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wayne

Neven,

For everyone who did not monitor the Polar sat pictures, the regular Mid-April clouding over of most of the Arctic Ocean has happened, that was and is good news, it is a slow starter, but from a second lowest maximum volume, sea ice needs all the good news it can get, which will likely not come until mid June onwards, for a little while.

The High over the Arctic Ocean gyre is still more or less about its business, despite GFS predicting there should have been a big Low there by now:

http://eh2r.blogspot.ca/2018/05/invisible-invincible.html

Not a surprise, the GFS doesn't consider horizontal optical data at all.

wayne

I remember reading many contrarian arguments that some tree rings were not equal all over the world suggesting that their usage is inadequate , or some
country couldn't have vineyard during a certain period, but it was quite warm elsewhere therefore there is no such thing as Global Warming. However to the contrary, we have as I write, excellent example of a cool region, the CAA
which is fueling warmth over a vaster region (the Arctic Ocean), in particular when cyclones are blocked from coming from the North Atlantic. Grasping this is called met or climate 101 for adults with a serious bent in learning.

BTW GFS and ECMWF show an important Gyre anticyclone for at least until the 15th to 19th of May. Lesson learned :)... Bad for sea ice though...

gkoehler

Dramatic decline in Arctic sea ice extent over last week. Two weeks ahead of 2012 as of May 11. Arctic weather forecast shows more above normal 2-meter air temps on the way. But is the ice loss driven more by air temperature or by influx of warm ocean water temperature? What is a good source to see forecast Arctic ocean water temps?

Still early of course, but Neven and others have commented on the importance of spring melt pond conditioning ahead of the main summer melt season. From the looks of it so far, this may be an echo of 2007 and 2012, for another big dip in ice extent and volume unless June-August weather brings a relatively cool summer.

Interesting quantitative measure of the albedo impact from reduced ice cover (2000-2014 vs. 1979-1999) at https://www.nature.com/articles/s41598-017-08467-z#Fig4

Neven

Personally, I think it's the worst May I have seen so far (but I would have to check my writing in May 2012). Of course, this can flip within days. But things couldn't be much worse for the ice than they are right now. If we see this kind of prolonged weather conditions in June, let alone July, there's no telling what might happen to the ice pack.

Susan Anderson

Nice (April 29) visual comparison of Bering Sea this year and 2013 on EarthObservatory "Historic Low Sea Ice in the Bering Sea" May 3, 2018
https://earthobservatory.nasa.gov/IOTD/view.php?id=92084&eocn=home&eoci=iotd_grid

(Yes, I know, it's only part of the picture, and a couple of weeks old.)

John Christensen

Thank you for another great sea ice volume update Neven!

Regarding the anti-cyclonic weather pattern: Remember that in 2016 anti-cyclonic pattern persisted until the end of May, but still the cyclones arrived in June and persisted for much of the summer period.

As said earlier: With significant temperature increases on the continents and relatively high sea ice volume in the CAB, chances for a return to cyclonic weather patterns should be high - once temperatures have gone up a bit further in the next couple of weeks..

Neven

Regarding the anti-cyclonic weather pattern: Remember that in 2016 anti-cyclonic pattern persisted until the end of May

Yes, and this probably helped 2016 come in second lowest after all (in combination with some big cyclones in August, here's the 2016 overview).

I'd say the high pressure is more widespread and higher later into the month than it was in 2016, but it's close. And we still have some ways to go until the month is out. The 10-day forecast isn't looking all that great, though, even if it has improved somewhat.

But you're right that June may be even more important.

wayne

"But is the ice loss driven more by air temperature or by influx of warm ocean water temperature?"

It is both for certain ghoehler

And more

Snow is very major but poorly mapped, thinner sea ice mix with thicker configurations as well. And there is plenty more factors.

It is hard to say with the surface data we have, but it appears that Arctic Ocean cyclones are still warmer than the High pressure over the gyre, of interest is when these temperatures will be equal, then the switch should happen when cyclones cool surface air instead.

gkoehler

Then again...
Polar Portal chart shows Arctic sea ice volume above 2016 and 2017, and too far below 2004-2013 average
http://polarportal.dk/fileadmin/polarportal/sea/CICE_curve_thick_LA_EN_20180510.png
from
http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume/

The NSIDC extent chart shows 2018 identical with 2016 for early May
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

NSIDC 2016 September average extent was 4.7M km2. But it seems like two more warm winters (2016-17, 2017-18) since 2016 melt season must have "softened" up the Arctic sea ice to be more sensitive to summer melt in 2018.

Wipneus linear trend for Sept. mininum volume shows 2018 at about 4.2 km3.
https://sites.google.com/site/arctischepinguin/home/piomas

That would be put 2018 about tied with 2011 for second lowest above the dramatic 2012 record. The 2012 new low record had a lot to do with August storm, so I guess we'll just have to see what kind of weather summer brings to the Arctic this year.

Will be interesting to see the spread among the September minimum predictions from the various models.

AmbiValent

It seems the conditions for Fram export are getting worse, both for ice coming from the Siberian and the Greenland side. But is there actually such a data trend, or is it just born from the fact that the Arctic Ocean used to be frozen further to the South compared to now?

John Christensen

"Yes, and this probably helped 2016 come in second lowest after all"

Neven,

I would disagree: 2016 already by far had the lowest SIE coming into May and the anti-cyclones in May only kept the difference in place, until cyclonic weather patterns got in place and slowed down melting overall for the remainder of the 2016 season.

2013: The first cyclone only formed in earnest by May 25th after which the cyclonic weather pattern dominated most of the remaining melting season.

Therefore, the 10-day forecast does not worry me much (today).

What I am worried about, is the combination of higher than average temps across the CAB, while northernmost Siberia is colder than average. If northern Siberia does not heat up, then the necessary depressions may not form in the northern part of the Urals and the coming melting season could look more like 2007 and 2012 with significant high pressure areas over the sea ice during summer months.


GrayWolfBG1

Well I am becoming increasingly freaked!
I have it in my head that low solar played a part in the last spate of record lows across the basin and any return of the synoptics driving them will certainly leave the basin in a mess!
If the same processes that leads to the observed increase in northern blocking in the Atlantic,over winter through low solar, migrates north as the sun crosses over the equator then we may have a pattern of solar forcings for melt seasons?
Low solar leaning toward HP dominance and high solar bringing more cloudy, and so cool, conditions?
Of course it would be a background forcing with other events , like the WACCy snows of west Siberia last year? impacting the weathers locally.
The recent papers looking at ocean ingress into the basin is also a worry when we look at the SST's of those waters in Fram and Bering.
This is not 2012, we have weaker, younger,warmer ice and ocean entrances pouring ice melting heat into Chukchi/Beaufort and Barentsz/Kara.
All we can do is pray we drop off the 'perfect melt storm' pathway before it's too late!

Nothing so far this year has disabused me of the notion!

gkoehler

From PNAS article on how Arctic sea ice extent decline affects global albedo:

"We find that this decline has caused 6.4 ± 0.9 W/m2 of radiative heating since 1979, considerably larger than expectations from models and recent less direct estimates. Averaged globally, this albedo change is equivalent to 25% of the direct forcing from CO2 during the past 30 years."

Source: Observational determination of albedo decrease caused by vanishing Arctic sea ice.
Kristina Pistone, Ian Eisenman1, and V. Ramanathan. PNAS March 4, 2014. 111(9) 3322-3326; https://doi.org/10.1073/pnas.1318201111
http://www.pnas.org/content/pnas/111/9/3322.full.pdf

Sorry, I don't know how to paste image into comment, so here is description in case you can't reach the links.

Figure 1 shows change in clear-sky albedo between the mean of the last five Septembers (2007–2011) and the mean of the first five Septembers (2000– 2004) of the CERES record.

Results for March-August are included in Fig. S1. (Supplemental file also online). It shows albedo decline of about 10% for small areas of the Arctic ocean for March-May.

For June and August, area of 10% albedo decline covers about half of Arctic ocean. For July the whole Arctic Ocean is affected, with about half of it at ca. 10-15% albedo decline, and the other half roughly 5% decline. September similar to June, but different locations. Graphics more impressive than this description.

Would be interesting to see values updated from the 2007-2011 period covered in the study.

wayne

I have made a stunning snow temperature measurement 2 days ago, some -4.3 C below surface air temperature 2 meters above, with sun 20 degrees high shinning on the surface of mixed snow layers, fresh on top, harder below.
This means that looser snow was sublimating fast, nevertheless, we find where the deeper snow lies we find where the colder air is:

http://eh2r.blogspot.ca/2018/05/the-cold-air-mirror-snow.html

John Christensen

This is very interesting Wayne - especially how the cold zone around Laptev may impact circulations..

wayne

Hi John

It may sound simple, sublimation (and other factor?) takes over by astounding 4 degree drop (at times) , but a snow column temperature profile varies daily, largely depending on clouds, but is the result of the energy flux at the interface between snow and air. Top of snow temperature is very helpful in finding the extent of the cryosphere, only if "skin temperatures" are readily available again. Laptev sea area will be the last remnant of the North Eastern Passage cold zone....

John Christensen

Mid-May status:

Although sea ice melting for the first half of May has been limited ( http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume/ ) I am getting increasingly worried about the two cold zones with colder than average temps:

http://polarportal.dk/en/weather/nbsp/current-weather/

Between the cold zones with associated low pressure areas we have - ta da - a warmer area dominated by a high over the CAB:

http://ocean.dmi.dk/arctic/weather/arcticweather_imagecontainer.php

I do not see yet on ecmwf forecasts that this melt pond creating pattern is changing.

I will need to dig a bit deeper to find reasons for remaining optimistic about this melting season..


Neven

The ECMWF forecast is actually looking somewhat better (for the ice) than it did a few days ago. The high pressure isn't as high, going below 1030 hPa again in a few days, and instead of covering almost the entire Arctic, it gets restricted to the Beaufort Sea.

But it hasn't been good so far. And according to GFS temps will remain anomalously high. June is going to be very important.

John Christensen

Hmm, for the last day of the medium range ECMWF forecast (5/26) small lows remain around Ural and Hudson Bay, while a broad high extends from Beaufort to Barents..

Are you looking at a different forecast Neven?

Neven

It's the same forecast, but it has changed again. I tend to check out the ECMWF forecast on Tropical Tidbits, because it shows highest and lowest pressure of systems.

There's not much use looking beyond D6, because the forecast becomes very volatile from one day to the next (as we see today, for example).

But here's what I wrote over on the ASIF, posting D1-D6:

The ECMWF SLP forecast is looking a bit worse again now, with high pressure remaining relatively high and quite extensive. D7-10 has the high pressure moving over to the Siberian side of the Arctic, but forecasts that far out tend to be volatile, and so there's no use in posting them.
wayne

ECMWF is usually very good except for the Arctic, which has sparse data from many of its regions. On frequent occasions it shows quirky movements. Right now my own projection outlook of last month stands very sound, but I am cheating, I use data no one else has.

http://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=1

Supercomputers versus the dawn of new kind of meteorology....

wayne

http://eh2r.blogspot.ca/2018/05/deep-refraction-observing-vs-super.html

that was NOAA model catching up with refraction methods

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