Arctic Sea Ice

PIOMAS April 2019

Apologies for not posting an update last month (busy).

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Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:

Look at the red line in the graph above. Do you see it essentially flatline towards the end of March? That's the primary cause for 2019 smashing the record for lowest March volume increase in the 2007-2019 period (and probably before that as well). The March average for that period was 1869 km3, the record was 1557 km3 (March 2015), and this year's March came in at 1339 km3. 2019 went from 7th to 4th place in the rankings, with 2011 just 89 km3 lower and a gap with leader 2017 that went down from 2279 km3 to 1834 km3.

Here's how the differences with previous years have evolved from last month:

Wipneus' version of the PIOMAS graph shows that 2019 still has some ways to go to catch up with 2017 (that went extremely low because of a horror winter, but luckily bounced up again during spring and early summer):

PIOMAS June 2017

Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:

Finally some good news, relatively speaking. The cold that crept over the Arctic during the last week of April, lingered for two more weeks into May, causing volume loss during that first half to be third lowest since 2007. But then the weather flipped, causing volume loss to pick up speed again and ending third (behind 2010 and 2012) for the latter half of May. Overall volume loss was just below the average since 2007.

And so the gap with number two has now become somewhat smaller. At the end of last month 2017 was 1595 km3 lower than runner-up 2011. In the meantime 2016 has become the runner-up, 1211 km3 behind 2017 at the end of May. The difference with 2012 has also been slashed by almost 1000 km3.

Here's how the differences with previous years have evolved from last month:

Wipneus' version of the PIOMAS sea ice volume graph clearly shows that the gap has become smaller, but 2017 is still well below all other years:

Nares Strait ice on the move

The fast ice in Nares Strait is finally giving way, relatively late again compared to recent years, after staying open over winter for a relatively long time as well. In the period the ice arch finally formed, it even got pushed back and forth a bit, probably making it stronger. But now it's failing, enabling multi-year ice floes to be transported from the Central Arctic Basin to Baffin Bay.

Commenter oren posted the following animation of LANCE-MODIS satellite images on the Arctic Sea Ice Forum to show how the arch has been breaking up in the last couple of days, which is always impressive and fun to watch:

There's an added angle to the Nares Strait story this year, with professor in oceanography Andreas Muenchow and a bunch of other scientists going into Nares Strait and as far as Petermann Glacier to make all kinds of measurements. Will the strait clear enough and fast enough so that Swedish icebreaker Oden can take them there?

Andreas explains on his Icy Seas blog:

Oceanography of Nares Strait Ice Flushing

I need the ice out of Nares Strait, a 20 mile wide and 300 miles long pathway to the North Pole between northern Canada and Greenland. The ice blocks our way to Petermann Fjord where a large glacier pushes thick ice out so sea as a floating ice shelf. We plan to drill through the floating section of the glacier that is about as thick as the Empire State Building is high. The ship to get us there is the Swedish icebreaker Oden. She is passing the Faroe Islands to the north-west of Scotland and will arrive in 2 weeks at Thule Air Force Base where we will meet her.

Image of northern Greenland (top right) and Ellesmere Island (center) showing open water as black, land as gray, and sea ice as gray/white. The two red dots are Thule Air Force Base in the south and Petermann Glacier in the north. Note the bands of black water along the coast of Ellesmere Island that result from east to west blowing winds that move ice offshore and reduce the southward flow in Nares Strait.

The voyage from Thule to Petermann usually takes about 2-3 days, but if the sea ice does not flush out with the generally southward currents, then it may take a week or two wrecking havoc to our busy science schedule. So, why is the ice still lingering in Nares Strait this year?

Read the rest here.

Erase and rewind

I don't know what the most interesting forum thread on the planet was last week, but this week it's definitely the Nares Strait thread, over on the Arctic Sea Ice Forum.

All who regularly follow Arctic events, know that one of the coolest places in it is Nares Strait, the waterway between Ellesmere Island and Greenland that I write about every now and again.

Even though the strait is narrow, it transports ten times more water than the Amazon River (according to physical oceanographer Andreas Muenchow from the Icy Seas blog) and can flush out as much as 10% of the much larger Fram Strait sea ice export, like it did in 2007. Most of this ice is multi-year ice, sometimes mixed with Manhattan-sized icebergs from Petermann Glacier.

Almost every winter the strait gets closed off by so-called ice arches or bridges that can form at various spots in the strait. It happened relatively late this winter, around the end of last month, with an arch forming at the south end of Nares Strait, called Kane Basin (adapted from an animation made by Wipneus):

Normally that would've been the end of it, but not this year. Where normally the newly-formed arch would now become stronger because of thickening ice, and break up somewhere in June or July, some really intense weather the past couple of days, in the form of very strong winds from the South, has caused the arch to break up and retreat back up the strait again! As can be seen in this animation by commenter Espen:

2014 Nares Strait ice bridges

This remains one of my favourite fascinating events in the Arctic. University of Delaware professor in oceanography Andreas Muenchow, the Nares Strait go-to guy, posted the following on his Icy Seas blog:

Formation of Nares Strait Ice Bridges in 2014

Darkness and cold covers North Greenland, Ellesmere Island as well as Nares Strait, the waterway that connects these two inhospitable places. And despite the darkness of the polar night, I can see that three beautiful arches made of ice connect Greenland to Canada. It is possible to walk across water, if the water is frozen. Stuck to land, ice arches or ice bridges shut down ice motion while the ocean under the ice keeps moving. Lets have a peek at how this looked from space yesterday:

The colors above show the temperature that satellite sensors “see” at the surface of the ice. Red is warm, blue is cold, and grey is land, but “warm” here is still below the freezing point of sea water near -2 degrees Celsius, so even the red or “hot” spots are covered by ice. The 300 deep ocean in Nares Strait generally flows from north to south without trouble under the ice, but just behind the fixed arching ice bridges, it sweeps the newly formed thin ice away to the south. The “warm” spots that form to the south of each ice arches have their own stories:

Nares Express is ready to leave

Title and image both stolen from Espen on the Arctic Sea Ice Forum:

Nares Strait is an old favourite on the Arctic Sea Ice blog, because every year it's a surprise when the ice arch/bridge - preventing ice transport from the Lincoln Sea towards Baffin Bay - is going to collapse. This year it happens almost two weeks later than last year, which in its turn was 10 days later than in 2011. What strikes me this year, and maybe I didn't pay enough attention in previous years, is that the break-up was already occuring from within through in situ melting, before the arch gave way.

Ice transport through Nares Strait contributes to ice loss from the Arctic Basin. It it isn't quite as significant as ice transport through Fram Strait (roughly 10% at the most), but the ice that gets transported, is some of the thickest and oldest ice in the Arctic. A NASA-led study by Ron Kwok in 2010 (PDF) showed that transport in 2007 was exceptionally high.

Nares: from collapse to transport

I haven't been making many animations this year as, unfortunately, there are only 24 hours in a day. Two weeks ago the ice arch at the southern end of Nares Strait collapsed. Even though we have seen how it works last year, the relatively clear images of the area in the past two weeks prompted me to make this animation that shows how all of the fast ice in Nares Strait quickle disintegrates after the collapse of the ice arch.

The animation starts on June 26th (day 178) and ends on July 10th (day 192):

It looks like transport from the Arctic Basin got underway 11 days after collapse of the southern ice arch, three days later than last year.

Ice transport through Nares Strait contributes to ice loss from the Arctic Basin. It it isn't quite as significant as ice transport through Fram Strait (roughly 10% at the most), but the ice that gets transported, is some of the thickest and oldest ice in the Arctic. A NASA-led study by Ron Kwok in 2010 (PDF) showed that transport in 2007 was exceptionally high:

To quantify the impact of ice arches on Arctic Ocean ice cover, the team tracked ice motion evident in the 13-year span of satellite radar images. They calculated the area of ice passing through an imaginary line, or "gate," at the entrance to Nares Strait. Then they incorporated ice thickness data from NASA's ICESat to estimate the volume lost through Nares.

They found that in 2007, Nares Strait drained the Arctic Ocean of 88,060 square kilometers (34,000 square miles) of sea ice, or a volume of 60 cubic miles. The amount was more than twice the average amount lost through Nares each year between 1997 and 2009.

Read the whole article here.

60 cubic miles is 250 cubic kilometres, so if I'm not mistaken the ice that was transported through Nares Strait in 2007 was on average 3 metres thick. No spectacular numbers, but the break-up and subsequent ice transport through Nares Strait remains a spectacular sight nevertheless.

Nares Strait 2012 Ice Arch Collapsing

It looks like the ice arch in at the southern end of Nares Strait has started to collapse, according to yesterday's satellite image from LANCE-MODIS:

This break-up is occuring 10 days later than last year. Back then it took about two weeks for all of the ice to start moving across the entire strait and transport from the Lincoln Sea to get underway. Looking at the weather forecasts and the fact the ice is blue and breaking up at the other side as well, I don't think it will take much longer. High time too, as Baffin Bay has almost run out of ice.

But if you want to know the real deal about Nares Strait, I urge you to go to the Icy Seas blog. This blog is run by sea-going physical oceanographer Andreas Münchow, who has actually been to Nares Strait and will soon go back there to retrieve all kinds of gadgets full of data on ice thickness, volume flux and what not. He graciously allows me to re-post his latest blog post:

2011 Nares Strait Animation

Now that the formidable ice plug in Smith Channel has finally broken up (see this blog post from a few days ago) the rest of the ice in Nares Strait gets a chance to start moving.

The coming days a high pressure system is forecast to roam the area, meaning 1) high temperatures and insolation that will further fragment the ice, and 2) clear skies that should deliver nice, clear MODIS images of the event. So the coming weeks I will update this animation that shows the whole of Nares Strait.

As always I advise to focus on one part of the animation, instead of trying to take it all in at once.

Nares Bridge is falling down

It looks like I'm back just in time to witness the breaking up of the ice plug in Kane Basin. This just in from the Aqua satellite:

It's a bit vague, but it looks as if the lower part of the plug is crumbling. If it is breaking up, how long will it take for ice transport to get going through Nares Strait?

This page will be updated the coming few days. Stay tuned...