Arctic Sea Ice

PIOMAS July 2018

What a coincidence. Just like last month, I will have to precede the PIOMAS update with a short news flash that a very strong cyclone is barreling through the Arctic. But this time too, the cyclone will be short-lived, and so it's not entirely clear whether, on the whole, it will be damaging or beneficial. It has gone further into the Arctic this time.

Either way, the cyclone' has bottomed out at 968 hPa according to Environment Canada, which is just 2 millibar more than last month's cyclone:

With their sub-970 hPa pressures these cyclones come close to the Great Arctic Cyclone of 2012 (963 hPa), but I think they lack in other parameters such as longevity to really deserve the GAC epithet. Nevertheless, to see two of these monsters in June and July in what hasn't otherwise been a very noteworthy melting season so far, is quite noteworthy. We might even see another one before the melting season is over, which could be a sign of some yet to be identified change going on in the Arctic, causing these extremely warm winters, followed by relatively cold and cloudy summers.

But that's all speculation. Let's look at the updated PIOMAS volume numbers.

----- 

PIOMAS June 2018

Before kicking off this latest PIOMAS update, there's a little piece of information I'd like to share: A massive cyclone is passing through the Arctic right now. The cyclone has bottomed out about half a day ago at 966 hPa, which is slightly lower than the 968 hPa storm we saw at the end of August 2016, and slightly higher than the Great Arctic Cyclone of 2012 (963 hPa). Even though pressure levels are similar, this current storm can't match the other big ones when it comes to longevity. But at the same time, bear in mind it's only June, and not August.

And also remember what IARC chief scientist John Walsh said back in 2012:

This past week’s storm was exceptional, and the occurrence of Arctic storms of extreme intensity is a topic deserving closer investigation. 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.

I think it's safe to say it's changing.

Here's an image of the moment this current cyclone reached its lowest pressure, according to Environment Canada:

I will soon discuss the consequences of this storm for the ice pack, and apologize for not having started writing regular ASI updates yet (too busy).

Okay, now for the PIOMAS update.

-----

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:

According to the PIOMAS model, volume decrease for May 2018 has been below average: 2285 vs 2650 km3. This means that 2018 is 5th lowest right now, and the difference with last year has grown to a massive 1915 km3, which is 299 km3 more than last month. It has also been overtaken by 2012, which saw a huge volume reduction in May. Likewise for 2016 and 2011, with 2010 not far behind now either.

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

PIOMAS February 2018

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:

A new year, a new trend line, and if you watch the above graph closely, you'll see how it dips right under the 2013 trend line at the end of January. This means that 2018 now has the second lowest sea ice volume on record, according to the PIOMAS model. A monthly total of 3005 km3 was well below the 2007-2017 average of 3195 km3, which means 2018 also extended its lead over most other years. Last year, however, January volume was 50 km3 lower still and so that gap has grown slightly bigger again. Given how volume fared during the first few months of 2017, it doesn't look like that 1407 km3 gap is going to be bridged any time soon.

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

Wipneus' version of the PIOMAS graph more clearly shows how the 2017 trend line (light red) goes off even further on a tangent:

PIOMAS March 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:

There haven't been any major changes compared to last month, and that's good, because it means things haven't gotten worse (according to PIOMAS). February 2017 saw an increase that was almost identical to the average for the last 10 years. Nevertheless, the difference with number 2, has increased from 1776 to 1851 km3. At the same time the difference with last year (now third in the ranking) has been reduced considerably, from 2374 to 1975 km3.

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

And here's Wipneus' version, showing the gap is still intact, but hasn't become larger:

PIOMAS February 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:

Things just keep getting worse. After this year's trend line went well below all others last month, I was hoping January would bring some relief, some cold weather. The weather was cold, colder than November and December, but evidently not cold enough for some seriously anomalous ice accretion. And so the gap has widened.

According to the PIOMAS model, in the past 10 years, only twice before was there a January in which less than 3000 km3 of volume was added to the sea ice pack: in 2007 and last year. So, these are the only two years that didn't see the gap get wider. All the other years did.

2017 is currently 1571 km3 below the previous record lowest number for January 31st, which occurred in 2013 (the year following record smashing 2012). That's almost 10% lower.

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

 And here's Wipneus' version, clearly showing the gap widening:

A new Arctic feedback (?)

Quote from the latest PIOMAS update (10 days ago):

There's just no end to this run we have had with anomalously warm temperatures, and storms blowing in from the Atlantic.

As we speak, a very powerful winter storm is battering the ice pack on the Atlantic side of the Arctic, as shown on this SLP map (source):

Lowest pressure was probably reached yesterday at 957 hPa, but it's still raging at 958 hPa right now. Remember, the GAC-2012 clocked in at 962 hPa, and the series of powerful storms we saw last August bottomed out at 968 hPa. Storms tend to be stronger during winter.

In the short term this might actually increase sea ice extent, as strong winds will be pushing out the ice towards the Atlantic, but in the longer term it will probably be detrimental to the ice pack, as a lot of the ice being pushed out is older and thicker. The storm and the moisture it brings with it, will also cause more snowfall, insulating parts of the ice pack so that the ice grows thicker at a slower pace, and thus be thinner than it could have been when the melting season starts.

The ECMWF forecast is showing another strong storm forming 9-10 days from now, but that's very far out, and so the forecast can change. But the storm we're seeing right now (I briefly mentioned it in this previous blog post), was also forecast 10 days ago and then came about. We'll have to wait and see what happens.

Now, what is causing all these storms and all that moisture to be transported all the way to the Arctic? We saw the same thing during last year's winter, but this time it's even worse. It might have to do with all the heat that the recent El Niño brought with it, but previous El Niños didn't seem to have such a marked effect. Perhaps it's something else, another reaction to Arctic sea ice loss, some sort of vicious cycle.

Yesterday this video was posted on Peter Sinclair's ClimateCrocks blog, showing an interview with Dr Jennifer Francis (Rutgers University)
at the AGU 2016 Fall Meeting this past December:

Another effect of this possible feedback is more clouds during summer, shielding the ice from the Sun's rays. But as we saw during last year's melting season, this didn't help much (except for preventing new sea ice extent/area records). That's probably because heat doesn't just enter the Arctic via the atmosphere, but via ocean currents as well.

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:

ASI 2016 update 6: hell and high pressure

During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Because of issues with data based on the SSMIS sensor aboard DMSP satellites, I mainly focus on higher-resolution AMSR2 data from the Japan Aerospace Exploration Agency (JAXA), as reported on the Arctic Data archive System website. I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.

The animation on the right consists of NSIDC
sea ice concentration maps, one for each ASI update.

Check out the Arctic Sea Ice Graphs website (ASIG)
for daily updated graphs, maps, live webcam images, and
the Arctic Sea Ice Forum (ASIF) for detailed discussions.

August 26th 2016

A spectacular start to the melting season is being matched by a spectacular ending. And that's probably putting it mildly.

In the past 10 days we've witnessed a storm that comes close to equalling the Great Arctic Cyclone of 2012 (see the three updates I've written: 1, 2 and 3) and even though cyclonic activity has now lessened, it is still there. Worse still, it is going to be joined by massive high pressure on the American side of the Arctic.

That means - you've guessed it - that the final stage of the melting season will be dominated by a so-called Dipole set-up, where the pressure gradient between the high over the Beaufort Sea and the low over the Siberian Seas is going to have a major impact on the final shape of the ice pack. Just when you thought you had seen it all, the Arctic throws another curve ball.

Although temperatures are now going down and the sun is too low to provide enough energy to melt the ice from the top, massive winds will keep moving the ice around and promote bottom melt. But more importantly, these atmospheric conditions are going to heavily compact the highly dispersed ice pack, and cause some extra transport of ice towards the North Atlantic that is running hotter than ever. It's like putting a plate of biscuits in front of the Cookie Monster (om nom nom).

Here's an animation of Uni Bremen sea ice concentration maps from the past week to show you the current state of Arctic sea ice:

Two questions pop up immediately: How much of the Wrangel Arm is going to survive this final onslaught? And how far will that wedge of open water, or 'bite' as we've called it during previous melting seasons, be pushed towards the pole? Further than the 86N we saw in 2014?

The rest of the update will be about what's in store and what this will probably mean for the minimum.

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?

2016 Arctic cyclone, update 2

So, the storm has been raging for a while now. The latest Environment Canada weather map shows it's at 984 hPa.

According to this tweet by PhD climatologist Brian Brettschneider a IABP buoy from the University of Washington measured a lowest central pressure of 966.5 hPa, which is somewhat lower than the 968 hPa reported by Environment Canada (see previous update):

This animation of Uni Bremen sea ice concentration maps for the past 4 days shows how the ice has started to follow the winds. Also notice how far open water is reaching into the ice pack now, almost getting past 85N:

The impact on the extent and area graphs isn't as outspoken as in 2012, because there was a lot of weak, preconditioned ice back then that was poised to go poof. But make no mistake, the current exceptional weather is keeping 2016 in the race for that top 3 position when the minimum is reached next month.

Cryosphere Today sea ice area as calculated by the inimitable Wipneus has 2016 in second place now: