The 2019 melting season

[petm]

I like to use that mode this way.
https://go.nasa.gov/2GIEqMM

Cool. I hadn't realized you could set different layers for A and B. I guess that explains why the feature is located under Layers lol. Very nice.

[Shared Humanity]

NW Passage has been clearing out quickly in the last few days. Only remaining obstacle is the ice south of Prince of Wales Island (Larsen Sound), correct? That ice is clearing out fast. Maybe it will open in about a week.

Anything other than the Parry Channel is cheating.

[petm]

Anything other than the Parry Channel is cheating.

I see... 
Yeah, I mean the southern route (bottom line on the map).
Parry Channel will be more than a week...

[grixm]

Anything other than the Parry Channel is cheating.

I see... 
Yeah, I mean the southern route (bottom line on the map).
Parry Channel will be more than a week...

Is it not also possible to go through here?

[petm]

Is it not also possible to go through here?

Yes I think so. Still need Larsen Sound to clear though. Also Bellot Strait sounds potentially dangerous: https://en.wikipedia.org/wiki/Bellot_Strait .

[NotaDenier]

This insolation graph gets posted from time to time, but I think it is missing a cruicial component for best understanding. So I added it. At approx 350, the insolation/radiation balance seems to be achieved.

As we enter the final month of melt, we can see that pretty much all the sun energy excess is in the past, and now a good stirring is what the melt doctor should write a prescription for.

(Once the ESS finishes melting out in a week or two, conditions for cyclone creation will be as ideal as possible in the Arctic.)

Do you have a paper that you can quote to back this figure up?

[philopek]

The low over Bering is fortunately in favour of the arctic proper and it's to hope that it stays that way.

Considering the critical areas that need to melt but not always do, that is CAA and upper beaufort all forecasts, far out and not so far out suggest heavy melt in those regions while some CAB ice is constantly driven south to melt in the warm waters of the Chucki.

TYPO: Needed f. NW-Passage (to open)

[Rich]

 while some CAB ice is constantly driven south to melt in the warm waters of the Chucki.

With the exception of a narrow band of water extending over the shallow Chuchki Plateau, the warm water in the Chuchki hasn't reached the 75N line.

CAB ice N of 80N will need to make a journey of at least 300km and perhaps over 600 km to reach warm water in the Chuchki.

It takes a lot of wind for a lot of days to push ice that far.

[Sterks]

An atomic ridge dominating the Pacific side from day 5 to end of forecast, potentially will crush the pack against America and pull quite some warmth. Day 1 to 5 won't be good either, but weaker. (EC 12z)

[philopek]

An atomic ridge dominating the Pacific side from day 5 to end of forecast, potentially will crush the pack against America and pull quite some warmth. Day 1 to 5 won't be good either, but weaker. (EC 12z)

Google didn't show me much (anything) for "Atomic Ridge" in relation to weather or sea-ice, can you enlighten me what that is exactly. Sorry my ignorance if it's obvious but since search engines as well did not provide any insight i thought it's legit to ask.

[DrTskoul]

YouTube

[grixm]

Both GFS and Euro predicts a huge intrusion of heat from the russian side starting at T+5 days.

[jdallen]

The low over Bering is fortunately in favour of the arctic proper and it's to hope that it stays that way.

Unfortunately, both GFS and ECMWF show pretty strong ridging showing up over most of the pacific side about 120 hours out - which is within our "reliability" envelope.  As noted above, there's also potential for a  low to form over the CAB smack on top of the pole.  It will be concerning if that strengthens and we get *both* a dipole *and* a major storm.

[Sterks]

An atomic ridge dominating the Pacific side from day 5 to end of forecast, potentially will crush the pack against America and pull quite some warmth. Day 1 to 5 won't be good either, but weaker. (EC 12z)

Google didn't show me much (anything) for "Atomic Ridge" in relation to weather or sea-ice, can you enlighten me what that is exactly. Sorry my ignorance if it's obvious but since search engines as well did not provide any insight i thought it's legit to ask.

Yes anomalous warming of the entire pacific side from surface to high levels of atmosphere. Causes high SLP, which by the way will pull warm winds from the Asian side into the basin and will push the ice toward America.

By atomic I meant it gets really strong by day 7 or so and gargantuan by day 10, but that may be too far into the future.

[philopek]

Nice to compare yesterday, especially "Beaufort Sea" and the "East Siberian Sea"

EDIT: THX for elaboration @Sterks

[petm]

Indeed. A lot of ice is in the process of going "poof" in the Beaufort, including the largest floes. Expect large drops there in area and extent over a few days. I posted some graphics of it over in the RAMMB thread, if you're interested:

https://forum.arctic-sea-ice.net/index.php/topic,2649.msg218925.html#msg218925

Edit: And before-after as seen using WV spy mode: https://go.nasa.gov/2GKSOUB

[FishOutofWater]

I was expecting to see heat flowing into the Arctic after the deep Urals trough formed. I was surprised when model runs a few days ago didn't predict it. Today's model runs make sense and are consistent with weather patterns we have seen all summer. There is still very hot weather in south central Asia and that heat is being blown towards the Laptev sea.

Expect the Laptev bite to expand in a big way over the next ten days.

[petm]

Expect the Laptev bite to expand in a big way over the next ten days.

Seems like the assault from multiple sides may now resume after having had a brief pause...

[Sterks]

Indeed. A lot of ice is in the process of going "poof" in the Beaufort, including the largest floes. Expect large drops there in area and extent over a few days. I posted some graphics of it over in the RAMMB thread, if you're interested:

https://forum.arctic-sea-ice.net/index.php/topic,2649.msg218925.html#msg218925

Nice.
Area is again falling, a sign of the effect of unsettled weather on the edge along the pacific, the ESS ghostly ice and the heat over CAA. Another storm coming over Beaufort. Then we have a very interesting weather ahead.
Let’s agree 2019 is somehow close to 2012. Now what happens to a “2012” without a GAC, but with pretty unsettled weather and perhaps a compaction event? we’ll see

[Sublime_Rime]

Whoa! Indeed, the EC 12Z looks especially nasty to me. With ridge gearing up straight through d5-10+ with a strong dipole from d7-9.

As a newb I may be oblivious, but truly am curious, and intention not dubious. My lack of experience makes speculation on the significance of this forecast somewhat...

Frivolous...

[Sterks]

Indeed. A lot of ice is in the process of going "poof" in the Beaufort, including the largest floes. Expect large drops there in area and extent over a few days. I posted some graphics of it over in the RAMMB thread, if you're interested:

https://forum.arctic-sea-ice.net/index.php/topic,2649.msg218925.html#msg218925

Edit: And before-after as seen using WV spy mode: https://go.nasa.gov/2GKSOUB

This is the Worldview version. Only one day! Look at those big floes. Wave action?
https://go.nasa.gov/2GFDWqH

[petm]

Yeah there were wind waves up to 5 4 m and high SSTs. Fun watching that big double-floe dissolve. It was ~10 km in radius...

[be cause]

  rare to see such agreement between gfs and ecm forecasts .. 7 days out they are near identical . Certainly the weather to put any ice left in the ESS to the test .
  The forecast event is no less extreme than the ongoing Greenland megamelt . It might even wake Friv again .. it will certainly be helping delay the refreeze .
  Just the sort of temps to start pushing August up the heat tables . b.c.

 ps .. and wow ^^ wave action after a lot of bottom melt ? .
 
1st place is looking increasingly back on the cards .. what ever the weather !
 

[DavidR]

Something of a milestone in the high Arctic last month according to ESRL-NOAA.
https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries.pl?ntype=1&var=SST&level=2000&lat1=90&lat2=80&lon1=0&lon2=360&iseas=0&mon1=0&mon2=0&iarea=1&typeout=1&Submit=Create+Timeseries

For only the fourth time ever the average SST in the area 80N+ was above 0degC.

Air temperatures in the same area were a record high nearly 0.5 degrees above the previous record.

https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl

[vox_mundi]

The cyclone spinning in the Beaufort over the last few days appeared to sit over a lens of warm water at depth. Wonder if Ekman pumping could have brought any of that heat to the surface?

Warming of the interior Arctic Ocean linked to sea ice losses at the basin margins, Aug, 2018
https://advances.sciencemag.org/content/4/8/eaat6773


Maps of heat content in the BG warm halocline. Beaufort Lens

[petm]

a lens of warm water at depth

That... is frightening. If it continues to build and gets a big stir one of these years...

[vox_mundi]

Some further info ...

https://forum.arctic-sea-ice.net/index.php/topic,2278.msg170187.html#msg170187
https://forum.arctic-sea-ice.net/index.php/topic,2278.msg170206.html#msg170206
https://forum.arctic-sea-ice.net/index.php/topic,2417.msg215667.html#msg215667

Yale Researchers Find Heat Held in Arctic Ocean Doubles in 30 Years
https://nationalpost.com/pmn/news-pmn/canada-news-pmn/yale-researchers-find-heat-held-in-arctic-ocean-doubles-in-30-years/amp
https://amp.livescience.com/63462-arctic-hidden-heat.html

Newly published research suggests the amount of heat stored in a vast section of the Arctic Ocean has doubled over the last 30 years, adding another blow to sea ice that helps regulate the planet’s climate.

“The most likely outcome for this heat is that it will slow the growth of winter sea ice, which further compromises the Arctic sea ice pack,” said Mary-Louise Timmermans of Yale University.

That ocean is composed of layers divided by both salinity and temperature. One of those layers, beginning at about 50 metres of depth, is both more saline and warmer than the surface waters.

The paper calculates that sea is now absorbing five times more solar energy than it did before.

That sun-warmed water has created what Timmermans calls “archived” heat in the Canada Basin.

“That layer of water is both increasing in temperature and also increasing in thickness. Overall, it’s increasing heat content.”

The warmth under the ice hasn't dipped or varied significantly since the 1980s, she added. It's just kept marching upward "like a staircase."

Although that water has only been warmed to a maximum temperature of about 0 C, the paper calculates there is currently enough new heat stored beneath the ocean surface to thin the ice cover of the entire basin by nearly a metre. It notes the amount of such “archived” heat will continue grow as the Chukchi loses more ice.

... The study shows that climate change doesn't only threaten the Arctic through the direct melting of ice along the northern ice cap's edges, Timmermans said. Instead, all the extra heat now present in our planet presents a long-term threat to the northern ice, independent of year-to-year shifts in weather patterns. Over time, she said, that heat will break through the insulating fresh water above it and eat away at the planet's remaining northern sea ice from within.

What’s happening in the Canada Basin is an example of how losing sea ice in one area can contribute to further sea ice losses in areas hundreds of kilometres away, the paper says.

[petm]

So that's a lasting, cumulative effect of reduced ice cover that is almost completely sequestered from our typical observations (extent, etc), except when it's stirred up by storms, such as maybe the little recent cyclone in the Beaufort (although was that big enough to stir up 50 m depth?) or the 2012 GAC (according to some).

It's not hard to imagine a tipping point going something like (on the Pacific side):

1. early melt (leads to...)
2. SST increase (leads to...)
3. strengthened storms (leads to...)
4. a storm strong enough that it mixes enough stored heat to melt out a huge area (leads to...)
5. reduced albedo -> further heating -> further storms
6. reduced freezing -> early melt -> goto #1.

Noteworthy that 2019 has so far had 1 & 2, and maybe 3 (? not sure). But even if we had 4 it's probably already too late for 5 to have a large impact. I guess...

[vox_mundi]

Based on the discussion last fall (2018 melting season) there may be enough heat accumulation for a breakthrough in the next few years.

[Rod]

There is more than enough heat in the deep water to melt the ice and keep the arctic ice free year round. 

However, the heat can not move upwards through the halocline. 

The halocline is 50 meters thick (at least) and is very difficult to breach.  If it ever happens, look out!   The arctic will be a completely different place. 

[be cause]

Hi petm .. I would place reduced albedo at no.2 . It has been significant this past 2 months ..

  This year has been sunny and warm . If there is another fortnight of agressive melt under predominantly sunny skies then a late storm could be devastating , especially if as I fear the remaining ice is thinning rapidly .
 
  Piomas ? b.c.

[petm]

Hi petm .. I would place reduced albedo at no.2 . It has been significant this past 2 months ..

No argument. Both 2 and 5 was my thought, a kind of bootstrapping...

[Coffee Drinker]

There is more than enough heat in the deep water to melt the ice and keep the arctic ice free year round. 

However, the heat can not move upwards through the halocline. 

The halocline is 50 meters thick (at least) and is very difficult to breach.  If it ever happens, look out!   The arctic will be a completely different place.

Maybe more open water and wind will create warm upwellings along the continental margins?

[DrTskoul]

The heat can mostly move through conduction. In the arctic the halocline is stabilizing and leads to stratification. Upwelling of atlantic water can lead to mixing. Some interesting info :

Pacific ventilation of the Arctic Ocean's lower halocline by upwelling and diapycnal mixing over the continental margin

[21] Data from the head of Barrow Canyon, 71°N [Woodgate et al., 2005b] show that a single up‐canyon flow event bringing ∼34 psu, −1°C water may last for ∼5 days at ∼50 cm/s, yielding a volume of ∼2–3 × 1011 m3. Thus of order 10 events per year would suffice for our mechanism. Whilst only 2 major events occurred in the 1 year of observations at this site, Mountain et al. [1976] recorded 6 events over 1 year just down the Barrow Canyon axis from this site. Aagaard and Roach [1990] report several events of similar magnitude in 1986–1987 data. The CTD and mooring data from 200–300 km west discussed above (see Figure 1) show the process also to occur elsewhere along the Chukchi slope. It is, thus, plausible that a sufficient quantity of Atlantic water could be elevated throughout the northern Chukchi slope region.

I guess velocities of 0.5 m/s or greater are needed to mix deep warm waters.

[Rod]

These types of studies cause me concern.  I have long thought the arctic ice will die from below, rather than from the weather above. 

So far, only the Barents and Laptev have shown a documented breakdown of the halocline.  But, common sense would say it is likely happening elsewhere. 

EDIT: before someone jumps on me, these are the only two places I have seen documented evidence of a breakdown of the halocline.  It might have happened elsewhere and I missed it.

[petm]

As expected, greatly accelerated drop in Beaufort on today's Bremen.

July 31 - Aug 3 (before - after cyclone).

3-day lagging median (left) vs. original (right).

Click.

[Wildcatter]

Looks like modeling north of CAA probable artefact given low pressure system and AMSR2 tendencies (on today's model). Possibly off NW Greenland as well, but not so sure about that one. NE Greenland and Ellesmere continuing to heat up pretty good though.

[nanning]

The heat can mostly move through conduction

You mean convection I assume?

[Aluminium]

July 30 - August 3.

2018.

Almost all ice outside the CAB has gone. The battle for the North Pole?

[jdallen]

The heat can mostly move through conduction

You mean convection I assume?

Nope. Conduction.  No convection through the halocline unless wave action stirs things up.

[blumenkraft]

The battle for the North Pole?

The cyclone is there right now.

M10 & Cloud Layer RGB bands

Greenland & Ellesmere upper right for orientation.

[slow wing]

The heat can mostly move through conduction

You mean convection I assume?

Nope. Conduction.  No convection through the halocline unless wave action stirs things up.

Very little heat moves up through conduction - the thermal conductivity of seawater is just too poor.


I just did a quantitative calculation of that here on the Stupid Questions thread. The amount of heat reaching the ice will seldom be enough to melt more than of order 1 millimeter of ice in a year.

[GoSouthYoungins]

This insolation graph gets posted from time to time, but I think it is missing a cruicial component for best understanding. So I added it. At approx 350, the insolation/radiation balance seems to be achieved.

As we enter the final month of melt, we can see that pretty much all the sun energy excess is in the past, and now a good stirring is what the melt doctor should write a prescription for.

(Once the ESS finishes melting out in a week or two, conditions for cyclone creation will be as ideal as possible in the Arctic.)

Do you have a paper that you can quote to back this figure up?

Nah. It is just common sense. For several reasons. Everywhere in the world that isn't coastal starts to freeze under 350 and starts to melt above 350. Also, earth receives an average of about 350 wm2 overall, so it is basic logic that if earth isn't changing temperature, there is an equilibrium near 350.

If you print this out, it will be paper. Then you can use this to back up the figure. Good luck.

[sja45uk]

The battle for the North Pole?

The cyclone is there right now.

M10 & Cloud Layer RGB bands

Greenland & Ellesmere upper right for orientation.

Will this cyclone push ice towards Nares?

[blumenkraft]

Will this cyclone push ice towards Nares?

Very good question. Could be IMHO.

Something to watch out for.

[binntho]

Nah. It is just common sense. For several reasons. Everywhere in the world that isn't coastal starts to freeze under 350 and starts to melt above 350. Also, earth receives an average of about 350 wm2 overall, so it is basic logic that if earth isn't changing temperature, there is an equilibrium near 350.

If you print this out, it will be paper. Then you can use this to back up the figure. Good luck.

I've answered this in the meaningless chatter thread.

[uniquorn]

These types of studies cause me concern.  I have long thought the arctic ice will die from below, rather than from the weather above

No real signs of mixing yet from whoi itp110 in open water just south of the beaufort ice front, under cloud today. Unfortunately it didn't send a report today but here is yesterday's microcat temp/sal (mounted at 6m) and recent profiler data from day208 to yesterday (click to run). A steady rise in near surface temperatures as the ice thins out.
https://www.whoi.edu/page.do?pid=163197

[Sterks]

Re: effect on Beaufort, I don’t think it was heat under the ice, looking at the pack the sudden disintegration of floes happens at the periphery where waves can reach the pack.

I posted a forecast of the storm six days before, because the isobars, despite its compact size and because of being surrounded by walls of high SLP, were impressing. And it travelled open ocean hundreds of miles before reaching the Beaufort, to lift those 4 m waves.
Below the forecast I cropped and posted Jul 28 and the analysis on August 3rd, which shows slightly weaker storm in appearance. What feeds a low like this to not dissolve in the middle of this high pressure background?

[Killian]

The cyclone spinning in the Beaufort over the last few days appeared to sit over a lens of warm water at depth. Wonder if Ekman pumping could have brought any of that heat to the surface?

Warming of the interior Arctic Ocean linked to sea ice losses at the basin margins, Aug, 2018
Maps of heat content in the BG warm halocline. Beaufort Lens

OMG. That's a "matter of time" bomb; a guarantee of a future ice-free Arctic. Yes, we know it's coming, but it's another thing entirely to see it's future with your own eyes. It may come of another mechanism/other mechanisms first, but that lens guarantees it.

[oren]

Indeed. A lot of ice is in the process of going "poof" in the Beaufort, including the largest floes. Expect large drops there in area and extent over a few days. I posted some graphics of it over in the RAMMB thread, if you're interested:

https://forum.arctic-sea-ice.net/index.php/topic,2649.msg218925.html#msg218925

Edit: And before-after as seen using WV spy mode: https://go.nasa.gov/2GKSOUB

This is the Worldview version. Only one day! Look at those big floes. Wave action?
https://go.nasa.gov/2GFDWqH

Wow. Those streamers around the ice. This is what happens when the CAB ice is exported south, initially extent seems to be holding up, but insolation, warm water, some stirring of the pot, and the weakness is exposed.
This year has seen crazy export, both towards the Atlantic (this thankfully stopped about a month ago) and towards the Beaufort (this never stopped). This is what gives it a shot at a new record or near-record.