The National Geographic magazine have just noticed a large increase in the Weddell Sea polynya (south of south America) that I brought to your attention earlier last month in an article that I found on the phys.org website. I can confidently predict that the polynya will continue to increase in size till it totally disappears later in the Antarctic summer!
It looks like this Winters maximum sea ice extent has been reached in the Antarctic a little earlier than average. The spot value for the 12th of September was 18.023 million square kilometres was the lowest maximum in the satellite record that started in 1979, but it was a very near thing, because the 2017 figure was just 4,000 square kilometres lower than the previous lowest maximum of September 1986. The sea ice could surge again and prove me a liar, but I got it right with the Arctic minimum, so maybe I’m on some kind of roll (pardon the pun).
Here is the table sorted from lowest to highest on maximum extent (fig 2). Before you ask 1978 is top of the list because the satellite record started on the 26th of October 1978, and the maximum for that year will have occurred a month earlier and been considerably higher than that figure, blame it on the programmer.
I would say on balance that the Antarctic sea ice extent has bounced back extremely well after what was a pretty dreadful start, back on the 1st of March sea ice extent was just 69.8% of the long-term average for that date, on the 12th of September they were back up at 97.4% of the long-term average for that day. This is the latest rather interesting ice extent picture for the Antarctic from the NSIDC (fig 3), which shows another polynya in the Weddell sea similar to the one in the news item I posted earlier this month. Who knows, maybe if that polynya hadn’t opened up, 2017 might not have been the new record low year!
I might be jumping the gun here but…
I think the Arctic sea ice minimum as measured by the NSIDC, reached its summer minimum on September 12th at 4.611 million square kilometres, making 2017 the 8th lowest minimum in the satellite series that started in 1978. The value was over 500,000 square kilometres higher than last years minimum. I’ll bring you the latest news from the Antarctic about the maximum, because the season down there has still not quite finished.
I noticed this interesting article about polynya on the Phys.org website (you might what to add this to your favourites because it looks a great site) that might interest some of you out there. I was thinking, it’s only because the upwelling of warm water occurs under an ice sheet that we realise that they’re happening at all. They must happen all the time in the worlds oceans, but we just don’t see them, apart I suppose from anomaly charts of very sensitive SST satellite sensor data.
If you read the blog the expectation of the Arctic mission was to reach 90° north in the late summer, in the end they reached 80° 10″ before skedaddling back south. Here’s an extract from the mission blog:-
Last summer (2016), we reviewed a range of satellite-generated images of the Arctic Ocean’s sea-ice cover, and believed there was a reasonable possibility of reaching 88N.
We monitored the satellite-observed sea-ice cover from November 2016 through to March 2017, which indicated less sea ice had formed in each month since records began in 1979. We concluded it may prove possible to reach 90N in the late summer of 2017.
If someone’s exclusive objective had been to go as far north as possible, undertaking no science and with a higher tolerance of risk regarding entrapment, they may have reached closer to 86N this season.
The day we reached 80N, strong NW winds to our north could have opened up the existing ice-free channels to beyond 85N. But within 24 hours the opposite happened, contrary to opinion onboard and ashore, and it was deemed prudent to head south and continue our scientific work in the CAO away from the highly concentrated ice.
It’s worth noting that detailed forecasts of sea-ice movements and ice-types are not available, and ice concentrations vary can dramatically day-to-day (notably due to surface winds and currents), so knowing which year is going to be the year to reach 90N is more by practical trial than infinite analysis. We believe 90N will likely be reached by sail-boat sooner than later.
I think they literally took the sea ice extent charts from the NSIDC (which outlines the extent of sea ice with concentrations greater than 15%), and thought that the dark blue was open water (fig 2). When they did reach the white bit on the map in their yachts, how did they expect to get the remaining 600 miles without the aid of an ice breaker? They were, and still are naive to think that they could have ever gone further north than they did. To my mind the whole thing was just an elaborate publicity exercise. I don’t believe that the ‘scientific research’ that they did will add a lot to what we already know about life in the Arctic Ocean, we already have research vessels that do that each summer, and much more thoroughly I suspect, but the images they took of the Polar bear family clinging to an ice floes were unexpected!
The irony is, that at the same time this publicity stunt of Pen Hadow’s was playing out, the Arctic sea ice which is close to its minimum for this summer, is bucking the trend, with more than 500,000 square kilometres than at the same time last year. I personally think that it will be a very long time before anyone can sail to the North Pole.
The Arctic Ocean has proved many pundits wrong about a record low minimum sea ice extent this summer, including me! My forecast projections for the minimum extent this summer was 3.7 million square kilometres, low but not a record. That forecast which I made in April, looks likely to be out by some 800,000 square kilometres if the sea ice extent bottoms out at 4.5 million square kilometres as looks likely. The Arctic sea ice figures on face value look much healthier than they did last summer to the tune of 500,000 square kilometres. In fact 2017 is now only the sixth lowest extent for the 1st of September, and don’t forget that on the 5th of March this year they were the lowest. So the Arctic this year, for whatever reasons, has managed to keep a lot more of its sea ice than was ever expected. The season still has a couple of more weeks to run, because the average minimum in the Arctic is not till the 11th of September, but I can’t see a catastrophic collapse happening in the next few weeks.
From reading the Arctic Mission blog it looks even more apparent that the BBC headline of a few weeks ago about the Arctic Mission of Pen Hadow Sailing to the North Pole as Arctic ice melts was just as it seemed at the time – completely unrealistic – even fake news of a kind. They’ve now at around 79° north and had their first sight of broken sea ice, and recently seen four Polar Bear’s who look remarkably healthy and are managing to survive on a small patch of sea ice in an Arctic Ocean that’s 98% open water, and it’s now time to do the science whatever that is. Maybe that’s just a euphemism for taking some video and heading back south to Nome, which now looks as if it was the goal of the mission all along, sail as far north as you can, and then return the way you came. Regarding the Polar Bears was a big surprise as even Pen Hadow admitted in his blog: –
Within 24 hours, we saw the FOUR polar bears on ONE ice floe! I confess even I was astonished!
I’d like to bet that this story alone just has to get some air time on the BBC news this Bank Holiday.
This image (fig 2) must have been taken by a drone, as they are moored their two yachts to an ice flow. It’s funny, when I look at the sea ice charts from the NSIDC as I’ve been doing for the last 5 years or more, you get the impression from the sea ice extent charts that the rest of the Arctic ocean is ice-free, when what the charts are telling you is that there maybe a lot of broken sea ice which covers less than 15% of the sea’s surface, which is exactly the part of the Arctic Ocean that the Arctic Mission is in now. These charts are a very valuable resource, but the estimates that they offer as to the area covered by sea ice are still rather crude.
I notice that there’s mention of rough seas and sea sickness in the blog, and the air temperature is now down to -4°C, now that they’ve reached 79° north and paused to do their science. I just can’t see them staying out there for another 22 days before they head for home.
To say that the Summer sea ice in the Arctic is in a terminal condition according to many scientists, and will soon be no more by this time in August in the years to come, it’s still doing remarkably well, if the latest figures for the 22nd of August from the NSIDC are to be believed. The sea ice extent on that day is only the fifth lowest, in a series that started in 1978, which is pretty remarkable, because if you remember the 2016/17 season ended up on the 5th of March as the all time lowest maximum year.
The red line (2017) series in the graph (fig 1) has gone higher than last years trace (black) and as stayed that way for a week. If you remember, it was about this time last year that sea ice values crashed very quickly. There is little chance that 2016 is going to produce a lowest maximum to add to its lowest minimum record, and is still almost 900,000 square kilometres higher than at the same time in summer 2012.
At the NSIDC there is a now very useful new comparison web tool that allows you to compare any two years. Here is a comparison between 2017 and 2016 for the 22nd of August (fig 2).
And here’s a comparison for 2017 and the record minimum year of 2012 (fig 3).
It’s day 19, and the ‘Arctic Mission’ team have now reached latitude 76° north, and although there is little sign of any sea ice, the air temperature is now down to -2°C, so no skinny dipping and time to break out the thermals. I still wonder what the web team in charge of the ‘follow the mission’ website will do if they ever reach 85° north, perhaps they’ll call it a day because the Google map projection they’re using to plot the course with doesn’t extend any further north than that.
A little off topic, but it seems that it’s not only Pen Hadow that want’s to sail around the North Pole at the moment.