Arctic Sea Ice

Circumnavigating Greenland

A quite spectacular event took place during the past two weeks, and if it had continued for a while longer, I'm sure it would've been reported widely. It's something I've semi-jokingly alluded to when setting up this blog back in 2010, in my third blog post called Dire Straits, and a partial answer to the question commenter fredt34* asked at the time:

The big hole opening in East Greenland re-activated my interest for this question: will we see Greenland being circumnavigable this year? If not, when?

That was July 23rd 2010, and now a little over 8 years later, we have almost seen it happen: a corridor of open water between Fram Strait and the Lincoln Sea (where Nares Strait starts). Here's an animation of NASA EOSDIS Worldview satellite images showing what has happened during the past two weeks, ending yesterday (click for a slightly larger version):

And here's the animation with only the first and last images, two weeks apart:

Bering goes extreme

The melting season hasn't started in earnest yet, but it seems the Bering Sea hasn't received the memo. For almost the entire winter, sea ice has been reluctant to form there, and now that the Sun has returned, the ice edge has started to retreat to record high latitudes, past the Bering Strait all the way up into the Chukchi Sea. Here's how that looks on Wipneus' regional graph:

To emphasize how truly exceptional this is, here's a comparison with the situation in all other years from the 2006-2018 period (images retrieved from the University Bremen sea ice concentration maps page on the ASIG, click for a larger version):

Now, if this was it, other years would maybe catch up in the next few weeks, but this isn't it. The coupled HYCOM-CICE model from the Naval Research Laboratory forecasts the sea ice to continue to drift northwards, until the end of the month at least:

The 2016 melting season in images

The Arctic year started with the warmest January and February on record:

The mild winter led to one of the lowest maximums on record, lowest even on some graphs.

And then in April, just before the melting season started, things got exciting very early in the Beaufort Sea (animation shows March 30th to May 4th):

This caused a big, early lead on sea ice extent graphs such as JAXA's:

2016 Mega-Dipole

As reported in the last ASI update, the forecast Dipole has now set up. Yesterday's last analysis chart provided by Environment Canada, at 18Z, showed the high pressure moving in via the Bering Strait at 1037 hPa, while a rapidly weakening storm that had moved in from Siberia (lowest central pressure was 967 hPa, two days ago) was still at 974 hPa on the other side of the Arctic. This then evolved to a massive 1041 hPa on one side of the Dipole, and 977 hPa on the other:

That's a humongous pressure gradient of 63-64 hPa! You don't see that often around this time in the Arctic, a not so nice story for the grandkids. Right now, the high is still at 1041 hPa, but the low has weakened further to 980 hPa. That's still a pressure gradient of 61 hPa.

It means very strong winds are blowing over the ice pack, from Siberia to Canada, compacting the ice pack and further pushing open water towards the pole, as can be seen on this animation of Uni Bremen sea ice concentration maps:

If one looks carefully at the ice in the so-called Wrangel Arm, you can clearly see the ice flash in and out of existence. There comes a point where the ice no longer flashes back, but in the meantime it makes for wild swings on the CT sea ice area graph, as calculated by Wipneus:

2016 Arctic cyclone, update 3

Two days have passed since the previous update, and in those two days the storm re-intensified, bottomed out at 971 hPa (slightly higher than the first lowest central pressure of 968 hPa), as can be seen on the image on the left, provided by Environment Canada. It quickly weakened after that, but lo and behold, the image on the right shows it has re-intensified again and is currently at 971 hPa as well!

Just like that, as if it's nothing. Which brings us to the first of three questions (there were two in the previous updates, but now there's a third one at the end of this blog post):

1. Is this a Great Arctic Cyclone?

I'm still not entirely sure how this storm will rank, compared to previous storms. Remember the quote from Simmonds and Rudeva paper I mentioned in update 1:

The plot shows that AS12 was at the tail of the distribution and, at 966.38 hPa, was the lowest in our record, beating the previous deepest (966.94 hPa) (for a storm at 06UTC 7 August 1995) by 0.56 hPa. The next lowest central pressure, 969.23 hPa, was associated with a cyclone at 06UTC 22 August 1991, followed by the fourth lowest storm central pressure in the earlier part of that month 00UTC 7 August 1991 (970.47 hPa).

But it's definitely a very powerful storm, and even if it doesn't boast the lowest central pressure, all these re-intensifications will probably have it score high in other requirements for GAC nomenclature. And that reminds me of something I wrote back in 2012, following a quote that is highly relevant today:

“This past week’s storm was exceptional, and the occurrence of Arctic storms of extreme intensity is a topic deserving closer investigation,” noted Walsh. “With reduced ice cover and warmer sea surfaces, the occurrence of more intense storms is certainly a plausible scenario. The limitation at present is the small sample size of exceptional events, but that may change in the future.”

That last bit is the reason I'm hesitant calling this the Great Arctic Cyclone of 2012, or Arcticane, or some such. What if we see a similar cyclone in 2013 or 2014? We'll run out of names.

Mind you, I don't want to downplay the importance and magnitude of this storm, it's by far the biggest thing I have seen in the Arctic since I started the blog, but to me this whole event isn't about the storm itself, but about a possible new regime - a new aspect of the new abnormal - with big summer storms in the middle of the Arctic.

I called it the new abnormal at the time, but if this becomes 'normal' (compare coverage of this storm to 2012, for instance), then what cachet does the name 'Great Arctic Cyclone' still have?

Beaufort final update

This isn't a final update as such, because I will certainly be mentioning events in the Beaufort Sea in upcoming ASI updates. But it is the last in a series of blog posts I have written (one, two and three) about this unprecedented event that started over 6 weeks ago and has led to a heavily cracked ice pack and a huge amount of open water on the American side of the Arctic.

The event has received some attention on other blogs and in the mainstream media. Just yesterday this image was posted on NASA's Visible Earth website, comparing this year to 2015 and 2014 (mind you, the Beaufort Sea opened up early last year as well):

The image is accompanied by a text, quoting Walt Meier:

“It really is quite remarkable,” noted Walter Meier, an ice specialist at NASA’s Goddard Space Flight Center. “There is always fracturing of the ice, but it seems to have become more prevalent and more widespread in recent years. This region used to be mostly multi-year ice, which is quite a bit thicker. Now, most of the Beaufort is seasonal, first-year ice. The thinner ice is weaker and more easily broken up by the winds.”

There are some links to other articles at the end of the Visible Earth article.

As I mentioned two weeks ago it looked as if that persistent high-pressure area was shifting away from the Beaufort, which would probably put "an (temporary) end to the massive cracking and ice movement". The animation below shows there has been some movement, but not as much as in prior weeks. Cloudiness makes it difficult to perceive, but if you focus on one of the two larger ice floes in the red circles, you can get an idea of the scale of movement/change:

Beaufort under relentless (high) pressure

When I wrote the Beaufort under early pressure blog post last month, I didn't quite expect this unprecedented pressure (timing and magnitude) to keep up for so long. High pressure areas tend to be short-lived in the Arctic, but this one was still going strong when the Beaufort quick update was published. Now, almost three weeks later, things still haven't completely calmed down, and this animation of satellite images showing weekly changes from March 30th to May 4th provides an astonishing sight:

Astonishing, mindblowing, frightening even. May is the month when melt ponds start to form on the ice, pools of water that lower the albedo and cause the ice to melt faster, leading to open water that absorbs solar radiation and warms up. The open water is already there in the Beaufort Sea. Look at all that open water!

No other year comes even close to it, as can be seen on the ASIG comparison of sea ice concentration maps, or on this sea ice extent graph (based on AMSR2 data, provided by Wipneus):

Jim Hunt provides this close-up view on the resources page of his Great White Con website (also be sure to read his latest blog post on early wave activity in all this open water):

Meanwhile, on the other side

Lately the focus has been on the Beaufort Sea where a high-pressure area has caused the ice pack to crack on a massive scale, even earlier than in previous years, with ice being transported away from the North American coast (see here). But such a large and persistent high-pressure system is bound to have an impact elsewhere in the Arctic as well, so here's an overview of what's been happening on the Atlantic side of the Arctic (and a bit of Siberia as well).

As we saw in the recent 2015/2016 Winter analysis blog post, the Arctic experienced an incredibly warm/non-cold winter:

On top of that, a string of cyclones crossed the Atlantic and veered off to the Arctic, causing increased ocean heat flux on the Atlantic side of the Arctic, which explains why the Barentsz Sea and Greenland Sea have been anomalously low in sea ice extent all winter. They're still extremely low:

In fact, Svalbard could almost be circumnavigated several times, with at one point very close to ice-free conditions from Svalbard all the way to Franz Josef Land.This graph from the PolarView website shows how anomalously low sea ice levels have been in the Svalbard region:

Beaufort quick update

It's been a week since I announced that the ice in the Beaufort Sea was going to come under early pressure. Here's a quick update on what has happened so far, how the forecast played out, and what the short-term conditions for this part of the Arctic will be.

As expected, the Beaufort Gyre kicked into action, big time, with winds causing large cracks in the ice pack, moving it westwards and away from the Alaskan and Canadian coasts. The massive polynyas that are left behind, get partially covered with a thin veneer of ice.

Here's an animation showing the difference between LANCE-MODIS satellite images on the first of the month and two weeks later:

Quite impressive, isn't it? As if someone threw a giant brick into it.

Here's an animation showing all days between April 1st and 14th (the file is somewhat large, apologies if it loads slowly):

Beaufort under early pressure

A high-pressure area has been moving in over the Beaufort Sea lately. It's quite big and quite high in pressure. Environment Canada has the current pressure there at 1042 hPa:

I've coloured the land masses to make it easier to orient. I've also put in the red arrows to show which way the winds blow along the so-called isobars.

This is the second notable high of this year, following another big one in February that produced strong winds that pushed the ice away from the coast. This phenomenon called the Beaufort Gyre resulted in what we call a cracking event around here (see this blog post). Of course, the Arctic was plenty cold around that time and so the leads froze over again, but the marks are still visible on this AVHHR image (provided again by Environment Canada):

On the one hand those leads let heat escape from the ocean water, on the other hand the thin ice between the enormous floes will melt out easily as soon as sunlight and higher temperatures start taking over, possibly making the entire zone more vulnerable early in the melting season.

The reason I've decided to dedicate a blog post to this, has to do with the current ECMWF forecast for the coming 6 days: