The 2020 melting season

[Aluminium]

July 14-18.

2019.

[Frivolousz21]

In fact, the 00z EC run is even WORSE after D7 as it targets the area where the thickest ice is. As always, it is far out but if that forecast comes true we should virtually for sure see a new record low volume this year.

On 7/15/2020 at 11:14 PM, donsutherland1 said:
Arctic sea ice extent fell to 6.996 million square kilometers (JAXA) today. The previous earliest figure below 7 million square kilometers was July 19, 2011 when extent was 6.995 million square kilometers.











From the Arctic sea ice forum.   

[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 18^th, 2020:
     6,551,222 km², a century drop of -124,140 km².
     2020 is the lowest on record.
     Highlighted 2020 & the 4 years with a daily lowest min in Sept. (2012, 2019, 2016 & 2007).
     In the graph are today's 10 lowest years.
     Source: https://ads.nipr.ac.jp/vishop/#/extent

[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 18^th, 2020:
     6,551,222 km², a century drop of -124,140 km².
     2020 is the lowest on record.
     Highlighted 2020 & the 4 years with a daily lowest min in Sept. (2012, 2019, 2016 & 2007).
     In the graph are today's 10 lowest years.
     Source: https://ads.nipr.ac.jp/vishop/#/extent

Just amazing. The RIDGING since mid May has been unbelievable even though if the long range forecast show it slowing down.  The extensive preconditioning had already set the table for what will happen the rest of the season.

I am giving 2020 a 51% chance to drop below 2012. 

I believe volume this year will be the lowest min on record by alot

I expect open water at the pole by late August.

If we actually get a 2 week dipole.  Game over!!!

2020 might be TRULY UNPRECEDENTED THIS SUMMER. 



how close can we get to Blue Ocean event??


THE 00Z EURO WOULD SET UP A DEMOLISHING OF THE PREVIOUS RECORDS.

A DOWNSLOPING FLOW COMING OFF OF CANADIAN ARCTIC ARCHIPELAGO AND GREENLAND UNBELIEVABLE JUST DEMOLISHING

[jens]

I expect open water at the pole by late August.

This is one of the things I'm looking forward to whether that could happen. It's not a BOE, but an ice-less pole is sort of a milestone in its own way. I think this would reach international news too.

[peterlvmeng]

The negative AO seems will last at least until end of July. I think that is enough to weaken the ice. I have to say this summer is bad for the ice. The ice seems to be not disturbed by the storm. No storm, heat is still stored in the ocean. No storm, the ekman pumping does not begin. But the storm will be gradually strong in August. Stronger storm with thin ice, horrible!

[JayW]

Close up of roughly 135°-150°E, . 74 hour loop, edit: oops, 59 hour loop. Contrast boosted.
Click to run.

[Artful Dodger]

Once we reach a 0.8 - 1M km2 headstart into August 2012 won't make this up most probably because the big fall of extent in 2012 was a round 1M in about 7-10 days and after that resumed to more moderate levels.

Indeed, the GAC of 2012 removed 1.0M km^2 of sea ice extent in 7 days. Here in 2020, if such an Arctic cyclone were to follow this extended period of high pressure and clear skies in the Central Arctic Basin, the carnage on the main pack will be unprecedented, perhaps approaching the mythical sub-1 million sq km level that has traditionally been held up as the threshold for an "Ice-Free" Arctic ocean.

IMO the main scenario for 2020 falling behind later in August would be an early slowdown which, due to the vast areas of warm open waters near the pole, is either less and less likely to happen or if it happens will happen on an already extremely low level of extent, area thickness and volume all together.

IMHO, if a hypothetical GAC-2020 were to occur, and causes a significant breakdown of the  halocline in the CAB, that 50m deep cap of relatively fresh seawater (< 30psu salinity), then the meltout will be total, and enduring.

We just don't know how much heat could be released which in now stored in the underlying Atlantic water layer, but physics tells us that the vertical overturning in a saline layer is continuous until the entire layer freezes. This layer could be a 500-1,000m thick reservoir of AW, which also remains connected to further warm, salty inflows from the Atlantic inflow.

This is a real risk this year, if such a late season cyclone were to spawn, say off the Siberian coast like in Aug 2012. I will be watching developments closely.

Regards,
Lodger

[F.Tnioli]

This is one of the things I'm looking forward to whether that could happen. It's not a BOE, but an ice-less pole is sort of a milestone in its own way. I think this would reach international news too.

This melt season has already reached international news, actually. This one recent CBS piece starts with siberian heat story, but follows it up with sea ice, Laptev situation (graph) and such.

This season is and will remain one for the history books and plenty breakthrough research for the years to come - no matter if it's BOE, open pole, both or neither.

[oren]

Lodger, welcome back. It's been a while.

[jens]

What strikes me is that the latest difference between this year and 2010's average is 902K km². A huge difference and I think that it will be closer to a million in a couple of days.

Usually the differences between decadal averages have been roughly 1M km2. So now - if already the very first year of the decade can get a whole 1M km2 on the 2010's average, then you can only imagine what the average of the 2020's is going to be. It looks like exponential curve is about to kick in.

[RikW]

Don’t forget that 2020 is maybe exceptional because of COVID-effects

[Tony Mcleod]

For a record low remaining melt needs to be 5.5% or more above average, as happened with remaining melt in 2012, 2015, 2016, and 2018.
From gerontocrat in the data thread.

[Artful Dodger]

So I speculate that the ice thickness may be being maintained due to ice floes stacking on top of each other as they are compacted, and you demand some that I prove it with evidence, even though it was only speculation.

The primary means that sea ice thickness grows beyond the 2-3 m limit imposed by its thermal insulating characteristics (depends on air temp) is through Wintertime leads and ridges:

Hopkins, Mark A., Jukka Tuhkuri, and Mikko Lensu. "Rafting and ridging of thin ice sheets." Journal of Geophysical Research: Oceans 104.C6 (1999): 13605-13613.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/1999JC900031

That is how the oldest ice in the Central Arctic Basin was able to grow to 10 or even 20 m in thickness. However, this effect due to leads + ridging does not occur during the Summer melt season, so is not a factor at this time.

Summer rotten sea ice is too weak to survive mechanical compression due to winds which, during the Winter, would lead to slabs overiding each other to form ridges, and eventually thickening of the entire ice floe via bottom melt/refreeze (which flattens the ridge and spreads out the ice, and thus even out the thickness of the entire floe).

Cheers!

[Jim Hunt]

Melt ponds or not, clouds or not, here's overall and CAB regional high res AMSR2 compaction:

[Jim Hunt]

Hopkins, Mark A., Jukka Tuhkuri, and Mikko Lensu. "Rafting and ridging of thin ice sheets." Journal of Geophysical Research: Oceans 104.C6 (1999): 13605-13613.

Long time no see Lodger!

Welcome back.

[Pagophilus]

Close up of roughly 135°-150°E, . 74 hour loop, edit: oops, 59 hour loop. Contrast boosted.
Click to run.

Great loop, thanks.  I am seeing net motion of ice towards the pole and a lot of meltout inside this section of the pack...   Here the rate of interior meltout is apparently outstripping the rate compaction.  The Beaufort, Chukchi, ESS also come to mind...

[Ice Shieldz]

The forecast trend for moisture and heat advection from Siberia has worsened. It's not like the laptev & ess ice stands much of a chance anyways, but this would certainly hasten the demise.

Surface winds and precipitable water next 5 days - click to play

[wallen]

At this rate, there will be next to no sea ice left south of 80N and the arc between 90E and 150E, by the end of July. Wonder when this last happened ?

After proof reading and correcting my previous post, a further look would suggest that arc will almost extend from 0 degrees to 150E by the end of July.

[Artful Dodger]

My concern is that if such a slight differentiation in salinity is the only thing protecting the CAB from warmer waters below, encroachment into the deep basins on the Atlantic side of the Arctic this year continues, and then we get a GAC near the minimum when the ice is not there over parts of the CAB to prevent mixing, will the halocline break down and then not quickly reform in winter due to the near equivalence in salinity in the ASW and AW, limiting ice formation in winter and triggering some sort of CAB accelerated death spiral of ever increasing ASW / Atlantic Water mixing year on year.  Perhaps I am reading too much into this?

No, you're not reading too much into this existential threat to the CAB main pack ice.

That is why I'm back.

[Jim Hunt]

Hi Jim, how are you?

At the risk of drifting off topic, I reckon I had a dose of Covid-19 (or something a lot like it!) over Xmas following an evidently rash trip across the River Tamar into Devon.

Suitably brassed off with BoJo's response to both "climate change" and Covid, perhaps great minds think alike?



Except that Elon et al. are allegedly not into AC V2G!

Meanwhile back in the high res Arctic:

[Jim Hunt]

I hang out these days on the TMC Investor's Forum. Read my posts there:

https://teslamotorsclub.com/tmc/members/artful-dodger.82946/#postings

P.S.

[igs]

The most recent day where extent did not have a century drop was July 2nd. If these century drops continue for the rest of July, sea ice extent will drop to 5,551,222 square kilometres or lower. The record low for July 31st is currently taken by 2019 at 5,955,851, which is over 400k higher than this extrapolation.

True that "IF" but they won't 

[uniquorn]

update on buoy drift, april-jul19
left a long name mosaic buoy in by mistake
Mosaic travelled a fair way west before heading south again recently

[oren]

Jim and Art, please continue this in the freeform chatter thread.

[BornFromTheVoid]

Latest projection has 7 of the last 20 years beating 2012, and the 10 year average melt reaching a low of 3.56 million km²

[Glen Koehler]

   Climate Reanalyzer got stuck by a power blip yesterday.  Some of the Arctic forecast animations are already updated to July 19, the rest will be back online in few hours by 1800 UTC July 19.  The updated pressure forecast no longer shows a sub-990 low pressure system.

[Killian]

Latest projection has 7 of the last 20 years beating 2012, and the 10 year average melt reaching a low of 3.56 million km²

But that's only if you attach the curves as they occurred in those years. If you first match those curves to the slope of 2020, because all but three years maintained their slopes from early July through mid-August, and those three didn't vary greatly, you get far worse numbers.

[Lord M Vader]

What numbers do we get if we use the most konservative numbers from now and onward?

[Killian]

The negative AO seems will last at least until end of July. I think that is enough to weaken the ice. I have to say this summer is bad for the ice. The ice seems to be not disturbed by the storm. No storm, heat is still stored in the ocean. No storm, the ekman pumping does not begin. But the storm will be gradually strong in August. Stronger storm with thin ice, horrible!

When did the negative AO affecting ASI become a thing? I remember being roundly criticized for saying this in past years - though I've been saying so since at least 2011 or 12.

[Pagophilus]

ESS and adjacent ice Worldview, today.  I pushed the contrast in photoshop to bring out the differences in grayness of the ice.

[gandul]

Close up of roughly 135°-150°E, . 74 hour loop, edit: oops, 59 hour loop. Contrast boosted.
Click to run.

That was quite a piece. Look at those holes of,total ice meltout opening up in the compacting ice.

[blumenkraft]

Sea ice & bathymetry.

[Killian]

What numbers do we get if we use the most konservative numbers from now and onward?

[blumenkraft]

Last week in data.

Fram export via SAR still not working. EZgif is trolling me. I'll figure it out... i hope.

7-day hindsight mean temperature anomalies and ice drift map. Click to play.

[pearscot]

I had to switch computers just to post this (not sure why my pinebook was doing the big struggle today), but anyways, the melting is just continuing at a prolific rate. It's amazing that the high remains in place and really is the hallmark of 2020.

Moreover, I never really thought I would see a reappearance of the 2019 mega crack, yet it continues to be impressive. It's certainly going to to have a profound impact on the mobility of the ice within the greater gyre. Plus heat absorption...I mean some areas are upon up to 25 MILES!

The ocean temps are equally insane. Atlantification Part II: The Whole Arctic Ocean!!

[jdallen]

Juan C, what outcome do we get if we use the most conservative historical numbers from now and onward? Where would that minimum end up in terms of SIE?

You need look no further than Gerontocrat's numbers.  2013 & 2014 both came in with ~2.67 million km2 loss between now and minimum.

That would give us an end of season total of approximately 4.2 million km2

Considering how different our weather has been, that's highly improbable.

Among other things, that low melt in 2013/14 was predicated on the fact that earlier weather in particular in July reduced the energy captured such that we didn't see as much bottom melt as typically takes place in August.  For 2020, that energy is *already* in the system.  We could return to 2013/14 conditions and still pass 3.0 million km2 melt between now and minimum, which would put 2020 solidly into the number 2 slot for melt seasons.

[Pagophilus]

How is area staying so calmly at #3 while extent is at #1 and plummeting? 

I realize draining meltponds may slow area numbers' decreases, but that applies to other years' melt too.  The peripheral seas are mostly melted out.  The margins of the icepack are visibly shrinking inwards.  The ESS is thinning radically.  I am puzzled...

[UCMiami]

update on buoy drift, april-jul19
left a long name mosaic buoy in by mistake
Mosaic travelled a fair way west before heading south again recently

I know 'compaction' of the CAB is supposed to be the result of the GAAC, but when I look at this and other indicators of ice movement (eg blumenkraft), I see very little motion that is north/right of prevailing wind indications.

I know the rightward motion from wind direction has been documented in open water - but how strong is that pressure? In a generally full ocean it doesn't seem to be that great a force. Direction of least resistance (eg open water) or currents (?) would seem to be a stronger indicator of ice movement as observed.

Large leads/open water in the CAB in July don't seems to be the norm in any year - and sparse areas like those currently observed in the Beaufort, Chukchi, and ESS form rather randomly every year due to localized melt out and ice movement.

The GIF posted by JayW above shows ice movement that expands and compresses frame to frame as that arm of ice moves northward and melts - there are some other forces that are moving those individual blocks of ice in multiple different directions.

I am not trying to deny the science - just wondering if people are not over-emphasizing a rather weak force and reading too much into 'compaction', and not enough into continuous melting in the CAB.

Just another question - the reason ice skates work so well, in that ice under the pressure of the blade melts reducing friction. in a generally warm arctic environment with long term compaction pressure, is the ice on the edges of individual flows being pushed together actually melting under that pressure? Is the force applied strong enough to actually provide another source of melt?

[Stephan]

Update of Jim Pettits "step by step" milestone graph.
The second "7 day step" in a row. And the third single digit number in a row. Unprecendented.
The only comparison is June/July of 2013 (!) where a 8 day interval was followed by a 6 day interval and a 10 day interval.
For those who don't have the link: http://iwantsomeproof.com/extimg/sie_nsidc_max_min_plus_step_days.png
See attached graph.

[BornFromTheVoid]

What numbers do we get if we use the most konservative numbers from now and onward?

Based on the last 20 years, the slowest melt was, by far, 2001. That would produce a minimum of 4.41 million km2, 7th lowest on record.
Next slowest is 2006, which would give a minimum of 4.16 million km2, 5th lowest.

[Stephan]

So, in fact, a position higher than #7 in the list is impossible for 2020, and a position higher than # 5 is very unlikely.

[Rod]

This map posted by Zack Labe today (on Twitter @ZLabe) showing the January to June 2020 temperature ranks is pretty incredible!

Notice there are no blue colors anywhere on the map. And, Siberia 🔥🔥🔥!

 

[bbr2315]

This map posted by Zack Labe today showing the January to June 2020 temperature ranks is pretty incredible!

Notice there are no blue colors anywhere on the map. And, Siberia 🔥🔥🔥!

There is a blip of blue in India adjacent to the Himalayas and I would imagine there would be quite a few blue areas if this was Jan-Mar and Apr-Jun instead of a six month block. With blues appearing in Apr-June across parts of North America and the Himalayas.

[Rod]

Such an event would be ideal for resolving +OHC / accumulated insolation however it will come at the expense of a huge chunk of the CAB, and if this occurs it could also be severely disruptive to the halocline.

In my humble opinion, this is a huge point. Others up thread (down thread from bbr’s post) have expressed similar concern.

I have always worried most that the death to the ice will come from below, not above. The summer insulation period is very short.

However, if the anomalously large areas of open water suddenly get hit with strong winds and storms, it can cause the warm salty water from below to get mixed into the cold fresh water above and cause a lot of damage to the ice even when solar insulation is decreasing.

This is something to keep an eye on heading into late summer and fall.

[oren]

So, in fact, a position higher than #7 in the list is impossible for 2020, and a position higher than # 5 is very unlikely.

Anything is possible, though highly unlikely. A year with low extent may find it more difficult to lose extent than the average year, simply because some regions of relatively easy ice are already empty. And a more compacted year may find it more difficult to lose extent because the "cheap trick" of compaction is no longer available. Thus, past performance is no guarantee of future results.
Still, this year is not just compacted and very low, it's also a year where the ice has soaked a huge amount of energy via insolation, and has probably lost quite a lot to bottom melt due to the increased transport of the ice. Thus, I do not truly expect it to go higher than #7 or #5.

[Rod]

This map posted by Zack Labe today showing the January to June 2020 temperature ranks is pretty incredible!

Notice there are no blue colors anywhere on the map. And, Siberia 🔥🔥🔥!

There is a blip of blue in India adjacent to the Himalayas and I would imagine there would be quite a few blue areas if this was Jan-Mar and Apr-Jun instead of a six month block. With blues appearing in Apr-June across parts of North America and the Himalayas.

Your eyes must be better than mine because I don’t see the blue. I will take your word for it that the map would be different if we broke it into smaller monthly time frames.

That does not change the fact that looking at the first six months of this year in total, we have seen extraordinary temperatures across the globe.   

[uniquorn]

peary channel, https://go.nasa.gov/2CvbeK5

[Pagophilus]

I had to switch computers just to post this (not sure why my pinebook was doing the big struggle today), but anyways, the melting is just continuing at a prolific rate. It's amazing that the high remains in place and really is the hallmark of 2020.

Moreover, I never really thought I would see a reappearance of the 2019 mega crack, yet it continues to be impressive. It's certainly going to to have a profound impact on the mobility of the ice within the greater gyre. Plus heat absorption...I mean some areas are upon up to 25 MILES!

The ocean temps are equally insane. Atlantification Part II: The Whole Arctic Ocean!!

Also of note is how the ice pack is just falling apart as large floes, which are spilling into these cracks. 

[Pagophilus]

Why are extent numbers dropping like a stone, and extent is #1, while area numbers are just bumbling along in #3 position?  I would have thought the two would start behaving similarly at some point, especially since the peripheral seas are virtually melted out, and the icepack is pretty much a clean-edged compact mass (with the exception of the ESS).  Is it meltpond draining?

[Rod]

Area numbers are very difficult to interpret in the summer.  That is why the official numbers are always reported as extent. Extent is certainly not perfect, but at least it is consistent.

People on this forum are very good at interpreting area numbers in the summer. Probably as good as the sea ice scientists. But, it is still impossible to rely on them. Wet clouds, dense fog, wet ice, melt ponds, rain, fresh snow, overnight freeze,  etc ... all cause bumps in area data.

Area is helpful in the summer, but the numbers need to be taken with a grain of salt.

[Pagophilus]

Area numbers are very difficult to interpret in the summer.  That is why the official numbers are always reported as extent. Extent is certainly not perfect, but at least it is consistent.

People on this forum are very good at interpreting area numbers in the summer. Probably as good as the sea ice scientists. But, it is still impossible to rely on them. Wet clouds, dense fog, wet ice, melt ponds, rain, fresh snow, overnight freeze,  etc ... all cause bumps in area data.

Area is helpful in the summer, but the numbers need to be taken with a grain of salt.

Thank you, Rod.  I guess all those bumps in data must cancel each other out pretty well, as area seems to decline evenly for the Arctic as a whole... understandable since it is such a large area with different things happening in different areas..