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Messages - Michael Hauber

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1
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: October 06, 2019, 05:51:10 AM »
RCP assumes emissions keep growing until about 2035, and allow emissions at 50% of 2005 values to continue until the end of the century.  Continued growth in emissions could continue somewhat past 2035 if we cut emissions back further in the second half the century.  RCP4.5 still allows for a substantial (but definitely smaller than today) fossil fuels industry even in 2100.  Why would anyone think this is fantasy land?

2
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: October 04, 2019, 02:46:54 AM »
I still say never is a reasonable possibility.  Or at least not this century, and on a regular basis.

Model predictions for Arctic ice under RCP 4.5 suggest ice extent above 1m for the rest of the century, although lower years could well go a fair way below 1m, this is not likely on a consistent basis.  I have updated a comparison of model to actual conditions.  This is based on a published chart which I have saved as a picture backdrop for an excel chart, where I have plotted NSIDS September monthly ice extent.  These observations don't match up perfectly with what was quoted as observations in the published chart, but are pretty close.


3
Arctic sea ice / Re: The 2019/2020 freezing season
« on: September 27, 2019, 03:27:04 AM »

I've seen a lot of debate about this, the consensus here is that continental snow doesn't really have much bearing on Arctic sea-ice. Recently (2017, 2018) the snow mass charts have gone off the scale in winter (ECCC had to make a new y-axis) and it really hasn't correlated with a change in Arctic sea ice melt.


More snow = more sunlight reflected = cooling.  But the best way to get a wider cover of snow on the continents adjacent to the Arctic is to disrupt the polar vortex and allow more cold arctic air to spread further away from the central Arctic, meaning the central Arctic becomes warmer.

4
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: August 25, 2019, 12:15:11 AM »
Gone quiet here. Was it my post that caused that?  ::) ;D

If so, was it because it was well argued, or so bad it wasn't worth arguing with?  ::)

Perhaps also the recent stall in melt, meaning this season is suddenly highly unlikely to break 2012's record. 

So now we are looking at minimum 8 years to break the record.  The previous longest time to break the record for minimum extent according to JAXA was 5 years.

5
Arctic sea ice / Re: Are you hoping to witness a BOE?
« on: August 23, 2019, 01:22:11 AM »
Well I think a BOE is not likely on a regular basis until late this century if at all, which might be beyond my lifetime (I'll be near 80 by 2050).  And I like being right about stuff.

I've often thought a perfect storm melt year like 2007 could lead to a BOE, but the difficulty in breaking 2012's record is starting to make me question this.  A one off BOE in the next few years would be lots of hype and doom and gloom, and then in following years there would surely be lots of claims of recovery etc.

A BOE event repeated over multiple years within the next 20 years would be a serous concern and mean I've underestimated the situation.  That would then be a case of trying to understand why it happened, and how that changes my expectations for global change.  Is methane venting rapidly from undersea clathrates?  Are temps rising rapidly?  Are other serious changes happening faster than commonly predicted?

I am reminded of storm and cyclone watching on weather forums.  I'm always excited about severe weather events, and kind of hope for these events to get as extreme as possible.  Then there is a bit of guilt because people can die in these events, or suffer serious property losses, and often discussions about how horrible it is that people are excited and hoping for severe weather, and many denials that no one is really hoping/excited, even though many posts seem to suggest that people are hoping/excited.  And I know that I personally am partly hoping/excited.  Maybe I'm sick.  Or maybe I'm just more willing to admit the excitement, and compartmentalise the guilt of the bad consequences under the logic of whether I hope or fear the severe weather event is coming anyway.  AGW has the additional element that we have (nearly?) all contributed, even if only a very small fraction of the total problem.

6
Arctic sea ice / Re: The 2019 melting season
« on: August 19, 2019, 01:24:54 AM »
I did say a month or so ago that the central ice was more solid/less dispersed than it was in 2012, so am not overly surprised at the melt slow down as the much weaker ice on the periphery has melted out.  Still the Laptev/Kara sector is being hit hard and is looking a bit weak now, and I wouldn't rule out rapid losses that depending on how next week's forecast plays out.  Record looks unlikely, but not quite ready to say its all over.

7
Arctic sea ice / Re: The 2019 melting season
« on: August 15, 2019, 12:29:08 AM »
Currently good view of ESS ice tongue for Aug 14.  Shows up as dramatically more solid than Aug 13 2012Aug 14 2012 hides the ESS region in clouds but shows large areas of gaping water in Laptev region where currently there is a high coverage of ice, although definitely looking thin and with many small holes.

8
Arctic sea ice / Re: The 2019 melting season
« on: August 14, 2019, 06:25:25 AM »
Not sure I've ever seen +4 temps at 850hp reach all the way to the North Pole.



For a fun comparison the current 850hp temp where I live in the subtropics is about +6, and forecast top temperature at surface level is 21 C.

9
Arctic sea ice / Re: 2019 vs 2012
« on: August 09, 2019, 06:11:34 AM »


Why are you commenting if you don't understand the theory?

I know enough about ENSO to correctly identify which years were el nino influenced and which were not.

10
Arctic sea ice / Re: The 2019 melting season
« on: August 09, 2019, 06:09:58 AM »
The central core looks fairly solid on Jaxa, much more so than IUP.  There is now a very small amount of weak ice left in ESS and Chukchi, and suspect that this could be the reason why extent loss has slowed down in the last few days so that 2012 now has a definite lead.  Or it could be the cooler weather.  The forecast heatwave is quite brutal and will extend over a fair bit of ice in and near the Laptev, which while fairly solid in 2 dimensions (relative to other recent years this late in the melt season) is quite likely relatively thin.  Without the heatwave I would be confidently calling the chance of record over.  With it, not sure....

 

11
Arctic sea ice / Re: 2019 vs 2012
« on: August 09, 2019, 05:58:48 AM »

It is no accident the lows of '05, '07, '10, '11 '12 and '16 are all associated with EN's.

Nino 3.4 index for September for the above years:

2005 -0.08
2007 -1.04
2010 -1.56
2011 -0.76
2012 +0.44
2016 -0.46

Warmest nino 3.4 index for 12 months prior to September for the above years:

2005 +0.71
2007 +1.1
2010 +1.81
2011 -0.23
2012 +0.44
2016 +2.57

None of those minimums occurred during el nino events.  Four of those six minimums occurred within 12 months after an el nino event, which is only one more than half.

12
Arctic sea ice / Re: "Stupid" Questions :o
« on: August 05, 2019, 12:22:01 AM »
Mike,

That is true for liquids that are not stratified with density. Try it at home with water and oil. It is generally more difficult to induce eddies across a cline. The description in the presentation is accurate for the top ocean layer generally across the boundary layer and deeper within the top 10-100 m.

Maybe, but the article I quoted seems to think that there is something going on for the ocean in general, and the article doesn't seem to be limited to the mixed layer, with comments that vertical mixing is much weaker than horizontal mixing due to temperature gradient induced stability, which would not apply to the mixed layer.  And much of the general ocean has much stronger vertical temperature gradients, and I'd guess stronger density gradients and therefore stability than the Arctic?

13
Arctic sea ice / Re: The 2019 melting season
« on: August 04, 2019, 11:13:35 PM »
Forecast 850hp temps at 96hr shows that the cooler air is reasonably anchored near the north pole.  There is some pressure from warm air from the Pacific and Russian side, but mostly over fringe ice that is pretty much certain to melt out anyway.



At 144 hour the pressure from the warm air becomes more substantial and the cool air is being squashed towards Greenland, but is still maintaining a presence in the Arctic.  The warm air is starting to impact the region of CAB ice that may or may not melt out by minimum.  Small changes at this range though could keep the warm air out of the central regions entirely, or result in a more significant warm air incursion that is able to displace the cold air entirely outside the central Arctic region, which is what happens in the most damaging heatwaves.


14
Arctic sea ice / Re: "Stupid" Questions :o
« on: August 04, 2019, 11:05:34 PM »
A surprising result.  I think there can also be some transfer of heat through eddies - the Arctic is not perfectly still but has significant currents.  See page 7 of this presentation  If momentum is transferred vertically due to mixing, I'm sure heat is as well. 

15
Arctic sea ice / Re: The 2019 melting season
« on: July 31, 2019, 04:13:59 AM »
Given the accuracy of past Slater projections to minimum, a record should not happen this year, but I don't think a Slater projection for 2012 is available.

Slater's prediction for 2012 can be seen at http://cires1.colorado.edu/~aslater/SEAICE/Slater_AGU_2013_poster.pdf.


His model did successfully predict a record low extent minimum 2012, but not as low as reality. The predicted 2012 minimum was just a bit under 4 million km2 - which is also what the Slater model predicts for this year.

Given its similar predictions for the extent minima in the record year 2012 and in 2019, the Slater model can't be said to rule out a new record low extent this year.

Thanks for that.  I should have said 'couldn't find a 2012 prediction'. 

It looks to me like a repeat of 2012 would be roughly at the lower limits of what is likely based on Slater's methods and history.  The current forecast suggests that it will be hard to get to the lower limits of what is likely.

16
Arctic sea ice / Re: The 2019 melting season
« on: July 31, 2019, 01:02:47 AM »
I guess I'm not seeing what you are seeing.

Me neither. These concentration maps have high daily variability due to clouds, but looking at averages (https://forum.arctic-sea-ice.net/index.php/topic,2792.msg217403.html#msg217403), 2019 currently looks quite a bit worse than 2012 almost everywhere. But of course the 2012 GAC will be dominating in a few days, so such comparisons can be moot or misleading.

IUP Bremen makes 2019 look worse compared to 2012, but Jaxa is the other way around.  I'm pretty sure this is regardless of 5 day average or not - the daily comparisons I do each day in Jaxa have told a similar story over the last few weeks.  From my time watching both images, and comparing carefully to EOSDIS visual images I trust Jaxa over IUP.

Lines added to highlight where I'm saying 2019 looks better than 2012





edit to add Slater projections.  The map is for a week or maybe two after minimum, but gives an idea of the significance of the current edge of the boundary between good/weak ice I've drawn.  Given the accuracy of past Slater projections to minimum, a record should not happen this year, but I don't think a Slater projection for 2012 is available.




17
Arctic sea ice / Re: The 2019 melting season
« on: July 30, 2019, 10:09:04 PM »
Comparing 2019 vs 2012 using Jaxa's analysis shows the central arctic basin ice is healthier than in 2012, while the ice towards the fringes is weaker/less of it.  This seems to correspond well with what I'm seeing in EOSDIS.





I believe the slater projection is significantly above record, which would seem to fit in with the above observation.  Considering the latest heatwave is now winding down and forecasts show a week of mild conditions with very slack wind, vs 2012's GAC,  I'd say a record this year is now quite unlikely.

18
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 29, 2019, 03:48:57 AM »
Two aspects to melt momentum, especially when referring to May melt ponds.  Firstly If we have a period of weak cool weather with strong melt ponds, then the melt ponds absorb more heat than frozen ice and so the melt ponds might stay melted.  If we have a period of cool weather following weak melt ponds, or unusually strong cool weather then the melt ponds might freeze anyway.  This might reset the albedo effect as if the melt momentum hadn't happened, however the ice is still thinner because it was melting faster before the freeze.  And could there be other changes in melt ponds that would make them easier to form again  following a brief freeze than if they had to form from scratch?  Can melt ponds freeze on top and still have liquid underneath, but on top of the sea ice?

19
Arctic sea ice / Re: The 2019 melting season
« on: July 25, 2019, 11:10:43 PM »
This heatwave is intense - high temps, widespread covering much of the American side of the Arctic, well placed over ice regions highly relevant to minimum while cooler air lies over ice that seems certain to melt out.  But not really all that long lived with maybe 3 or 4 days of extreme conditions before 850hp temps start dropping and the high starts weakening. 

And compare base of ESS now against [/url=https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2012-07-25-T00%3A00%3A00Z&z=3&v=-1279352.4928144752,689281.987323988,-579960.4928144753,989313.987323988]2012[/url].  The ice dispersion is stronger this year, but doesn't reach as far towards the pole.  Interesting that this is in my opinion the biggest reason to not expect a new record this year.  And the biggest reason to expect a new record?  The unprecedented retreat of the ice edge in Chukchi region.  The two areas highlighted in this chart:


20
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 25, 2019, 05:10:29 AM »
I'm back !

I'm looking the current GFS 10 day MAX 2M temp forecast. It's nicely color coded for low IQ folks like me.

In the center of the map, very close to 90N is a big chunk of real estate that's forecast to hit 3C.

It's surrounded by area that is only forecast to reach 2C.

Some of the very smart people on the melting season thread are telling me that the presence of ice limits the temperature to near freezing. If that's the case, how is the North Pole hitting 3C?

Other smart people say there is an exception for warm air advection from land. But there isn't any land near 90N.

Which factors determine the 2M temperature at 90N?

Relatively warm air is being advected at mid and higher levels of the atmosphere.  This air is then pushed down towards the surface of the ice as high pressure = sinking air.  This effect is strongest towards the center of the high pressure, so no surprise to me that greater surface warmth forecast in the middle.  Forecasts also suggest a bubble of warm air being pinched off from near Alaska and moving towards the pole.  Current forecasts suggest temps at 850hp peaking over 4 deg C near the pole.  Air will very roughly warm by about 10 C if forced down from 850hp to the surface, and so this is roughly equivalent to 14 C at the surface.

21
Arctic sea ice / Re: The 2019 melting season
« on: July 24, 2019, 01:37:34 AM »
With low-concentration ice extending to the pole and the ice in general thin enough that an icebreaker could run through at full speed without taking damage. 
My climate-skeptical friends are pointing out that the Norwegian "Kronprins Haakon" had to return from a planned trip to the North Pole.
https://www.arctictoday.com/for-norways-newest-icebreaker-its-almost-to-the-pole-and-back/

Report says 'decided to turn back after meeting first-year ice measuring up to 1.5 meters thick, patches of multi-year ice and little sign of thawing.' halfway from Svalbard to north pole.  Latest PIOMAS shows volume at record low, and thickness from Svalbard to pole starting near 1m and increasing to about 2m.  The article claims the sea was built to run through ice up to 2 meters. 

22
Arctic sea ice / Re: The 2019 melting season
« on: July 23, 2019, 12:07:34 AM »
Going Sea by Sea:

Beaufort - large amounts of dispersion, but also mostly larger floes, and weather has mostly been cooler in this region.  I suspect the ice is thicker and more durable than might be assumed at first glance looking at the broken appearance.  However the forecast high will hit this hard with heat and sun going into all that open water between the floes.  In 2012

Chukchi - the big story of the season with an ice boundary much further advanced than anything seen before.  Ice floes are much smaller than Beaufort, there is a lot of dispersion on the edge.  The forecast high will hit this area with heat, sun and wind, and the ice slaughter will continue.

ESS - Very weak ice, and an ice edge that has advanced further than 2012, but not as far as 2007.  Bore the brunt of early heatwaves, has been under low pressur and clouds since and the forecast continues this.  Ice would appear to be too weak to survive even under mostly favourable conditions.

Laptev - had a massive start early in June, but has been partly protected in the last few weeks.  A burst of warm air is pushed into this region with a sharp low early in the forecast which will do some more damage, but overall I see this region has fallen behind 2012 which had significant dispersion deep in the pack.  This year is a little like 2007 which had weaker melt in this region due to weather patterns pushing ice towards the Atlantic side, however NE passage remained blocked in this region in 2007 even at minimum and is now open (or at least very close to it).

CAB - the mystery.  Previous heat hasn't impacted this region as much, although there have been at least a couple significant warm incursions.  The forecast hits this region quite hard and it will be under serious assault from at least the Chukchi direction.  Perhaps the ice in this region is healthy enough to slow the melt down and prevent a record.  Or perhaps I'm clutching at straws.    Have a look at this region and compare to some other years.  Dispersion starting on top and left edge, 2012 maybe a little ahead, especially towards top right.  2016, 2008 and 2010 also have some significant dispersion much deeper into this region.  And 2010 wasn't a big melt year so no guarantees that this means anything.

23
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 22, 2019, 02:06:38 AM »
It has been stated in the melting thread that there's a possibility of a huge high pressure ridge forming over the Arctic Ocean, and that if it happens it will be very bad for the ice.

But would a huge high pressure ridge be bad for ice retention, and why? Just because insolation is still high for a few more weeks? But wouldn't it also bring an end to the winds? Wouldn't big storms be worse?

2007 - dominated by high pressure - record melt
2010/2011 - early high pressure domination, switching to more low pressure, early record melt rate stalling.  Later in 2011 due to later switch in 2011.
2012 - mix of high pressure and low pressure - record melt.
2013 - persistent low pressure - much less melt.

High pressure is more likely to work with Beaufort Gyre and move ice towards Atlantic, allows more solar heating, can only occur if upper polar vortext is broken down so allows more warmth imported in mid to upper levels, results in sinking air which warms that warmer mid/upper level air further and pushes it towards the surface.

Low pressure and winds mix heat around.  I think some low pressure as we saw in 2012 can be bad for the ice, but only if there is some heating as well, otherwise you get the 2013 result.


24
Arctic sea ice / Re: The 2019 melting season
« on: July 19, 2019, 03:47:31 AM »
Water temp in the Norton Sound has now reached 20C. Swim season officially open.


lol.  Middle of winter here in southern Qld Australia, sea temperatures are 22C, and its currently way to cold for swimming as far as I'm concerned.  Of course people from colder climates may see things differently.

25
Arctic sea ice / Re: The 2019 melting season
« on: July 19, 2019, 12:13:43 AM »
Since the 2012 GAC is being argued about, I thought I'd mention a couple of research papers into the question:

Parkinson and Comiso
Claim that the 2012 record was a result of the combination of preconditioning over previous decades of ice loss making the Arctic more vulnerable, and effectively put most of the blame for the record on the GAC.  The GAC sheared off a large area of ice which then melted and also made the remaining area of ice more vulnerable to melt.

Zhang et al
Claims that much of the sheared off ice would have melted anyway and that the GAC resulted in only a 150k reduction in final extent.  This is based on modelling the sea ice melt with and without the GAC.

Modelling of Arctic sea ice is off course far from perfect.  From my observations the process of shearing off the ESS section of the ice pack had well and truly begun from late June, with cyclones in June and July causing dispersion deep within the pack that enhanced melt in an area which eventually melted out totally in the GAC to shear off the ESS section.

26
Arctic sea ice / Re: The 2019 melting season
« on: July 17, 2019, 06:04:13 AM »
ESS,  and Laptev are going to get slaughtered, and soon.  Chukchi is already well ahead of everything else, and seems set to continue, at least at a moderate rate.  Beaufort while quite disperse is also marked by much larger invididual floes than the other and I think will do much better for the rest of the season.

Slaughtering ESS has only previously been done in 2007 and 2012, and close to it in 2016 and 2008.

The record?  One issue is how well the ice closer to the pole will hold up.  2012 had a disperse area deep within the ice that melted the ice pack from within, whereas 2007 was more melt from the edges, and this year is more like 2007 than 2019 in my opinion.  Dispersion has increased a lot in recent weeks, although dispersion is mostly from the edges - in some cases penetrating quite a distance from the edge, but not as deep into the pack as 2012.  Overall amounts of dispersion look reasonably similar in both years.  Compare 2019 where dispersion is limited to top and left of view, whereas in 2012 dispersion was further down and right towards the pole, but with more solid ice towards the top left near ESS. 

Another issue is the Chukchi melt rate.  I suspect warm water is entering from Chukchi, which I've seen reported as a significant factor behind 2007's result.  Chukchi is probably the fastest melting region, with ESS melting very fast, but not quite as fast as 2007.  However the weather this year seems to have been hotter towards ESS/Laptev.  If there is warm water moving into the Arctic from this direction will it continue towards the pole, or be caught in the Beaufrot Gyre and push into the ESS which is already doomed.

My opinion - if the current forecast with cool cloudy conditions continues we will even fall out of the top 3.  A return to moderately warmer conditions and 2nd.  But another strong heatwave similar to earlier, especially if it impacts deep towards the pole, and in with a big chance at 1st.


27
Arctic sea ice / Re: The 2019 melting season
« on: July 05, 2019, 07:43:21 AM »
I've often suspected a repeat of 2007 conditions may result in near ice free conditions, considering that 2007 had to contend with a much larger proportion of thicker multi-year ice than has been around since then.

With a lot of heat in June, a strong retreat in the Pacific and with more compaction and less dispersion evident this year seems to have some similarities to 2007.  In general there is more dispersal of ice currently in the ESS region than there was same day 2007

NSIDC ice comparison shows a strong retreat in the Pacific centre.  Compared to 2007 this year is retreating faster towards Chukchi and not as fast towards ESS.  Similar speed of retreat in Laptev which suprises me due to the severity of both wind and heat in that sector this year.



Temps at 925hp show how much hotter this year is than 2007.  The strongest heat is more towards Laptev this year, but is overall noticeably warmer.





Wind driven compaction and export was an important factor in 2007.  There were some quite strong winds over the Pacific sector that drove the ice towards the Atlantic.  Keep in mind Ekman transport will push the ice to the right of the wind vector so the ice will travel much more away from the Chukchi region than the roughly right angle winds suggest.



In contrast this year winds have definitely been milder over the Pacific sector, although there have been some very strong winds towards Kara and some moderate winds near Laptev.



Overall more heat, but less help from winds than 2007.  Assuming the pattern continues, is that enough to set up a similarly devestating melt season as 2007, and what impact would that have with the multi-year ice greatly reduced?

Is the fact that ice retreat towards Laptev is only similar to 2007 and not well ahead despite apparently much hotter conditions and solid wind important?  Was the ice there thicker this year?  Or was the heat perhaps not as strong as shown in the models (I believe a lot of extrapolation is involved producing these temperature maps).





28
Arctic sea ice / Re: The 2019 melting season
« on: July 03, 2019, 03:03:16 AM »
its a question of whether people trust my (and those who agree with me) subjective eyeball estimates, and whether anyone who disagrees can put together some convincing images to show otherwise. 

Translation - I'm not gonna present hard numbers or data to prove my point, but if someone disagrees with me, the burden of proof is on them to refute it with data.

Spoiler alert - Burden of proof is always on the person making outlandish claims. If you are so convinced about a particular point (i.e. - dispersion), presenting convincing data to prove it should not be difficult.

I presented the images that back up my claims, so I have provided the same level of evidence I ask of anyone who wants to dispute my claim.  Your accusation of double standards is false and offensive.

29
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 03, 2019, 02:23:42 AM »
Looking at some satellite images of the coast using google maps I'd say the ocean from directly above is quite transparent with shallow features such as sandbars very clearly visible, but deeper water gets dark, and with a grey shimmer of weak reflections on the surface.  Not perfectly black but relatively dark so depending on exposure sensitivity it could appear black.  Perhaps also the google map satellite views are much lower and so more variation from perfectly vertical whereas MODIS satellite(s) much higher so much closer to vertical.  However waves/roughness etc deviate from perfectly horizontal anyway so this shouldn't matter I'd think.  At any sort of angle blue reflection from the sky would dominate.

30
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 03, 2019, 01:59:51 AM »
Ocean also appears blue from close up - i.e. from a boat or from land.

31
Arctic sea ice / Re: "Stupid" Questions :o
« on: July 03, 2019, 01:08:49 AM »
Why does the ocean appear black in MODIS images?

32
Arctic sea ice / Re: The 2019 melting season
« on: July 03, 2019, 12:42:44 AM »
Most of the discussion about dispersion is pointless because we don't have a direct measure of ice dispersion. The area vs extent figures include the effects of melt ponds. We know from published research that early melt ponds are important to extent drops later in the summer. Thus the conflation of the effects of dispersion and melt ponds is a major problem in our discussions of dispersion, as Neven gently noted. As someone trained in science, not diplomacy, I do not tend to be so gentle.

Available data sets, such as JAXA extent, show that this year is running neck and neck with 2012. However, the distribution of early melt ponds, open water and thick ice is quite different. The weather has been different.


Yes there is a serious issue that dispersion  cannot be put on an nice numerical basis.  Concentration values from AMSRE2 etc should in theory do this but cannot tell between reduced concentration due to melt ponds and reduced concentration due to floe separation.  However having looked at many images in MODIS I think it is obvious that there is a quite dramatic difference between different years in this aspect, and that this year is a lower dispersion year.  Maybe an algorithm such as I've seen previously which sorts through all MODIS images to find cloud free portions to get a weekly view combined with some pixel counting could put it on a numerical basis.  Failing that its a question of whether people trust my (and those who agree with me) subjective eyeball estimates, and whether anyone who disagrees can put together some convincing images to show otherwise. 

Jaxa images would suggest that 2012 was massively more disperse than 2019, however the sensors used are totally different, with a change midway through 2012.  Any comparisons based on Extent Vs Area need to take this into account with some data serious starting midway through 2012, and others patching togther the different sensors, or NSIDC still using the same sensor throughout (I think?), but one which is very sensitive to melt ponds.

33
Arctic sea ice / Re: The 2019 melting season
« on: July 03, 2019, 12:08:47 AM »

This is not something that needs to be 'balanced'. The implication is that things aren't really that bad, because look, 2012 was much worse. This is what annoys people and brings out the troll accusations. Because practically no one is saying - as of yet - that 2019 is looking much worse than 2012 in every respect. Things simply look very bad, that's all, but we don't know what the next weeks will bring.


But I'm not saying things are not as bad as 2012 in every aspect either.  I'm saying that in one aspect things aren't as bad as in 2012, and definitely acknowledge than in at least one other aspect - mid to late June heating this year is substantially worse.  Balance is to take note of both facts.  And then the hard part is how to put them together, one person might see the heat as being more important and think it likely that we are overall worse than 2012, and another might think dispersion is more important and think we are overall not as bad as 2012.  I'm leaning towards second, but its far from certain and people who think the heat is more important could easily be correct.

34
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 02:38:05 AM »
Do you have some useful facts or data to bring to the discussion?

Yeah, I do so almost every day.

I meant the current discussion about how much dispersed ice there is at the moment.  Seems the answer is no

Do you?

I think the fact that the ice is currently less dispersed than 2012 is a useful fact.

35
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 01:36:58 AM »

So your defense to trolling is that if you didn't do it you'd be accused of it? Hats off! I can see you're not new to this game.

Do you have some useful facts or data to bring to the discussion?  Like a date and region which shows where I am wrong about 2019 being more dispersed than 2012?  Or do you only have insults?

Try 2012  vs 2019 from the 27th of June.

36
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 01:23:41 AM »

To compare ice patterns from visible wavelength photographs, you ought to compare a day from each year that is relatively cloud free, rather than cherry picking one from this year that is relatively cloudy.

Maybe I'm being overly cynical, but if I picked a date from a few days ago where it wasn't cloudy someone would have complained I was trying to hide something by not showing current data.  The data is quite easy to access to check alternate dates and see if they show something different to what I am claiming.

37
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 01:17:03 AM »
the ice does have a greyish colour and the breman charts do show slightly lower concentration in that area.


Yes lots (possibly unprecedented) of melt ponding and surface melt going on.

38
Arctic sea ice / Re: The 2019 melting season
« on: July 02, 2019, 01:15:09 AM »
Balanced:  someone who is willing to discuss and acknowledge both the reasons why melt might be high, such as the recent heatwave, which was certainly extreme.  And willing to discuss reasons that the melt might not be as high, such as current lack of dispersion, and less extreme heat and increased cloudiness currently occurring and likely to continue in the short term forecast window. 

Unbalanced:  someone who can only discuss the reasons why melt will be high and accuses anyone who brings up any reasons why melt might be reduced of being a troll.

39
Arctic sea ice / Re: The 2019 melting season
« on: July 01, 2019, 11:57:51 PM »
Current MODIS view.  Lots of clouds keeping things cooler.  No dispersion visible in the gaps except in Beaufort.  Dispersion exists all along the fringes.



Same day 2012.  Much more dispersion visible.  Partly because there were less of those cooling clouds.  But the circled area has substantial areas of somewhat dispersed ice.  Through the melting season this ice kept getting worse and worse and eventually melts out completely.  I have seen no evidence of anything like like this large area of partially dispersed ice deep within the pack in the gaps between the clouds on the Russian side.  There is some of this dispersion penetrating deep into the pack in the Beaufort area but it is a small area compred to what happened in 2012 on the Russian side.


40
Arctic sea ice / Re: The 2019 melting season
« on: July 01, 2019, 12:52:49 PM »

That's probably what most of us thought in 2012 as well, when the weather improved during the second half of July. Let's just wait what PIOMAS has to say, and keep melting momentum in the backs of our minds.

Well if I remember right I didn't think 2012 was going to be a big melt season. One thing I learned from 2012 was that heat wasn't the full story of a melt season, and my current theory is that the high level of dispersion seen deep in the ice pack in 2012, followed by further heat was the key factor in making 2012 a big melt season.  Early start to melt pond probably important as well.

2016 - June was quite cold, but dispersion quite high.  That was followed by very hot temperatures in July, and we got to second place.  Looking back at images near minimum the ice was much closer to 2012 than the extent stat suggests.

I think there would be a much higher chance of a record this year if there was more dispersion, and that other than Beaufort region dispersion is on the low side this year.

41
Arctic sea ice / Re: The 2019 melting season
« on: July 01, 2019, 07:37:35 AM »


'Improvement' doesn't necessarily mean 'good'.
Agreed

If your 'improvement' lasts for a week or two, a new record low minimum will be almost guaranteed this year.

Do you mean if the improvement only lasts a week or two and then we are back to extreme conditions like a week ago?  That would put us at high chance or record minimum in my opinion. 

If it improves further after a week or two we could be looking at something more like 3rd.

42
Arctic sea ice / Re: The 2019 melting season
« on: July 01, 2019, 06:52:37 AM »

I don't know about the trolling, but I agree that calling a shift of bad conditions from one location to another 'improved conditions for ice retention' is pushing it.

It is a shift of the heat from an area where it is easy to melt the ice to an area where it is hard to melt the ice.  It is an overall reduction in the intensity of the heat with the area forecast to be at or above +10C anomalies a fraction of what we say several days ago.  It is an increase in cloudiness due to upper level low pressure activity which is already very obvious in MODIS vies of the Arctic.

I'm puzzled as to how anyone could not recognise the substantial reduction in intensity of heat within the arctic evident in these two frames:





Quote
When everything falls silent, and low pressure/clouds takes over completely, no dipole, no clusters of isobars, that's when we have 'improved conditions for ice retention'. I'm not seeing it in the D1-D6 forecast. Maybe after that.

Considering how extreme conditions were for much of June we don't need perfect ice retention conditions to note an improvement.  Pretty much any type of weather would actually be an improvement.

43
Arctic sea ice / Re: The 2019 melting season
« on: June 30, 2019, 11:38:32 PM »
Current forecast continues to be for improved conditions for ice retention.
- a large upper level low has spread over the ESS sector.  This is already spreading cloud cover to protect the ice.  The surface is responding with only weak low pressure so the benefits of cloud cooling with less of the problem of increased winds and disersion.
- The high pressure is weaker that what we saw over the last week or so.  The strongest heat is not as strong or widespread as the extremes recently seen.  The strongest heat is forecast to be over the CAA, and the CAA/Greenland sector of CAB.  CAA has lots of land and less ice to melt, and the adjacent CAB is very hard to melt.  Also it is normally cooler than the rest of the Arctic, so warm anomalies in this sector represent less melting than they would in say the ESS sector.
- Surface melting momentum is disrupted with the areas on the Russian side that saw extreme heat in June and a big build up of momentum mostly going cool.  The heat is now hitting the Canadian side which has experienced much cooler conditions in June.  However Beaufort, while mostly cool has become quite dispersed so the heat will be able to pour into lots of little bits of open water in between all the floes.  Chukchi has significant melting momentum and will be  on the edge of the heat.

Forecast for EC init 12Z June 30, 48 hours, 850hp temp anomaly:



GFS is running a bit cooler.

850 temps analysed near peak of recent heatwave:



Images sourced from Tropical Tidbits NH forecast and snipped due to the large size of the complete forecast area.

44
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 08:17:32 AM »
The 00Z forecast for 850hp temp improves conditions for the sea ice quite significantly.  48 hours ago it was a severe heatwave:



By 96 hours the cooling from extreme to somewhat above average is obvious:







45
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 01:16:17 AM »
Forecast for 850 temps is a signfiicant drop, from extreme values that appear to be close to peak now, to something still warm, but probably reasonably close to average for the last 5 years.  At extended range low pressure takes over, reminding me of 2010 which had a blistering start in June, but stumbled to be an also ran as cloudy low pressure weather took over in July.  Cooler low pressure is set to take over in ESS/Laptev which will test the area hit hardest by the heat with potential dispersion and mixing, but will cool and slow down surface heating.  Warmer conditions will move towards Chukchi and Beaufort.  Beaufort has been quite cool through June but had a really early melt in May, and has a fair bit of dispersed ice.  I think the ice is likely in quite good condition for being as dispersed as it is, and now it will be tested with heat, which will be able to take advantage of all the open water in between the floes.

Overall in 2 dimensions the ice looks more like 2007 for this date, and in better shape than 2012.  Hard to be sure about what the 3rd dimension is doing, but I think it if it was really bad then we'd see evidence in 2 dimensions with worse conditions around the edges.  If the ice is a good distribution of thicker in the middle and thin around the edges than extent and area should drop with similar speed as thickness.  If the ice is uniform thickness everywhere then you can get all the ice melting at once as can happen in a small lake.

I expect July will see a continuation of top 3, with 1st possible, but a large lead in 1st unlikely.  If low pressure takes over as hinted at by extended maybe even dropping out of top 3.

46
Arctic sea ice / Re: The 2019 melting season
« on: June 27, 2019, 12:52:59 AM »
Top part of this picture (near Beaufort/Chukchi boundary) is dominated by much smaller floes that are too small to see individually at this resolution.  Bottom half is much larger floes with many individually discernable.  The rough boundary is also marked by much more discoloured ice - I believe that is algae?  Or is it dust and/or smoke?  There is also a transition from fast ice that is currently not obviously breaking up to no fast ice on the shore.

Is the difference due to a boundary of warm water entering from Pacific vs cooler water in the Beaufort?  Or are the much smaller floes towards the top the remnants of sea ice from the Bering that have been melting for a much longer period than the Beaufort floes?


47
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 26, 2019, 07:21:16 AM »
The St. Lawrence. The universal opinion is that there is zero ice here. Spurious, artefacts***. Huh, you're all a bunch of unbelievers.

The final proof from the University of Bremen is attached

Is the labrador area part of St Lawrence or Baffin?  I see some ice on the 13th June.  Cloudy since then, that ice survived at least another couple days, was definitely breaking up, but hard to tell with all the cloud whether its 100% gone now.  Most of the Gulf of St Lawrence can be seen ice free as at the 13th.

48
Arctic sea ice / Re: The 2019 melting season
« on: June 26, 2019, 05:18:41 AM »
Quote from: Frivolousz21

I'm not sure what short lived matters???? 
A short lived low creates dispersion with only a short period of cooler weather.  A long lived low creates dispersion with a long period of weather.

Quote from: Frivolousz21
The weather in June of 2019 has been worse for the ice than in 2012.

Its been hotter than 2012.  But I don't think heat is the only factor.  Have a look at some of the dispersion created in 2012.  Look at the same area today

49
Arctic sea ice / Re: The 2019 melting season
« on: June 26, 2019, 02:27:06 AM »

Also anyone who thinks the ice isn't heading into July in the worst shape we have ever seen it overall is clueless.

As soon June 15th 2019 THIS YEAR WAS SECOND LOWEST VOLUME ON RECORD.

SINCE JUNE 15TH:

2012 VERSUS 2019.

NOT EVEN CLOSE.


Is one week of 'NOT EVEN CLOSE' hotter weather in 2019 enough to catch up to 2012?

Consider also that that week of cooler weather in 2012 was due to a strong but short lived low pressure system which had a dramatic impact on the visual appearance of the ice, introducing stripes of open water to a large part of the pack, which then proceeded to melt  through the rest of the season.  2013 showed that constant low pressure which causes ice dispersion helps maintain ice overall, but I suspect that 2012 was strongly assisted by short periods of low pressure increasing dispersion and allowing warm weather afterwards to have a much larger impact over a larger area of the ice.


50
Arctic sea ice / Re: The 2019 melting season
« on: June 26, 2019, 12:22:14 AM »
I think it has no chance.

5th or 6th IMO

In what criteria?

Thats almost impossible at this point.

The weather would have to abruptly go to cloudy and cold and not change back.

I recall 2010.  That was a massive year for volume drop, with a substantial record set for PIOMAS.  June 2010 was a brutal melt month and at about this time extent was well clear of 2007, with a record well on the cards.  Most of the drop in volume anomaly happened in June, and I remember looking at the numbers at the end of June and noting that if the anomaly drop was repeated in July we would be getting pretty close to 0 volume.  The size and speed of the drop caused a few comments in the blogosphere at the time.

First week in July cooler low pressure dominated weather set in, and the melt season stuttered.  2010 found its way to 3rd at the time for extent, or 10th if you include the years 2011-2018.  I think a repeat this year might put us somewhere near 6th this year.  The break from pre-2007 to post 2011 was huge so I think a repeate would put us further back then 3rd, but given 9 years of general warming since 2010 I'd think we'd do better than 10th.  The volume record set in 2010 was beaten in both 2011 and 2012, but has not been beaten since.

I certainly consider top 2 a much better prediction than 5th or 6th, but I wouldn't go so far as to say 5th or 6th is almost impossible.  Maybe a roughly 1 in 10 chance.

Extended GFS does have a low pressure taking over around day 10, but EC doesn't agree.  Extended GFS has forecast something similar for a while, but it seems to be something that is staying out near day 10 and not coming closer.

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