSR. Vast amounts of data and a plethora of visualisation tools are freely available to allow you to do your own research regarding a wide variety of climate metrics. Steve neglects to impart that information to his readers as well.

[Edit – May 9th]

As has been alluded to above, in the soon to be shipped hardcover edition of his new book Steve Koonin makes much mention of “snow cover” whilst ignoring “sea ice” entirely. There are also a grand total of 48 reference to the perhaps overly esoteric term “albedo“. On page 84 of the Kindle edition of “Unsettled” we are reliably informed that:

Among the most important things that a model has to get right are “feedbacks.”

Despite that the entire electronic volume makes no mention whatsoever of the phrase “ice-albedo feedback” or any synonym thereof. A brief course teaching the topic has recently been developed as part of the outreach activities of the MOSAiC Arctic drift expedition. Perhaps Dr. Koonin would be well advised to read it at his earliest convenience?

The ice-albedo feedback is an example of a positive feedback loop. A feedback loop is a cycle within a system that increases (positive) or decreases (negative) the effects on that system. In the Arctic, melting sea ice exposes more dark ocean (lower albedo), which in turn absorbs more heat and causes more ice to melt…the cycle continues.

Here’s another explanatory video which will also no doubt never make it into “Unsettled – The Movie”:

Watch this space for further revelations about the gigantic Arctic canary in the room!

Facts About the Arctic in April 2021

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As part of his March PIOMAS gridded sea ice thickness update Wipneus also produced this graph of sea ice export from the central Arctic via the Fram Strait:

So far this winter export has been remarkably subdued, but that has now changed. A persistent dipole with high pressure over Greenland and low pressure over the Barents Sea is generating strong northerly winds in the Fram Strait, and even bringing some April snow showers to South West England:

Precisely how high the pressure has been over Greenland is the subject of much debate. See for example this discussion on the Arctic Sea Ice Forum about whether a new world high pressure record has just been set. Different weather forecasting models have come to very different conclusions about the mean sea level pressure of a high pressure area situated over the Greenland ice sheet, which reaches an altitude of over 3,000 metres. Here’s GFS for example, showing 1097 hPa at 06Z on April 4th:

whereas the Canadian Meteorological Centre synopsis for the same time shows a mere 1070 hPa:

At least all the assorted models agree that the isobars are closely packed over the Fram Strait, and hence some of the thickest sea ice remaining in the Arctic is currently heading towards oblivion in the far north Atlantic Ocean:

Here’s the US Navy’s sea ice drift forecast for Saturday 10th:

Continue reading Facts About the Arctic in April 2021 →

The 2021 Maximum Arctic Sea Ice Extent

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Here’s the latest graph of Arctic sea ice extent from JAXA/ViSHOP, with 2021 and 2015 highlighted:

Extent fell by over 100,000 square kilometres between February 16th and 17th! Can that steep fall continue, as it did for one more day in 2015?

Here too is Zack Labe’s 2021 overview of JAXA maximum extent over the previous couple of decades:

2015’s maximum was very early, on February 15th. Hence the current extremely tentative 2021 maximum is already both higher and later than that. The decadal average extent graphs show the date of the maximum getting later and later, and the 2010’s peaks in the middle of March.

It therefore seems likely that there is more freezing still to come this year. However lets take a look at the high resolution AMSR2 sea ice area graph for the Sea Of Okhotsk:

The recent fall in Arctic wide extent has evidently been driven by the recent rapid decline in this peripheral sea, where SMOS reveals more thin ice ripe for further melting:

In conclusion, the high res AMSR2 extent metric shows the tentative 2021 peak below that of 2015!

Continue reading The 2021 Maximum Arctic Sea Ice Extent →