Is the melt season too short to produce a BOE?

[Glen Koehler]

<snip> I still feel whilst we got the multi year ice, a BOE will be very difficult to achieve.

     Only saying this because after I wrote a similar sentence I realized it was a mental loop  ---
If we had no MYI, that by definition means that there was no ice at the end of the previous melt season and therefore we already had a BOE!   .  Actually, it should be   

[The Walrus]

Yep we should not be forgetting that despite no record lows during September, we have seen record lows at various times in most years in the past decade, even last year.

That is not entirely correct.  According to NSIDC, these are the record daily lows by year (excluding leap day):

2022:
2021:      3
2020:    48
2019:    35
2018:    61
2017:    28
2016:  113
2015:      5
2014:
2013:
2012:    65
2011: 
2010:      7

Most have been grouped during a particular time, for instance all the 2012 lows occurred from August 10 - October 13, and  2016 occurred from May 2 - June 27 and November 3 - December 28.

All things being statistically equal, if the sea ice were steadily declining, we should be seeing an increase in the daily new lows each year.  If the sea ice was flatlining, daily new lows would remain steady over the flat period (for instance, 36.5 annually over a 10-yr).  If the sea ice was increasing, we would expect a decrease in daily new lows.

[gerontocrat]

Correct me if I'm wrong, but the winter of 2021-22 saw a record breaking export of ice through the Fram. That once in a lifetime expedition - to get frozen into the ice during winter ( I forgot the name) - couldn't have picked a worse year...

EDIT - Changed Arctic Winter Months from Oct-Mar to October 1 to May 31.
However, the result is the same

PIOMAS Data says - Nope, 2021 didd not see record Fram Export in Winter 2020-21

Indeed, the 2020-21 Winter continued the  long-term decline in Fram Export volume. But that may be mainly due to thinning of ice in the main Central Arctic Basin.

[Glen Koehler]

Glen,

I think noone on this site doubts that we are heading towards a BOE and the trend is intact.

However, I think that an interesting question is whether we have reached a new state ("the slow transition") where due to various factors (bathymetry, currents, stratification, you name it) the rate of decline has significantly slowed. It is not obvious whether this state will last another 30 years or will be over next year. If we can get closer to the truth of this matter then we will be able to answer the question:  "Is the melt season too short to produce a BOE? "

btw, even during the "hiatus" (1998-2013), despite not having a major El Nino, global temperatures hit a new high in 2002, then 2005, then 2010, so the uptrend remained evindent. Not so with ASI

    I wasn't trying to throw shade on anybody, and just deleted an unnecesary phrase about "no reason to believe otherwise" to tone it down.  And btw while I don't have enough info to evaluate whether it will require the Barents and Bering to be open all year before a before a BOE can occur, it seems pretty clear that it will require very early season melt (or perhaps year-round open water as you propose) for Chukchi and other High Arctic seas around the CAB before a BOE can occur.

     The thread question as I understood it was "is melt season inherently too short to produce a BOE".   For which the answer is "Yes, for now, because we haven't had a BOE yet".  My post was an attempt show that the long-term trends support the idea that while there has been a recent slow down, even the "Slow Transition" with fall open-water heat-loss and the rapid winter FYI refreeze feedback cannot hold out that much longer, much less forever (which I took to be the essence of the question).  Rather than seeing any inherent limit (e.g. Arctic night) prohibiting a BOE, I think that due to climate inertia and human intransigence a BOE is probably already baked into the system within the next 20 years or so no matter what we do at this point.  (Like the recent Greenland ice cap melt study by Box et al.)
   
    As for the temperature hiatus analogy, the fact that there were some new records set in the years following 1998 did not prevent the skepticism that the lack of a blatantly obvious year-on-year warming trend generated in the U.S.  We had Senators with power over government policy holding hearings to decry the fraud imposed by science on the public as shown by a lack of obvious incremental warming.  Case in point, Ted "Cancun" Cruz in 2015: 

    Applying Admiral Titley's comment about the warming "pause" to the ASI, if you start with a really low point (2012), then the trend from 2012 onward looks like it is not going down (for a while).

     As Tamino stated, and time proved, the only missing ingredient for warming to reappear was a few more years for natural variability to get done with its temporary excursion and regress to the trend.  Even after the temperature blowouts of 2014-2015-2016, the denial crowd still refused to admit that warming had resumed.  Heck, some of them STILL won't admit that the climate is warming, much less that humans are causing it.  I was just looking at a report today by the very seriously named "Global Warming Policy Forum" that basically says "Nothing to see here folks, everything is fine".  How do these people sleep at night?  (animation below requires click on replay to work)
     

[binntho]

I decided to have a go at calculating my ratio idea, i.e. a ratio showing the amount of open ocean in a given year in the Arctic Ocean as limited by the continents and islands, i.e. within the red outline below.

The data is MASIE NSIDC/NIC Sea Ice Product G02186 - Daily Ice Extent by Region in Square Kilometers

The regions are Central Arctic, Beaufort, Chukchi, ESS and Laptev.

My earlier guess was that the ratio was in "the low second digits" and it turns out that only two years have reached ratio of 0.01 (2021 and 2019). The ratio is trending upwards very slowly, I'd guess that once we have another decade or two of data, an exponential trend will become apparent.

[binntho]

Here is another way of looking at it - percentage covered in Ice per day.

My conclusion: No BOE until the dips widen and deepen significantly. And that doesn't look likely in the near future, although I must repeat that my feeling is that this could change very rapidly.

[El Cid]

My take is that the kara-bering-barents need to be reliably ice free almost all year around for an attack on the Center to be successful. So I calculated the average annual piomas volume for kara+bering+barents. Here it is, it seems to be going rather sideways but you could say the downtrend is still there:

[kassy]

Michelle McCrystall is a post-doctoral researcher with the University of Manitoba’s Centre for Earth Observation Science. She was the lead author of a study published last November, which predicted the Arctic could see more rain than snow as soon as 2050, decades earlier than previously thought.

McCrystall said data from weather stations indicates the region is already seeing the transition to less snow and more rain.

“What really astounded us was kind of the rate at which change happens,” she said.

So one new variable is the amount of rainfall which will change significantly going forward. This is basically not a factor in the historic data we have so that makes extrapolating that problematic because it does not tell the whole story anymore.

[Glen Koehler]

My take is that the kara-bering-barents need to be reliably ice free almost all year around for an attack on the Center to be successful. So I calculated the average annual piomas volume for kara+bering+barents. Here it is, it seems to be going rather sideways but you could say the downtrend is still there:

     The flattening of the downward trend in the Bering, Barents, and Kara sea volumes is striking.  My impression has been that those areas have been hard hit by early melt in recent years.  I think the question at hand is not "Is melt season too short to allow BOE", but "What factors explain the strength of the recent ASI decline slowdown?" 

      Surely the reduction of MYI ice and the "Slow Transition" feedback play a role, but there might be other factors involved.  Perhaps the weather folks have something to add about the Pacific Ocean temperature cycle or the persistence of the Arctic Oscillation.  I don't think northward heat transport on the Atlantic side has slowed down, and the decay on the Atlantic side is consistent with that.  I don't think transport drift has changed much either way.  I have seen comments about ice melt creating a stronger freshwater layer and thermal barrier on the surface. Uniquorn might have something to say about that.

     The Arctic rain study cited by Kassy looks like the kind of qualitative switch that could cause the situation to change quickly.  Rain is devastatingly effective at melting snow and ice, much more so than warm air alone.  The spring floods in my area are always due to the timing and amount of rain on early spring snowpack, not the air temperature or amount of snowpack.

[FishOutofWater]

Oceanic heat transport from the Atlantic into the Arctic ocean peaked in the period from 2005 to 2012. I'm not sure what paper that data set is in and I suffer from memory overload.

There will be no "BOE" for many years without an increase in oceanic heat transport into the Arctic.

Here are a few recent papers that are relevant to the topic here.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2021JC017762

Abstract

The impact of horizontal resolution on meridional Ocean Heat Transport (OHT) and sea ice in the Arctic is investigated using the GFDL CM2-O climate model suite (1°, 1/4°, and 1/10°) in both preindustrial control and climate change simulations. Results show an increase in OHT associated to a decrease in sea ice extent (SIE) in the Arctic on interannual and decadal timescales. This link, however, is not monotonic with spatial resolution. While OHT increases and SIE decreases from the Low to the Medium resolution, the reverse is true from the Medium to the High resolution. Differences in OHT and SIE between the three model configurations mostly arise from the preindustrial state. As the spatial resolution increases, the Irminger Current is favored at the expense of the North Atlantic Drift. This rerouting of water to the Western side of Greenland results in less heat delivered to the Arctic in the High-resolution configuration than in its Medium counterpart. As a result, the Medium-resolution configuration is in best agreement with observed SIE and Atlantic OHT. Concurrent with the change in the partitioning in volume is a change in deep convection centers from the Greenland-Irminger-Norwegian Seas in the Low resolution to the Labrador Sea in the Medium and High resolutions. Results suggest a coupling between OHT into the Arctic and deep convection in the North Atlantic.


https://link.springer.com/article/10.1007/s00382-020-05540-8#Abs1

The recent increase in Atlantic and Pacific ocean heat transports has led to a decrease in Arctic sea-ice area and volume. As the respective contributions from both oceans in driving sea-ice loss is still uncertain, our study explores this. We use the EC-Earth3 coupled global climate model and perform different sensitivity experiments to gain insights into the relationships between ocean heat transport and Arctic sea ice. In these model experiments, the sea-surface temperature is artificially increased in different regions of the North Atlantic and North Pacific Oceans and with different levels of warming. All the experiments lead to enhanced ocean heat transport, and consequently to a decrease in Arctic sea-ice area and volume. We show that the wider the domain in which the sea-surface temperature is increased and the larger the level of warming, the larger the increase in ocean heat transport and the stronger the decrease in Arctic sea-ice area and volume. We also find that for a same amount of ocean heat transport increase, the reductions in Arctic sea-ice area and volume are stronger when the sea-surface temperature increase is imposed in the North Pacific, compared to the North Atlantic. This is explained by the lower-salinity water at the Bering Strait and atmospheric warming of the North Atlantic Ocean in the Pacific experiments. Finally, we find that the sea-ice loss is mainly driven by reduced basal growth along the sea-ice edge and enhanced basal melt in the Central Arctic. This confirms that the ocean heat transport is the primary driver of Arctic sea-ice loss in our experiments.

[El Cid]

  I don't think northward heat transport on the Atlantic side has slowed down, and the decay on the Atlantic side is consistent with that.

I attach Barents only average annual piomas volume. It is quite a mystery to me. Like you I would presume that heat transport should be stronger and stronger into the Arctic every year from the Atlantic side, so the Barents should have less and less ice every year. Alas, it is not so!

(maybe melting Greenland ice stopped the northward transport and caused the famed "cold hole" S of Greenland...but this year that hole disappeared and now the region is warm, so maybe that "blocking" is gone. If it is so, then the warm water should hit the Barents hard during the next years...or maybe I am just clueless)

[Glen Koehler]

Here is another way of looking at it - percentage covered in Ice per day.

My conclusion: No BOE until the dips widen and deepen significantly. And that doesn't look likely in the near future, although I must repeat that my feeling is that this could change very rapidly.

   Binntho - this might be of interest

[kassy]

There is no predictive value in the spikes whatever way you plot them. Does that matter?

[binntho]

   Binntho - this might be of interest

It is indeed interesting - I remember this from some previous discussion. But all those lines are way to straight for me!

I have a predilection for absolutes with caveats (yummy!), my favourite one being: The Arctic is huge, cold and protected by continents and thus very resilient to BOE, at least until we start to see significant amounts of open water.

And my feeling is that change will happen very rapidly once it starts, bending those straight lines into more interesting shapes.

[El Cid]

Now this might be totally stupid, but anyway:

I've been looking at water temps off the coast of NE USA. Surface temperatures have been steadily rising for some year (chart 1). However, after 2012 this water could not (for some reason) move on to the north, evidenced by sea temperatures S of Greenland (chart 2). After 2019-20, the heat seems to be so much off the coast of the USA that it penetrated into the previously (for some years) surprisingly cold waters S of Greenland and the "blocking" there seems to be gone now. In fact, this September, sea temperatures there are up across the roof - truly as if some sort of blocking would be gone and now the warm waters from the Gulf Stream would be able to move north (chart 3).

This is already speculative enough but to add some more speculation: if this is so then these warm waters should arrive into the Barents in a few months/years and keep it open all year making the perfect staging ground for an attack on the Center.  In this case the melting season would not be short for a BOE to happen

[The Walrus]

Much of the anomaly can be attributed to ENSO conditions; Waters south of Greenland tend to warm during La Nina years and cool during El Nino.  This is due largely to circulatory steering patterns over Canada and Northern Europe.  Hence, the warm anomaly may continue into the winter.

While the North Atlantic has been very warm recently, the tropical portion has been cooler.  This has inhibited formation off the coast of Africa.

https://www.severe-weather.eu/global-weather/ocean-anomaly-atlantic-gulf-stream-forecast-winter-united-states-europe-fa/

[binntho]

Much of the anomaly can be attributed to ENSO conditions; Waters south of Greenland tend to warm during La Nina years and cool during El Nino.

A new one for me! But all is explained in the excellent article, well worth a read and with great
graphics:

https://www.severe-weather.eu/global-weather/ocean-anomaly-atlantic-gulf-stream-forecast-winter-united-states-europe-fa/

On another note altogether, Stephan has posted his excellent long-term graph over on the 2022 Sea ice area and extent data thread. I noticed that there have been several long periods of stagnation and even upward trends, e.g. most of the '90s. Stephan's graph is shown below, and further down my own version which shows that almost the entire graph can be divided into decade-long flatliners.

A click on the image is helpful!

[The Walrus]

Thank you binntho.  I could not have said it any better.

[FishOutofWater]

I agree that the third year of La Niña in a row has transferred a large amount of ocean heat from the tropics and subtropics to the northwestern Atlantic and Pacific oceans. La Niña causes the jet stream to tighten around the poles and the subtropical highs to intensify. The driving energy behind all of this is the intensification of tropical convection in the Indonesian region.



There is already a large positive ocean heat anomaly in the Barents sea region and the European side of the pole in the CAB. That's the immediate issue for the sea ice this winter, not the warmth off of New England.

[El Cid]

There is already a large positive ocean heat anomaly in the Barents sea region and the European side of the pole in the CAB. That's the immediate issue for the sea ice this winter, not the warmth off of New England.

That really is the IMMEDIATE issue.

 My point was (and I acknowledge that I may be totally off track here) that as the Equatorial/Carribean waters get ever warmer this warm water moves northwards but during the past years it seems to have been blocked South of Greenland (evidenced by cold anomalies there) and that is why the waters off the NE coast of the USA were getting extremely warm (evidenced by extreme warm anomalies). But now the blocking S of Greenland seems to be gone so it is logical to assume that this water will eventually (in months? years?) will reach the Barents and might create all year ice free conditions there, which would make a BOE much more likely.

But maybe even current Barents heat is enough for an icefree state, I don't know how this year's heat content compares to previous ones

[oren]

I think that when north winds blow out of the CAB in Jan-Feb-Mar it is near impossible for the Barents to remain ice free, regardless of heat content.

[gerontocrat]

I think that when north winds blow out of the CAB in Jan-Feb-Mar it is near impossible for the Barents to remain ice free, regardless of heat content.

But does it need to be totally ice-free?

Note - all the graphs here are from NSIDC 5-day sea ice AREA data. I use area, not extent, as we are basically talking about the Arctic seas changing from an icy desert to open water, with all the climate changes that that implies.

As you can see from the first graph, Barents sea ice is melting earlier and earlier and refreezing later and later. Also winter sea ice in the 2010s is about half that of the 1980s. This suggests that more ocean heat is being accumulated during melting than is lost through the greater open water due to the later refreeze.

I started thinking about measuring the loss of sea ice a couple of years ago. My first attempt was to look at the number of days each year sea ice area was less than various percentages of the total area of each sea (or for seas like the Barents bounded by open ocean, the maximum daily extent in the satellite record). I plumped for less than 50%, less than 15%, and less than 5% (which to me is near enough ice-free).

The results for the Barents is in the second graph. The trend in the number of days the Barents is virtually ice-free has increased from around 50 in 1980 to around 125 in 2021. But that tells me little about winter sea ice. However, the trend in the number of days when sea ice is less than 50% has increased from around 150 in 1980 to around 325 in 2021. i.e. for only 40 days in the year can one expect sea ice to be more than half the area of the sea.

My last graph looks at sea ice area for various periods of the year. But instead of looking at trhe sea ice, I looked at the percentages of open water. The graph shows that at maximum sea ice, this sea is now more open water than sea ice. It also shows well the increase in open water for the period November to January from around 60% in the 1980s to 80% or more in recent years.

When you look next door to its neighbour, the Kara, you see since around 2012 a significant change, especially in volient yearly variation in open water in the period November to January, with a smaller increase in open water in the period of maximum sea ice (Feb to April). Perhaps this has something to do with the Barents being less of a hindrance to change.

click images to enlarge

Goodnight all

[El Cid]

I think that when north winds blow out of the CAB in Jan-Feb-Mar it is near impossible for the Barents to remain ice free, regardless of heat content.

But does it need to be totally ice-free?

great charts gerontocrat!

I think it needs to be ice free in May so that the "attack" could start early (which means it need to be ice free all year). If there is still ice in the Barents in May, then it will take time to melt that out and the attack on the CAB starts too late (and then the season is short for a BOE in that case)