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wayne

We forget Hudson Bay and the average daily annual extent? Especially Hudson Bay, where there was a massive low temperature event during winter past... This ranking , 6th place is meaningless without that caveat:

http://eh2r.blogspot.com/2018/07/sea-ice-extent-analysis-should-be.html

Neven

There's a big caveat at the end of the post, showing volume and extent/area graphs without the periphery like Hudson Bay.

wayne

Hi Neven,

Yes, the only good thing is the Cyclone you cited, is there where it should be, hopefully likewise Lows will stay in the region.

iceman

Nice work, especially highlighting Oren's contribution.
Looks like Greenland Sea has flipped from being a negative to a positive for ice volume later in the season, unless Fram export picks up again.

wayne

At 80 degrees North, the sea ice pictures between 2012 and 18 can not be more different:

http://eh2r.blogspot.com/2018/07/hollowing-from-within-at-80-degrees.html

It is a new ice-scape, unfamiliar territory for all who analyze.

John Christensen

Thank you for another great PIOMAS update Neven - the comparison with prior years clearly shows how much weather slowed melting in June of '16 and '17 - and just how massive the 2012 melting momentum was already by June.

One comment puzzled me though:

"What makes this melting season interesting so far, is that melting has been progressing relatively slowly the past few weeks"

Melting has been progressing relatively slowly ever since the max volume was reached, as you have stated in the April, May, and June PIOMAS updates also, but I guess the understatement was not intended?

Neven

The real slowdown - relatively speaking - started around mid-June, so that's a couple of weeks. The point is 'that 2018 isn't far behind at all in those regions that determine the minimum'.

If it weren't for the current weather forecast, I would say that the melting season may have some tricks up its sleeve. But the clock is ticking.

Michael Hauber

I think the key difference between this event and the 2012 event is the size of the cyclone. Looking back at your blog post for the 2012 event the Canadian analysis chart shows the main circulation of the low covering almost the entire Arctic basin. The chart above shows the circulation mostly in the Canadian quadrant. The squeeze between the high pressure towards Siberia adds a bit of impact though. The ice in that direction had already been showing signs of weakness IMO so the impact could be interesting.

John Christensen

Hi Neven,

I am sorry, but I cannot detect any slowdown in melting in the second half of June. I will make just one more comment on this, as this is your space.

Subsequent to the SSW event late February, we saw a drop in DMI 80N temp and a consolidation of the Arctic circulation causing a reduction in heat influx.

The effect of the SSW event (As also observed in early 2013) was a switch to rapid sea ice gains followed by reduced melting - but with a waning effect, as we got further removed from the event.

Your monthly PIOMAS updates seem to reflect this:

April:

“sea ice volume growth during March was the largest in the 2007-2018 period, well above the average of 1832 km3”
[About 450 km3 above average]

May:

“sea ice volume grew by 373 km3 during April, which is the largest increase in the 2007-2018 period, almost 200 km3 above average.”

“After the maximum was reached, the trend line flattened, with sea ice volume going down by a meagre 91 km3”

June:

“volume decrease for May 2018 has been below average: 2285 vs 2650 km3”

July:

“After a slightly below average June volume decrease (6199 km3 vs 6217 km3 for the 2007-2017 period)”


The relative level of melting therefore has been accelerating from a very slow start in April, and seems forecast to continue with moderate acceleration in July also.

If you do not mind, please share by what metric you observe a relative slowdown in melting by mid-June.


Neven

JAXA SIE. It went from second lowest on June 10th, to 10th or 11th one month later. This doesn't apply as much to PIOMAS, I agree, but there too the gap with other years has been slowly increasing. So, relative to other years, melting has been on the whole below average these past few weeks.

But this seems to be mostly caused on the periphery, because 2018 still is among the lowest in the 'inner core'. This implies, like you say, that melt will accelerate again (relative to other years). That was the whole point.

2018 may be 10th or whatever on some charts, but it isn't telling the whole story. There's a discussion on the ASIF whether weather conditions need to be more conducive to melt for that to happen ostensibly, or whether there will be a cliff, regardless of the weather.

I'm inclined towards the former, but there seems to be a lot of (late) melt ponding and dispersion, so when the weather does switch, this melting season may go a lot lower than the numbers predict right now.

No signs of that in the weather forecast as of yet.

John Christensen

Got it, makes sense considering the change in SIE, thanks Neven.

BTW, following an impressive drop of 751 km3 on June 25-27, PIOMAS registered a massive 464 km3 drop for June 28 - the second largest daily volume drop in the PIOMAS record after June 19th 2007, but ahead of July 21st 2012 in third spot.

Robert S

Looks like the hottest spot in Canada today is northwest of Hudson's Bay, almost on the shores of the Arctic Ocean. That's somewhat anomalous, and if that heat starts getting sucked north it'll certainly accelerate the melting in the CAA, which would likely have knock-on effects.

John Christensen

For the 'inner core' sea ice:

I agree with you Neven that weather needs to be more conducive to melting for further significant volume drops in the most northern region.

As it is the weakened low, which seems to continue hovering over the CAB for the next days, has had its impact:

- DMI 80N temp ( http://ocean.dmi.dk/arctic/meant80n.uk.php ) has dropped both due to cloud cover, as well as below freezing temps extracted from northern Greenland into the Fram Strait and north of Svalbard and Frans Josef Lands ( http://ocean.dmi.dk/arctic/weather/arcticweather.uk.php )

DMI also translated a recent article on the cold summer in Greenland, exceptional precipitation, and the record temperature set in May at -46.5C:

http://polarportal.dk/nyheder/nyheder/cool-summer-in-greenland/#c23815

With Greenland in completely reverse mode compared to 2012 and weather conducive to reduce sea ice melting for the next week, we are going to see the divide with 2012 widen, and the preconditioning will not be in place for a repeat of August 2012, where all indices kept plummeting due to the significant amount of heat that had been built up in that summer.

wayne

I wont be surprised if we get a 200K drop day, perhaps has happened yesterday.

Meantime back at the action on hand

http://eh2r.blogspot.com/2018/07/beaufort-rapid-retreat-met-by-thinning.html

2018 melt is complicated, rife for misinterpretations, nevertheless quite interesting, perhaps key area is Beaufort sea ice speed floes loosing sea ice opacity day by day.

wayne

It may sound counter intuitive, but Beaufort sea should be literally closed choked with ice at present, there is a massive amount of broken up sea ice heading its way:

http://eh2r.blogspot.com/2018/07/massive-counterclockwise-river-of.html

Yet there is melting nevertheless, new Melt zones like Fram Strait popped up at 2 other locations as well..

AnotherJourneybyTrain

From looking at DMI temps over the last week or two it's only got (relatively) colder... so the interesting thing will be just how much of a recovery year 2018 counts as in the overall narrative IMHO!

Greenland isn't out of whack either so the story of recovery can't be too far off,.. atleast this year.

John Christensen

Hi AJbT,

Agreed; by early July we are at 2014/15 levels for area, extent and volume from near or at record low by the end of February on all of these metrics.

At some point discussion must surface about the reasons for this relative recovery, which I see being closely linked with the SSW event by the end of February - exactly as we saw in January 2013 and subsequent months.

Wild speculation on my part:

- Could major wintertime SSW events in general be linked to subsequent Arctic circulation reinforcement?
- Secondly, and in particular if the above-mentioned hypothesis has validity, we have seen fewer major wintertime SSW events in the past decade compared to prior decades: Could the reduction in major SSW events be caused by AGW, and if not caused by AGW, could the randomly reduced occurrence of major SSW events have contributed to enabling more heat to enter the Arctic region in the past decade?

wayne

"Could major wintertime SSW events in general be linked to subsequent Arctic circulation reinforcement? "

Nonsense

What we are witnessing is a major summer time circulation change, coming in large part due to thinner sea ice. Which by the way is fitting exactly as I projected last April, so I do have some authority on this.

The cool spell of winter 17-18 came over the Southern CAA, the entire Arctic ocean was mostly warmer. It should be very interesting explanation on how sea ice can be reinforced by warmer air?

ECMWF calls for the return of clockwise gyre High pressure at month End, then it will be interesting, for those who predict correctly have done sound science work....

Written in April

"It is during this June-July period again when the sea ice melts slows, because cold air in Arctic summer is a great cloud saver, they don't evaporate as quick as with anticyclones. "

http://eh2r.blogspot.com/2018/04/2018-annual-spring-summer-projection-by.html

It does not mean that at end of July the melt season is over and we can speculate over mysterious means by which warmer air creates more sea ice...

" switch back to their more winter like modes. It is in early August when we will be able to evaluate if the Arctic sea ice will have a new all time low extent in September. "

Written same page. It is complicated folks, don't make it muddier.

John Christensen

wayne,you write:

"The cool spell of winter 17-18 came over the Southern CAA, the entire Arctic ocean was mostly warmer"

This is not a correct statement.

You see clearly on DMI 80N first the immediate heating caused by the SSW by the end of February, and next the drop by 20K by mid-March of the DMI 80N - bringing this measure below the 1958-2002 average:

http://ocean.dmi.dk/arctic/meant80n.uk.php

Next:

"It should be very interesting explanation on how sea ice can be reinforced by warmer air?"

Sea ice volume growth in both March and April were highest of the 2007-2018 period, as reported by Neven, so what is really called for is an explanation of this reality, which is offered by the reinforcement of the Arctic circulation, not "warmer air".

In your forecast of April 27th, which was overall great, you place the primary cold temperature north pole in the CAA and then mention that the normal high north of Norway would make NW Europe cooler.

In fact the CTNP was primarily based over Greenland, pushing the Scandinavian high much further south causing record high temperatures across much of NW Europe - a situation that still persists mid-July.

Consequently, we have a situation opposite that seen in 2012:

2012: Greenland high/extreme melting and 'heat-dome' delivering substantial heat to Arctic region
2018: Greenland low/cold ice sheet delivering colder air to Arctic region

wayne

Hi John

"This is not a correct statement."

I let NOAA answer that:

http://eh2r.blogspot.com/2018/07/neven-blog-stuff.html

Figure 1, latter part of winter had a huge positive surface temperature anomaly for the entire Arctic Ocean.

"primary cold temperature north pole in the CAA and then mention that the normal high north of Norway would make NW Europe cooler."

It was so in every way. please refer figure 2 and 3

I did not project for NW Europe after April and May period, I should have but did not do so, I am thrilled they had a nice summer so far.

"In fact the CTNP was primarily based over Greenland, pushing the Scandinavian high much further south causing record high temperatures across much of NW Europe - a situation that still persists mid-July."

The CTNP might have been centred over Greenland for a couple of days, but overall was primarily centred just North of Ellesmere Island.
Refer to figure 4.

"2018: Greenland low/cold ice sheet delivering colder air to Arctic region"

Nope, so far it was a dominant cloudy period mainly by 2 factors, 1 is the persistent yet expected Arctic Ocean Gyre cyclones increasing albedo not allowing the larger part of Arctic Ocean to warm up, and 2 the biggest factor, anti dumping of sea ice at Fram Strait, instead vast badly broken up sea ice constantly rushed towards Beaufort Sea barely handling the melt load, but melting sea ice by the ton loads nevertheless, the scattering of sea ice where there should be open water has decreased surface temperatures, the broken up sea ice spanning a huge section of the Arctic Basin has also stimulated cloud formation, but all this will change in a week or so.

We must remember, that was it not for Anthropogenically Enhanced Global Warming, we would be in the midst of a full fledged massive cooling La-Nina period, in response to 2016 Historically warm El-Nino.
Instead I see partial La-Nina effects, namely one smaller region cooled more than many. All this has changed in a mere 20 years, as we do remember the cooling post 1998.

My April projection is so far so good, now the last very hard to be correct real test is left , sea ice..... It is rather why I do this, weather is becoming to easy.

wayne

Too easy as opposed to very very hard getting our message through to the rest of the world, there are other challenges to surmount, all in the name of a better planet for our descendants and all living beings.

John Christensen

Hi wayne,

Thank you for sharing these metrics at this late hour of your day!

Figure 1 – Arctic temperature anomaly:

You measured the temperature anomaly from 2/15-4/30, which is not the period I am referring to above and includes both the warming part of the SSW as well as the subsequent cooling.

Try again with 3/15-4/30 to capture the relative cooling of the CAB, as the Arctic circulation stabilized subsequent to the SSW event.

Figure 2 (April/May pressure) and 3 (May temperature) – NW Europe:

Figure 2 clearly marks the high placed centrally in Scandinavia, and figure 3 shows the record heat in NW Europe. UK, Norway, Sweden, Denmark, and I believe Finland all had warmest May on record. People in Spain and NW Africa possibly felt a shiver..

Figure 4 – June air temperature:

Do you see more of the coldest air above Greenland or the CAA landmass? Seems like splitting hairs – and probably depends on the final status of the “Hans Island” in Nares Strait.. ;-)

https://www.nytimes.com/2016/11/08/world/what-in-the-world/canada-denmark-hans-island-whisky-schnapps.html

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