The Northwest Passage in 2023

Prompted by a comment by Tom in the June open thread, the time has evidently come to open the 2023 Northwest Passage passage thread. First of all let’s get our bearings with the help of this map of the area:

and another map detailing the routes through Canadian Arctic Archipelago that have previously been successfully traversed:

As our starter for ten for 2023, there is already plenty of open water in the Amundsen Gulf, together with plenty of melt ponding on the remaining fast ice in Franklin and Darnley Bays:

“False colour” image of the Lena Delta on June 3rd from the MODIS instrument on the Terra satellite
Continue reading The Northwest Passage in 2023

Facts About the Arctic in June 2023

By way of a change, which is allegedly as good as a rest, let’s start the new month with a very pretty and almost cloud free “pseudo-colour” image of the Lena Delta and adjacent areas of the Laptev Sea:

“False colour” image of the Lena Delta on June 1st from the MODIS instrument on the Aqua satellite

Laptev sea ice area decline has been in high gear recently:

Continue reading Facts About the Arctic in June 2023

Facts About the Arctic in May 2023

At the beginning of May AWI’s high resolution AMSR2 extent metric is at the top of the historical range:

After a period of melt in the East Greenland Sea, export of sea ice from the Central Arctic via the Fram Strait has increased recently:

Sea ice area in the Barents Sea peaked in the first week of April and has declined steadily since then:

SMOS data is flowing again, and the gaps have been filled. Here’s the final pre melt ponding map of the spring:

It reveals large areas of thin ice that have recently developed in the Kara Sea. Here’s a pseudo colour glimpse of the region through the clouds:

Continue reading Facts About the Arctic in May 2023

Facts About the Arctic in April 2023

Arctic sea ice extent in early April is singularly unexceptional. Here’s the AWI AMSR2 version:

Things start to become more interesting when looking at the third dimension. Here’s the PIOMAS gridded thickness map for March 31st:

and the CryoSat-2/SMOS map for the same date:

Note the differing distribution of thick ice north of Greenland and the Canadian Arctic Archipelago between the two maps. Note also the area of thinner ice along the coast of the Beaufort Sea visible on the CS2/SMOS map.

By way of explanation for that phenomenon see the March sea level pressure map from the latest edition of the NSIDC’s Arctic Sea Ice News:

Continue reading Facts About the Arctic in April 2023

Facts About the Arctic in March 2023

We’ll come on to the Arctic in a moment, but at more temperate latitudes I am proud to announce that my Cornish alter ego has been officially outed as an “environmental campaigner” by the BBC. Moving pictures of yours truly, discussing drought rather than sea ice, are available via BBC iPlayer until around 18:30 this evening, possibly to UK residents only.

[Stop Press! A shorter version of Kirk England’s report on two potential desalination plants in Cornwall (also including my 15 seconds of fame!) is available here until around 22:30 this evening ]

Alternatively we have recorded our own moving pictures of this momentous event:

And an added still image as well:

Continue reading Facts About the Arctic in March 2023

The 2023 Maximum Arctic Sea Ice Extent

March has arrived, so it’s time to start taking a serious look at where and when the 2023 maximum Arctic sea ice extent will occur.

To start with here’s Zack Labe’s overview of previous years’ maxima:

Zack’s graph displays the JAXA/ViSHOP version of Arctic extent, so here too is JAXA’s own graph of the current sea ice extent:

It doesn’t look as though the 2023 maximum has been achieved yet, but extent on March 1st was 14.01 million km². That is evidently not going to be the lowest in the satellite era!

[Edit – March 8th]

As Tom has already mentioned below, JAXA extent has declined significantly since the (so far!) peak extent of 14.12 million km² on both the 2nd and 3rd of March:

It’s too soon to be certain of course, but we certainly now have a good candidate for the 2023 maximum JAXA extent.

NSIDC 5 day averaged extent is still increasing, but let’s see what this afternoon’s update (UTC) reveals…

Which is a decrease of 0.001 million km² from March 6th, leaving a current NSIDC maximum extent of 14.62 million km²!

Finally, for the moment at least, AWI’s “high resolution” AMSR2 extent looks a lot less convincing than JAXA’s:

[Edit – March 11th]

NSIDC Arctic sea ice extent took a tumble yesterday, so with only mild trepidation I’m calling the 2023 maximum extent. In the case of the NSIDC’s 5 day average metric that’s still a rounded up 14.62 million km² on March 6th:

The JAXA/ViSHOP maximum extent remains at 14.12 million km² on March 2nd:

The “high resolution” AMSR2 based metric from AWI peaked at 14.24 million km² on March 5th:

[Edit – March 16th]

They are of course a bit late with the news, but the NSIDC have now called the 2023 maximum Arctic sea ice extent:

Arctic sea ice has likely reached its maximum extent for the year, at 14.62 million square kilometers (5.64 million square miles) on March 6. The 2023 maximum is the fifth lowest in the 45-year satellite record. NSIDC scientists will present a detailed analysis of the 2022 to 2023 winter sea ice conditions in the regular monthly post in early April:

The date of the maximum this year, March 6, was six days earlier than the 1981 to 2010 average date of March 12…

The ice growth season ended with below average sea ice extent in the Bering Sea, Sea of Okhotsk, Barents Sea, and Labrador Sea. Above average extent was in the Greenland Sea. Extent was well below average in the Gulf of St. Lawrence for a second year in row.

Watch this space!

New Record Antarctic Sea Ice Minimum Extent

I should of course add “in the satellite era”, but the title is pretty unwieldy as it is!

I was up early (UTC) to check the latest JAXA data, and sure enough that confirmed a new record minimum Antarctic sea ice extent of 2.11 million km² was reached yesterday:

Having added a note to that effect the Arctic open thread, Lars Kaleschke from the Alfred Wegener Institute pointed out over on Mastodon that the AWI had published a press release about the event this morning:

Let’s take a closer look at what the AWI had to say:

On 8 February 2023, at 2.20 million square kilometres, the Antarctic sea ice extent had already dropped below the previous record minimum from 2022 (2.27 million square kilometres on 24 February 2022). Since the sea ice melting in the Antarctic will most likely continue in the second half of the month, we can’t say yet when the record low will be reached or how much more sea ice will melt between now and then,” says Prof Christian Haas, Head of the Sea Ice Physics Section at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), with regard to the current developments in the Antarctic. “The rapid decline in sea ice over the past six years is quite remarkable, since the ice cover hardly changed at all in the thirty-five years before. It is still unclear whether what we are seeing is the beginning of a rapid end to summer sea ice in the Antarctic, or if it is merely the beginning of a new phase characterised by low but still stable sea ice cover in the summer.”

Here’s how that news looks in the AWI’s official press release:

and here’s how it looks in Lars’ experimental AMSR2 graphic, with current minimum at 1.97 million km²:

By way of prognostication here too is the current JAXA AMSR2 concentration map:

There are some low concentration areas which suggest further extent reductions still to come, despite the recent uptick in the high resolution graph.

Getting back to the AWI’s text:

The melting has progressed since December 2022, especially in the Bellingshausen and Amundsen Seas in the West Antarctic; the former is virtually ice-free. That is also where the research vessel Polarstern currently is, exploring the evidence left behind of past glacials and interglacials. According to expedition leader and AWI geophysicist Prof Karsten Gohl, who is now in the region for the seventh time, having first come in 1994: “I have never seen such an extreme, ice-free situation here before. The continental shelf, an area the size of Germany, is now completely ice-free. Though these conditions are advantageous for our vessel-based fieldwork, it is still troubling to consider how quickly this change has taken place.”

Polarstern in ice free Bellingshausen Sea, West Antarctica, in January 2023. (Photo: Daniela Röhnert)

Analyses of the current sea ice extent, conducted by the Sea Ice Portal team, show that, for the entire month of January 2023, the ice was at its lowest-ever extent recorded for the time of year since the beginning of record-keeping in 1979. The monthly mean value was 3.22 million square kilometres, ca. 478,000 square kilometres (an area roughly the size of Sweden) below the previous minimum from 2017. With regard to its long-term development, the Antarctic sea ice shows a declining trend of 2.6 percent per decade. This is the eighth consecutive year in which the mean sea-ice extent in January has been below the long-term trend.

But what has caused the current lack of Antipodean sea ice? The press release continues:

This intense melting could be due to unusually high air temperatures to the west and east of the Antarctic Peninsula, which were ca. 1.5 °C above the long-term average. In addition, the Southern Annular Mode (SAM) is in a strongly positive phase, which influences the prevailing wind circulation in the Antarctic. In a positive SAM phase (like today), a low-pressure anomaly forms over the Antarctic, while a high-pressure anomaly develops over the middle latitudes. This intensifies the westerly winds and causes them to contract toward the Antarctic. As a result, upwelling of circumpolar deep water on the continental shelf intensifies in the Antarctic, promoting sea-ice retreat. More importantly, it also intensifies the melting of ice shelves, an essential aspect for future global sea-level rise.

Air temperature anomalies in °C at 925 hPa pressure level in Antarctica in January 2023 compared to the long-term mean 1971-2000. (Graphic: meereisportal.de)

The press release concludes:

Historical records also reflect the tremendous changes. For example, in the Antarctic summer 125 years ago, the Belgian research vessel Belgica was trapped in the massive pack ice for more than a year – in exactly the same region where the Polarstern can now operate in completely ice-free waters. The photographs and diaries of the Belgica’s crew offer a unique chronicle of the ice conditions in the Bellingshausen Sea at the dawn of the industrial age, which climate researchers often use as a benchmark for comparison with today’s climate change.

Belgica became ice bound near Peter I island on February 28th 1898. On board was second officer Roald Amundsen. The leader of the expedition, Adrien de Gerlache, published a French language book about the voyage in 1902: “Quinze mois en Antarctique“.

Belgica ice bound in the Bellingshausen Sea

Finally, for the moment at least, here is the University of Bremen’s map of Polarstern’s current location and the sea ice concentration in the vicinity thereof:

[Edit – February 11th]

JAXA Antarctic sea ice extent is now down to 2.06 million km². Accompanied by a significant fall in Arctic extent, JAXA’s flavour of global sea ice extent has now also reached the lowest level ever recorded in the satellite era, at 15.51 million km² :

P.S. The NSIDC’s 5 day averaged extent hasn’t quite reached a record minimum yet:

However their daily extent has reached a new satellite era record minimum:

[Edit – February 14th]

The NSIDC’s 5 day average Antarctic sea ice extent metric has duly reached a new record low level of 1.91 million km² :

P.S. The NSIDC has now published its own article about the record minimum:

With a couple more weeks likely left in the melt season, the extent is expected to drop further before reaching its annual minimum. Much of the Antarctic coast is ice free, exposing the ice shelves that fringe the ice sheet to wave action and warmer conditions…

Extent has tracked well below last year’s melt season levels since mid-December. As noted in our previous post, a positive Southern Annular Mode has led to stronger-than-average westerly winds. Along with a strong Amundsen Sea Low, the weather conditions have brought warm air to the region on both sides of the Antarctic Peninsula. This has largely cleared out the ice cover in the Amundsen and Bellingshausen Seas, and reduced the sea ice extent in the northwestern Weddell Sea. Sea ice is patchy and nearly absent over a long stretch of the Pacific-facing coastline of Antarctica.  Earlier studies have linked low sea ice cover with wave-induced stresses on the floating ice shelves that hem the continent, leading to break up of weaker areas.

Antarctic sea ice extent has been highly variable over the last several years. While 2022 and 2023 have had record low minimum extent, four out of the five highest minimums have occurred since 2008. Overall, the trend in Antarctic minimum extent over 1979 to 2023 is near zero. The current downward linear trend in the Antarctic minimum extent from 1979 to 2023 is 2,400 square kilometers per year, or 0.9 percent per decade, which is currently not statistically significant. Nevertheless, the sharp decline in sea ice extent since 2016 has fueled research on potential causes and whether sea ice loss in the Southern Hemisphere is developing a significant downward trend.

Watch this space!

Facts About the Arctic in February 2023

A new month has arrived, and during January several Arctic sea ice metrics have been drifting towards the bottom of their respective decadal ranges. To begin with here is AWI’s high resolution AMSR2 extent graph, which is currently very close to being lowest for the date in the AMSR2 record:

However that is less the case for area:

Taylor is keen to see the PIOMAS volume data for January, but whilst we wait for the latest Polar Science Center update here is the CryoSat-2/SMOS volume graph, which now includes a couple of month’s worth of reanalysed results as well as more recent near real time numbers:

Here too is the start of month CS2/SMOS thickness map:

Continue reading Facts About the Arctic in February 2023

Facts About the Arctic in January 2023

At the beginning of the New Year all the central regions of the Arctic are now refrozen apart from a small area of the Kara Sea:

Most Arctic sea ice metrics are near the middle of their respective ranges over the last decade. By way of example, here is a graph of Arctic Freezing Degree Days based on the Danish Meteorological Institute’s temperature data for the area north of 80 degrees latitude:

Rutgers Snow Lab’s northern hemisphere snow cover anomaly for December 2022 is slightly negative:


Here too are the high resolution AWI AMSR2 area and extent graphs:

The latest AWI CryoSat-2/SMOS volume graph tells a similar story:

Although overall volume is in the middle of the pack, the associated thickness map:

and the thickness anomaly map from the Finnish Meteorological Institute reveal an unusual distribution of thicker ice:

A considerable volume of ice currently situated between Svalbard and North East Greenland seems destined to exit the Central Arctic Basin via the Fram Strait over the coming months.

[Edit – January 24th]

In a somewhat belated mid month update, here’s the PIOMAS daily Arctic sea ice volume graph:

together with the PIOMAS thickness map on January 15th:

For comparison purposes here’s the AWI CryoSat-2/SMOS thickness map using the same scale:

Note the change of scale from the beginning of the month CS2/SMOS map at the top.

Here too is Lars Kaleschke’s animation of recent Arctic sea ice concentration, with the width of leads exaggerated to reveal ice motion:

Click to animate (10 Mb!)

Evidently sea ice export from the so called “last ice area” is continuing via the Nares Strait and in particular via the Fram Strait between Greenland and Svalbard.

Although not on the same scale as the cyclone at around the same time last year, surface pressure of a storm near Svalbard bottomed out at 965 hPa yesterday:

It will be interesting to see what effect the storm has on the ice on the Atlantic periphery over the next few days.

Further news is now available on the February 2023 open thread.