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Arctic Sea Ice by Neven - 1w ago

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.

----- 

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:

After a slightly below average June volume decrease (6199 km3 vs 6217 km3 for the 2007-2017 period), 2018 has dropped to 6th place. The difference with 2017 - lowest on record as of June 30th - has been reduced from 1916 to 1659 km3, but the gap with record-breaker 2012 has grown by a whopping 1097 km3. That's how much of a difference June can make, which shows how crucial this month is for the melting season.

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

Wipneus' version of the PIOMAS graph shows the 2018 trend line right in the middle of the post-2010 pack, already hinting at which trajectory it may take until September:

Even though 2018 isn't among the very lowest years, the trend line has shot down below the linear trend on the PIOMAS volume anomaly graph:

I had actually expected PIJAMAS average thickness to be lower, because JAXA was relatively high at the end of June, while PIOMAS is still holding up somewhat. Remember, PIJAMAS is a crude average sea ice thickness measure, which you get by dividing PIOMAS volume with JAXA extent. So, if JAXA is relatively high, average thickness should go down.

There is something of an abrupt downturn towards the end of June, but maybe this effect will be more pronounced next month:

I don't believe the Polar Science Centre thickness graph is showing anything out of the ordinary either:

A small addendum thanks to a series of fantastic regional volume graphs, posted by Oren over on the Arctic Sea Ice Forum.

What makes this melting season interesting so far, is that melting has been progressing relatively slowly the past few weeks, as expressed in the various extent graphs and the PIOMAS volume graphs as well. However, if we look into the distribution of melt by checking regional graphs, we notice that 2018 isn't far behind at all in those regions that determine the minimum (as opposed to the regions that melt out completely).

Take, for instance, Oren's PIOMAS volume graphs for the Central Arctic Basin and this inner core of the Arctic sea ice pack (Central Arctic Basin, Canadian Arctic Archipelago and Greenland Sea):

Wipneus has a couple of graphs showing extent and area of this inner core, without the periphery. The large graph shows the combined Beaufort, Chukchi, ESS, Laptev and CAB numbers in the Uni Hamburg, JAXA and NSIDC datasets, which all three have different resolutions, for the 2012-2018 period (NSIDC includes 2007). The lower two graphs show only NSIDC extent and area for said regions in the 2006-2018 period. For now, 2018 is among the lowest there too (click for a larger version):

Right now, the weather forecasts aren't pointing to any weather conditions that will melt the ice like crazy (as said, I'm not sure what the over-all effect of the current cyclone will be). If that keeps up, I expect the inner core numbers to start slowing down their descent as well. But I wouldn't exclude some minor surprises as of yet.

This melting season won't be breaking any records, but it's not entirely clear where it's going to end up. However, there's a good chance that the ice in the western Arctic is spared the worst, and this could potentially be good news for the ice.

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Arctic Sea Ice by Neven - 1M ago

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.

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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:

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:

Here's how things are looking on Wipneus' version of the PIOMAS graph:

Despite May 2018's below average volume decrease, there has been a small downtick on the PIOMAS sea ice volume anomaly graph. The trend line will probably dive below the linear trend at some point:

What's interesting, is that there hasn't been an indication of below average melting for JAXA sea ice extent, being second lowest on record for most of the month of May. The consequence for PIJAMAS (a crude average sea ice thickness measure, which you get by dividing PIOMAS volume with JAXA extent) is that it's also relatively high for the time of year, compared to most post-2010 years:

The exact same thing goes for the Polar Science Centre thickness graph:

Even though we're only one week into June, it's already interesting to look ahead at what this month may bring volume-wise. Not only because of the short-lived, though intense storm, but also because of the current weather forecast. After bottoming out over the Kara and Laptev Seas, the ECMWF model has the storm moving over the Central Arctic, to slowly fade out over the Beaufort Sea. Meanwhile, high pressure takes over on the Siberian side of the Arctic (images retrieved from Tropical Tidbits):

Those isobars between the low and high pressure areas, especially in the 24-72 hours timespan (first three images), represent strong winds that will further pull away the ice from the Siberian coast, most of all in the Laptev region where there is already a substantial patch of open water for the time of year, at the same time bringing in lots of heat and sunshine to the entire eastern half of the Siberian coast.

The reason that all of this is interesting, is that according to PIOMAS the ice is thicker along Siberian side of the Arctic when compared to the 2011-2017 period:

This means that if this kind of weather persists during the second half of June - which remains to be seen, of course - 2018 could be moving back to third place or so. This, in turn, will have consequences for the rest of the melting season. But that's something we'll discuss, if and when it happens. Right now, everything is open.

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Arctic Sea Ice by Neven - 2M ago

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:

The maximum for sea ice volume was reached during April. According to the PIOMAS model, it peaked on April 16th at 22,376 km3, which is the second lowest maximum on record, 1594 km3 above last year's stunning record low maximum, and 301 km3 below 2011's maximum. The total freeze during the 2017/2018 freezing season was the highest since 2013, but not all that much above the 2006-2017 average. This bar graph shows total freeze for the 2006-2018 period:

So, that's the maximum. After the maximum was reached, the trend line flattened, with sea ice volume going down by a meagre 91 km3 from the 16th to the end of the month, which can clearly be seen on Wipneus' version of the PIOMAS graph:

In the end, total sea ice volume grew by 373 km3 during April, which is the largest increase in the 2007-2018 period, almost 200 km3 above average. This means that the gap with years that had more volume than 2018 has become smaller, and the gap with 2017 -the only year with less volume than 2018 so far - has grown some more. In fact, 2011 has swooped below 2018 by 3 km3. It's safe to say they're on a par, but 2016 isn't that far off either, and, of course, 2012 is about to have some very large drops.

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

The trend line on the PIOMAS sea ice volume anomaly graph has shot up some more, but is still in 1 standard deviation territory:

Now, with JAXA sea ice extent being quite low for the time of year, and PIOMAS sea ice volume stalling a bit, average thickness will inevitably go up (which you get if you divide PIOMAS volume by JAXA extent,  resulting in PIJAMAS):

The same can be seen on the Polar Science Centre thickness graph:

One very interesting bit of extra information the UW's Polar Science Center has shared this month, is how both PIOMAS (model) and CryoSat (satellite observations) are in agreement with each other when it comes to sea ice volume distribution. In other words, where the ice is thicker and thinner, as compared to previous years. It turns out that both say that the ice is thicker on the Siberian side of the Arctic, but thinner in the thickest/oldest ice zone North of the Canadian Arctic Archipelago, when compared to the 2011-2017 period:

The fact that they are both in agreement, is also an indication that less snow has fallen on the ice than last winter, because this tends to make CryoSat deviate from PIOMAS. I'm saying it because this snow may have played a role in last year's lack of preconditioning during May and June, and thus the remainder of the melting season as well.

If weather conditions are detrimental to sea ice in the Siberian seas, sea ice volume may drop to low levels this melting season, as that's where more volume seems to be than on average in the last seven melting seasons. Right now those regions are seeing quite a bit of sunshine due to open skies, and temperatures are anomalously mild as well, but it's just the first week of May and so we can't say anything definite about it for now.

What we definitely can say, is that with the volume maximum behind us now, the melting season has officially started! I'm looking forward to see what the Arctic has in store for us this melting season.

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Arctic Sea Ice by Neven - 3M ago

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:

March 2018 turned out to be quite cold, relatively speaking (more on that below). And thus, as expected, volume increased by a lot, especially given that it was relatively low at the end of last month. In fact, with 2278 km3, sea ice volume growth during March was the largest in the 2007-2018 period, well above the average of 1832 km3. This means that the gap with 2017 has widened again, whereas the difference with all other years has become smaller. 2011 is now hot on this year's tail, being just 217 km3 behind. I expect this year to end up having the second lowest maximum on record, but you never know.

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

The 2018 trend line can clearly be seen moving back towards the pack on Wipneus' version of the PIOMAS graph:

Naturally, the trend line on the PIOMAS sea ice volume anomaly graph has shot up, moving away from the linear trend line again, meaning volume loss is slightly less than expected, if one were to extrapolate the data average into the future:

If volume is going up, but extent is among the lowest on record, and you divide the one by the other to get average thickness, the number will go up, of course. Hence the PIJAMAS trend line going up slightly faster than the rest, but differences are marginal at this stage anyway:

As often is the case, the same can be said of the Polar Science Centre thickness graph:

So, how cold was March? It was bloody cold, as the British would say. But unlike the British, the Arctic was actually in need of some serious cold, after a bloody mild winter so far. This can clearly be seen on Zack Labe's excellent ranking graph, showing monthly temperatures north of 70° latitude. After being in the top 3 for five months in a row, the last month of winter came in 26th:

My own temperature graphs, for the Arctic as a whole and for the Arctic divided into four quadrants, show the same, with especially the Siberian side of the Arctic taking a plunge compared to previous years, rivaled only by 2013 (click for a larger version):

And here's a visual representation of that, with the temperature anomaly distribution map of the Arctic, as provided by the ESRL PSD daily mean composites website:


With such low temperatures on the Siberian side of the Arctic, it's no wonder that PIOMAS indicates that the sea ice is thicker there, when compared to the 2011-2017 average (image courtesy of the Polar Science Centre):

It will be interesting to see whether that can put a break on sea ice loss this summer, especially as it will be aided by a large amount of land snow, in Siberia as well as the Northern Hemisphere in general. Here's the latest from Rutgers Global Snow Lab, showing the March average, up quite a bit, compared to the previous four Marches:

On the other hand, volume is still second lowest on record, and extent is now lowest, after a large drop was reported yesterday by JAXA. Winter was mild overall, and the situation on the Pacific side of the Arctic is nothing short of spectacular. Things are slowly warming up, the Sun is slowly climbing higher in the Arctic sky, volume is going to hit its maximum this month, and then the circus starts again in May. It could go either way. Nothing in the Arctic is a dead certainty.

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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:

This ice drift is caused by winds, of course. These winds have already brought some anomalous heat with them, right past Bering Strait, as can be seen on this DMI temperature map:

According to the GFS weather model, these winds will continue to bring in mild air well into April(images provided by Climate Reanalyzer):

The winds are probably pushing in warmer water from the North Pacific as well. Here's how sea surface temperature anomalies in the Bering area compare to those of 25 March last year, when SSTs were already relatively high:

These images from the VIIRS instrument aboard the joint NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi-NPP) satellite show how the ice has already been retreating from the Alaskan coast during the past few days (hat-tip to JayW over on the ASIF, who created the original animation):

This is going to continue for a couple of days, and we'll have to see what happens to the open water that the ice is inevitably going to leave behind. I don't know whether there will be enough cold to let it freeze over again, or whether the ice gets shoved back towards the coast when the winds turn (if they turn any time soon). Either way, this can't be good for the ice, even though the winds cause ridging further into the pack. At the same time, even further away, the ice gets pushed towards Fram Strait, which may increase sea ice area/extent in the Atlantic regions for a while, but isn't good for the ice pack in the long-term. I'll look closer into this next week.

One thing we do know, and that is that what we are witnessing in the Bering Sea, is unprecedented in the satellite era. This will make the Pacific side of the Arctic extremely vulnerable to further, rapid melt-out, if weather conditions wish it so. We'll see.

If you want to follow this stuff in near real-time, go to the Arctic Sea Ice Forum and become a member.

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For a while it looked like the record for lowest maximum was going to be broken for the third year in a row, especially after an extreme warm event shook the Arctic. But this anomalous heat was followed by anomalous cold, which was just enough to nudge JAXA sea ice extent above last year's record low maximum. By 13 thousand km2, to be precise, which is around 0.1% of total sea ice this time of year.

I don't mind, as I correctly guessed both this maximum's date as well as the final number on Arctic Sea Ice Forum polls, probably for the first (and last) time in my life as an Arctic observer, as the maximum is incredibly difficult to pinpoint.

Here's the best visual representation of maximums throughout the years, produced by ASIF member Hautbois, as it shows when the maximum of a given year was reached, as well as how high it got:

Not a record low maximum, but the fourth maximum in a row that has ended up (well) below 14 million km2. That's for JAXA sea ice extent data (formerly known as IJIS, now provided by ADS-NIPR).  The NSIDC has just reported that for their SIE product this year's maximum was also second lowest on record.

Here's the spectacular drop from anomalously warm to anomalously cold on the DMI 80N temperature graph, which normally isn't all that representative for the Arctic as a whole, but in this case it is:

Now that's quite the roller coaster ride. Lots of extreme weather, not just in the Arctic weather, but all over the Northern Hemisphere, ever since that sudden stratospheric warming event caused the polar vortex to split and fall apart, back in February. It'll take a while longer for things to stabilize, if stable is the right word for an atmosphere that continues to warm due to an increase in greenhouse gas concentration.

As can be seen on Wipneus' collection of regional graphs, it was Baffin Bay that was the largest contributor to ending the freezing season, and with Okhotsk about to join the party, it's downhill from now on:

That doesn't mean that things will get spectacular right away, even though 2018 is currently second lowest on the JAXA SIE chart. In fact, the sea ice pack will continue to thicken a while longer in the middle of the Arctic Ocean, even though melting will start all around the periphery (which is why volume reaches its peak in April). Nevertheless, it will be interesting to see how things get positioned before melt ponds start to form in May. Things have been especially crazy on the Pacific side of the Arctic. More on that later.

Further reading on the Robertscribbler blog: Unusually Warm Early Arctic Spring Predicted Following Second Lowest Sea Ice Maximum on Record

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Arctic Sea Ice by Neven - 4M ago

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:

During February Arctic sea ice volume increased by 2075 km3, according to the PIOMAS model, which is well below the 2007-2017 average of 2437 km3. Only 2014 and 2016 managed to score lower, at 1930 and 2047 km3 respectively. This means that 2018 has consolidated its second place in the ranking, creeping somewhat closer to 2017. Especially the gap with 2013 has widened spectacularly from 166 to 1261 km3. Closest follower is now 2011 at 817 km3. 

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

Wipneus' version of the PIOMAS graph clearly shows how the 2018 trend line strongly deviates from all the other trend lines during February:


The trend line on the PIOMAS sea ice volume anomaly graph has gone down some more and is now hugging the linear trend line (how romantic!):


As for PIJAMAS average thickness, crudely calculated by dividing PIOMAS numbers with JAXA sea ice extent numbers, the 2018 trend line has crept in second position here as well:

Not quite there yet on the thickness graph from the Polar Science Centre:


Now that we've discussed the monthly numbers, it's time for some interesting stuff, and it has to do with CryoSat-2 observations. Here's a tweet that was tweeted out yesterday by AWI senior scientist Stefan Hendricks:

#CryoSat #SeaIce Feb 2018 thickness and volume update: Extent is at record low, but sea ice volume in Arctic Basin at levels of previous years (6th lowest / 3rd highest). Above average Jan to Feb growth due to ice dynamics? https://t.co/2UQXlZpvUX @esa_cryosat @AWI_Media pic.twitter.com/0GP39Tnxeu

— Stefan Hendricks (@sthendric) March 5, 2018

According to CryoSat February growth was above average, whereas PIOMAS says it was well below average (as stated at the start of this update). So, what's going on here? As the latest NSIDC summary explains, February was very stormy and warm, especially near the end when warm winds swept in via the North Atlantic and caused some unprecedented stuff to happen. In fact, these winds pushed ice back through Fram Strait, as shown on this graph based on PIOMAS data and compiled by Wipneus:

Of course, winds pushing ice back cause compression and ridging, and in theory volume goes up, but that doesn't explain the divergence between PIOMAS and CryoSat. Air temperatures clearly don't either. A more likely culprit, that I've blogged about last year, is snow.

It is known in scientific circles that the sensor on CryoSat-2 has trouble determining the freeboard of sea ice when it is covered by snow. Or to quote from Alfred Wegener Institute scientist Robert Ricker's PHD thesis paper: Recent studies show that the influence of the snow cover is not negligible and can highly affect the CryoSat-2 range measurements. Last year a series of Atlantic storms transported large amounts of heat and moisture into the Arctic, causing PIOMAS and CryoSat to diverge a lot. There has been less of that this year, until February.

My suspicion is that, during last year's melting season, all this snow helped keep the sea ice reflective for a bit longer, slowing down the build-up of melt momentum through melt pond formation, effectively precluding a new record low minimum (there are other factors as well, of course). Whether this event will play a similar role this year, remains to be seen, but it's other side of the warm knife that negatively affected the ice pack this winter.

The second half of the 2015/2016 freezing season was extremely mild, while for the 2016/2017 freezing season it was the other way round. This year seems to be more of an all-rounder, with relatively mild temperatures every winter month, enough to beat last year's record for warmest Oct-Feb, as this tweet by Zack Labe shows (hat-tip to Robertscribbler):

Air temperatures (at 925 hPa) are a record high for the #Arctic freeze season (October - February, >67°N) in this data set

Graphic: https://t.co/kO5ufUWrKq pic.twitter.com/dazYCGqEv8

— Zack Labe (@ZLabe) March 5, 2018

Here are my NCEP reanalysis temperature graphs for February (courtesy of ESRL, Physical Sciences Division). For the Arctic as a whole it was the second highest temperature on record, while individual sectors ranked as follows: Atlantic 2nd, Siberian 4th, Pacific 1st and Canadian 33rd (click for a larger version):

And so, besides all the unknowns, snow seems to be the big wild card again. Whereas the PIOMAS-CryoSat divergence is less pronounced this year, implying there won't be as much snow on the sea ice, it's a different story for the land masses surrounding the Arctic Ocean. Rutgers Global Snow Lab shows the February anomaly is slightly larger than last year, though not as high as in the 2010-2014 period:

At the same time, Northern Hemisphere snow cover seems to be quite extensive, says NOAA's Automated Multisensor Snow/Ice Mapping System:
Moreover, it seems that this snow is quite thick overall, if this snow water equivalent graph from the Canadian Croyspheric Information Network is anything to go by (I'm trying to find out whether the graph is accurate, but haven't received any replies as of yet): 
Depending on weather conditions, it may take longer for all this land snow to melt out, and this in turn may affect weather conditions and temperatures over the ice. ASIB commenter Rob Dekker as well as the late Andrew Slater convincingly theorized there's a correlation between land snow cover and the September minimum.

Snow may very well be what the coming melting season needs to dodge another bullet/cannonball. In the meantime, the forecast is for the Arctic to cool down significantly in the coming week, which also should help a bit, even though it cannot make up for a mild winter and a record low sea ice extent for much of this year so far.

I'll have a post up later this week discussing the sea ice extent maximum which is just around the corner, if it hasn't already turned it. In the meantime, you can follow the latest discussions on the Arctic Sea Ice Forum for the details, and be sure to check out Robertscribbler's latest: 

Delving Further into Uncharted Territory: Arctic Sea Ice Greatly Weakened at Start of Spring 2018.

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In the preceding post on Global sea ice minimum records getting broken for the third year in a row, I mentioned how the situation on the Pacific side of the Arctic was quite unprecedented, with the sea ice graph for the Bering Sea showing a sharp downturn (and even a small one for the Chukchi Sea). Well, there's an equally unprecedented event taking place on the Atlantic side of the Arctic as well. Yesterday, Prof. Dr. Lars Kaleschke from the University Hamburg tweeted out the following:

There is open water north of #Greenland where the thickest sea ice of the #Arctic used to be. It is not refreezing quickly because air temperatures are above zero confirmed by @dmidk's weather station #KapMorrisJesup. Wacky weather continues with scary strength and persistence. pic.twitter.com/YMnvCD8XvL

— Lars Kaleschke (@seaice_de) February 25, 2018

This probably has a lot to do with the splitting of the Polar Vortex due to a sudden stratospheric warming event a while back. I'm grateful for a bit of winter, finally, in my neck of the European woods, but not too happy about the consequences for the Arctic. The cause of all this heat and ice being pushed away from the northern coast of Greenland is an atmospheric set-up that during summer we'd be referring to as a Reverse Dipole (low pressure over the Canadian side of the Arctic, high pressure over the Siberian side). This animation of DMI SLP maps shows how the set-up got set up in the past 10 days, resulting in a pressure gradient as high as 75 hPa:

Such a pressure gradient means lots of winds. The animation in Kaleschke's tweet shows what happened to the ice between Fram Strait and the Lincoln Sea, but here are two images by ASIF commenters Uniquorn and A-Team showing the situation (from the 2017/2018 freezing season thread):

In the same thread bbr2314 comments:

I can't imagine reds, however faint, have ever appeared in Northern Greenland in February before.

He's referring to these DMI maps for the 24th and 25th, showing the day 's surface mass balance compared to the day before (in mm water equivalent per day):

It wasn't winds causing the surface in Northern Greenland to melt, it was heat. Robert Fanney posted a fantastic article on his Robertscribbler blog yesterday, describing the heat entering the Arctic during the past week: A Hole in Winter’s Heart: Temperatures Rise to Above Freezing at the North Pole in February.

An excerpt:

An extreme wave in the Jet Stream was developing and elongating over the North Atlantic, delivering more and more warm air northward.

By February 21st, the wave had extended into a knife-like extension east of Greenland and through the Barents Sea. Beneath this abnormal Jet Stream wave, which was starting to look more and more like a trans-polar river (of a kind predicted by Dr. Jennifer Francis as a result of human-caused Polar Amplification), was an intensifying thrust of outlandishly warm surface air.

Over the past 72 hours, gale force warm, southerly winds gathered in the Atlantic, then blasted north.

At this point, we were starting to see some seriously outlandish temperatures in the higher latitude regions. Cape Morris Jesup, which is the furthest north location on Greenland, by Friday the 23rd experienced a 6 C or 43 F temperatures on the shores of what should be a frozen solid Arctic Ocean just 400 miles from the North Pole.

The average high temperature in Cape Morris Jesup is -20 degrees Fahrenheit during February — making Friday’s reading a whopping 63 degrees F warmer than average. For reference, a similar departure for Washington, DC would produce a 105 degree day in February.

But it wasn’t just Cape Morris Jesup that was experiencing July-like conditions for the Arctic during February. For the expanding front of that ridiculously warm winter air by Sunday had expanded into a plume stretching tens of thousands of square miles and including a vast zone of temperatures spiking from 45 to 54+ degrees F above normal.

And at the center of the warm air pulse was today’s earlier reading of 1.1 C or or 34 F at the North Pole (see image at top of post). What would typically be a summer-time temperature for this furthest north location of our world happening during February. A highlight warm point in the midst of a vast plug of far warmer than normal air. A hole in the heart of winter.

Here's an animation of DMI temperature maps showing how these changes came about during the last 17 days:

See how the blue gets replaced with green? Here's how this year stacks up, compared to 2013, 2014, 2015 and 2017 (2016 is missing from my archive):

As I wrote in the preceding post:

There's so much heat coming into the Arctic from both sides that the temperature north of 80° is spiking to new record heights, as shown on Zack Labe's rendition of the DMI 80N temperature graph, and it will most probably climb some more.

And climb it did. I wonder if it will climb much more, as the current temperature is almost as high as the peaks for April:

To close off, all of this is now even having an effect on the Central Arctic Basin sea ice area graph (hat-tip to Wip):

Of course, that trend line will go up again, the open water north of Greenland will refreeze as soon as the winds turn, the surface of Greenland will stop melting. But talk about unprecedented!

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This is starting to become an annual tradition, here on the Arctic Sea Ice Blog. Just like last year and the year before that, the record for lowest global sea ice minimum has been broken. The lowest global sea ice extent minimum on record (NSIDC and JAXA) was reached two weeks ago. I wanted to wait a bit and see whether the record for NSIDC global sea ice area would be broken too, but it wasn't, although the minimum came in at a solid second place, practically on a par with last year.

Here's the graph, as provided by Wipneus:

And here you see the anomaly of all those trend lines in chronological order, having hovered between 2 and 4 σ (standard deviations) since the 2016 crash:

Not enough Antarctic sea ice melted to clinch the lowest Antarctic sea ice minimum record (coming in second lowest 'only'), and so the decisive nudge was given by the sea ice in the Arctic, refusing to freeze along some of the edges, most notably in the Bering Sea. Here's how the graph for that region looks as of today, with some of the open water even spilling into the adjacent Chukchi Sea, which is highly unusual for this time of year:

But that's not all. The Arctic has been extremely mild all winter, and still is, with temperatures forecast to soar above zero degrees at the North Pole a few days from now, in the dark, dead of winter (Robertscribbler has an excellent piece on that, as do Mashable, The Washington Post and Weather Underground). There's so much heat coming into the Arctic from both sides that the temperature north of 80° is spiking to new record heights, as shown on Zack Labe's rendition of the DMI 80N temperature graph, and it will most probably climb some more:

Which also has consequences with regard to Freezing Degree Days. As Nico Sun's graph shows, 2018 has caught up with 2017 anomaly-wise since the start of the year (for the freezing season as a whole this year is in second spot):

Much more is going on, of course, avidly followed by Arctic Sea Ice Forum members on the 2017/2018 freezing season thread. It looks like it's another bad winter for the Arctic sea ice, the third one in a row (not that they were all that great before that), but as we've seen in 2016 and 2017 a bad winter does not a record breaking melting season make. Maybe the Arctic will get record cold during March and April to help thicken the ice to a reasonable shape, or large amounts of snowfall help keep the surface reflective for a bit longer in May and June, but as things stand right now, it looks like the Arctic will have to try and dodge another bullet/cannonball in the upcoming melting season. Because if it doesn't, it'll head our way.

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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:

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:

The trend line on the PIOMAS sea ice volume anomaly graph bends down again:

Nothing much has changed on the PIJAMAS average thickness graph (crudely calculated by dividing PIOMAS numbers with JAXA sea ice extent numbers):

The same goes for the thickness graph from the Polar Science Centre:

February started just one week ago, but has already been eventful so far. A powerful storm was hurled into the Arctic via the North Atlantic, eventually bottoming out at 952 hPa. The forecast hinted at possibly above freezing temperatures near the North Pole (as happened in December 2015), and even though it didn't pan out that way, a lot of heat was advected toward the Arctic's heart:

At the same time the ice edge was pushed back (which is still ongoing), as can be seen on this animation of Uni Hamburg AMSR2 sea ice concentration maps for the past 5 days, as provided by Jim Hunt on his Great White Con blog (he provides lots more info, check it out):

Of course, all these strong winds are preventing ice - some of it thick - from escaping the Arctic via Fram. As the latest NSIDC monthly summary has it:

A single storm event can lead to significant redistribution of sea ice mass through ridging and new leads. As part of the Norwegian Young Sea ICE (N-ICE2015) expedition, colleagues at the Norwegian Polar Institute made detailed sea ice thickness and ice drift observations before and after a storm in an area north of Svalbard (Figure 5). Results showed that about 1.3 percent of the level sea ice volume was pressed together into ridges. Combined with new ice formation in leads, the overall ice volume increased by 0.5 percent. 

At the same time, Atlantic heat is accompanied by moisture, which is deposited as snow on the ice pack. We've seen what effect last winter's train of Atlantic storms may have had during the start of the melting season, when possibly large amounts of snow on the ice managed to deflect early solar radiation that determines the timing and magnitude of melt pond formation, which in turn can play a significant role with regards to melting momentum.

Nevertheless, these short-term effects may be just enough to nudge Global Sea Ice Extent to yet another record low minimum (although Antarctic sea ice also has a say in this, of course):

Ah, I fondly remember the days when climate risk deniers would argue everything was normal 'because global sea ice'. It is indeed normal, as in SNAFU. ;-)

As for snow, according to the Rutgers University Global Snow Lab, the Northern Hemisphere snow cover anomaly was barely positive and a lot lower than most years of the previous decade:

There appears to be a correlation between spring/summer snow cover and the September minimum, so this is something to keep an eye on. 

I'm not sure how PIOMAS will handle this storm (which may be followed by more, given the current atmospheric set-up using Greenland as a flywheel), but if extent stays as low as it currently is (lowest on record in several data sets) and the Arctic stays as mild as it has been so far, relatively speaking, there's a very good chance 2018 sea ice volume will still be second lowest come next month.

To close off, here's my NCEP reanalysis temperature graph (courtesy of ESRL, Physical Sciences Division). A record non-cold December was followed by the second 'mildest' January on record. This, again, mainly had to do with temperatures in the Pacific sector (also second lowest), while temps in the Atlantic, Siberian and Canadian sectors were 6th, 7th and 5th lowest on record respectively.

If you want to know what's going in the Arctic in near real-time, go to the 2017/2018 freezing season thread on the Arctic Sea Ice Forum. Lots of great stuff.

Rendez-vous next month, same time, same place.

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