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FishOutofWater

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Re: The 2020 melting season
« Reply #1050 on: May 23, 2020, 11:08:37 PM »
The most prominent aspect of last winter's Arctic weather was the strongly positive Arctic oscillation. There was a very strong stratospheric polar vortex all winter and there was strongly cyclonic flow at the surface of the Arctic ocean. What was surprising is how warm it was for a winter with a strong polar vortex.

All in all it was a pretty poor winter for sea ice because stormy winters have more clouds and less energy loss to the dark sky and because a positive AO increases Atlantic water inflow and Arctic fresh water export. Moreover, the cyclonic flow is dispersive of ice.

The end product is another summer starting with very low sea ice extent and volume.

A few weeks of cooler than normal water temperatures in the central equatorial Pacific does not qualify as La Niña. Some models predict it will develop, others say no. What ever, most models are predicting a cooler than average central equatorial Pacific over the NH summer and stronger than normal convective activity over Indonesia and the Indian ocean. There can be couplings between enhanced Indian ocean region convection and Siberian heat waves. Perhaps we will see that happen this summer. It has already been an exceptional prelude to summer in Siberia.

bbr2315

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Re: The 2020 melting season
« Reply #1051 on: May 23, 2020, 11:27:06 PM »
925mb temp anomaly for the first 3 weeks of May.
The magnitude of this year's anomalies for this time period is worse compared to all other years since 2005.

The change since 2012 has been worsening in magnitude. Consistency of springtime patterns has begun to increase coupled with increasing magnitudes within said springtime patterns.

These changes center on --

1) Unsteady drops in Siberian / Eurasian snowcover. While wintertime snow volume here is also apparently increasing very quickly, every few springtimes we see a new WORSE May X-XX or June X-XX period on record. The deeper we get into the 21st Century, the earlier these events are occurring. These drops also appear to be increasingly accompanied by gains in SOUTHERN elevated regions of Eurasia, aka the Himalayas and mountain belts to their west.

2) Steady drops in Arctic extent / area / volume. Year over year, all three of these are slowly dropping, albeit somewhat unevenly, it is nevertheless happening consistently. This is coupled with year-over-year gains in oceanic heat content.

3) Uneasy gains in Quebecois / North American snowcover. Wintertime snow volume is increasing here MOST quickly, and every few springtimes we see a new COLDEST May X-XX or June X-XX period on record. The deeper we get into the 21st century, the LATER these events are occurring (i.e. snow is taking longer to fully melt out).

As the amplitude from 2012 has been increasing, we can see all three events described above appearing on a year-over-year animation of the upper air charts from ESRL. 2020 is notable as it has, by far, the STRONGEST amplitude in all three categories. The heat spike over Eurasia due to dwindling coverage is by far the broadest and most potent for May. The heat over the Arctic Ocean also qualifies as worst on record, though 2019 approaches and 2010 comes kind of close. And the cold over Canada is also most potent of any year during the reference period due to major extant anomalies and depth, perhaps rivaled but not surpassed by 2009 (IMO).

Besides the 2009 comparison in North America, the only "analog" of the recent bunch that comes anywhere near to matching the High Arctic and Eurasia is 2010. The only year that comes close to matching the Himalayan / mountainous Eurasian cold spell, which is also an emerging notable new feature, is 2005.

Those analogs may give some insight into ENSO cues. A La Nina appears to be developing. Both 2005 and 2010 featured potent episodes of La Nina, especially 2010.

On the contrary, 2009 was a Nino. And while half the planet looks more like a scenario preceding Nina, the half that borders the EPAC is looking more like a year that preceded a Nino. So perhaps we have a strong tilt towards impending Nina given surface observations and analogs of 2010 and 2005, but it should be noted that the year most similar to our own this May in North America was 2009, which went in the other direction in the tropical Pacific.

I also attached two GIFs of this year vs 2012 which best illustrate ongoing changes mentioned ^. It looks like things are way sunnier, much more pre-conditioning is underway, and oddly enough less yellow (?) I wonder if this is due to differences in the satellite data or due to drop in aerosols etc.

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Re: The 2020 melting season
« Reply #1052 on: May 24, 2020, 12:33:55 AM »

By your logic, 2013 should have been a blow-out, as thickness and over-all volume were massacred at the end of 2012. 
You are clearly not fully understanding the logic, so I'll try to explain it for you by comparing 2012, 2013 and 2020 (which is a work in progress).

The logic is that the outcome of a melt season in the form of a minimum is a function of three things. 1) The previous season minimum, 2) The previous freezing season and 3) The melting season.

Looking at factor #1. All three of these years began on the foundation of a low previous minimum (2011 was the lowest volume prior to 2012).

Factor #2 - Of the three, the 2011-12 freezing season was by far the weakest. The 2012-13 freezing season was characterized by an outstanding recovery in sea ice. So there is no logic there supporting a low 2013 minimum. The 2019-20 freezing season was cold relative to the average of

Factor #3 - The wonders of the 2012 melt season have been well written here, no need to rehash. 2013 was meh, hence the outcome. 2020 remains to be seen.

Preconditioning and weather are more critical to the melt season's progress than the modest increase in volume which may have been gained.

I agree that the preconditioning and weather are important to the melt seasons (Factor 3) progress. I am merely arguing that Factor 2 (freezing season) is also important to the season ending minimum.

The additional ice won't be enough to off-set the increase in heat budget we are seeing, presuming weather continues on in the dismal trend it is currently following.

We'll see what the weather holds.

Continental snow pack has been smashed, especially in Eurasia, and the Siberian Arctic coast increase in temperatures are astonishing.

Yes. It is bloody hot in Siberia. The Kara, Laptev and ESS are going to get an early season roasting. But getting heat from Siberia to the areas of the Arctic likely to retain ice at the minimum (CAB, CAA and Beaufort) is not so obvious. 2012 had some very novel mechanisms for bringing heat to the surface of these regions in the form of the Mackenzie River discharge event and the GAC. These are not events which can be predicted to reoccur in 2020 and that's a long,long way for warm air advection.

I think we are seeing late June ice conditions moving up to late May. 

I assume you are referring to a forecast and not present conditions.
« Last Edit: May 24, 2020, 01:03:58 AM by Phoenix »

Paul

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Re: The 2020 melting season
« Reply #1053 on: May 24, 2020, 02:11:38 AM »
Well the heatwave in Siberia should finally subside shortly as the weather turns alot cooler and wetter, the conditions may help the ice conditions also in the Laptev sea as its set to be under a cold low for the foreseeable future.

I must say though, apart from the rapid snow cover melt and parts of the Kara sea having quite a bit of open water this early, I look at worldview and too me the ice pack does not look that much different from other years. One may argue so far in 2020, the ice looks somewhat healthier in the Beaufort compared to 2011 and 2015 where there was quite a bit of melt ponding going on for example. The slowish melt in the Bering sea/Stright has meant SSTs are fairly cool here compared to 2019 in particular which may help the ice later on in the melt season.

The clear concern for me is the ESS ice, lack of fast ice and diffuse looking ice in general with polynas on the northern shores of Siberia which when the winds turn next week could increase those holes again. If the ESS had a fairly healthy dose of fast ice and better looking ice in general then I would of said the 2012 record would be fairly unlikely but I think the chance is certainly there, the lack of ice in the ESS by September was a factor why ice went so low last year.

On the debate of whether this winter was good for ice growth, the volume charts suggest it was but again like 2019, spring has not been as favourable for the ice it would seem. Also the positive AO means increased fram export and less thick ice in the ESS hence there seem to be a link between a positive AO and low summer minimums.

gandul

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Re: The 2020 melting season
« Reply #1054 on: May 24, 2020, 02:42:28 AM »

By your logic, 2013 should have been a blow-out, as thickness and over-all volume were massacred at the end of 2012. 
You are clearly not fully understanding the logic, so I'll try to explain it for you by comparing 2012, 2013 and 2020 (which is a work in progress).

The logic is that the outcome of a melt season in the form of a minimum is a function of three things. 1) The previous season minimum, 2) The previous freezing season and 3) The melting season.

Looking at factor #1. All three of these years began on the foundation of a low previous minimum (2011 was the lowest volume prior to 2012).

Factor #2 - Of the three, the 2011-12 freezing season was by far the weakest. The 2012-13 freezing season was characterized by an outstanding recovery in sea ice. So there is no logic there supporting a low 2013 minimum. The 2019-20 freezing season was cold relative to the average of

Factor #3 - The wonders of the 2012 melt season have been well written here, no need to rehash. 2013 was meh, hence the outcome. 2020 remains to be seen.

Preconditioning and weather are more critical to the melt season's progress than the modest increase in volume which may have been gained.

I agree that the preconditioning and weather are important to the melt seasons (Factor 3) progress. I am merely arguing that Factor 2 (freezing season) is also important to the season ending minimum.

The additional ice won't be enough to off-set the increase in heat budget we are seeing, presuming weather continues on in the dismal trend it is currently following.

We'll see what the weather holds.

Continental snow pack has been smashed, especially in Eurasia, and the Siberian Arctic coast increase in temperatures are astonishing.

Yes. It is bloody hot in Siberia. The Kara, Laptev and ESS are going to get an early season roasting. But getting heat from Siberia to the areas of the Arctic likely to retain ice at the minimum (CAB, CAA and Beaufort) is not so obvious. 2012 had some very novel mechanisms for bringing heat to the surface of these regions in the form of the Mackenzie River discharge event and the GAC. These are not events which can be predicted to reoccur in 2020 and that's a long,long way for warm air advection.

I think we are seeing late June ice conditions moving up to late May. 

I assume you are referring to a forecast and not present conditions.

I can see that what the experts here are kindly trying to make you understand is that factor #1 is a 5%, factor #2 is a 15% and factor #3 (melting season weather) is an 80%.
2013 weather was not meh, it was the reason of the rebound that year, just as 2017, a year with a low 2016 volume, #1, and record low volume past Winter, factor #2 but a pretty late summer #3.

Glen Koehler

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Re: The 2020 melting season
« Reply #1055 on: May 24, 2020, 02:45:30 AM »
      FWIW - Useful to clarify the question and frame of reference.  Phoenix puts more emphasis on conditions that affect the ice in the CAB and along the northern edge of the CAA that is considered likely to be the last to succumb to September melt.  Other folks generally refer to conditions for the Arctic overall. 

       So another question within the discussion is to what degree is the "last to go in September" ice isolated vs connected to conditions in the larger Arctic system.  For example, if the Kara Sea gets roasted early this year, as appears to be the case, how much does that affect the overall ASI September minimum?
« Last Edit: May 24, 2020, 03:06:47 AM by Glen Koehler »

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Re: The 2020 melting season
« Reply #1056 on: May 24, 2020, 03:07:34 AM »
       A while back Stephan calculated the R values for Volume and Extent at the end of each month to the following September minimum.  Accepting a few assumptions (that seem reasonable), squaring those values gives the R2, a measure of the percent of interannual variation that can be explained by knowing those values, and thus reducing the width of the confidence interval for estimating the subsequent September minimum.  https://forum.arctic-sea-ice.net/index.php/topic,2348.msg257955.html#msg257955

Improved Volume prediction accuracy as melt season observations become available. 
R-square reduction in variability derived from R values posted by Stephan at https://imgur.com/a/O82kzZZ

        Linear model estimate for 2020 September average Volume before any 2020 observations:  3.9M (1.2 – 6.6) km3, (95% of cases expected to fall within 1.2 – 6.6M km3, i.e  +/- 2.7M km3).
   
      With MARCH observation as predictor, confidence interval (CI) reduction for September average Volume estimate: 4%.  Width of 95% CI with March observation: +/- 2.6M km3.
      With APRIL Volume observation, confidence interval reduction: 7%.  Width of 95% CI with April observation: +/- 2.5M km3.
      With MAY Volume observation, confidence interval reduction: 32%.  Width of 95% CI with May observation: +/- 1.9M km3.

      With JUNE Volume observation, confidence interval reduction: 63%.  Width of 95% CI with June observation: +/- 1.0M km3.

      With JULY Volume observation, confidence interval reduction: 83%.  Width of 95% CI with July observation: +/- 0.5M km3.

      With AUGUST Volume observation, conf. interval reduction: 94%.  Width of 95% CI with August observation: +/- 0.2M km3.

-----------------------------
      Those values indicate that until we have the end of May, and really the end of June, volume observations, prior observations don't give us much foresight about the September volume minimum.  Which in turn suggests that melt season conditions (temperature, cloudiness, and storms) that take effect in June, July, and August are the primary determinants for the September volume minimum.  (Some of those conditions, such as melt pond formation, may have been established earlier, but do not manifest as changes in volume until after May 31).  Thus, about 68% of the variation in September minimum Volume becomes apparent after May 31 (100% minus 32% = 68%).

     The same approach for Extent shows the R2 at the end of March, April and May at insignificant level, only reaching 22% by the end of June, and 56% at the end of July.  Thus, changes that manifest in July and August account for 78% of the variation in September minimum Extent (100% minus 22% = 78%).   

      An expert analysis by Walt Meier and NSIDC concluded  “Plotting the de-trended maximum versus minimum extent (Figure 2) shows a near-random distribution.”  “The seasonal maximum extent and the September minimum extent are not correlated...“  "because summer weather conditions strongly shape the September minimum.”
     

Figure 2. This plot compares de-trended maximum extent (x-axis) with minimum extent (y-axis). The yearly values shown are calculated by subtracting the linear trend value for that year from the total extent.  Credit: W. Meier, NSIDC.  From “Maximum extent is not predictive of minimum extent” https://nsidc.org/arcticseaicenews/2020/03/
« Last Edit: May 24, 2020, 04:34:34 AM by Glen Koehler »

Phoenix

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Re: The 2020 melting season
« Reply #1057 on: May 24, 2020, 05:39:07 AM »
I can see that what the experts here are kindly trying to make you understand is that factor #1 is a 5%, factor #2 is a 15% and factor #3 (melting season weather) is an 80%.

Your %'s are completely arbitrary, but let's just assume that they are correct. You are in essence agreeing that freezing season is a factor worthy of consideration. The fact that the 2019-20 freezing season was a little more robust than some recent years doesn't fit the most sensational depiction of potential 2020 outcomes.

As Glen correctly indicates, I am not focusing on the Arctic as a whole so much as I am on the relative strengths and weaknesses of the areas more likely to retain ice at the minimum. I begin with the assumption that the Kara, Laptev, ESS and shallow CAB on Atlantic side in the 80-82N range will all go close to zero so watching them disappear is not so exciting for me.

The interesting mystery for me is the siege of the remaining ice which has rarely if ever melted in the past. Which attributes explain why these areas have been better protected and which processes will AGW and weather variation throw at them to eventually overcome these defenses?

As far as experts are concerned, none of us are experts when it comes to the future of the Arctic. The complexity and of weather, EMR, ocean currents, ocean stratification, wind circulation, topography, bathymetry and human influences like GHG's and aerosols are staggering and this is a largely wilderness setting. This is a place for "interesting discussion" among primarily hobbyists and learners.

Phoenix

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Re: The 2020 melting season
« Reply #1058 on: May 24, 2020, 06:05:27 AM »
Interesting weather development to check out on Monday.

Three high pressure centers extending together thousands of km from the mid-Atlantic to the Kara Sea and a solid low off the the east coast of Greenland. All working together to push warm surface winds into the CAB.

Probably good for a couple of days of WAA and another early spike in the DMI 80 temps.

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Re: The 2020 melting season
« Reply #1059 on: May 24, 2020, 06:34:06 AM »

We don't know what is going to happen in June but so far we are likely going into June in best modern set up to ravage the inner Arctic basin.

I guess that's a matter of opinion. 2012 and 2016 had very weak freezing seasons which preceded them and set the stage with thinner ice. By comparison, 2020 was a much better freezing season. Hoping for a mid-May PIOMAS volume update which gives us a better idea of thickness.

That isn't what we use to define a melting season.

Everyone agrees that 2007 was the melt season on record.

Because the conditions for melt June-Aug were amazing.

If we had an exact repeat of 2007 weather wise we would crush 2012 lows.

The preconditioning that has taken place and is still to come taking place is putting 2020 in one of the best spots  going into June in modern times.

2020 having slightly more ice thickness means nothing if we have melt weather going into June.

Yep, 2011-2012 had a strong winter +AO (Arctic Oscillation) and high area/extent with more volume coming into that spring, yet it was quickly destroyed by preconditioning and the early June dipole. Winter/spring thickness does have an impact, but it explains somewhere around 30-40% of final volume. The rest is up to progressively earlier melt and albedo destruction as the Arctic warms up progressively earlier in the spring. (One small caveat to comparing directly to that season is that the 2011 melt season was a sneaky CAB ice destroyer that didn't show up particularly well on area/extent metrics.)

Speaking of preconditioning, MODIS is indicating some sneaky patchy surface melt and diurnal wetting of the surface in the CAB as we speak. There's a good chance we start seeing more substantial melt by the 28th as that new ridge attempts to set up. Surface temps have been running a little higher than would be expected given the 850/925mb temps we're seeing, but that's probably down to the fact that the big ridge we saw last week has effectively destroyed the low-level cold pool that's typically still present at this time. Since it cannot be regenerated radiatively given the (now) late May sun angle, this might prove crucial. Generally, in the warm season, it takes diabatic processes (cooling through precip and lift), cloud cover, fresh snow and recirculation within a low or TPV to generate a new cold pool and protect the ice. That can still happen, but we're running short on time before the onset of more severe preconditioning. The EC and GFS are in agreement that we should start to see near basin-wide melt starting on the 28th or so.

A couple of important surface stations to watch over the next week (in addition to MODIS pictures) will be Eureka (CWEU) and Alert (CYLT). If those stations are near or above freezing by then and we're seeing significant reddening on the 3-6-7 bands on MODIS, the game is on.


With the Hudson Bay region staying below normal temperature wise, this year is potentially setting up for a big June cliff (Bay melt will probably be delayed to coincide with Basin melt).

Exactly...

The modis images do show the cab having darker low albedo spots.

Albedo is likely to drop hard over the Beaufort, Chuchki, and Western CAB over the next week.  The 00z gfs and 12z euro both show enhanced warning and qauasi-dipole winds.

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Re: The 2020 melting season
« Reply #1060 on: May 24, 2020, 06:42:51 AM »
There is a huge correlation between May snow cover loss and Arctic sea ice loss in summer.

We'll see....

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Re: The 2020 melting season
« Reply #1061 on: May 24, 2020, 07:13:37 AM »
May 19-23.

2019.

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Re: The 2020 melting season
« Reply #1062 on: May 24, 2020, 07:27:49 AM »
There's a reason that MYI is a proxy for thick ice... Ice can only thicken so much in a single winter when it starts from open water. When temps get to ~-20C extent grows quickly, but in the arctic a few degrees difference in a single winter does not thicken the ice significantly. THe amount the ice can thicken in one year is not more than can be melted out in a summer season.

oren

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Re: The 2020 melting season
« Reply #1063 on: May 24, 2020, 08:29:08 AM »
the areas of the Arctic likely to retain ice at the minimum (CAB, CAA and Beaufort).
Get your numbers straight. The areas most likely to retain ice at minimum are the CAB, the CAA and the Greenland Sea. Of the 8 years in the AMSR2 record, 5 had near-zero ice area in the Beaufort in early Sept, the rest had 150k-200k. The ESS had 3 years with 150k-250k, 3 years with 50k, and only 2 at near-zero. The Laptev is also sometimes a contributor, and even the Kara and Barents with some small amounts.
Later I will calculate average contributions to the Sept area minimum, of course you can do that yourself by downloading the file from Wipneus.


https://sites.google.com/site/arctischepinguin/home/amsr2/data/UH_AMSR2_3.125km_Area_Extent-v0.0.txt?attredirects=0&d=1

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Re: The 2020 melting season
« Reply #1064 on: May 24, 2020, 09:20:50 AM »
Average AMSR2 area contribution in mid-Sep (sorted, unrounded, km2):
CAB: 3,300,562 (max 3,606,190)
CAA: 169,524 (max 244,075)
Greenland Sea: 100,082 (max 179,770)
ESS: 65,956 (max 227,358)
Beaufort: 61,956 (max 189,835)
Laptev: 31,930 (max 112,984)
Baffin: 16,394 (max 31,070)
Barents: 7,976 (max 59,347)
Kara: 6,513 (max 28,714)
Chukchi: 3,619 (max 13,253)

Beaufort is indeed a variable sea, thus important to deciding the minimum, but the ESS is more variable, and the Laptev is also a respectable region of interest. In addition, the actual date of the minimum matters a lot and can vary by 2 weeks.

Phoenix

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Re: The 2020 melting season
« Reply #1065 on: May 24, 2020, 09:47:39 AM »
Looking at Gerontocrat's NSIDC area #'s for more insight on 2020 vs. 2019.

Overall, 2020 has 108k km2 lead on 2019....but where is the lead?

With the benefit of hindsight, we know where 2019 finishes. Huge leads in places where we know 2019 gets to zero or close to it are almost meaningless, especially in peripheral locations like Baffin and Hudson.

Baffin, Hudson, Laptev and  Kara combined are ~ 500k km2 ahead of 2019 and is offset by Bering being ~ 60K behind 2019. Knowing where 2019 ends, we know that 2019 is going to catch up at least 400K in these seas. The current 100k lead is vapor.

CAB and ESS are pretty comparable at this stage in the two years.

2019 is ahead of 2020 in seas which are less certain to be complete melt outs as Beaufort, Chuckchi and CAA are behind 2019 by almost 300k km2.

On the whole, 2020 has work to do to put itself in position to be a favorite to surpass 2019.

bbr2315

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Re: The 2020 melting season
« Reply #1066 on: May 24, 2020, 10:20:40 AM »
Looking at Gerontocrat's NSIDC area #'s for more insight on 2020 vs. 2019.

Overall, 2020 has 108k km2 lead on 2019....but where is the lead?

With the benefit of hindsight, we know where 2019 finishes. Huge leads in places where we know 2019 gets to zero or close to it are almost meaningless, especially in peripheral locations like Baffin and Hudson.

Baffin, Hudson, Laptev and  Kara combined are ~ 500k km2 ahead of 2019 and is offset by Bering being ~ 60K behind 2019. Knowing where 2019 ends, we know that 2019 is going to catch up at least 400K in these seas. The current 100k lead is vapor.

CAB and ESS are pretty comparable at this stage in the two years.

2019 is ahead of 2020 in seas which are less certain to be complete melt outs as Beaufort, Chuckchi and CAA are behind 2019 by almost 300k km2.

On the whole, 2020 has work to do to put itself in position to be a favorite to surpass 2019.
Kara Laptev and Barents border CAB and losses in these three will translate into CAB earlier and more thoroughly than 2019... the 100k lead is not "vapor".

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Re: The 2020 melting season
« Reply #1067 on: May 24, 2020, 01:03:32 PM »
Average AMSR2 area contribution in mid-Sep (sorted, unrounded, km2):
CAB: 3,300,562 (max 3,606,190)
Some people might get confused  because
- the CAB area in the NSIDC analysis is 3.224 million km2,
- the area of the CAB used by Wipneus is larger (the surrounding seas smaller).

And this is where I get confused - I thought the CAB area used by Wipneus was around 3.45 million km2, not the 3.60 million you quote. Do you think you could post the sea areas as used by Wipneus. I think you've done it before (or someone else has).

ps: The Barents, Kara Seas & CAA boundaries are the same, it is the Laptev, ESS, Chukhi & Beaufort Sea areas are lower in the Wipneus analysis, as NSIDC (Stroeve et al) moved the boundaries north by a series of straight lines along 80 North.
« Last Edit: May 24, 2020, 01:26:40 PM by gerontocrat »
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Re: The 2020 melting season
« Reply #1068 on: May 24, 2020, 01:08:43 PM »
... Huge leads in places where we know 2019 gets to zero or close to it are almost meaningless, especially in peripheral locations like Baffin and Hudson.
...
Incorrect. Unusually faster melt in peripheral locations can often indicate faster melt in high Arctic, which would happen later in a melt season. Whenever cause(s) which resulted in much faster peripheral melt early in a season would largely persist through the whole melting season, and we have a number of such indeed, for 2020.

... Baffin, Hudson, Laptev and  Kara combined are ~ 500k km2 ahead of 2019 and is offset by Bering being ~ 60K behind 2019. Knowing where 2019 ends, we know that 2019 is going to catch up at least 400K in these seas. The current 100k lead is vapor.
....
My bold. I believe that the two statements i enhanced with bold text - can not be true simultaneously. Those seas are either 500k km2 ahead - or 100k ahead. I am surprised to see such "wordplay" in this topic. I think it has no place here.

...
On the whole, 2020 has work to do to put itself in position to be a favorite to surpass 2019.
My italic. On the following graph, we can see how 2012 did ~1800k of such "work" between 23rd May (at which date 2020's line ends on this graph) and September minimum. See, by 23/05, 2012 was ~1000k higher than 2019, but at the minimum 2012 was ~800k lower than 2019. Which number - 1800k - dwarves numbers you gave, and in my opinion, proves your whole point wrong:



So, 2012 is one good "hindsight" about how much melt work a season can do. One can easily see how much lower-than-2019 this melting season can end up, if it'll just do "same amount of melt work" 2012 did, while "starting" from today's much lower than 2012's extent (and thus, roughly, also much lower-than-2012's area).

Given those facts, can you please elaborate what was, exactly, the meaning of your statement i quoted (the one in italic right above)? How, exactly, this statement helps us understand this melting season? What's its "meaning", exactly?
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Re: The 2020 melting season
« Reply #1069 on: May 24, 2020, 01:34:25 PM »
the 100k lead is not "vapor".

150k of the lead is Hudson alone.  That's vapor ! 8)

Also, bc's sig line reads "....2019+2=2021". It's already in the prophecy that 2020 won't be noteworthy for sea ice.  8) 8)

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Re: The 2020 melting season
« Reply #1070 on: May 24, 2020, 02:21:53 PM »

... Baffin, Hudson, Laptev and  Kara combined are ~ 500k km2 ahead of 2019 and is offset by Bering being ~ 60K behind 2019. Knowing where 2019 ends, we know that 2019 is going to catch up at least 400K in these seas. The current 100k lead is vapor.
....
My bold. I believe that the two statements i enhanced with bold text - can not be true simultaneously. Those seas are either 500k km2 ahead - or 100k ahead. I am surprised to see such "wordplay" in this topic. I think it has no place here.


FT. 100k refers to the lead of 2020 vs. 2019 over the entire Arctic. 500k refers to the lead of 2020 in a specified subset of Arctic seas where we know the end result in 2019 is close to zero. Therefore, we know that with respect to the end measurement of just that subset of seas, 2019 will make up ground vs.today. The 100k and 500k are mutually exclusive measures. Not a contradiction.

Of course, 2020 can counter by making up ground in other places like the CAB as bbr has suggested. In order to finish ahead of 2019 at the minimum, 2020 must make up ground elsewhere. That's just math. Of course this is possible. I'm not intending to put any constraints on the possibilities...just highlighting the math.

At this point I've made my point enough about a perspective that 2020 is not a monster at this time. I am content to let this go and move on if there are no more questions or challenges. If there are follow-ups, I'm also happy to take them.





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Re: The 2020 melting season
« Reply #1071 on: May 24, 2020, 02:55:45 PM »
We are almost without snow on the Taymyr Peninsula already. A good piece of Severnaya Zemlya is also melting. Whole Siberia is becoming a forge. Northerlies will cool it to near normal next days. But later the Arctic may meet Armageddon's Blade.

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Re: The 2020 melting season
« Reply #1072 on: May 24, 2020, 03:04:06 PM »
Lena river delta May 20th vs 24th.

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Re: The 2020 melting season
« Reply #1073 on: May 24, 2020, 03:21:58 PM »
Quote
So, 2012 is one good "hindsight" about how much melt work a season can do. 
Indeed F. Tnioli, and very well explained, good post.

To your point Phoenix, yes it's true that early losses in peripheral seas such as Okhotsk, Hudson and Baffin are less meaningful than the same losses in the Inner Basin.

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Re: The 2020 melting season
« Reply #1074 on: May 24, 2020, 03:34:43 PM »
In recent days sea ice area losses in the Central Seas greater than sea ice area loss in the Peripheral Seas.
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Re: The 2020 melting season
« Reply #1075 on: May 24, 2020, 03:46:43 PM »
What concerns me most at this point is not the lead of 2020 over 2019 by extent or area numbers, but rather the conditions that seem consistent with persistent preconditioning all around the CAB. I agree that its too early to call this year a "monster," implying that its completely unprecedented in every way. Rather I'm concerned that current conditions are setting up to leave the CAB vulnerable by July and the peripheral seas (and even high arctic) able to soak up enough sun to screw us over come winter and years ahead.
 
We have just seen massive WAA anomalies set the stage in the Kara and Laptev, while the next 7-10 days seems to shift intensity to the pacific side. Several have noted how we're behind in Beaufort and Chukchi, but those are the very areas to be blow-torched this upcoming week (see both GFS and Euro temp anomalies at 48hrs from 00Z below).
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Re: The 2020 melting season
« Reply #1076 on: May 24, 2020, 04:18:00 PM »
I'm glad to see that someone brought up the topic of vapor. The large region of northern Siberia that is having the massive heat wave and snow melt has developed a large positive water vapor anomaly. It's not quite the steaming swamp that eastern North Carolina is today but heat trapping water vapor amounts are far above normal in northern Siberia. It's not just the albedo. It's the warm water and high absolute humidity that stores and traps heat contributing to subsequent sea ice loss in the Arctic.

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Re: The 2020 melting season
« Reply #1077 on: May 24, 2020, 04:41:09 PM »
Can someone tell me why we care about compactness, or point me to another thread where it is explained? Is it bec more dispersed ice is more vulnerable to a variety of inputs? Or is that too simplistic? Thank you.

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Re: The 2020 melting season
« Reply #1078 on: May 24, 2020, 04:52:14 PM »
Extent is the most widely watched measure. Simply put, low compaction (area/extent ratio) signals a high risk of upcoming extent losses.
For a given amount of area, indeed lower compaction means the ice is more vulnerable.

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Re: The 2020 melting season
« Reply #1079 on: May 24, 2020, 05:48:06 PM »
Average AMSR2 area contribution in mid-Sep (sorted, unrounded, km2):
CAB: 3,300,562 (max 3,606,190)
Some people might get confused  because
- the CAB area in the NSIDC analysis is 3.224 million km2,
- the area of the CAB used by Wipneus is larger (the surrounding seas smaller).

And this is where I get confused - I thought the CAB area used by Wipneus was around 3.45 million km2, not the 3.60 million you quote. Do you think you could post the sea areas as used by Wipneus. I think you've done it before (or someone else has).

ps: The Barents, Kara Seas & CAA boundaries are the same, it is the Laptev, ESS, Chukhi & Beaufort Sea areas are lower in the Wipneus analysis, as NSIDC (Stroeve et al) moved the boundaries north by a series of straight lines along 80 North.
The max I gave in the above post was max area in mid-Sep, not total area of the sea, as determined by max over the whole AMSR2 record (in km2). Note the Wipneus map, previously used by Chris Reynolds, was taken from the now-defunct Cryosphere Today (CT) website.

CAB: 4,432,026
Chukchi:  606,637
Beaufort:  529,475
ESS:  934,240
Laptev:  736,842
Kara:  885,647
CAA:  769,964

Phoenix

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Re: The 2020 melting season
« Reply #1080 on: May 24, 2020, 06:35:53 PM »

To your point Phoenix, yes it's true that early losses in peripheral seas such as Okhotsk, Hudson and Baffin are less meaningful than the same losses in the Inner Basin.

I'm not sure how often this occurs, but in this case we're likely to have 2020 take the area / extent lead in early June on the basis of early advantage in peripheral areas that is destined to be short lived.

It could be good for site traffic to get a new leader for a while, even if it doesn't last.  ;D


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Re: The 2020 melting season
« Reply #1081 on: May 24, 2020, 07:01:49 PM »
<snip>
I'm not sure how often this occurs, but in this case we're likely to have 2020 take the area / extent lead in early June on the basis of early advantage in peripheral areas that is destined to be short lived.

It could be good for site traffic to get a new leader for a while, even if it doesn't last.  ;D

Or maybe it does! tee-hee  :-X :) ;) ;D

Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.

It predicts 7.34 m km² for July 13th, currently nosediving ...


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Re: The 2020 melting season
« Reply #1082 on: May 24, 2020, 07:12:28 PM »
The max I gave in the above post was max area in mid-Sep, not total area of the sea, as determined by max over the whole AMSR2 record (in km2). Note the Wipneus map, previously used by Chris Reynolds, was taken from the now-defunct Cryosphere Today (CT) website.

CAB: 4,432,026
Chukchi:  606,637
Beaufort:  529,475
ESS:  934,240
Laptev:  736,842
Kara:  885,647
CAA:  769,964
So here is a table comparing the CryosphereToday-Chris Reynolds-Wipneus sea areas with the NSIDC-Meier-Stroeve-Fetterer-2007 sea areas.

Just a pity for people like me we haven't got just one.
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ps: & Now the scientist have done the same for the gold standard definition of drainage basins of the Greenland & Antarctic ice sheets (per Zwally 2012, per Rignot 2016).
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Phoenix

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Re: The 2020 melting season
« Reply #1083 on: May 24, 2020, 07:26:41 PM »

Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.

It predicts 7.34 m km² for July 13th, currently nosediving ...

LOL. The ice apocalypse is a cottage industry. I'll take the over.  8)

PS - There's a dedicated thread for Slater and another dedicated 2020 prediction thread.

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Re: The 2020 melting season
« Reply #1084 on: May 24, 2020, 07:57:49 PM »

Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.

It predicts 7.34 m km² for July 13th, currently nosediving ...

LOL. The ice apocalypse is a cottage industry. I'll take the over.  8)

PS - There's a dedicated thread for Slater and another dedicated 2020 prediction thread.
Yes, and there is a thread for meaningless melting chatter, where most of your theory would fit in.
When your first claims were  thoroughly refuted by Simon92 and Oren, you all of a sudden picked 2019 as the year ... and from there on continued ... and continued  ... a lot of talking and very little data.

LOL indeed

Slater's model predictions, on the contrary, have a proven track record and nothing to do with apocalypse.
The model is imho very good in picking up different melting conditions; if conditions change to the better (for the ice), the model will show an uptick; at the end it will be close as in the last 6 or 7 years.

But enough, for once you are right: this is off-topic

PS: Sorry Oren for veering off-topic, please delete as you see fit

<Removed a couple of words. O>
« Last Edit: May 24, 2020, 11:12:28 PM by oren »

gerontocrat

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Re: The 2020 melting season
« Reply #1085 on: May 24, 2020, 07:58:42 PM »

Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.

It predicts 7.34 m km² for July 13th, currently nosediving ...

LOL. The ice apocalypse is a cottage industry. I'll take the over.  8)

PS - There's a dedicated thread for Slater and another dedicated 2020 prediction thread.
Clever fellow, that Slater - keeps at it even though he's dead.
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Re: The 2020 melting season
« Reply #1086 on: May 24, 2020, 08:43:39 PM »
Indeed F. Tnioli, and very well explained, good post.

To your point Phoenix, yes it's true that early losses in peripheral seas such as Okhotsk, Hudson and Baffin are less meaningful than the same losses in the Inner Basin.
But this wasn't his point. This is your point - this one about "less meaningful than". What he said - was "almost meaningless". The two are much different IMO. I objected to his point, and i still think my objection holds true. But your point, in contrast, i entirely agree with. Less meaningful indeed; but still plenty meaningful overall. What you think?
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GoSouthYoungins

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Re: The 2020 melting season
« Reply #1087 on: May 24, 2020, 08:44:41 PM »
I'm going to save the ice, for a year, by predicting....

HUGE MELT IN 2020!

Seriously though, things are looking pretty bad.

The extent and area are alright, but everything else looks horrible.

Snow cover in Russia is crazy low. The ability for the land to soak up heat during the next two months is very scary.

And the arctic ice all looks slushy way too many places.


High-Arctic Albedo during the month before the solstice is a great predictor of low CAB area at minimum.

Below are images:
 
-showing high arctic albedo anomaly may-20ish to june-20ish. 2012, 2016, 2019 in that order (with 2020 ready to set records)

-showing the CAB area from late August thru most of October INVERTED. 2012, 2016, 2019 in that order.
big time oops

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Re: The 2020 melting season
« Reply #1088 on: May 24, 2020, 09:14:14 PM »
Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.
It predicts 7.34 m km² for July 13th, currently nosediving ...

   Wow, if that forecast verifies, then 2020 would be 600K and 8% below the previous records for July 13 Extent in 2019, 2016, 2012. 

    It is useful to have Phoenix provide a skeptical check on habitual ASIF catastrophism (as in "this year is the big one!"), but it is also true that 2020 has come out of the gate strong, and that the current Extent and Volume numbers do not yet reflect the preconditioning that has occurred.  In addition, the current GFS forecast shows surface temperature for most of the Arctic Ocean above 0C from May 29 - June 3, combined with substantial areas of clear sky and what seems to be high amounts of precipitable water along the Atlantic front and north of Greenland (but I lack the historical perspective to interpret the precipitable water forecast).   

    I worship at the church of the long term linear trend, which has the 2012 volume record remaining intact for 2020 but then a ca. 50% chance of falling in 2021, and increasing each year thereafter.  For Extent, the trend estimate shows the 2012 record being safe for 5-10 years.  While it is far too early to say anything definitive about 2020, considering the recent conditioning, the current GFS forecast, that scary albedo graph posted by Sublime_Rime, and the Slater model forecast (which has been pretty accurate in recent years), 2020 seems to have a greater than 50% chance of going below the 2012 volume record.  The Extent record from 2012 was due to a freak event (the GAC) that is unlikely to be repeated in 2020, so is less likely to be surpassed.  But that is less important anyway, as I also worship at the church of Volume vs Extent with the Rev. Juan C. Garcia.
« Last Edit: May 24, 2020, 09:21:02 PM by Glen Koehler »

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Re: The 2020 melting season
« Reply #1089 on: May 24, 2020, 09:27:28 PM »

Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.

It predicts 7.34 m km² for July 13th, currently nosediving ...

LOL. The ice apocalypse is a cottage industry. I'll take the over.  8)

PS - There's a dedicated thread for Slater and another dedicated 2020 prediction thread.
Probably you don't even know, but ignorance is really showing.
PS. There are other threads for verborrhea

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Re: The 2020 melting season
« Reply #1090 on: May 24, 2020, 09:47:50 PM »
   Wow, if that forecast verifies, then 2020 would be 600K and 8% below the previous records for July 13 Extent in 2019, 2016, 2012. 

    It is useful to have Phoenix provide a skeptical check on habitual ASIF catastrophism (as in "this year is the big one!"), but it is also true that 2020 has come out of the gate strong, and that the current Extent and Volume numbers do not yet reflect the preconditioning that has occurred.  In addition, the current GFS forecast shows surface temperature for most of the Arctic Ocean above 0C from May 29 - June 3, combined with substantial areas of clear sky and what seems to be high amounts of precipitable water along the Atlantic front and north of Greenland (but I lack the historical perspective to interpret the precipitable water forecast).   

    I worship at the church of the long term linear trend, which has the 2012 volume record remaining intact for 2020 but then a ca. 50% chance of falling in 2021, and increasing each year thereafter.  For Extent, the trend estimate shows the 2012 record being safe for 5-10 years.  While it is far too early to say anything definitive about 2020, considering the recent conditioning, the current GFS forecast, that scary albedo graph, and the Slater model forecast (which has been pretty good in recent years), 2020 seems to have a greater than 50% chance of going below the 2012 volume record.  The Extent record from 2012 was due to a freak event (the GAC) that is unlikely to be repeated in 2020, so is less likely to be surpassed.  But that is less important anyway, as I also worship at the church of Volume vs Extent with the Rev. Juan C. Garcia.
While i disagree with some parts of your post, i really enjoy it in whole, such a fair and straight one. Thanks for writing it!

Why sure, that nose-diving line is wow alright, yes? Except me, i'd be more "wow" if it wouldn't end up something like that line, this season. But anyhow, "we'll see" and all.

A "skeptical" check requires rationality. Rationality in our here case, as rightfully mentioned by you, means acknowledging that we have preconditioning that has occured already; it's quite a big deal / scale and can not be ignored. Thus, a sceptic would find some rational way to demonstrate how/why such preconditioning would not nesessarily result in "ASIF catastrophism", if to put it using your term. I like the term btw, the irony... Anyhow, ignoring said preconditioning is therefore not sceptical, see. It's merely dumb. That's all it is.

Worshipping linear trend church will do no good, i'm plenty sure. I mean, even simplest check of sure-deal historical data of any kind - be it Earth glacials, or sea level, or temperature, what have you - shows how things have changed in all kinds of non-linear matter, whatever time scale you pick. Why things would suddenly start to work "strictly linearly" now? It's easy to go check this kind of data out, and worth an extra look for "linear church" fellow in particular, i'd say...

And about 2012's freaky GAC - it sure was that, but since then, plenty things got substantially more melt-encouraging. Like GHG air content, big drop in multi-year ice, etc. So now, it'd take way less than 2012's GAC to repeat the same amount of melt. Especially with cleaner air this time, due to big-time reductions in fuel burning around the globe at the time, and its implications to clouds, precipitation, near-vertical surfaces' wettening / melt, etc as discussed above in the topic.

So if we'd want a bottom line for now? "All bets are off" i'd say. We're entering unknown waters now in terms of this melt season. Pun, sadly, intended.
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HapHazard

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Re: The 2020 melting season
« Reply #1091 on: May 24, 2020, 09:53:17 PM »

...but it is also true that 2020 has come out of the gate strong, and that the current Extent and Volume numbers do not yet reflect the preconditioning that has occurred.

It seems to me that we need to dodge more and more bullets each melting season in order to avoid a [near]record minimum.  The Arctic will need to turn into Neo from The Matrix in order to fend off catastrophe for much longer. :-\

Pavel

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Re: The 2020 melting season
« Reply #1092 on: May 24, 2020, 09:54:24 PM »
The ice is very blue in the Hudson bay despite the land snow refuses to melt in that region during the entire spring.

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Re: The 2020 melting season
« Reply #1093 on: May 24, 2020, 09:56:04 PM »
The models are picking up on a spoke vortex forming over the Eastern CAB about day 7 that hinders the quasi-dipole.

However we have to remember that around June 1st is when the long range models have a hard time.

We'll see.

But the GIS large vortex isn't going anywhere for now.
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Re: The 2020 melting season
« Reply #1094 on: May 24, 2020, 10:07:35 PM »
The ice is very blue in the Hudson bay despite the land snow refuses to melt in that region during the entire spring.
May indicate significant heat content in the water right below that ice?

This reminds me. I am unable to get real-time ICESat-2 data (don't confuse with CryoSat-2 please!) myself. Do we have anybody able to give us the simple average snow thickness for Arctic sea ice for as close to "now" as possible? It'd be great to know what ICESat-2 instruments tell at this time.

We know that average maximum (= April) snow thickness on 1st-year ice is 16.8 cm, and average snow thickness on multi-year ice is 26.6 cm. Those are of course estimated and wildly vary in practice from season to season, but seeing what we have left now directly form instruments - can possibly be quite telling.
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Re: The 2020 melting season
« Reply #1095 on: May 24, 2020, 10:50:33 PM »
It's so insanely warm (relatively speaking) in Utqiagvik today! Not the mention the amount of melt ponds on the landfast ice appeared almost instantly. So too did the melting of the lake. Wild!

pls!

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Re: The 2020 melting season
« Reply #1096 on: May 24, 2020, 11:01:29 PM »
I get the Blue in Hudson. But what is turning the ice grayish around Akimiski Island ?

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Re: The 2020 melting season
« Reply #1097 on: May 24, 2020, 11:05:59 PM »
wild speculation as to the cause: an algal bloom
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Re: The 2020 melting season
« Reply #1098 on: May 24, 2020, 11:07:42 PM »
The ice is very blue in the Hudson bay despite the land snow refuses to melt in that region during the entire spring.
May indicate significant heat content in the water right below that ice?

This reminds me. I am unable to get real-time ICESat-2 data (don't confuse with CryoSat-2 please!) myself. Do we have anybody able to give us the simple average snow thickness for Arctic sea ice for as close to "now" as possible? It'd be great to know what ICESat-2 instruments tell at this time.

We know that average maximum (= April) snow thickness on 1st-year ice is 16.8 cm, and average snow thickness on multi-year ice is 26.6 cm. Those are of course estimated and wildly vary in practice from season to season, but seeing what we have left now directly form instruments - can possibly be quite telling.

The ice is very blue in the Hudson bay despite the land snow refuses to melt in that region during the entire spring.

Hudson Bay dissipates heat much more effectively than the Arctic, it is much shallower and also much fresher, so I do not think it denotes heat under the ice, rather, significant melt ponding / snow cover atop ice which is THICK, hence its ability to support that hue of blue.

There is a lot of COLD water in the NW NATL, and a lot of SWE remaining in North America (about 600KM^3 or 2X normal). Hudson Bay is going to melt but I would hedge that overall thickness / impressive surrounding +SWE aerial and volume anomalies will prolong the season into August.

Of note, Baffin Island is particularly white this year (snows have evidently been DEEP here).



We should have the 5/25 update soon, but keep in mind all the dark green in ^ image is ice thicker than 1.2 meters, i.e., almost 4 feet.

One other thing to note is that while sites like Rutgers accurately compute snow-covered vs. non-snow-covered, they do a poor job of computing the differential between snow on the ground vs. 90% albedo (which is a huge difference). This year has featured such an albedo differential over Nunavut in particular, which has been thoroughly bright white through spring to date, whereas in previous years, the snowcover was already much reduced either in depth and/or scope.

Finally, the lack of melt in Nunavut this year has coincided with a lack of downsloping winds into the CAA and ice remaining relatively firm in said region. Flipping through EOSDIS reveals an anecdotal correlation between early melt-out of snowcover in this region and an early break-up of the ice north of Alaska and the Yukon. I wonder how much the shifting dynamics of regional snowmelt in springtime affect the seasonal evolution of the ice pack as a whole? (I.E., much more mobile ice / earlier melt on Eurasian side, more immobile / later melt for pack on NAmerican side = what result + impact on CAB and other regions?)

Finally, I will update the other thread, but it should be noted that Lake Winnipeg has retained substantive ice cover into today's EOSDIS snapshot (5/24), which means melt-out will occur 5/25 or later. This puts it definitively into the "latest" melt years of recent record, which includes 2018, 2014, 2013, 2009, 2008, 2004, and 2002, since the year 2000.

If Lake Winnipeg manages to hold out til 6/1, it will beat every year but 2014, however, I do not see that happening. Nevertheless, the evolution of spring over the North American sector in each of the aforementioned years from this point through solstice featured residual cold anomalies over much of the eastern part of the continent, with substantive warmth in the far NW / Rockies / Alaska. This group ALSO featured severe warmth in June across Siberia.

I think this serves to bolster the notion that June of 2020 could truly be SCORCHING over parts of Eurasia, especially those which were warmest in the composite grab featured above. Simultaneously, the cooling this year has been worse in amplitude / scope (IMO) in NA vs. any year in the subset. I would think this portends a very MIXED and odd next thirty days in the Arctic, with accelerated melt in regions that do not normally melt fully until July (Kara, Barents, Laptev), and "protective" conditions in Hudson and the CAA. While Hudson will melt fully regardless, the conditions this spring could result in a very late or overall minimal melt-out in the CAA, and ensure it is relatively protected compared to the CAB this season.

oren

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Re: The 2020 melting season
« Reply #1099 on: May 24, 2020, 11:18:47 PM »

Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.

It predicts 7.34 m km² for July 13th, currently nosediving ...

LOL. The ice apocalypse is a cottage industry. I'll take the over.  8)

PS - There's a dedicated thread for Slater and another dedicated 2020 prediction thread.
Phoenix, I will not tolerate more such posts with no content and inflaming language that stirs up this thread for no good reason..