Sea Ice

The monthly Sea Ice Index [SII] from the National Snow and Ice Data Center [NSIDC] provides a quick look at the latest changes to both the Arctic and Antarctic sea ice extent and concentration, and provides a consistently processed sea ice extent data since 1979.



Arctic sea ice doing better than expected

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).

Figure 2 – Courtesy of NSIDC

And here’s a comparison for 2017 and the record minimum year of 2012 (fig 3).

Figure 3 – Courtesy of NSIDC

What happens at 85° north?

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.

Russian LNG tanker navigates Arctic sea route in record 6.5 days

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.

Pen Hadow heads out into the Chukchi Sea

Figure 1 – Courtesy of Arctic Mission and Google Maps

That brave chap Pen Hadow and his Arctic Mission team have now entered the Arctic Ocean proper, in fact they have now entered the Chukchi Sea on their journey north. You can follow the expedition by means of the Arctic Mission website. It’s a shame that they don’t seem to have an observer on board who can send out a SYNOP observation every six hours, although they reported that the air temperature at 10 UTC this morning was +3°C and they were around 67° north, so they still have a long way to go before they meet the ice edge at around 80° north.

Polarstern at 79° north

Figure 1 – Image courtesy of the AWI

The German research icebreaker the  RV Polarstern of the Alfred Wegener Institute for Polar and Marine Research [AWI] is currently at around 79° just to the west of Svalbard in the Arctic Ocean.

Figure 2 – Courtesy of www.sailwx.info

As far as I can see, the Polarstern is reporting the coldest air temperature in the northern hemisphere, either on land or sea at the moment. The air temperatures at 15 UTC this afternoon was around -2°C, and the sea temperature a very balmy +1.5°C.

Figure 3

I think the reason for the sub-zero temperatures must be the cold air flowing off the drift ice just to their west and north, in the light northwesterly breeze (fig 4). I don’t think they’re going to try to go any further north, as they have done in previous years, but I can’t see anything about their plans for this summer expedition to the Arctic on their blog, so who knows.

Figure 4 – Courtesy of the NMI

June’s Arctic sea ice extent

Figure 1 – Images courtesy of the NSIDC

On the 22nd of July, 2017 had the third lowest sea ice extent on record for that day in the Arctic (fig 2). 2017 has now dropped 2016 for the first time, and it’s neck and neck at the top (or should that be the bottom) of the table at the moment, I shouldn’t wonder that people bet on what the outcome of this well end up in September at William Hill’s.

Figure 2

New Antarctic lowest maximum sea ice extent likely

Figure 1 – Data courtesy of the NSIDC

The Antarctic sea ice extent has staged a recovery since the lowest minimum of just over 2 million square kilometers occurred on the 1st of March, but despite that recovery, it still heads the lowest extent for the 30th of June, with only 93.3% of the average for that day (figs 1 & 2).

Figure 2 – Data courtesy of the NSIDC

My simple way of extrapolating the curve to detect the amount and the date of the maximum extent, shows that the maximum will fall well below the 18 million square kilometer mark (~17.6), and 2017 looks likely to see a new lowest maximum, to complement the lowest minimum of the Spring. Here’s the plotted projection for 2017 outlined in yellow (fig 3), the black line is last years extent, and the blue line is the current lowest maximum year 1986.

Figure 3 – Data courtesy of the NSIDC

 

Three horse race in the Arctic

Figure 1 – Data courtesy of the NSIDC

The latest sea ice extent figures for the 29th of June show that it’s a tight race between this year, last year and 2012, the year that currently holds the record for the minimum sea ice extent in the Arctic (fig 1 & 2). I think 2017 has surprised a lot of people, well it surprised me at least, because after a disastrous showing at the end of last winter, the sea ice extent held up very well during the spring. At the moment 2017 is fourth lowest for the 29th of June, behind 2016, 2012 and 2010.

Figure 2 – Data courtesy of the NSIDC

I’ve decided to look at how sea ice in the Arctic did in 2012 and 2016 in a little more detail, I’ve left out 2010, because in that year sea ice values during that summer held up after falling off sharply in the spring. I’ve plotted a pink area of projections for how 2017 might go this summer (fig 3), I’ve plotted the upper line using changes in the rate of decline of the 90th percentile, and the lower line using the changes in the 10th percentile.

So if these simple projections of mine are correct, 2017 won’t break any records come September, and it could end up with a minimum extent that’s slightly higher than last year, somewhere around 4.3 million square kilometres even if it follows the lower line.

Of course 2017 might decide to decline at an even sharper rate than the changes at the 10th percentile, in fact 2017 might follow the rate of changes that occurred last year, or it might follow the rate of change in 2012, and crash below four million square kilometres. The next 10 to 12 weeks or so will tell, thanks always to the NSIDC for the free data.

Figure 3 – Data courtesy of the NSIDC

Arctic sea ice doesn’t seem to be following the script at the moment…

The Arctic sea ice extents still doesn’t seem to be following the script that most people have prepared for it so far this Spring. In the last fortnight it’s still been making ground up on the -2 SD line, and on the 28th of May, was only the 6th lowest for that particular date in the 39 year-long series (fig 1). The sea ice is now just 5% below the long-term average for this date, and I’m sure some people are arguing that the extent has changed little since 1995, even though it maybe a lot thinner.

Figure 1 – Data courtesy of the NSIDC

Meanwhile in the Antarctic, the sea ice is following the script and is the third lowest for the date of the 28th May, and 10% below the long-term average.

Arctic sea ice stages a late spring fight back

I notice that the latest Arctic sea ice extent for the 14th of May was only the fifth lowest for that particular day of the year, which means it’s staged a late spring fight back from a disappointingly low maximum in early March. Having said that, although it’s higher than last year at the same date, it’s still lower than the record low year of 2012.

Figure 1

I have revised my estimated September minimum up from 3.7 to 3.9 million square kilometres of sea ice. This doesn’t come close to breaking the lowest ever minimum of 3.34 million, which occurred on the 16th of September 2012. If the sea ice pundits are correct though, the pack ice has never been thinner and the Arctic could see an unprecedented collapse in sea ice this summer  – we shall see how right they are in around four months time.

Figure 2 (yellow outlined series is my estimate)