Sea ice extent projections for the coming season

Figure 1

I’ve just been projecting forward the sea ice extent using the statistics the data that I download from the NSIDC. I’ve used the rate of change of the 10th percentile, and applied it from the 16th of April running forward (fig 1) to the extent on that day. If these projections are correct, unsurprisingly the Summer minimum in the Arctic will be a new record low of around 3.7 million square kilometres. This is the first time the extent will have ever fallen under the 4 million level in the satellite series, that should happen at the start of September, which it almost managed to do last year. I’m sure a lot of people are looking at a much lower minimum, but the Arctic has put on a bit of extent this Winter, after suffering substantial losses during the run up to Christmas.

Rather more severe is the Antarctic projection for their upcoming Winter. I see the maximum at around 15.8 million square kilometres in the second week of September, the previous lowest maximum extent was 17.803 at the very start of the satellite series in 1978 (fig 2), so this figure is seriously low if it comes about. This year (the red line) will track much lower than 2017 (the black line), if anything the gap will widen between the two if anything, this is because up until the 28th of August last year the Antarctic was doing very well, with the extent slightly above average, but after that date the extent suddenly collapsed in September when it should really have been peaking. So I reckon that all eyes might be on the Antarctic this September, rather than the Arctic.

Figure 2

I will revisit these projections in September, it maybe by then, that I’ll have some serious egg to wash of my face, who knows my projections could end up being optimistic!

I will be the first to admit that what I’ve done is not scientific in any way, it’s just playing with the statistics of the last 40 years, but what the hell.

April 2017 – Polar sea ice figures

Figure 1 – Courtesy of the NASA Goddard Space Flight Center

There’s a lot of fear and apprehension going about on the Internet about the current state of the polar sea ice extent. I’ve always kept a close eye on how it’s performing both in the Arctic and Antarctic over the past 5 years with the help of the NSIDC, certainly in the Antarctic sea ice has fluctuated wildly in the past few years, but in the Arctic it’s been more or less just down. The latest data for the 14th of April is at a record low for this time of the year (fig 2), but it’s only slightly worse than at the same time in 2007. Perhaps the quality of the ice cap in the Arctic is thinner that it has been in the past, and maybe once it reached a critical ‘thinness’, then the extent will just crash one of these summers.

Figure 2

I’ve added a curve fitting series to both graphs, rather than just my usual linear trend which doesn’t lend itself to the Antarctic data at all well. The Antarctic curve is showing signs of taking a nose dive at the moment, because of the massive decline in the sea ice extent in the last few seasons (fig 3).

Figure 3

This graph of the Arctic sea ice volume anomaly (fig 4) does lend itself to a linear trend. Perhaps PIOMAS is a better way of looking at sea ice extent than the SII is, I don’t really know.

Figure 4 – Courtesy of the Polar Science Center

And just to give the full perspective on my earlier graph of the Arctic sea ice extent.

A night to remember – 14/15 April 1912

Figure 1 – Courtesy of Wikipedia

The RMS Titanic sank in the early hours of Monday the 15th of April 1912, after striking an iceberg at 11.40 am on the previous evening. The exact date and time it struck the iceberg fixes the time of the disaster, which depends on which time zone that you use. If you get a chance, I read a short but fascinating article about the disaster on the Encyclopedia Britannica web site. There is so much written about the event that there are literally hundreds of articles available on the Internet. Wikipedia, as you would expect has a complete and detailed report about it, 10 things you might not know about RMS Titanic  and the Titanic Facts websites also make interesting reading.

Titanic was south of Newfoundland that evening, and steaming at almost full speed (22.5 knots) west south-west after ’rounding the corner’ and heading on a Rhumb line for New York (fig 2). Who knows, if the First Officer William Murdoch hadn’t try to avoid the infamous iceberg and Titanic had hit it head on, rather than as we know with a glancing blow, that created a series of holes below the waterline in five of the ship’s watertight compartments, this disaster may never have occurred.

Figure 2 – Courtesy of Mark Chirnside

All I can offer about the weather at the time of the sinking, apart from that we know it was a clear and starry night, and the sea was like a mill-pond, is the midnight chart for the 15th of April, which I’ve generated using the 20th century reanalysis data (fig 3).  Titanic as you can see was in a col like area between two anticyclones in a belt of high pressure that stretched right across the North Atlantic that night, winds will have been light and from the northwest, rather spookily weather reports from ships in the North Atlantic at that time may well have been used in this reanalysis.

Figure 3 – Data courtesy of NOAA/NCEP 20th Century Reanalysis

In an eye-witness account from Jack Thayer a 17-year-old survivor, who said:

It was a brilliant, starry night, there was no moon and I have never seen the stars shine brighter; they appeared to stand right out of the sky, sparkling like cut diamonds. I have spent much time on the ocean, yet I have never seen the sea smoother than it was that night; it was like a mill-pond, and just as innocent looking, as the great ship quietly rippled through it.

Figure 4

The risk of icebergs was well-known in April in that part of the western North Atlantic (fig 5), and if the Captain of the Titanic had only done what the Captain of the SS Californian had done, and that was to stop the ship overnight, or at least slow it things might have been so different.

Figure 5

  • Interestingly the SS Californian was later sunk herself, in November 1915, by a German submarine, in the Eastern Mediterranean during World War I.
  • Titanic’s sister ships HMHS Britannic struck a mine in the Aegean Sea also in the first World War, and sank in a similar way to how her sister ship sank four years earlier.
  • Titanic’s other sister ship lead an interesting life, RMS Olympic was used as a troop ship in World War I, and collided and managed to sink a German submarine. On the 15th of May 1934 she managed to collide with something else, this time the Nantucket lightship (see map fig 2) with the loss of seven lives, her final voyage ended when her hull was towed in for scrap at Inverkeithing in September 1937.
  • In July 1918, the RMS Carpathia which played such a big part in rescuing so many of the survivors from the Titanic, was herself torpedoed by another German submarine U-55 in the Celtic Sea.

It certainly was a dangerous life for any merchant seaman back then.

Evidence of mild Arctic Winter in Svalbard

Courtesy of ITV News

The title of this news item that I read this morning ‘Fears for Arctic after warmest winter on record‘ (courtesy of the ITV news) is a bit on the emotive side – personally I’m not at all worried at all about the future of the Arctic it’s not going anywhere – but it’s sea ice unfortunately is. Why is it when weather becomes news do we always have to send out a reporter to witness first hand what’s going on? I suppose a video of a boat in a fjord free of ice in early April is more striking than any graph or a satellite image.

Stratus reluctant to clear from central England

Figure 1 – Courtesy of the Met Office

The low stratus across central England has been very reluctant to clear today, and I notice this afternoon that it’s now spilling down the north coast of Devon in the easterly flow (fig 1). I also notice that there’s still some sea ice visible in the northern Baltic (fig 2).

Two big questions regarding Polar sea ice

Now that we’ve seen both the lowest Arctic sea ice maximum and the lowest Antarctic sea ice minimum records broken this year, the two big questions regarding Polar sea ice are:

  • How low can the Arctic sea ice minimum get this summer?
  • Can the Antarctic sea ice bounce back this winter after such a catastrophic melt in the summer?

Figure 1

The Arctic rallied towards the end of this Winter but the 14.447 still couldn’t quite match the previous lowest maximum of 14.554 million square kilometers set on 22nd of February 2015.  So just by looking at the stats, it seems that this summer may push the minimum of 3.34 million square kilometers of September 16th 2012, but the minimum that year was abnormally low even for the Arctic, and may take some beating.

Figure 2

The Antarctic sea ice on the other hand is starting the year extremely low at 2.075 million square kilometers. It will be interesting to see if it can catch up, but that’s a tall order, and this winter we might see a record low maximum, the previous lowest maximum was 18.027 million square kilometers set on September 18th 1986.

The end of Arctic sea ice in summer is still a long way off as far as I can see. A simple linear trend on each years minima puts zero summer sea ice in 2066. I’ve tried another type of polynomial line fitting curve but I can’t extrapolate a forecast from that, so that’s my best guess at the moment.


Latest Polar sea ice extent – 4 March 2017

Figure 1

It’s make or break in the next couple of weeks for Arctic sea ice, the rally it’s been staging since the middle of January has faltered, but today’s value (4th March) is it’s maximum extent this season, and it’s now within 120,000 square kilometres of the lowest maximum year of 2014-15. Last years Arctic maximum occurred very late on the 21st of March, so there is still time for it to make up this shortfall.

Meanwhile in the Antarctic summer, I would say that we have now have seen the minimum ice extent this year (on the 1st of March), which as well as being the lowest in the series since 1978, was also the second latest minimum, the average date for that is the 20th of February. One thing the sea ice extent did manage was to stay above the 2 million square kilometre mark, but only just. It will be interesting to see if the sea ice extent continues to spiral down in the coming season or if it will manage to stage some kind of recovery.

Figure 2

Arctic sea ice stages late fight back

Figure 1 – Data courtesy of NSIDC

For the first time since the 3rd of October last year, this Winter’s (2016-17) sea ice extent in the Arctic is higher than last seasons (2015-16), which is something of a minor miracle if you had last looked at the figures just after the New Year when the trace had flatlined (fig 1). In fact the latest total is less than 0.253 million square kilometres shy of the lowest maxima set in 2014-15. I make the average date that the maxima occurs in the Arctic is the 9th of March, so it still could be at least a couple of weeks away, and it may well be, that the Arctic is not going to go along with most people’s expectations of record low sea ice extents at both Poles this year.

Figure 2 – Data courtesy of NSIDC

Pardon me for my simplistic unscientific view on what’s go on, but perhaps the Arctic is not venting as much of its cold air south (fig 3), and is consolidating more deep cold air for itself, and allowing the sea ice to flourish this late in the season.

Figure 3 – Courtesy of ECMWF

Certainly last week’s incredible warm spell in Svalbard has come to an abrupt end, and temperatures there at the moment are as cold as anytime during this Winter (fig 4).

Figure 4

Record lowest Antarctic sea ice extent

Figure 1 – Data courtesy of NSIDC

It’s always been a question of when, rather than if the Antarctic sea ice extent record would be broken this season, but finally the 2.246 million square kilometres for the 12th February (fig 1), has dipped just a fraction lower than the 2.264 of the 22nd of September in 1997, to break the lowest minimum record in the satellite series that started in 1978. Earlier in the season it looked like the extent would be as much as 30% below the long-term minimum, but the decline did slow, and at the moment (12th February) it’s only 25.8% lower than average for that date. The decline in Antarctic sea ice is even more spectacular, considering that it was just over two years ago that they were at record high levels (fig 2), and the decline is set to continue for another four weeks before the minima is reached, so a sub 2 million minima is a distinct possibility.

Figure 2 – Data courtesy of NSIDC

I notice that the National Geographic were able to do an article about the record yesterday even before the figures were released by the NSIDC, which is fair enough, because if it wasn’t for the Americans, there wouldn’t be a SII anyway. And finally, here is this season overlaid on the previous 38 or so, to put it into some kind of perspective (fig 3).

Figure 3 – Data courtesy of NSIDC

Antarctic sea ice flirting with record lowest extent…

Figure 1 – Data courtesy of NSIDC

The Antarctic sea ice extent at the moment, is hovering fractionally above the record lowest extent of 2.264 million square kilometers that occurred on 27 February 1997. I’ve been watching it over the last few weeks but the decline has now flattened as the Summer minima approaches in the next couple of weeks. The Antarctic minima occurs on average around the 20th of February, so there is still plenty of time for a final dip, although I still can’t believe just how much improved the extent looks now than it did a month or so ago.

Figure 2 – Data courtesy of NSIDC

Todo: Check that average it looks a bit lopsided.