At the beginning of April 2019 all the assorted Arctic sea ice extent metrics are at their respective lowest levels for the date in the satellite record. Just for a change let’s start with the JAXA/ViSHOP graph for April 1st, based on AMSR2 data:
That shows extent apparently on an inexorable decline. However the higher resolution graphs derived by Wipneus from University of Hamburg AMSR2 concentration data reveal that Arctic sea ice extent has changed little over the last couple of days, and area has even increased somewhat:
Whilst we wait for Wipneus’ latest PIOMAS thickness and volume update, here’s the gridded merged CryoSat-2/SMOS thickness data from the Finnish Meteorological Institute:
Watch this space for some other extent graphs once they’ve updated to April 1st. In particular the DMI’s version of events will be of great interest, since by way of a little All Fools Day fun I passed on the latest Arctic sea ice news to Tony Heller and the denizens of his “Deplorable Climate Science Blog” yesterday. They were not amused! By way of example, Rah solemnly informed me that:
Tony consistently has used the DMI data as his primary source on the conditions in the Arctic, while you jump to whatever source you think justifies your bias. Get a life. Arctic air temps this year so far have been running below what they were at this time last year.
This is the graph that Steve/Tony used in an attempt to make his point:
Plus the April 2nd DMI “Arctic temperature” graph:
[Edit – April 3rd]
Snow White asked Axel Schweiger nicely on Twitter, and as if by magic the PIOMAS numbers for March have been released, including gridded thickness. Wipneus has crunched them to reveal the following end of March sea ice thickness map:
plus a rather unusual volume graph:
Here’s a closeup view:
According to the PIOMAS model Arctic sea ice volume has been flatlining for the last couple of weeks, and may even have peaked already!
Meanwhile returning to 2 dimensions the decline in area has resumed:
[Edit – April 7th]
Wipneus’ UH high resolution extent fell another 129k yesterday:
Plus a close up look at the FMI merged Cryosat-2/SMOS thickness for both the Atlantic and Pacific sides of the Arctic:
Apart from the usual thick ice queueing for the Fram Strait exit there’s not a lot to prevent the comparatively swift early melt from continuing apace.
March 2019 has arrived, which in recent years has proved to be by far the likeliest month to contain the maximum extent of Arctic sea ice for the year. To begin with, here’s our favourite high resolution extent graph calculated by “Wipneus” from University of Hamburg/JAXA AMSR2 data:
Hopefully you can plainly see the pronounced sharp peak towards the end of February 2019? The current maximum Arctic sea ice extent for 2019 is 13.83 million square kilometers on February 22nd. Here’s Arctic sea ice area for good measure:
The current maximum area for 2019 is 13.10 million square kilometers, also on February 22nd. Here too is the NSIDC’s 5 day averaged extent:
This reveals a current maximum extent for 2019 of 14.705 million square kilometers on February 24th.
At this juncture you may well be wondering what the cause of that sudden sharp peak might be? Here’s your starter for ten:
Whilst overall Arctic sea ice area is unremarkable for the current decade, sea ice area in the Bering Sea is remarkable low for the time of year! What’s more much like last year the Chukchi Sea is not currently full to overflowing with sea ice, and is also lowest for the date in the AMSR2 satellite records:
I’ve also been experimenting with the new gridded CryoSat-2/SMOS thickness data from the Finnish Meteorological Institute, which reveals this:
That’s a weekly overview dated February 24th, but it does perhaps explain how such a large area of sea ice could melt so swiftly?
As luck would have it the skies are reasonably clear over the Bering Strait this morning (UTC). Here’s Terra’s view from on high of the current situation:
In addition, here is the underlying sea ice concentration data from the OSI-SAF:
Since Michael is also asserting that there currently exists “the greatest February Arctic sea ice extent (according to DMI) in your blog’s history”, here’s Arctic sea ice area excluding the extremely peripheral Okhotsk and St. Lawrence regions:
P.S. Wipneus’ Pi has processed the AMSR2 data now, and area shows another, more modest, decline today:
Both area and extent are still moving inexorably upwards:
The late February maximum still holds, on the high resolution numbers at least. The JAXA/VISHOP web site is down at the moment, so we’ll have to wait for an update to that particular metric, as well as a post weekend update to the NSIDC’s Charctic chart.
P.S. Jaxa is still down this afternoon, but here’s the latest from the NSIDC:
[Edit – March 13th]
Arctic wide area and extent have blasted past their respective late February maxima:
However Arctic sea ice area excluding the Okhotsk and St. Lawrence peripheral regions has still not exceeded the maximum formed on January 25th:
[Edit – March 14th]
This morning’s data reveal the first decline in extent for several days:
The (extremely!) tentative new maximum Arctic sea ice extent for 2019 is 13.89 million square kilometers on March 12th.
[Edit – March 15th]
JAXA is back!
UH AMSR2 confirms that extent is still declining:
[Edit – March 16th]
Arctic sea ice extent continues to decline, whilst area is still flatlining:
Meanwhile a look at freezing degree days based on the DMI’s dubiously weighted data for north of 80 degrees reveals the story of the freezing season. A historically warm start, but now back in amongst the pack of the 2010s:
[Edit – March 17th]
It looks as though there’ll be no going back from this. Arctic sea ice area is finally following extent’s decline in no uncertain terms:
Barring exceedingly unforeseen circumstances after this year’s “double top” that leaves the 2019 Arctic sea ice maximum extent numbers as follows:
UH/Wipneus AMSR2 – 13.89 million square kilometers on March 12th
JAXA/VISHOP AMSR2 – 14.27 million square kilometers on March 12th
NSIDC 5 day SSMIS – 14.78 million square kilometers on March 13th
[Edit – March 19th]
Arctic sea ice area has fallen off the proverbial cliff over the last few days. There can now be no doubt that the 2019 maximum extent has been reached:
That being the case, all other Arctic sea ice discussion for the month of March can now take place over at:
On March 13, 2019, Arctic sea ice likely reached its maximum extent for the year, at 14.78 million square kilometers (5.71 million square miles), the seventh lowest in the 40-year satellite record, tying with 2007. This year’s maximum extent is 860,000 square kilometers (332,000 square miles) below the 1981 to 2010 average maximum of 15.64 million square kilometers (6.04 million square miles) and 370,000 square kilometers (143,000 square miles) above the lowest maximum of 14.41 million square kilometers (5.56 million square miles) set on March 7, 2017. Prior to 2019, the four lowest maximum extents occurred from 2015 to 2018.
The date of the maximum this year, March 13, was very close to the 1981 to 2010 median date of March 12.
Please note this is a preliminary announcement of the sea ice maximum. At the beginning of April, NSIDC scientists will release a full analysis of winter conditions in the Arctic, along with monthly data for March.
We generally write our periodic reports on the state of Arctic sea ice around the time the PIOMAS volume numbers are published. It seems as though we’ll have a long wait for that to happen at the moment though. According to The Economist today:
America’s government shutdown has become the longest in history. Hundreds of thousands of federal workers remain either stuck at home or forced to work without pay. To reopen the government President Donald Trump is demanding $5.7bn for his border wall. Nancy Pelosi, who presides over the most polarised House of Representatives in recent memory, does not want to give it to him.
Due to the US Government Shutdown, PIOMAS ice volume and thickness data which depend on federal government generated reanalysis products, are currently not updated.
Instead of PIOMAS, let’s start instead with the January 2019 edition of the National Snow and Ice Data Center’s Arctic Sea Ice News:
As 2018 came to a close, Arctic sea ice extent was tracking at its third lowest level in the satellite record, while sea ice in the Antarctic remained at historic lows. Slightly faster growth in the first few days of the new year, mostly in the Pacific sea ice areas, has the daily sea ice extent at fifth lowest as of this post.
Now let’s take a look at our favourite high resolution AMSR2 area and extent metrics:
You can see that towards the end of December Arctic sea ice extent was verging on lowest for the date, since when it has risen quickly to reach highest for the date in the brief AMSR2 records a few days ago.
The NSIDC also mention the US Government shutdown:
Unfortunately, as a result of the partial government shutdown, we are unable to access the National Oceanic and Atmospheric Administration (NOAA) pages to retrieve information on atmospheric air temperatures and sea level pressure patterns. Instead, we turn to daily (2 meters above the surface) mean air temperatures north of 80 degrees North from the European Centre for Medium-Range Weather Forecasts (ECMWF) operational model. This analysis shows that air temperatures remained above the 1958 to 2002 average for all of December.
That brings us on to our Arctic freezing degree days graph, based on DMI data:
After a very slow start to the freezing season the FDD numbers are now vying for second place with last year, behind the astonishingly warm winter of 2016/17. In the absence of the PIOMAS volume numbers we can at least take a look at sea ice thickness. Here’s CryoSat-2:
All those sources seem to be agreed that large areas of both the Barents and Kara Seas are currently covered by young thin ice. Finally, for the moment at least, let’s take a look at some extracts from the NSIDC’s review of 2018:
January 2018 began the year with record low sea ice extents for the Arctic as a whole.
The seasonal maximum, reached on March 17, 2018, was the second lowest in the satellite record. While low extent persisted through April and May, sea ice loss during early summer was unremarkable despite above average 925 hPa air temperatures over the Arctic Ocean and Eurasia.
Air temperatures over the Arctic Ocean in July were below average, followed by above average temperatures in August. In fact, on average, August temperatures were higher than July temperatures in 2018. This is highly unusual in the Arctic and something not seen in at least 40 years.
The September 2018 seasonal minimum extent ended up slightly above the long-term linear trend line, tying with 2008 for the sixth lowest in the satellite record. After the minimum, the ocean was slow to freeze up, and October sea ice extent ended up as the third lowest. However, ice growth was very rapid in November, such that November 2018 extent approached the interquartile range of the 1981 to 2010 median. Nevertheless, large amounts of open water remained in the Barents and Chukchi Seas. By the end of December, ice conditions in the Chukchi Sea were back to average, while extent remained unusually low in the Barents Sea.
Coverage of old ice (greater than 4 years old) over the Arctic continued to decline. Such old ice covers only 5 percent of the area it used to in 1980s.
[Edit – January 13th]
Arctic sea ice area and extent have both been falling over the last few days, possibly as a result of the recent cyclone which created strong northerly winds in the Fram Strait. This is from Earth at 09:00 UTC on January 10th, showing a MSLP of 946 hPa:
Here’s what used to be referred to as JAXA extent:
A somewhat belated start to our October 2018 coverage, but firstly please take a look at this graph:
Following a remarkably sluggish refreeze this year JAXA extent is currently the lowest for the date since their records began. Meanwhile Wipneus has just released his mid month PIOMAS volume update on the Arctic Sea Ice Forum:
That graph reveals that Arctic sea ice volume has been increasing much more slowly than usual during October. The fact that the DMI freezing degree days graph is currently below all previous years in their records no doubt has something to do with that:
Wipneus has also updated the mid month PIOMAS gridded thickness map:
For a handle on the areas of thinner ice where refreezing is taking place around the periphery of the pack, here’s the latest SMOS map:
Finally, for the moment at least, here’s our favourite high resolution AMSR2 area and extent metrics based on JAXA data processed by the University of Hamburg to produced gridded concentration which is then used to derive area and extent by the inimitable Wipneus once again:
[Edit – October 28th]
Here’s the latest thickness maps from SMOS:
and CryoSat-2:
There’s been a recent rapid refreeze, leaving large areas of thin ice around the edges of the central pack:
First of all Wipneus has been very quick off the mark this month with his PIOMAS gridded thickness map. Here is what it reveals for the last day of March:
Here too is the latest PIOMAS volume graph:
together with the associated anomaly graph:
They show 2018 still in second lowest position, albeit much closer to third place than last year’s line, which is currently leading the pack by a considerable margin.
By way of comparison here are the current Arctic sea ice thickness maps from SMOS:
and CryoSat-2:
All eyes are still on the Bering and Chukchi Seas, where significant extent declines look likely over the coming days.
Meanwhile “JAXA” extent has just edged above 2016!
[Edit – April 11th]
The focus has been on the Bering and Chukchi Seas until now. However there were clear skies over the Mackenzie Delta yesterday, revealing some open(ish) areas in the Beaufort Sea:
NASA Worldview “true-color” image of the Beaufort Sea on April 10th 2018, derived from the MODIS sensor on the Terra satellite
There’s only the merest hint of a blip on the area graph so far though:
It will be interesting to see if the decline in Beaufort Sea area continues from here, or whether this year’s “flatline” resumes and continues for a while longer.
[Edit – April 19th]
It’s not so apparent on the other extent metrics, but as the periphery melts the high resolution AMSR2 version looks to be heading into virgin territory on the downside:
According to the latest edition of the National Snow and Ice Data Center’s “Arctic Sea Ice News”
On March 17, 2018, Arctic sea ice likely reached its maximum extent for the year, at 14.48 million square kilometers (5.59 million square miles), the second lowest in the 39-year satellite record, falling just behind 2017. This year’s maximum extent is 1.16 million square kilometers (448,000 square miles) below the 1981 to 2010 average maximum of 15.64 million square kilometers (6.04 million square miles).
The four lowest seasonal maxima have all occurred during the last four years. The 2018 maximum is 60,000 square kilometers (23,200 square miles) above the record low maximum that occurred on March 7, 2017.
Here’s a close up view of recent maxima via the NSIDC’s Charctic interactive sea ice graph:
Next let’s take a look at extent data from the Japanese National Institute of Polar Research, colloquially referred to as “JAXA extent”
In this case the maximum was 13.89 million square kilometers, also on March 17th.
Here too are the extent and area graphs based on Wipneus’ processing of the University of Hamburg’s AMSR2 based concentration data:
They highlight the surge in Arctic sea ice area in the middle of March due to the sudden “cold snap”:
Looking at the third Arctic dimension, here’s the latest SMOS thickness map from the University of Bremen:
and here’s the latest CryoSat-2 thickness map:
They reveal large areas of relatively thin sea ice in the Okhotsk and Barents Seas where the ice can now be expected to melt as quickly as it formed. There is also remarkably little sea ice in the Bering Sea for the time of year:
After a comparatively cool May, surface air temperatures in the high Arctic are back up to “normal”:
The condition of the sea ice north of 80 degrees is far from normal however. Here’s what’s been happening to the (normally) land fast ice north west of Greenland:
NASA Worldview “true-color” image of the sea ice north west of Greenland breaking up on June 2nd 2017
Further south surface melt has set in across the southern route through the Northwest Passage:
NASA Worldview “false-color” image of the Coronation Gulf on June 1st 2017, derived from the MODIS sensor on the Terra satellite
Whilst the gap with previous years has narrowed during May, PIOMAS Arctic sea ice volume is still well below all previous years in their records:
The PIOMAS gridded thickness graph suggests that a large area of thick ice is currently sailing through the Fram Strait to ultimate oblivion:
and just in case melt ponds are now affecting those numbers here is extent as well:
The rate of decrease is inexorably increasing! 2012 extent is currently still well above that of 2017, but those positions may well be reversed by the end of June? Here’s NSIDC’s view on the matter:
[Edit – June 8th]
As requested by Tommy, here’s the current Arctic Basin sea ice area:
This includes the Beaufort, Chukchi, East Siberian and Laptev Seas along with the Central Arctic. It excludes the Atlantic periphery, which currently looks like this:
[Edit – June 10th]
At long last a clear(ish) image of water from the Lena Delta spreading out across the fast ice in the Laptev Sea:
NASA Worldview “true-color” image of the Lena Delta on June 10th 2017, derived from the MODIS sensor on the Terra satellite
NASA Worldview “true-color” image of the Lena Delta on June 10th 2012, derived from the MODIS sensor on the Terra satellite
[Edit – June 11th]
DMI’s daily mean temperature for the Arctic area north of the 80th northern parallel has reached zero degrees Celsius almost exactly on the climatological schedule:
We calculate our freezing degree days on the basis of the freezing point of Arctic sea water at -1.8 degrees Celsius. On that basis this winter’s grand total of 3740 was reached on June 1st:
Despite the “coolish” recent weather total FDDs are way below the climatology and other recent years. Consequently there’s a lot less sea ice in the Arctic left to melt at the start of this Central Arctic melting season than in any previous year in the satellite record. However whilst there are some melt ponds visible in the Arctic Basin on MODIS, in that respect 2017 is lagging behind both last year and 2012.
A sub 970 hPa cyclone is starting to enter the realms of realistic possibility, and also forecast are some significant waves in the Chukchi Sea and the expanding 2017 “Laptev Bite”:
[Edit – June 27th]
The forecast cyclone was nowhere near as deep as predicted. According to the analysis by Environment Canada it bottomed out at 980 hPa yesterday:
[Edit – June 29th]
O-Buoy 14 is currently firmly embedded in the fast ice of Viscount Melville Sound, deep in the heart of the Northwest Passage. Here’s the view from the buoy’s camera:
In 2017 Antarctic sea ice extent is beating all the records. All flavours of the metric are already below the minimum of all previous years in the satellite record, and it looks like there’s still some more melting left to go. Here’s the NSIDC’s 5 day averaged extent:
It seems highly likely that the 2017 Antarctic sea ice minimum extent has now been reached. Here’s the NSIDC 5 day averaged extent graph:
The minimum extent of 2.106 million square kilometers was reached on March 3rd. Here’s the University of Bremen’s Antarctic sea ice concentration map for March 3rd:
It’s far too early to be sure about this yet, but it’s not beyond the bounds of possibility that the 2017 maximum is already in place. Here’s our favourite high resolution extent graph calculated by “Wipneus” from University of Hamburg/JAXA AMSR2 data:
The current maximum Arctic sea ice extent for 2017 is 13.49 million square kilometers on February 19th. Here’s Arctic sea ice area for good measure:
The current maximum area for 2017 is 12.88 million square kilometers on February 20th. Here also is the NSIDC’s 5 day averaged extent:
This reveals a current maximum extent for 2017 of 14.302 million square kilometers on February 20th.
[Edit – March 1st]
Here are the high resolution AMSR2 area and extent graphs for the end of February:
With each day that passes the highs of February 19th/20th look more likely to have been this years maximum. Nonetheless past experience suggests it’s still far to soon to be sure about that.
[Edit – March 10th]
Arctic sea ice area and extent are declining again, having reached new heights for the year on March 3rd:
However the 2013/14 winter showed a late surge is still possible.
[Edit – March 18th]
A “late surge” is looking increasingly unlikely. That being the case, here is our provisional long term graph of NSIDC daily Arctic sea ice extent:
Subject to an unanticipated “surge” the 2017 maximum of 14.447 million square kilometers occurred on March 5th.
JAXA extent has dropped steeply over the last couple of days, and it is now once again “lowest for the date since records began”:
The 2017 JAXA maximum of 13.878 million square kilometers occurred on March 6th.
In the continuing absence of updates to Cryosphere Today area, here’s the high resolution Arctic sea ice area graph calculated by “Wipneus” from University of Hamburg/JAXA AMSR2 data:
The maximum for that particular metric was 13.03 million square kilometers on March 3rd.
September 2016 is here at last! I posed this question at the start of the recent “Great Arctic Cyclone“:
I wonder what the minimum for 2016 will be, and on what date?
I’m still wondering, and the answer does of course depend on which Arctic sea ice metric you happen to be looking at. Here’s a few examples to be going on with. Firstly there’s Tony Heller’s extent metric du jour, from the University of Bremen:
Finally here are “Snow White’s” favourite high resolution AMSR2 metrics derived by “Wipneus” from University of Hamburg AMSR2 concentration data:
Are there any other suggestions for numbers to keep a close eye on over the next few weeks?
[Edit – September 3rd]
Arctic sea ice volume, as modelled by PIOMAS, has been updated to August 2016:
It’s currently 3rd lowest for the month, just a whisker behind 2011. Here’s the PIOMAS gridded data for August 31st 2016:
and for comparison purposes here’s the high res AMSR2 concentration map for the same date:
As suggested by Bill, here too are the Arctic Regional Ocean Observing System numbers. Much like the high res AMSR2 data they allow comparison between area and extent from the same sensor/algo combination, in this case SSMIS/NORSEX on a 25 km grid:
Both sources agree that currently the remaining ice is less compact in 2016 than it was in 2012.
[Edit – September 4th]
An interesting inter-metric comparison from Lars Kaleschke of the University of Hamburg:
Here’s another twist on the University of Hamburg’s AMSR2 extent, courtesy of Lars Kaleschke:
[Edit – September 11th]
Several of the metrics displayed above have increased over the last day or two. The 2016 minimum may be upon us, but another few days will have to go by before that’s finally confirmed. Whilst we wait here’s another metric to consider, as described on “Tamino’s” Open Mind blog:
A plot of annual average extent also clearly shows the decline, and includes data from throughout the year rather than just the annual minimum. The figure for 2016 is the lowest on record, but the year isn’t done yet. If instead of averaging January-through-December we do September-through-August (to make the final year complete), we find that the most recent year is still the lowest on record:
Any way you look at it, Arctic sea ice is in decline. If you look at the entire year rather than just the annual minimum, the record year is this one.
[Edit – September 14th]
The refreeze has certainly started now. A quick look through the metrics. First of all the Hamburg University high resolution AMSR2 matched set:
Area just squeezed under 3 million km². Next up is JAXA extent:
which just failed to fall below 4 million km². Last but not least, just for the moment, is the NSIDC 5 day trailing averaged extent:
The most striking this year is the unusually large gap between area and extent for this time of year, illustrated by this “compactness” graph from Arctische Pinguin:
Note too the striking difference between different sensor/algo combinations for this metric!
[Edit – September 15th]
With the minimum now beyond doubt, here’s a new graphic from Lars Kaleschke of the University of Hamburg:
Need I say more?
[Edit – September 20th]
The September cyclone has now done its worst:
NASA Worldview “true-color” image of the Beaufort Sea on September 18th 2016, derived from the VIIRS sensor on the Suomi satellite
Leaving the area and extent metrics with an intriguing “double dip”:
2016 Minimum Milestones
September 3rd – JAXA extent dropped to 2nd place below the 2007 minimum at 4.05 million km²
September 7th – JAXA extent minimum of 4.02 million km²
September 8th – NSIDC single day extent dropped to 2nd place below the 2007 minimum at 4.083 million km². This proved to the minimum value for the year as a whole.
September 9th – NSIDC 5 day trailing averaged extent dropped to 2nd place below the 2007 minimum at 4.146 million km²
September 10th – NSIDC 5 day trailing averaged extent minimum of 4.137 million km²
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