Tag Archives: Hamburg Uni

The 2022 Maximum Arctic Sea Ice Extent

Here’s the latest graph of Arctic sea ice extent from JAXA/ViSHOP, which looks a bit unusual to say the least:


It certainly caught my eye! Could that sudden peak on February 23rd be the maximum extent for the year? To be frank it looks more like an artifact in the underlying gridded AMSR2 concentration data, but it’s not wholly beyond the bounds of possibility. The Pacific side of the Arctic is anomalously warm at the moment:

and parts of the Bering Sea are above freezing point:

For the moment then the (extremely!) provisional JAXA Arctic sea ice maximum extent for 2022 is 14.39 million km².

By way of an AMSR2 second opinion let’s also take a look at our favourite “high resolution” AMSR2 metrics, which combine recent data from the Alfred Wegener Institute with historical data from the University of Hamburg:

The extent peak on the 23rd is of much smaller magnitude, and it’s almost non existent on the area graph.

Curiouser and curiouser.

[Edit – March 1st]

The JAXA maximum on February 23rd is definitely an artifact of dodgy AMSR2 data. Take a look at the Denmark Strait between Greenland and Iceland in particular:

The University of Hamburg version also shows an anomaly in the Barents Sea:

However the 5 day averaged NSIDC extent graph now shows a significant peak on February 25th:

Is anybody willing to put money on 14.875 million km² just yet?

[Edit – March 7th]

Here are the latest “high resolution” AMSR2 graphs:

The February 23rd maximum holds, for the moment at least.

[Edit – March 11th]

Here’s the latest JAXA Arctic sea ice extent graph:

A late surge is now looking exceedingly unlikely. However given that the maximum seems to have occurred during the brief period of dodgy data around February 23rd, what magnitude and date should be assigned to the 2022 maximum?

Whilst I ponder that thorny problem…

[Edit – March 12th]

Now I’ve really gone and done it! Started the “2022 melting season” thread on the Arctic Sea Ice Forum that is:

https://forum.arctic-sea-ice.net/index.php/topic,3749

Lots of heat heading in the direction of the North Pole sealed the deal:

[Edit – March 24th]

According to the latest edition of the NSIDC’s Arctic Sea Ice News:

Arctic sea ice has likely reached its maximum extent for the year, at 14.88 million square kilometers (5.75 million square miles) on February 25. The 2022 maximum is the tenth lowest in the 44-year satellite record. On the same day, on the other pole, Antarctic sea ice reached a record minimum extent, at 1.92 million square kilometers (741,000 square miles).

The date of the maximum this year, February 25, was fifteen days earlier than the 1981 to 2010 average date of March 12. Only two years had an earlier maximum, 1987 and 1996, both on February 24. This year is the second earliest date on the satellite record, tying with 2015, which also reached its maximum extent on February 25.

Watch this space!

Facts About the Arctic in May 2020

Let us begin this month’s report from the far north with the high resolution Arctic sea ice area and extent graphs based on the University of Hamburg’s AMSR2 concentration maps:

Area is currently lowest for the date in the AMSR2 record. After briefly occupying that position extent has increased over the last few days of April due to winds causing sea ice to move in the direction of the far North Atlantic:



The Alfred Wegener Institute has now finished reanalysing their CryoSat-2/SMOS thickness data, and the resulting volume graph looks like this:

“Measured” Arctic sea ice volume is the lowest in the CryoSat-2 era as we head towards the main 2020 melting season, which in my calendar at least begins on June 1st. The PIOMAS modelled volume numbers should be released shortly.

[Edit – May 5th]

The April 30th PIOMAS gridded thickness numbers have been released, and Wipneus has worked his usual magic. By way of comparison with the AWI metric:

Obviously differing from CryoSat-2/SMOS, PIOMAS has 2020 volume a long way above 2017, in amongst a gaggle of other years.

[Edit – May 13th]

The middle of May is rapidly approaching, so let’s start to set the scene for the forthcoming melting season. First off here are the hi res AMSR2 area and extent graphs:

Extent is currently significantly above 2016 due to the recent “dispersion” mentioned above, but area is very close to an all time low for the date.

Next take a look at the current northern hemisphere snow cover anomalies from the Rutgers University Snow Lab:

Whilst there is a positive anomaly near Hudson Bay, there are significant negative anomalies across Siberia and Alaska. This does not augur well for sea ice retention along both the Northern Sea Route and Northwest Passage by September 2020.

Watch this space!

The 2019 Arctic Sea Ice Metric Minima

September is here once again, so the assorted minima of a variety of Arctic sea ice metrics will be reached soon, if they haven’t happened already!

In the latter category let’s first take a look at the NSIDC’s 5 day averaged SSMIS based Arctic sea ice extent:

It looks entirely feasible that the current minimum of  4.29 million square kilometres on September 7th will hold for the rest of the calendar year. The daily NSIDC number is currently 4.24 million km² on September 4th.

By way of contrast the JAXA/ViSHOP AMSR2 based extent hit a new low of  4.11 million  km² yesterday:

And what of our much beloved high resolution AMSR2 metrics derived by “Wipneus” from the University of Hamburg’s AMSR2 concentration data? Area certainly looks to be past the minimum for this year, whereas extent is still conceivably capable of another push lower:

The provisional minimum extent for 2019 is 3.80 million km² on September 3rd.

The minimum Arctic sea ice volume generally occurs slightly later than area or extent. The data certainly arrives later! Here’s the PIOMAS graph up to August 31st:

and here’s the associated thickness map:

Note that Arctic wide modelled volume is only slightly higher than in 2012 at the same time of year, but there is a noticeably greater percentage gap in extent. That implies that average ice thickness across the Arctic is lower in 2019 than in 2012.

Note also that the thickest ice is no longer located along the north coasts of Greenland and the Canadian Arctic Archipelago. Here are the equivalent maps for previous years for comparison purposes:

Perhaps JAXA extent will head still lower over the next few days? Perhaps PIOMAS volume will sneak below 2012 before the peripheral refreeze begins?

[Edit – September 13th]

JAXA Arctic sea ice extent has reached a new minimum of 4.09 million km².

NSIDC daily extent is currently 4.28 million km², still just above the September 4th minimum.

[Edit – September 14th]

JAXA Arctic sea ice extent has reached a new minimum of 4.05 million km², which now puts it below the 2007 minimum that occurred somewhat later in September:

[Edit – September 14th PM]

NSIDC 5 day averaged extent has also (by a whisker!) reached a new minimum for the year of 4.285 million km²:

The daily number fell to 4.21 million km².

[Edit – September 15th]

I have somewhat belatedly discovered that in the build up to the forthcoming MOSAiC Expedition the Alfred Wegener Institute recently announced  that:

The sea-ice extent in the Arctic is nearing its annual minimum at the end of the melt season in September. Only circa 3.9 million square kilometres of the Arctic Ocean are covered by sea ice any more, according to researchers from the Alfred Wegener Institute and the University of Bremen. This is only the second time that the annual minimum has dropped below four million square kilometres since satellite measurements began in 1979.

[Edit – September 16th]

JAXA/ViSHOP extent has dropped below the 2016 minimum, and now measures 4.01 million km²:

Only 2012 left to beat!

Wipneus’ high resolution AMSR2 extent has also posted a new low for the year, but still has a little way to go before passing 2016:

Area is also currently declining, but is still well away from a new minimum for 2019:

[Edit – September 19th]

After some more modest declines JAXA/ViSHOP extent has just increased marginally from the previous day, and now measures 3.98 million km²:

That puts the (very!) tentative minimum for 2019 at 3.96 million km² on September 17th.

[Edit – September 20th]

The mid month PIOMAS gridded thickness and volume numbers have been released:

As anticipated given recent extent values, the volume difference from 2012 has increased somewhat over the last two weeks.

[Edit – September 23rd]

The National Snow and Ice Data Center have called the 2019 minimum in their latest edition of Arctic Sea Ice News:

On September 18, 2019, sea ice extent dropped to 4.15 million square kilometers (1.60 million square miles), effectively tied for the second lowest minimum in the satellite record along with 2007 and 2016. This appears to be the lowest extent of the year. In response to the setting sun and falling temperatures, ice extent will begin increasing through autumn and winter. However, a shift in wind patterns or a period of late season melt could still push the ice extent lower.

[Edit – September 24th]

To summarise the assorted minimum extent metrics for 2019:

University of Bremen – 3.77 million km² on September 18th, 2nd lowest behind 2012.
JAXA/ViSHOP – 3.96 million km² on September 17th, “Statistical tie” with 2016 for 2nd lowest.
NSIDC 1 day – 4.10 million km² on September 17th, “Statistical tie” with 2016 for 2nd lowest.
NSIDC 5 day – 4.15 million km² on September 18th, 2nd lowest behind 2012.

[Edit – October 1st]

Two sides of the same coin? Sea ice area on the Pacific side of the Arctic has been at historic lows for most of the melting season:

whereas on the Atlantic side:

[Edit – October 7th]
The September monthly numbers have arrived from the NSIDC, together with some intriguing annotations by Walt Meier:

Watch this space. Just in case!

Facts About the Arctic in April 2019

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:

Accompanied by his sage thoughts on the matter:

That has to be your lamest cherry-pick on record.

Here too is the latest graph of Rah and Tony’s beloved DMI “Arctic air temps”:

P.S. Here are the April 1st numbers from Steve/Tony’s current metric du jour:

and from the National Snow and Ice Data Center:

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.

Facts About the Arctic in March 2019

Wipneus has recently updated the mid month PIOMAS gridded thickness map, which looks like this:

The accompanying PIOMAS volume graph currently shows 2019 in seventh place:

We now have a new thickness metric to peruse each month. Here’s the gridded merged CryoSat-2/SMOS thickness data from the Finnish Meteorological Institute:

Since the FMI make the gridded data available as well as that visualisation, here’s a closer look at the Bering/Chukchi area:

There’s an awful lot of thin ice in the region ripe for rapid melting now that the sun is shining down for a rapidly increasing number of hours per day. Over on the other side of the North Pole there’s also some significant swell forecast to hit the Atlantic edge of the Arctic ice pack. Here’s the current WaveWatch III forecast for 09:00 UTC tomorrow morning:

Finally, for the moment at least, here are the current Arctic wide high resolution AMSR2 sea ice area and extent graphs:

 

[Edit – March 22nd]

This Sentinel 1 SAR image of the Lincoln Sea from PolarView suggests that the northern arch of the Nares Strait is breaking up once again:

It is therefore conceivable that sea ice in the Lincoln Sea will continue to break up and flow south through the Nares Strait for the entire 2018/2019 winter.

 

[Edit – March 23rd]

Bering Sea ice area has “rebounded” over the last few days:

and taken the Arctic wide metrics with it:

Here’s the latest Sentinel 1 SAR image of the Lincoln Sea and northern Nares Strait:

 

[Edit – March 24th]

The “rebound” has reversed:

With temperatures above freezing point across the Bering and Chukchi Sea forecast for tomorrow morning expect the decline in Arctic sea ice extent to accelerate:

 

[Edit – March 25th]

There was a 162k decline in high resolution extent yesterday:

Here also is the current state of the thick sea ice exiting the Lincoln Sea via the Nares Strait:

 

[Edit – March 27th]

Here’s another week’s merged CryoSat-2/SMOS thickness data from the Finnish Meteorological Institute:

 

[Edit – March 30th]

We’re still waiting for Wipneus’ Raspberry Pi to crunch the high resolution AMSR2 numbers, but here’s the latest from JAXA:

2019 currently in 3rd place by a whisker.

P.S. The high resolution AMSR2 numbers are out:

Area is certainly lowest for the date in the AMSR2 era. Extent will almost certainly achieve that status tomorrow. Excluding the two most peripheral seas reveals perhaps an even more worrying picture?

 

[Edit – March 31th]

Arctic sea ice coverage is now firmly in the “lowest extent for the date in the satellite record” category, whichever metric you care to choose:

The NSIDC 5 day average is in a “statistical tie” for first place with 2017:

The 2019 Maximum Arctic Sea Ice Extent

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:

charctic-20170221

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:

Terra's view of the Bering Strait on March 1st 2019
Terra’s view of the Bering Strait on March 1st 2019

 
[Edit – March 1st PM]

The “low resolution” version of JAXA extent has fallen once again today:

Do you suppose that the current maximum of 14.19 million square kilometers on February 22nd will hold until All Fools’ Day and beyond?

 
[Edit – March 2nd]

An animation of recent movements of sea ice in the Bering and Chukchi Seas:


 

Note the recent spread of open water across the southern Chukchi Sea.

 
[Edit – March 3rd]

Another angle on the Chukchi Sea, plus significant areas of open water now becoming evident in the Beaufort Sea:

 

[Edit – March 5th]

Some alternative views on Arctic sea ice thickness:

PIOMAS via Wipneus:

Blended CryoSat-2/SMOS:

plus close ups of the Bering/Chukchi area:

and the Atlantic periphery:

Please note the change of scale.

 

[Edit – March 6th]

Arctic sea ice extent is currently rebounding:

although not in all the peripheral seas:

 

[Edit – March 7th]

High resolution AMSR2 area and extent both declined today:

Long distance swells are already reaching the Bering Sea, with much more to come:

 

[Edit – March 9th]

Wipneus’ trusty Raspberry Pi hasn’t crunched the high res AMSR2 numbers yet, so let’s take a look at some other extent metrics.

Here’s JAXA’s “low res” AMSR2 numbers:

Here too is the NSIDC’s 5 day average:

By special request from Michael Ohere for the first time is the DMI’s take on Arctic sea ice extent:

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:

In addition, here is the underlying sea ice concentration data from the University of Hamburg:

 

[Edit – March 10th]

Both area and extent increased today:

including increases on both the Atlantic:

and Pacific sides of the Arctic:

 

[Edit – March 11th]

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:

Facts About the Arctic in March 2019

 

[Edit – March 21st]

The NSIDC have provisionally confirmed this year’s maximum extent:

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.

Facts About the Arctic in October 2018

A somewhat belated start to our October 2018 coverage, but firstly please take a look at this graph:

VISHOP_Extent_20181020

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:

piomas-trnd4-2018-10-20

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:

DMI-FDD-2018-10-20

Wipneus has also updated the mid month PIOMAS gridded thickness map:

PIOMAS-20181015

That’s the output of a model of course, but here too is the CPOM version of CryoSat-2 “measured” thickness:

Both sources agree that there’s a remarkable lack of thick ice in the Wandel Sea off north east Greenland this Autumn.

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:

UH-Arctic-Area-2018-10-20

UH-Arctic-Extent-2018-10-20

 

[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:

The 2018 Arctic Sea Ice Metric Minima

September is upon us once again, the month in which the assorted Arctic sea ice area and extent metrics (almost) always reach their respective annual minima. Now we are free to start speculating about what the assorted minima will be, and on what date.

To begin with let’s take a look at our much beloved high resolution AMSR2 metrics derived by “Wipneus” from the University of Hamburg’s AMSR2 concentration data:

Arctic-Area-2018-09-01

Arctic-Extent-2018-09-01

There’s currently some divergence between the area and extent graphs. Area is declining rapidly for the time of year, whilst extent seems to almost have come to a standstill!

Next here’s the prediction of the late, great Andrew Slater’s Probabilistic Ice Extent algorithm:

SPIE-extent-20180901

Before looking at some of the other metrics we’ll wait for the effect of the assorted storms currently circling the Arctic to play out. Here’s how the AMSR2 concentration map looks at the moment:

Arc_20180901_res3.125

whilst here’s the University of Bremen’s summer SMOS sea ice “thinness” map:

SMOS-20180901

 

[Edit – September 3rd]

UH AMSR2 area and extent both increased yesterday, so we have a (very!) provisional minimum extent of 4.35 million square kilometres on September 1st.

 

[Edit – September 4th]

Area and extent have both increased again:

Arctic-Area-2018-09-03

Arctic-Extent-2018-09-03

Is the minimum already in, or will the storms still circulating around the Arctic Ocean reverse that trend over the next few days?

 

[Edit – September 6th]

High resolution area and extent both posted marginal new lows for the year yesterday:

Arctic-Area-2018-09-05

Arctic-Extent-2018-09-05

 

[Edit – September 29th]

According to the latest edition of the NSIDC’s Arctic Sea Ice News:

On September 19 and 23, Arctic sea ice appeared to have reached its seasonal minimum extent for the year, at 4.59 million square kilometers (1.77 million square miles). This ties 2018 with 2008 and 2010 for the sixth lowest minimum extent in the nearly 40-year satellite record.

Please note that this is a preliminary announcement. Changing winds or late-season melt could still reduce the Arctic ice extent, as happened in 2005 and 2010. NSIDC scientists will release a full analysis of the Arctic melt season, and discuss the Antarctic winter sea ice growth, in early October.

Figure2_09232018

The NSIDC numbers are based on a 5 day average, whereas the one day high resolution AMSR2 extent reached a minimum of 4.195 million square kilometers on September 17th:

Arctic-Extent-2018-09-28

The AMSR2 area minimum occurred significantly earlier. 3.737 million square kilometers on September 9th:

Arctic-Area-2018-09-28

The 2018 Maximum Arctic Sea Ice Extent

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:

Charctic-20180323

Next let’s take a look at extent data from the Japanese National Institute of Polar Research, colloquially referred to as “JAXA extent”

VISHOP_Extent-20180323

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:

UH-Arctic-Extent-2018-03-23

UH-Arctic-Area-2018-03-23

They highlight the surge in Arctic sea ice area in the middle of March due to the sudden “cold snap”:

meanT_2018-03-24
Looking at the third Arctic dimension, here’s the latest SMOS thickness map from the University of Bremen:

SMOS-20180323

and here’s the latest CryoSat-2 thickness map:

CS2-thk_28-2018-03-21

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:

UH-Bering-Extent-2018-03-23

The 2017 Arctic Sea Ice Metric Minima

September has arrived once again, the month in which the assorted Arctic area and extent metrics (almost) always reach their respective annual minima. Now we can start to speculate about what the assorted minima will be, and on what date.

First of all let’s take a look at “Snow White’s” favourite high resolution AMSR2 metrics derived by “Wipneus” from University of Hamburg AMSR2 concentration data:

UH-Arctic-Area-2017-09-02

UH-Arctic-Extent-2017-09-02

As you can see, today’s values are both higher than yesterday’s. Hence we already have potential minima to consider! In this case:

UH AMSR2 Area – 3.65 million km² on September 1st
UH AMSR2 Extent – 4.30 million km² on September 1st

Personally I don’t think those numbers will last long, and here’s one reason why. The “surf forecast” for the far North Atlantic for midday on September 6th:

Significant_height_of_combined_w in multi_1.glo_30mext.20170903_00029

Mean_period_of_swell_waves_order in multi_1.glo_30mext.20170903_00029

Some significant swells are currently forecast to batter the ice edge on the Atlantic side of the Arctic over the next few days.

 

[Edit – September 3rd PM]

Shock news! Tony Heller has made a prediction about this year’s minimum!! Unlike last year, this year the NSIDC 5 day average extent seems to be his Arctic metric of choice:

Charctic-20170902

Tony tells his faithful flock:

The Arctic sea ice minimum this year is very likely going to be be larger than 2016, 2015, 2012, 2011 and 2007.

It is also likely that the minimum extent will be higher than 2010 and 2008.

Instead of reporting the huge gain in ice and massive failure of their forecasts, climate alarmists will report that extent was “8th lowest on record.”

All those years are on the graph above. We shall see.

 

[Edit – September 15th]

Our normal Arctic sea ice extent 2017 minimum service will be restored as soon as possible. Meanwhile here is the test card:

That comes to you via the Daily Express of all places!

On the way the cruise’s resident naturalist and Smithsonian lecturer, Michael Scott, risked the wrath of Trump supporters by pointing to some of the changes Greenland is undergoing.

A Nasa map based on data between 2004 and 2014 revealed that the ice is melting across most of Greenland – an area nine times the size of the UK.

Pulling together several papers, Michael said Greenland’s summer melt season now lasts 70 days longer than in the early 1970s.

This melting is unfreezing the fringes of the permafrost, which may explain why Nasa satellites are picking up fires raging where the ice has retreated.

 

[Edit – September 16th]

It is of course still to early to be 100% certain about this. However:

UH-Arctic-Extent-2017-09-15

It certainly looks as though the bottom is in for the University of Hamburg AMSR2 extent: 4.25 million km² on September 11th.

It’s much the same story for JAXA extent:

VISHOP_Extent-20170915

4.47 million km² on September 9th and 10th.

 

[Edit – September 19th]

The NSIDC have followed in Snow White’s glass slippered footsteps and tentatively called the minimum:

On September 13, Arctic sea ice appears to have reached its seasonal minimum extent of 4.64 million square kilometers (1.79 million square miles), the eighth lowest in the 38-year satellite record. The overall rate of ice loss this summer was slowed by a persistent pattern of low sea level pressure focused over the central Arctic Ocean.

Please note that this is a preliminary announcement. Changing winds or late-season melt could still reduce the Arctic ice extent, as happened in 2005 and 2010. NSIDC scientists will release a full analysis of the Arctic melt season, and discuss the Antarctic winter sea ice growth, in early October.

The ever industrious Wipneus has also called the PIOMAS minimum volume for 2017:

Minimum volume was reached at 11th September: 4.542 103km3, which is fourth lowest after 2012, 2011 and 2016 (resp 3.673, 4.302, 4.402) and just below 2010 (4.582).

piomas_gridded_thickness_20170911

 

[Edit – September 23rd]

Here’s the 2017 edition of our annual NSIDC daily max/min extent graph:

NSIDC-NH-MaxMin-2017

The maximum extent was the lowest in the satellite record, and the minimum was just fractionally above the trend line. For those that concern themselves with “statistical significance”, the PIOMAS minimum volume was a “statistical tie” for second place:

PIOMAS-20170915

Watch this space!