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The logic of the concept of causality prevents us from finding the cause of a particular event. Causality can only be determined scientifically for a type of event. Thus the inevitable frustration in this endeavor. We find a cause of an event by repeating the conditions minus a factor to see if the event still occurs. Repeatability is only possible with types of things.

Kevin McKinney

Yes, which is why attribution studies are done by modeling. Of course, that's never quite exactly the same 'type of event,' since though we may hope models are useful, they are never perfect.

But we sure do want to know. If the Whattses and Mont-whatsis turned out to be correct, I'd be delighted--so much less to worry about! So much more music to write!

But that does not, sadly, appear to be the case.

Bob Bingham

I have been looking to see if the prolonged drought we have been having in NZ could have been caused by the jet stream.
It has barely rained since Christmas.

Pete Williamson

Totally OT but another lovely arctic image.

A really deep arch has formed in the Nares Strait


Ac A


"How could it not?"

Well, I think it is James Hansen who points out to the non-existing trend in the Arctic oscillation index concluding, that there is no evidence (yet) that recent waether events could be at least partly attributed to arctic sea ice loss...



Modeling can certainly never establish causality for a particular event, though it might suggest a cause for a type of event.

Jim Hunt

Hi Neven,

I wondered if you and your readers might be interested in reading the latest news from the sharp end here in soggy South West England, just down the road from the Hadley Centre?

I'd also like to point out that the denialistas are a well organised "guerilla army of the rich". I humbly suggest to you and Steve that if you do choose to wander into their minefields, you do so forewarned and forearmed.

Anyone want to join The Pirates?

Steve Bloom

I suggest everyone listen carefully to the Julia Slingo interview Neven linked. Her stance isn't entirely new, noting that she seems to have started working up to it a year ago (article), but the message is now much more loud and clear.

Jim, I may be able to get a little information on the planned conference, and if so I'll pass it on. As a general matter, though, when she says "best scientists" I expect she means the published experts on the subject (e.g. Francis and Petoukhov) and the top experts on atmospheric circulation (e.g. Trenberth). No engineers, sorry, and likely few if any sea ice experts (since the rapid decline is a given). Bear in mind the other main function of such a conference, which is coverage for the exposed collective Met Office posterior. Unlike in the U.S., the Met Office is a single prominent target. They don't want to be on their own on this given the sort of pushback of which the British press and politicians have shown themselves to be capable.

Thanks for the advice re the denialists. Someone once said that forewarned is four-armed, and as you can see I've got Neven's back. Re piracy, come the day. Arr.

Mdoliner 43, some single event attribution has been done recently. It takes an exceptional extreme event, though.

Bob, IIRC it very much is a blocking event. The NIWA site should have something on it.

Alex, Trenberth was also iffy at first. I suspect neither of them is doubtful about the observed effects, but probably think the causation is much more likely to be Arctic amplification in general rather than sea ice in particular. Given the feedback relationships involved, IMO that's a distinction without very much meaning.


Hi Jim, I am the bearer of wet news! There is hardly not a way to think your lands not being affected by the relocations of the coldest densest NH atmospheres, no thanks to the melting of the great Arctic Ocean thicker ice. What is left is Greenland, a sure bet in finding where the colder spring and summer air will be. http://eh2r.blogspot.ca/

Susan Anderson

ClimateCentral's Lemonick posted a new article:



L. Hamilton

We have a new public-opinion survey paper in progress, data collection finished this week. Sixty percent of the large statewide sample (n = 1,688) think that Arctic warming will have "major effects" on the weather where they live.

Interesting breakdowns by personal characteristics and beliefs. We're checking for daily weather effects on how people answer.

Ethan O'Connor

The data and code used for the analysis in the "Warmest Arctic Summers in 600 Years" study is available at


in case anyone wants to have a go at creating some non-paywalled visualizations!

Aaron Lewis

Weather is the internal work as the Earth functions as a comes to equilibrium after differential heating. The differential heating is caused by day/night, summer /winter cycles, geothermal, and etc.

The laws of thermodynamics apply to the energy flows that are weather.

There is no question of causality. All the heat (including global warming) in the Earth's weather systems affects all the weather on Earth. If the weather is weird, then it is because there is more heat in the system than there was in the recent past.

We think of snow as cold. However large snow events require large amounts of water vapor - and water vapor is latent heat. When you think of a snow storm as a flow of latent heat, then more snow as a result of global warming is very likely.

Wayne Kernochan

I'm sorry, it may be off-topic but I can't resist posting this Flanders & Swann ditty on English weather:

January brings the snow;
Makes your feet and fingers glow!

February's ice and sleet -
Freeze the toes right off your feet!

Welcome March with wintry whine ...
Would thou wert not so unkind :(

April brings the sweet spring showers ...
On and on for hours and hours!

Farmers fear unkindly May:
Frost by night and hail by day.

June just rains and never stops!
Thirty days and spoils the crops.

In July the sun is hot!
Is it shining? ... No, it's not! :(

August, cold and dank and wet
Brings more rain than any yet.

Bleak September's mist and mud
Is enough to chill the blood!

Then October adds a gale!
Wind, and slush, and rain, and hail ...

Dark November's chill and fog -
Should not do it to a dog!

Freezing wet December then ...

Bloody January again!!!!

(January brings the snow, etc.)

Richard Pauli

Seeking a mapping tool for observing the sea level rise flooding to lands around the Arctic Ocean.

There are a few map programs out there, all seem to stop short of displaying areas around the Arctic.

Any ideas?

Artful Dodger

Hi Richard,

Visualize the impact of sea level rise in google earth.


Bob Bingham

For sea level I use http://flood.firetree.net/
and for a few comments http://www.climateoutcome.kiwi.nz/sea-level.html

Arnd Bernaerts

Much of Britain’s cold today and recently come from the North Sea:
___see toady SST +Anomalies at http://ocean.dmi.dk/satellite/index.uk.php
___see SST anomalies yesterday (13.Apr): http://climate-ocean.com/2013/b/9_4_16b.jpg
and more material and discussion:
___ 'Urgent' need to see if Arctic affects UK extreme cold? No! MetOffice should investigate the impact of human activities in the North- and Baltic Sea ! (co_9-4)___ http://climate-ocean.com/2013/9_4.html
___ Did the cold March 2013 came from Siberia ? A not well founded claim! (ocl_9-9) __ http://www.ocean-climate-law.com/13/Arch/9_9.html

Chris Reynolds


I live in the North West of the UK.

The other day while stood outside the lab smoking it occurred to me - finally we have a westerly wind. We've had easterlies for so long we've been getting used to them. Cold in the North Sea is not the issue, nor is the temperature in Siberia.

The point is we've been having anomalous air flow, which is what the Arctic linkage is all about.

Arnd Bernaerts

About the NORTH SEA in: Monthly Outlook for April 2013, Published: Apr 1, 2013 :
“Sea temperatures are now several degrees below normal, especially the North Sea, with temperatures as we enter April between 2C near Denmark to 5C along the east coast of Britain. These low temperatures will undoubtedly have an impact on the Spring temperatures, and perhaps at times even early summer in eastern Britain when winds come from the east. “

Shared Humanity

Weird weather?

I've been a resident of Chicago my entire life. Today is the 9th straight day of overcast, unseasonably cold weather, wet weather although there was only a light rain early this morning. Is this weird? I suppose not. It is certainly not the first time we have had cold and wet Aprils, likely even persistent cold and wet Aprils.

What is weird and has been for several years is how short term weather forecasts can't get it right anymore. We were forecast yesterday for a warming into the 50's and a partial break of cloud cover. The forecast yesterday for today was 70F and sunny. At 11:00 AM, the current temperature is 42F and the radar suggests some rain is likely later today.

Has anyone else noticed a breakdown in weather forecasting?


Kudos to Professor Julia Slingo for deciding to take an urgent look at the weather weirding and a possible (I'd say likely) link to the loss of Arctic ice. Would that the policy makers in the USA should listen to their scientists in the same way. But when the Koch brothers own half of a gerrymandered House of Representatives, such hopes will be vain until after disaster strikes.

Chris Reynolds


And why were North Sea temperatures cooler than normal?

Zonal Wind is a measure of air movement around bands of latitude. In the following plots -ve is an easterly wind (coming from the east), +ve is westerly.

Long Term Mean Zonal Wind.

March 2013 Mean Zonal Wind.

It can be seen that the climatological wind over the UK and North Sea is from the west. But this March, and for a lot of the winter before, it was from the East.

Mean March temperatures over UK and North Sea are of the order of 5degC. This year they were of the order of 3degC cooler. It really doesn't matter that, as you say in your blog, Siberia wasn't exceptionally cold. This easterly airflow was dragging continental airflow out of the cold continental masses, where it was more normal, and into regions normally warmed by Atlantic airflow, making anomalously cold weather.

Earlier in the winter episodes of deeper penetration of negative zonal wind (easterly wind) were dragging air from Russia over Europe. Whether or not the conditions in Russia were abnormally cold is irrelevant. The presence of air at near Russian temperatures in areas normally used to Atlantic winter air would have still caused cold anomalies, regardless of whether Russia was abnormally cold.

The cold in the north sea is a result of the easterly winds and the cold, not the cause.

Incidentally your claim that the oceans drive the weather isn't founded. In fact the evidence indicates that the atmosphere is more the driver of the oceans (e.g. the arguments of Carl Wunsch).

Chris Reynolds


Comment posted twice held by the spam filter.

I'm on the verge of giving up posting here I'm afraid.

R. Gates

I hope as the "bloody cold" weather of England is being discussed in relationship to the decline in sea ice, that the close relationship to SSW's and the outbreak of cold is kept in mind, as it has nothing to do with sea ice. As this chart clearly shows, the weather was rather nice in December and first few days of January in England, based on the CET record:


But then the Jan. 6 SSW event occurred (marked on the graph), destroying the Arctic vortex and creating all sorts of nasty weather at lower latitudes.

Furthermore, is should be noted that, during SSW events, it is warmth at lower latitudes, combined with the proper vertical lifting factors that ultimately leads to the "bloody cold outbreaks" across Europe as the refrigerator door of the Arctic is flung wide open through the destruction of the vortex.

I'm on the verge of giving up posting here I'm afraid.

I'm really sorry about this, Chris (released your comment). I want to give TypePad a chance to get this right, as I'm sure they receive a lot more complaints, but they better have the new spam filter working properly at the start of May.

Arnd Bernaerts

@ “The cold in the north sea is a result of the easterly winds and the cold, not the cause.”

A not very convincing argument, as the SST in the NE Baltic Sea remained in the normal range of average, for example:
__SST, 8 March http://www.ocean-climate-law.com/13/Arch/_b/10_2_2_b.jpg
__SST; 23 March http://www.ocean-climate-law.com/13/Arch/_b/10_2_4_b.jpg
MORE at http://www.ocean-climate-law.com/13/Arch/10_2.html
Also the low air temperature only briefly stretched beyond the Ural, see e.g. T°C anomaly-forecast:
___27.Feb – 7.March: http://www.ocean-climate-law.com/13/Arch/_b/9_9_3b%20Kopie.jpg
___9. – 16. March: http://www.ocean-climate-law.com/13/Arch/_b/9_9_4b%20Kopie.jpg
___27.Mar – 3.Apr. http://www.ocean-climate-law.com/13/Arch/_b/9_9_7b%20Kopie.jpg
MORE at. http://www.ocean-climate-law.com/13/Arch/_b/9_9_7b%20Kopie.jpg

In addition here is the map for global SST on 31st March 2013:
http://www.ocean-climate-law.com/13/Arch/_b/9_9_16b.jpg indicating the exceptional low water temperatures in the western Baltic and North Sea.
The question is whether human activities in the regional seas have contributed to the cold spring condition in the UK and Central Europe in March and early April, a matter which would start in autumn and continue until the loss of heat ends, either by sea ice (temporarily) and/or absorbing more heat as loosing.

Arnd Bernaerts

Chris @
the “…claim that the oceans drive the weather isn't founded.” is answered with a statement the famous oceanographer H.U. Sverdrup (1942) assumed necessary to tell meteorologists 70 years ago:
__"It might appear, therefore, as if the oceanic
circulation and the distribution of temperature
and salinity in the ocean are caused by the
atmospheric processes, but such a conclusion would be
erroneous, because the energy that maintains the
atmospheric circulation is to be greatly supplied
by the oceans."
("Oceanography for Meteorologists", New York 1942, page 223.)
Excerpt from: http://climate-ocean.com/book%202012/j/j.html

Chris Reynolds

I know it's out of your hands Neven. But it's a simple rule - comment retrieved from spam 3 (or so) times -> poster is trusted at this site.

It's so easy it makes whoever's behind this look like they're in the wrong job.

Chris Reynolds

R Gates,

Do you think the winter of 2009/10 was due to SSWs?

If so I strongly disagree.
Cohen et al, GRL, 2010, "Winter 2009–2010: A case study of an extreme Arctic Oscillation event."

And part of that process was SSWs triggered by Wave Activity Fluxes from the surface. As I don't know how to get NCEP/NCAR to give me WAF information I can't investigate the role of WAFs in this winter, but we've seen SSWs associated with cold outbreaks, we've had a strong snow advance last autumn, and the same WACC pattern has been active, so I presume that the same mechanism has been at play.

I've been in email discussion with Dr Cohen previously. I can ask him if that would help.

Chris Reynolds


A not very convincing argument, as the SST in the NE Baltic Sea remained in the normal range of average...

Look again.

March 2013 Mean Zonal Wind.

Note the March easterly zonal wind band doesn't go across the Baltic.

Chris Reynolds


There's another post held in the spam filter.

For example: Wunsch 2006: "Abrupt climate change: An alternative view" The arguments relate to Dansgaard Oeschger events, but part of it relates to atmosphere vs ocean.
See the section on N Atlantic Circulation Control.

Overturning circulation is maintained by thermohaline effects, but the net meridional ocean transport is maintained by Gyres (earth rotation) and overhead wind motion. More is now known that when Sverdup wrote. Atmospheric wind movements, Hadley/Walker/trade winds etc are driven by atmospheric heat imbalances modified by the rotation of the earth.

R. Gates

Chris Reynolds said:

"R Gates,

Do you think the winter of 2009/10 was due to SSWs?

If so I strongly disagree..."


Chris, I've not analyzed the winter of 2009/2010 in detail, but in looking at the SSW events of that winter, we had a small to moderate one in mid-December 2009 and a bit larger one at the end of January to the beginning of February 2010. In both cases higher pressure was forced over the polar region with colder air spilling to lower latitudes. I could look into this further to see the exact disruption of the vortex in each case, and specifically whether the vortex was highly disrupted by the SSW (causing crazy cold weather at all lower latitudes) or if it was just offset from the pole (causing warmer mild weather on one side of the NH, but colder weather on the other).

Any regions or specific part of the 2009/2010 winter you're referring to?

Richard Pauli

Thanks for the Sea Level rise tracking maps. We keep hearing that inundation of permafrost by rising seas will trigger vastly more methane and more warming. Seems totally plausible for a tipping event.

I just wonder how much area are we talking about? I see from Google Earth that so much of the polar regions of AK, Canada and Siberia are near sea level. I just wonder what a half meter or full meter of sea level rise might flood. Three meters?

Of course the black sheep wild cards are the Arctic storms and tidal surges... how much does an ice sheet dampen tidal forces? I read that Antarctic ice sheets will rise an fall with tides. Even the thickest 700feet will flex. But a surge or large tide would break ice, wouldn't it?

If Frankenstorm Sandy surged 3 meters above high tide, then shouldn't models evaluate 3 meters of sea level rise around the Arctic Ocean?

Maybe there is a map plotted for this already. Soggy permafrost - there's another experiment: flood a small field of permafrost and measure the melt and methane release. Evaluate a one-time flood, and standing water on a field in summer. Even a few square meters would give good information.

Anybody know if this been done already?

Richard Pauli

Forgive me, I can search for this, and I will post links of what I learn.

Arnd Bernaerts

@ Chris
Carl Wunsch, 1984, “The ocean circulation in climate”, in: John T. Houghton (ed), The Global Climate, Cambridge, p.189, 190 said:
___”_Atmospheric climate is, to some as yet unclear degree, controlled through the interaction of air and sea.”
____J.T.Houghton, et al. (ed), 1990, Climate Change -The IPCC Scientific Assessment, Chapter 7, Observed Climate Variation and Change, Cambridge 1990p. 223, said :
”Even the upper few metres of the ocean can store as much heat as the entire overlying atmospheric column of air. Scientists have long recognized (Rossby, 1959) that the ocean could act to store large amounts of heat, through small temperature changes in its sub-surface layers, for hundreds or thousand of years. When this heat returns to the atmosphere /cryosphere system it could also significantly affect climate.
The magnitude and extent of the observed changes in the temperature and salinity of the deep North Atlantic are thus large enough that they cannot be neglected in future theories of climate change.”
Stored with other notions "This & That" at: http://www.whatisclimate.com/f.html

It might be of interest to see how effective the sun operates in the Baltic at latitude of Stockholm (this year since about 1st April) : http://climate-ocean.com/2013/b/9_4_13b.jpg, taking note of the context that:
___”The heat capacity of the upper 3m of the oceans is equivalent to the entire heat capacity of the atmosphere”. MORE at: http://climate-ocean.com/2013/9_4.html

R. Gates


You are aware of the close association between SSW's and a very negative AO index as I have previously discussed here, right? The physical mechanism is quite straight forward with the onset of a strong SSW having a high direct causal correlation to a negative AO. Strong downwelling air right over the pole from the mesosphere into the middle stratosphere does amazing things to both the pressure and temperatures.

Chris Reynolds

R Gates,

Cohen's work shows that SSWs are an intermediate part of a process starting with snow advance over Eurasia.

Arnd Benaerts,

e.g. Hadley/Walker - no need to include ocean as a driving mechanism.

When ocean water heats it forms a warm cap, not convection throughout the ocean column. So it cannot drive the net meridional transport. Unlike the atmosphere. Take the Atlantic - the atmospheric gyre formed by the trade winds due to modification of net poleward atmospheric heat flow drives the ocean gyre in the Atlantic. The ocean is not driving atmospheric flow.

Take figure 10 of the Wunsch paper I showed you: Ocean Heat Flux falls off before entering mid latitudes due to heat loss. The bulk heat transport into mid latitudes is from the atmosphere.

Jim Hunt

Steve - Arrrrh Jim lad?

If you've "got Neven's back" then I still wonder why you jointly give The Mail the O2 of publicity on an ASI authority site without accompanying it with a much stronger denunciation than merely "sensationalist".

I'd love to hear any news you may receive about Julia's "climate change task force". You're quietly confident there won't be any "geo-engineers" on it?

Wayne - I'm sure you're right. However there was at least a brief respite from the cold and damp in London last night. I unexpectedly found myself dancing to a reggae beat at Admiral Nelson's feet to celebrate!

I Ballantinegray1

As for N.Hemisphere 'weather' the continent will now warm up under the continental high so any easterlies we see in the UK will only have the N.Sea to temper the temps?

If the 2012 ice low adds as much of a ramp to the n.Hemispheres summer climate as 07's low did then we should expect a distinctly different mix for summer here in the UK?

Even less energy for the jet (polar) might see it fall off the charts for periods over the summer (as the wind speed criteria for it being plotted is not achieved) leaving only 'jet Streaks' around the N.Hemisphere?

Home grown inner continental highs, as we have seen this winter, will then dominate leading to heatwaves ,drought and wildfires in the regions most impacted by them (again!) butmaybe areas like the U.K., blighted by 'stuck' low pressure systems will have a respite as those areas diminish/move location due to the lower energy Jet becoming ever more sinuous/absent?

Just a thought?

Steve Bloom

Hi Jim, I have confirmation from Richard Betts that Julia Slingo is indeed convening an expert meeting. I'm reasonably confident I'm right about the nature of the invitees, but we shall see. As this is a meeting rather than a conference as such I expect it will happen pretty soon.

Re the Mail, I dislike them as much as the next person but there was nothing problematic about that particular article. The silver lining is that they're complete opportunists, and as soon as covering climate impacts becomes the thing to do all the time (sadly a not-too-distant time, more than likely), they'll drop the denialist crap like a hot potato and the persuasive power of those spectacular photo spreads will become, dare I say it, a force for good.

Arnd Bernaerts

Chris@ “When ocean water heats it forms a warm cap, not convection throughout the ocean column.”
The “warm cap” is subject to sea surface (ss) mixing:
__A hurricane reaches down to max. ~ 50 metres,
__all other winds from the ss to ~ 40 metres,
__a big tanker down to ~ 15 metres ,
__a million and more vessels at sea -every day- down from the ss to 14 meters.
The entire water column is subject to mixing due to differences in salinity and temperatures, and than one has to take into account the dimension of the oceans versus the atmosphere?
• Only about 0.001 percent of the total Earth's water volume is in the atmosphere.
• The volume of water in the atmosphere at any one time is about 12,900 km3 .
• The volume of the Baltic Sea is about 20,000 km³
• The entire water in the atmosphere is replaced about 35 times in one year.
• Each water drop (vapor) in the air remains there for not more than about 10 days.
• The ocean mean temperature is about 4°C.
More at : http://www.seaclimate.com/g/g1.html or in a graphic on
“Ocean Dimension” here: http://www.seaclimate.com/a/a3/mid/big/A3b-5.png
In conclusion it can be said: The oceans drive the climate. The North- and Baltic Sea moderate the weather from London to St. Petersburg, inter alias.

Remko Kampen

" All other temperature map indicates a cold anomaly only up to the Ural, which means that not all cold had been coming from the East, ..."
[From the third link by Posted by: Arnd Bernaerts | April 14, 2013 at 10:58]

Air trajectories during the virtually unique length of time of cold easterly winds over the North Sea countries for considerable time came consistently from Nova Zembla - northern Ural over Russia and Poland to us. Obviously this would result in pretty cold anomalies in these countries like we saw.

Obviously, too, and this is the thing you seem to miss: the very cold air in the Russian arctic has to be replaced as it is transported south(west)wards. This replacement air can only come from the climatologically warmer wide environment - therefore if it is far colder than normal in the North Sea countries it MUST be much warmer than normal in the regions the frigid air comes from.

The low North Sea temperature is itself caused by this prolonged cold spell. In its turn this will depress temps on the coasts somewhat _if_ wind direction is from the sea. If it is not, nothing the matter. In fact in Holland from less than a day of southerly winds the 14th of April became quite warm, with a record high minimum temp for the date (records for max/min temps going back to 1901).

Remko Kampen

On SSW's, about the strongest ever observed was about second, third week of February 1989. The winter until then was characterized by a remarkably strong, northwards displaced Atlantic jet. As the effect of this SSW took its dozen days time to percolate downward a gargantuan Alaskan high with cold air outbreak over the US evolved. Also the jet over the Atlantic tended south for a week or so, getting one of the many very lows lost over the Netherlands resulting in the lowest air pressure reading in a century or more there. Thereafter the northerly displaced westerlies simply resumed and held out all of March. That Alaskan high was soon gone too.
The result: mildest winter in at least 300 yrs in Holland (and around). A different result btw was that cRR was convinced of global warming since then.
Conclusion: SSW's may be a precursor to blocking patterns, but they also may not.

Chris Reynolds


But the mixing is surface mixing, not throughout the whole column of >300m in the bulk of the ocean. Bottom line; warm water rises, the energy input into the oceans is from the sun at the surface. That's why the deeps are still holding relic cold from the last glacials. The major force mixing the oceans at depth is overturning circulation, and that is slow.

You list disparate facts, then conclude something that is not a forcible conclusion from that list.

No comment about your claim that the Baltic being warmer than the North Sea is contrary to my claim about easterlies, when the easterly zonal wind clearly didn't cover the Baltic?

No comment about Wunch' arguments, in particular his presentation of ERBE data which demonstrates the main warming factor at the latitude of Europe is the atmosphere, not the ocean?

A few more loose ends like that and I will conclude you don't have a serious argument and that I should stop wasting my time.

Actually, before posting this I thought I should have a dig around your links to see what you're saying. You say:

Since December 1941 huge sea areas were churned and turned up-side-down over depths even hurricane wind force do not have any compareable equivalence.

Ah! I see.

Chris Reynolds


SSW's may be a precursor to blocking patterns, but they also may not.


R. Gates,

Sorry, was rushed this morning. To explain in more detail:

Here's figure 1 of Cohen et al 2010.

The process Cohen outlines proceeds as follows, using the numbered points in that diagram.

Stage 1 is the massive snowfall across Siberia during the last two weeks of October.

Stage 2 is the initial atmospheric response to that; surface temperatures in Siberia went from being above average to below, this lead to the development of a region of high pressure over the region.

Stage 3 is shown in panel b; this was an upward moving train of atmospheric waves that translated the surface high pressure into impacts upon the stratosphere.

By stage 4 the process was affecting the stratosphere substantially, leading to a dipolar pattern of warming centred on the Canadian Arctic Archipelago and cooling over Siberia.

At stage 5 the stratospheric temperature and pressure changes lead to changes in the atmospheric column that propagate downwards into the troposphere, until at...

Stage 6 a negative index AO becomes apparent in the surface pressure fields.

The process then repeated a second time leading to the second cold wave that affected the mid latitudes of the Northern Hemisphere during January.

I haven't had the time to follow closely what you've been posting. And as I cannot follow the wave activity flux linkage I can't strongly argue w.r.t. your recent work. But you might want to look at 2009/10's winter in terms of your approach.

Arnd Bernaerts

Remko K @ “The low North Sea temperature is itself caused by this prolonged cold spell. “ etc.
Could it not be possible that warm water which is moved, for example in a baby bath tub, lose more rapidly heat to the air, than unmoved water? Offshore platform in the tidal current and ships mix around a lot of water. How many sizeable ships are navigating in the North- and Baltic Sea at any time? The figure for the Baltic is about 2000.

Chris R. @ “Since December 1941 huge sea areas were churned and turned up-side-down….”

Since 1st September 1939 the North- and Baltic Sea was churned and turned … etc. ….contributing to the most extreme winter conditions in Central and Northern Europe for more than 100 years.

Since 8th December 1941 the U.S.A. became a war party and naval war covered the entire North Atlantic and soon the Western North Pacific as well.
For the first three war winter in Europe see Chapter A-F (book page 1-160), and Chapter G & H on naval war in the Atlantic an Pacific (book page 161-188), all at : http://www.seaclimate.com/ or http://climate-ocean.com/book%202012/index.html

R. Gates


In regards to SSW's and the winter of 2009/2010, I am preparing a longer post on SSW's for this site, and I think there will be some rather eye-opening information in it, but somewhat briefly, I've looked at that period and the charts you provided from Cohen and find them quite fascinating. Specifcally though, from an SSW perspective, I am looking at two events during that winter. The first one took place in mid-December, and can be seen clearly on these two charts (again, look at December, and not at January's large SSW in 2009 which was part of the winter of 2008/2009):



Now, about the time that this mild SSW hit in mid-December 2009, we began to see the AO index going into the negative:

2009 11 28 0.055
2009 11 29 -0.620
2009 11 30 -0.597
2009 12 1 -0.227
2009 12 2 -0.329
2009 12 3 -0.400
2009 12 4 -0.842
2009 12 5 -1.647
2009 12 6 -1.432
2009 12 7 -1.005
2009 12 8 -0.833
2009 12 9 -1.240
2009 12 10 -2.614
2009 12 11 -3.618
2009 12 12 -3.767
2009 12 13 -3.846
2009 12 14 -3.821
2009 12 15 -3.890
2009 12 16 -3.610
2009 12 17 -3.744
2009 12 18 -4.238
2009 12 19 -4.651
2009 12 20 -5.341
2009 12 21 -5.821
2009 12 22 -5.503
2009 12 23 -5.577
2009 12 24 -5.256
2009 12 25 -5.052
2009 12 26 -4.406
2009 12 27 -3.724
2009 12 28 -3.696
2009 12 29 -3.836
2009 12 30 -3.969
2009 12 31 -4.100

Why are the two so closely related? Downwelling air over the pole, leading to the higher pressure seen in the second chart linked above. This downwelling air provided a one-two punch very rapidly to the polar stratosphere, as not only is it already warmer than average, as it sinks it is compressed even more and warms rapidly as pressures rise. But the real smoking gun for the mid-December 2009 SSW event is in the origin of the warm air that was advected to the pole. Here's a chart showing the NH 10 hPa temperatures a few weeks prior to the SSW event:


Note in this chart, that a "bubble" of warm air is forming over Southern-Central Asia at 10 hPa. For those of you not familiar, this is in the mid-stratosphere. This is point that is critical to the eventual SSW event to take place a few weeks later and I will be returning it this point, and this geographic region in detail in my longer post. This bubble migrates poleward as it expands. Here's a similar chart of 10 hPa temps just a week later:


It is this bubble of warm air that eventually descends over the pole, warming and increasing pressure as it does so, leading to the very negative AO we saw in December 2009.

Moving foward a month or so, into late January 2010, we see a very similar set-up take place. Once more, here's 2010's charts showing the SSW event in late January into February:


Here's what the event did to the pressure over the pole:


And here's what it did to the AO index:

2010 1 16 0.163
2010 1 17 0.519
2010 1 18 -0.080
2010 1 19 -0.747
2010 1 20 -1.386
2010 1 21 -1.805
2010 1 22 -2.022
2010 1 23 -2.138
2010 1 24 -1.780
2010 1 25 -0.991
2010 1 26 -0.728
2010 1 27 -0.769
2010 1 28 -1.677
2010 1 29 -2.580
2010 1 30 -3.231
2010 1 31 -3.132
2010 2 1 -2.596
2010 2 2 -2.300
2010 2 3 -2.750
2010 2 4 -3.806
2010 2 5 -4.706
2010 2 6 -5.205
2010 2 7 -5.005
2010 2 8 -4.734
2010 2 9 -4.459
2010 2 10 -4.266
2010 2 11 -4.638
2010 2 12 -4.758
2010 2 13 -4.945
2010 2 14 -5.132
2010 2 15 -4.730
2010 2 16 -4.292
2010 2 17 -4.125
2010 2 18 -3.943
2010 2 19 -4.026
2010 2 20 -4.320
2010 2 21 -4.462
2010 2 22 -4.403
2010 2 23 -4.591
2010 2 24 -4.211

And, once more, here's the wave of warm air moving up to the pole at 10 hPa levels from over Asia a few weeks prior to the SSW:


R. Gates

Just one more point to add to the "brief" post above- Asia is definitely the key to nearly every SSW event that I've studied going back the 1950's using reanalysis data, and more specifcially south central Asia. I will in fact, show a few of the very specfic geographic trigger points where topographic lifting create upwardly directed Rossby waves that send a stream of warm air through the tropopause into the upper stratosphere, intiating a sequence of events that lead to SSW's over the pole and creating chaos for NH winter weather. This point is critical and will be one of the key points of my longer posts on SSW's.

Hans Verbeek

@Chris Reynolds + Arnd Bernaerts:
North Sea surfacetemperature is on a downward trend since 2006

It is not a temporary cooling

Hans Verbeek

Neven, I'm puzzled by the lag of 4 months or more between the Arctic summer-melt and the winter-cooling of Eurasia.
I can understand that an icefree, warm Arctic Ocean causes more snow in October, November and December.
But now can the ice-covered Arctic Ocean still influence weatherpatterns in February and March?

Maybe 2013 is just a freak anomalous winter like 1963.


Could be, Hans. I'm also not sure about the link to Arctic sea ice on this particular April weird weather event.


Remko, I read your comments with pleasure.

But, quoting from my rant triggered by the Overland/Wang letter ( the PIOMAS April 2013 extra update; posted April 13, 2013 at 10:23 ): “…we may have given them (systems within the biosphere) individual names, posed attributes to them, but do they ‘exist’ at all…”

It is necessary for the communication to name these phenomena. But we should be careful to appoint the same meaning or attributes. What we categorize as the ‘Sudden Statospheric Warming” February 1989 is not easily compared to the events this past winter.
I mean, these phenomena are temporary and regionally bound stages within complicated interdependent matrices. I see the danger in this thinking; blurring out all cause and effect, but that’s not where I want to go.
What I would like to clear up (…) is that these phenomena evolve in a chaotically extrapolating theatre under forcing and a failing biosphere buffering capacity. What could be analysed about a category of phenomena in the past, doesn’t have the same value/meaning now anymore.
To assess the rapid deterioration of biospheric systems, we can’t compare to snippets from the past on a one-on-one basis.
One example is the assessment of last half year’s weirdness; the mix is unique.


R.Gates, thanks for the explanation.

In what does last winter show its singularity? The mechanism you point out looks the same, but shapes up in a different context. As I recall, the 500 hPa height has been anomalously high ever since mid-September, indicating a lessened gradient in pressure and heat content between the Equator and the Pole. Winter Power wasn’t strong north of the Polar Circle. The cold outbreaks haven’t been exceptionally frosty, although they lasted annoyingly long.
It seems contradictory that mean 500 hPa height has been lower than the climo over Mongolia, but that was NTL a favoured sector for ridges to cling to.

I’m looking forward to your further analysis and hope you can examine in what sense there’s a difference now?

R. Gates

Neven & Hans,

You're right to question (in some regards) the link between this winter/spring weather and a direct link to the state of sea ice, though there could be an indirect link. If you consider the polar vortex as being the "refrigerator door" that holds in the main bulk of the coldest Arctic air formed during the winter polar night, then something (namely an SSW such as we had January 6th)is the kind of serious nudge it takes to crack open that door and release the air to lower latitudes. The sea ice does not cause the SSW, but lower sea ice into the fall can prevent the vortex from being quite as strong as it might otherwise, perhaps making it a bit easier for SSW's to breakdown the vortex and create the havoc at lower latitudes that can last for months.

Steve Bloom

Bear in mind that a number of scientists thin the weather link is to Arctic amplification generally rather than just sea ice loss. That makes it a lot easier to consider the effect on spring events.

Remko Kampen

Arnd Bernaerts | April 15, 2013 at 20:48
North Sea, Baltic Sea are simply by far to shallow and small bodies of water to have any bearing on hemispheric or even regional (+/- European) circulation patterns. Churning effects of shipping are negligable, temperature stratification in these shallow seas is as well.
Certainly the cold winters 1939-42, 1947 et c cannot be attributed to these small seas at all (neither could older winters like 1823, 1789, 1740, 1709 or the the 1690's be attributed to them).

Arnd Bernaerts

Remko @ „North Sea, Baltic Sea are…”

Thanks for your comment, but it ignores one of the most basic knowledge. These seas are paramount for moderate winters in Northern Europe. I would be happy to discuss the three extreme war winter 1939/40, 1940/41 and 1941/42 in North Europe in depth, but I can not outline here a subject, which I discussed over more than 160 pages with hundreds of graphics and figures, here , http://climate-ocean.com/book%202012/index.html . You will not find, or be able to offer a more convincing explanation. Kindly note these considerations are about the mentioned three war winters, covering the months Dec/Jan/Feb. .

However as this thread is about the cold March 2013, one should reckon that 2000 sizeable vessels at sea “churn and turn around” the entire Baltic sea surface in about two weeks. That has a impact throughout all seasons, and may - for example - during the winter season force more heat out of water column (Sept-Feb), or delays (or even prevent) the forming of sea ice. Even during the world wars some March months may have a link to naval war, as any activity at sea during spring would exchange sun-warmed surface water with colder water from lower levels.
Here are some March temperatures (Skagerrak & Baltic region) since about 1880 of
Potsdam/Dahlem (Berlin) : http://climate-ocean.com/2013/b/10_2_2b.jpg
Stockholm /Tallinn : http://climate-ocean.com/2013/b/10_2_3b.jpg
Copenhaven/ Torungen Fyr-NO, etc.: http://climate-ocean.com/2013/b/10_2_4b.jpg

In each case are WW years prominently present, in particular March 1942!
Take particular note of Copenhaven with a temperature deviation in 1942 of – 4°C, succeeding the second coldest March 1888 by -1,2°C, and the third coldest March 1917 by -2,3°C!

For those particularly interested in UK climatology, two March months in WWI should not go unnoticed. The other day Met Off regarded as the 4th and 5th coldest month March 1916 (+2°C) and March 1917 (+2°C). Two in a row is extreme exceptional. And than the circumstances: After a slow start in 1914, naval war activities increased dramatically during the next two years, due to new weapon and mass production:
Extract: “The situation became dramatic when U-boats destroyed more ships than Britain could build in early 1917. In April 1917, the same total rate of the previous annual rate of 1916, ca. 850,000 tons, was destroyed by U-boats. In April 1917, Britain together with the Allies lost 10 vessels every day.” From http://www.arctic-heats-up.com/chapter_8.html

On 15th April the SST Anomalies in the North Sea was still extreme low http://climate-ocean.com/2013/b/9_4_22b.jpg , but has meanwhile slightly improved. The impact of off-shore wind farms, shipping, and fishing on the extreme March conditions should not be ignored and thoroughly understood. March 2013 offers a unique case for investigation.


Just to follow up a bit on R. Gates, I found WorldView (as discovered for us by Jim H) quite convenient for animated comparisons to past years, in this case collapse of the Amundsen Gulf ice shelf west of Banks Island.

In recent years, that has been the first to go along the CAA, before the Mackenzie warm water plume kicks into the Beaufort.

If fracture and melt observables of 2013 continue to run 5-6 weeks ahead of 2012 -- as they have since February -- then we might expect the Amundsen to disintegrate quite a bit earlier than the 27 May 12 of last year. Five weeks earlier would be 22 Apr 13.

Indeed, already on 17 Apr 13, the Amundsen looks 'on the verge' on infrared. Even the Mackenzie is shelving a bit. (Because of variable cloud cover and image quality, the picture below is a composite of 5 separate shots, with the most useful part of the most recent showing and the rest made transparent.) Jaxa radar confirms the precarious state of this ice.

We are looking at a prodigous, unprecedented melt season in 2013 if this pace continues (or picks up).

 photo BanksMelt12P2_zpsa89c2e2b.gif

 photo mckenzeBanks_zps631b099b.jpg

 photo 17Apr13Jaxa_zpsdd05d9e7.jpg


After so much weather talk limited to proximate causes if that, I'm looking forward to a deeper explanation by which "nearly every SSW event in south central Asia arises from very specfic geographic trigger points where topographic lifting create upwardly directed Rossby wave".

In effect, this would be saying SSW result from the collision of India with Asia. (I'm guessing here that the trigger points are by the Tibetan plateau.)

I wonder if SSW arising there could explain the fact almost all dust in Greenland ice cores originating from Tarim Basin in the Taklimakan Desert of Mongolia (based on isotope ratios).

A lot of climate is driven by land distribution -- the 45 meter sill at the Bering Strait comes to mind. (Sill depth hasn't been significantly affected by isostatic rebound or erosion.)

Adapted from http://www.globalwarmingart.com/

 photo BeringSill_zps6c2b2f28.png

Ocean vs atmosphere driving weather? ... I wonder if a clever extra-terrestrial with reams of reanalysis data but only globe diameter, tilt, angular velocities and solar inputs could deduce our current land distribution and topography (including ocean sills) to some degree of resolution. Or vice versa.

James Dunlap

Hi Neven,

A bit off topic but Hansen just put out a new discussion that is very good. Maybe you can find a use for it.

Titled: Exaggeration, Jumping the Gun, and the Venus Syndrome from 15 April

found at his site


R. Gates

A-Team said:

"After so much weather talk limited to proximate causes if that, I'm looking forward to a deeper explanation by which "nearly every SSW event in south central Asia arises from very specfic geographic trigger points where topographic lifting create upwardly directed Rossby wave".


And I am busy preparing that post and think there may be a few eyes opened regarding the singular uniqueness of the south central Asian region of our planet. Neven has graciously given me guest privileges here, so I can include lots of nice original research graphs, some animations, etc. Some of the information I'll present will be presented for the first time anywhere, and I can think of no better place than the #1 site for discussions of all things Arctic.

What I can tell you with a high degree of confidence (the proof of which you can judge for youself) is that without the unique topographical features of south central Asia, the entire nature of SSW's in the NH winters would change, and be more like the SSW's seen in the SH (weak and infrequent). And if SSW's in the NH did not exist to the extent they do, the charcater of our NH winter's would be dramatically different.

I hope to have this rather lengthy post ready by next Monday.

Chris Reynolds

R Gates,

Great stuff, I look forward to it.

R. Gates

In preparing for my longer post on SSW's, here's an interesting image I came across that may not be included in my guest post, but some of you might find interesting. It compares the progression of 2013's stratosphere/troposphere temperature anomaly with the most recent year that has a similar profile based on when their SSW event occurred. The closest year is 2006:


The most interest feature is the fact that this years "cold air recoil" event, that always follows on after an SSW, and also progresses down from the stratosphere into the troposphere has penetrated much deeper into the troposphere this year, even though 2006's SSW event was of greater intensity. The cold air anomaly from the stratosphere this year has penetrated down to around 700 hPa, whereas in 2006 in only came down to about 400-500 hPa. What (if anything) these means for the spring/early summer melt remains to be seen, though we know that 2006 saw a vigorous early season melt before slowing. We also had a generally warmer troposphere in the higher NH latitudes in 2006 than we have this year at this time in the season, but the ice was much thicker back then, as we all know.

Chris Reynolds

Where do you get these plots for past years?

R. Gates


You can get zonal mean stratosphere/troposphere historical charts going back to 1979 here:

R. Gates

A-team said:

"I wonder if SSW arising there could explain the fact almost all dust in Greenland ice cores originating from Tarim Basin in the Taklimakan Desert of Mongolia (based on isotope ratios)."


Do you have a source for this?



Sure. Note I posted this back on 29 Jan 13. It is just taken out of GISP2, NGRIP and NEEM ice core publications and less relevantly Dye-3 in southern Greenland. They look at strontium 87/86, neodynium 143/144, uranium 238/235 and less commonly hafnium 176/177 isotope ratios. Sahara dust (which reaches the US east coast) and deserts of the American southwest seem alot 'closer' to Greenland than the Tarim Basin, yet to get to northern Greenland latitudes of GISP2, NGRIP and NEEM, only the Taklimakin dust gets wafted high enough (ie into the upper troposphere, ref 1 below).

In these ice cores, the loess quartz dust is primarily from Luochuan in north central China. Dated tephra is almost entirely attributed to eruptions of nearby Jan Mayen and Iceland volcanoes with rarely input from Alaskan. Prevailing westerlies do not notably bring in tephra from the western US or massive Ring of Fire events as the latitudes of origin give them downwind trajectories that don't deposit significant amounts in northern Greenland

Note these cores go back to the Eemian, so the dust events history covers some 125,000 years, though sometimes melt pooled from several years is required to get enough for analysis.

So to associate them consistently with SSW events requires that the latter's geographical generating mechanism be operative for many millennium. Conceivably, the core dust profile could provide a long term record of major SSW events, at least the ones significant enough to descend on Greenland.

You could start with these and their internal literature reviews:


R. Gates

Thanks A-Team. This is not an area I have much knowledge of but this association between the Tarim Basin and Greenland ice core dust has really made my day. You'll see why on Monday, after I do some additional confirmatory research-- but I think my SSW post just got a bit longer.

Susan Anderson

R. Gates and A-Team:

You sure are kicking up some dust! Looking forward to the post. That is just fascinating, I agree.

Paul Beckwith

@R. Gates
Why do a blog/post on this. Why not write it up in a paper and submit it to Science or Nature. Include A-Team and others, a neven group publication. Instead of blogging on Monday there could be a paper on the following Monday.

It looks like Tarim Basin, which is actually in China as opposed to Mongolia is in the perfect spot to contribute dust to the jets. It is behind the Himalaya's so when the jets are forced upward by the 5.5 km or so high mountains the leeward vortices pick up the dust and carry it into the stratosphere where it is above all the scavenging weather, so remains there until it plops down on Greenland.

So what is the initial trigger for the SSW events. Obviously the jets have to move to the right spatial location, and height is important. The latitude of about 37 degrees N suggests the tropopause height to be about 13 km or so high, so if the jets are at that height the 5.5 km mountains are a bump and the jets may not get a sufficient vertical velocity component to crack into the stratosphere.

It seems to me that the lower the altitude of the jets, the larger the vertical velocity kick and the larger the SSW event. Also, in this part of the world the jets have really large speeds. Not only that, but as the jets are torqued upward they acquire strong rotation about a horizontal axis, which aids in picking up the Tarim dust. With climate change and increased CO2 the tropopause thickness can decrease, making it easier to penetrate into the stratosphere. Not to mention the latitudinal change of the jets as the global circulation changes with collapsing Arctic albedo.

Over Greenland the ice surfaces are over 3 km high, and the tropopause is down to about 7 km, so the descending jets from the stratosphere have good reason to come down over Greenland as opposed to other Arctic regions, and deposit their dust there.

Steve Bloom

R. Gates, I expect you've reviewed them, but just to make sure I wanted to point out the large number of recent papers on SSWs and related topics.

Remko Kampen

“These seas are paramount for moderate winters in Northern Europe.””
(Posted by: Arnd Bernaerts | April 17, 2013 at 15:01 )

In fact the Atlantic, not its tiny rim seas, plus the normally westerly circulations are the factor for moderate winters in Northern Europe.
Reverso, cold winters in this region always result from anomalous circulation types called ‘blocking events’ and these effectively cancel away all sea influence, for they induce northerly to easterly air currents (thus resulting in weather belonging more to the Newfoundland climate, which is continentally cold by virtue of same westerlies!).

“The impact of off-shore wind farms, shipping, and fishing on the extreme March conditions should not be ignored and thoroughly understood. March 2013 offers a unique case for investigation.”

No, the impact of those were nil. The extreme March conditions reigned over the entire northern hemisphere and were actually most marked more inland – Poland to western continental Russia up to deep in Siberia; also the US had a fairly cold March. The reason for this anomaly pattern was a huge Arctic high pressure zone which displaced Arctic air all over the hemisphere to moderate climate regions. The influence of little splashes of water like North- and Baltic seas on this kind of event is nil. It was also locally nil simply because the continental winds never travelled over those seas (or wind farms, for that matter). It was cold because easterlies in Europe are cold in wintertime and March this year sported a uniquely long spell of such easterlies.

You should leaf through an archive like this to expand your meteorological world view: http://www.wetterzentrale.de/topkarten/fsreaeur.html

Actually the one comparison to the recent Arctic high pressure event is this: http://www.wetterzentrale.de/pics/archive/ra/1940/Rrea00119400117.gif
Look at the giant Arctic high pressure zone, and please evaluate how totally negligable the little European seas are compared to this.

On average, by the way, March 1987 in the North Sea countries was colder. Why? Big blocking event resulting in easterly, therefore and only therefore (in March) frosty winds. See: http://www.wetterzentrale.de/pics/archive/ra/1987/Rrea00119870308.gif
Again, the North Sea is no more than a droplet compared to the scale of Rossby patterns.

Arnd Bernaerts

@ Remko Kampen 19/Apr.
Thanks again, but regrettably you have not taken any look at the reference given for the extreme winters 1939/40, 1940/41 and 1941/42, and not indicated or offered a more convincing explanation.

The statement “In fact the Atlantic, not its tiny rim seas, plus the normally westerly circulations are the factor for moderate winters in Northern Europe.” is to a high percentage very correct, but only a detailed analysis show how regional climate is also strongly influenced by tiny seas. This is particular effective (and much easier to investigate) during the time of the years when the influence of the sun is low, e.g. in sea areas north and east of Creac'h (Quessant Island) Light (SW English Channel).

Concerning the winter 1939/40, your reference to the 500pPa-airpressure over N-Europe on 17 Jan, 1940 (wetterzentrale.de), tells nothing about the developments since the 1st Sept. 1939, which indicate to the build-up of a huge blocking system in place since about mid December 1939 that started many weeks earlier, see Chapter 5, p.67-74, at http://www.seaclimate.com/c/c5/c5.html . On several days since October the marine weather service “Seewarte” complained that the usual maritime air moving across Central Europe was low, not existing, or moving elsewhere.
See another source on air pressure development
___in late autumn 1939 http://www.seaclimate.com/c/c4/images/buch/big/C4-3.png
__in December 1939 http://www.seaclimate.com/c/c4/images/buch/big/C4-4.png
which finally cause an extreme winter 1939/40 with the center over North-Europe, shown in a global map for the 1st Quarter, plus Jan. to May 1940:
__ http://www.seaclimate.com/c/c1/images/buch/big/C1-6-TM4.png
There are innumerable signs and evidence between naval war and war weather conditions. For example:

To understand how naval war in the North and Baltic Sea already influenced wind in Western Europe (UK) is highlighted in observation by A. J. Drummond from Kew-Obs published 1943. During 155 years of observation only in the winters 1814, 1841 and 1940 wind came from the NE-sector, see graphic: http://www.seaclimate.com/c/c5/images/buch/big/C5-9.png . The “Seewarte” also recorded a reverse in the wind direction during October 1939 in Central Europe: http://www.seaclimate.com/c/c5/images/rand/big/7.jpg . This eventually presumably led to the most severe blocking of westerly winds over Europe for which sufficient data are available. The influence of the North- and Baltic Sea, which usually supply heat to the atmosphere (ensuring moderate temperature in the region) until the last winter days very, is essential for a moderate winter season. Here is an example on SST from the German Bight (Ems) from 13-27 March 2013, http://www.2007seatraining.de/Archiv/images/b/1310_11b_.jpg , the annual for the year 2011 is here : http://www.bsh.de/de/Meeresdaten/Beobachtungen/MARNET-Messnetz/historisch/ems_his/ems_temp_salz.html/ems_tem_2011.jsp

The most relevant point is not the volume of the NS + B, but the size of the surface, the capacity for a months long heat release, and the surrounding geographical features. This would be better understood if cause, relation and impact of the war winters 1939/40, 40/41 & 41/42 in Europe would – eventually after more than 70 years - thoroughly be investigated. The anthropogenic link can presumably be more easily established during the war years, than in any other winter. Nevertheless, spring 2013 with sub-normal sea ice conditions in the Baltic and sub-low water temperatures in the western Baltic and North Sea since early March until now (19/Apr) may also offer a number of interesting climatic mechanisms on weather in Europe, and the overall condition during winter 2012/13.


Paul, papers take forever and a day. Only one paper in four submitted to Science is even sent out for review and only one in three of those is ever published.

Behind their paywall. Where it doesn't move the needle. Not that it would anyway.

That takes a title like "Life after SSWs: will there still be a cannabis crop?"

Last week, I had a paper (hopefully my last) accepted for May 2013 publication in PNAS. I finished my end of it in mid-July 2012. And this is with 2 of 3 reviewers saying it represented a major breakthrough unifying two large academic disciplines.

I favor real-time open-source publishing. For the last ten years, I've just posted daily work-in-progress on the local campus implementation of wikipedia.

That's a great collaborative environment (that you control as originator) and best of all, has infinite undoes, is free of length constraints, but provides no deleting. Knowing I'm going irrevocably on the record that day induces me to get my data and exposition halfway together as it will show up forever on google search.

You might think some jerk -- like Watson and Crick -- would come along and steal the ideas before I could write it up for a journal. Hasn't happened -- most scientists have more integrity than that.

Mostly I have met collaborators who shared my interests. Whether the other millions of visitors got useful information or quickly realized their mistake, I couldn't say.

Journals have not taken this as pre-publication but instead have allowed it as direct supplemental material.

The bottom line however is someone has to sit down and create real content. Having a bunch of mice sitting around waiting for a volunteer to bell the cat just doesn't go anywhere.

Good news and bad news:

The bad news is now I will have a lot more time for climate blogging. Since that amounts to typepad haiku, I've been laying down bits and pieces the last few months so future posts can be more in-depth, just citing older ones for background.

The good news is from Monday on, I will be offline camping in southern Utah until mid May, with motel internet only during bad weather. So post away, no adult supervision.

Remko Kampen

Arnd Bernaerts | April 19, 2013 at 15:11 -

I am beginning to wonder how you are going to relate the febs 1929 and 1956 to naval operations. Or the two massive winters of 1947 and 1963.

"The most relevant point is not the volume of the NS + B, but the size of the surface, the capacity for a months long heat release, and the surrounding geographical features"

I'd surmise capacity has all to do with volume. Please show me on charts like these where and how the circulation of half a hemisphere is drastically influenced by North Sea and Baltic Sea, you may add in a feature like the Scandinavian mountains:

A bitterly cold pre-war December snap:

A most ordinary, mild northerly displaced westerly pattern in the thick of war:

Advent of the most spectacular blizzard of one of the strangest European winters ever, 1979:

I repeat: North/Baltic Sea could've just as well not existed but be grasslands. Big features like the entire North Atlantic, Greenland and the Arctic seas/ice - yes, they count. It so happens the patterns that determine our weather are of comparable size. They do not 'feel' puddles like the North Sea.

The run of particularly severe winters during the 40's is remarkable, but not unique - by the way, you cannot put 1939-1940 into your set because this was the winter of the 'Phony War' - there was virtually NO fighting during that winter!
For a worse run of bizarly cold winters, try the 1690's. If you test for an anthropogenic link to the WW II winters then you MUST show how this link could NOT be attributed to the 1690's AND you MUST show that the 1690's were cause by something totally different.

Ps, you are quite right to check the days/weeks leading up to a particular chart. Of course 17th January 1940 cannot be understood just like that. It is a snapshot of a process.

Remko Kampen

Arnd posted: "Here is an example on SST from the German Bight (Ems) from 13-27 March 2013, http://www.2007seatraining.de/Archiv/images/b/1310_11b_.jpg"

The drop in SST's was the result of the prolonged cold easterlies of during the second half of the month of March (the first half btw sported some extremely warm days).
Not the other way round.

During past March, negative from climate temp anomalies were largest in Poland and western Russia. These regions were never touched by air from the North Sea or Baltic during the period (neither was Holland). Everything came from the Russian arctic and only that explains the cold weather in western Europe, and only that explains the drop in SST's there.

Presently SST's in North and Baltic Seas are rising again. Single and simple cause: air transport from warmer zones (between Iberian Peninsula and Azores). In fact in Holland and region half April was remarkably warm, notwithstanding that very cold North Sea water.

How small the North Sea pool actually is could be witnessed yesterday. The entire day very windy from the west, with gale force winds moving even up to 50 km inland.
Chart: http://www.knmi.nl/klimatologie/daggegevens/weerkaarten/2013/analyse_2013041818.gif .

Nevertheless temps yesterday were about 4° C above normal values for the time of year.
http://www.knmi.nl/klimatologie/maand_en_seizoensoverzichten/maand_260_grafiek.html .
So this event showed: you have a North Sea with SST's around +5° C; you have a full day of westerly breeze to almost severe gale force winds blowing over that sea inland and you are also actually behind the cold front, and you still get a day that is far warmer than climate wants it to and over ten degrees above SST. This simply PROVES the larger scale origin of the maritime polar air cruising through our country is MUCH more important than the little pool before the Dutch doorstep.

Arnd Bernaerts

@Remko Kampen | April 19, at 15 & 16;

Not once the years/months in 1929 and 1956 or 1947 and 1963 were ever mentioned, because the discussion is about March 2013 and previous comments indicate cold March months during the two world wars. Kindly take note of an overview on winter severity by C.B. Groismayr (1944), based on three successive winters from 1854 to 1942, http://www.seaclimate.com/b/images/buch/big/B-4.png and the exceptionality of the war winters 1939/40 to 1941/42.

___@ “A bitterly cold pre-war December snap:”
The winter of 1938/39 had been mild except for a brief cold spell in December 1938 that lasted from 15 to 20 December; see Global T°C map, winter 1938/39 (Dec/Jan/Feb): http://www.ocean-climate-law.com/Material/nasa_imag/9Q1.gif , and the recent December 2012 cold spell was presumably more interesting: see here: http://www.2007seatraining.de/Archiv/dec9_12.html , resp. in December 2010, here: http://www.2007seatraining.de/Archiv/dec2_10.html

___@”1939-1940 …. was the winter of the 'Phony War' - there was virtually NO fighting during that winter!”
At sea the war was real and huge naval activities were going on; read Ch. 3,6,7 & 8 at: http://www.seaclimate.com/_ToC/_ToC.html ; for example on mining (p. 55f): During the first four months of war the number of mines laid was possibly in the range of 75,000 to 150,000 or more. The Germans plastered the Helgoland Bight with 40 to 80,000 mines before the end of 1939, and the British Admiralty intended laying a 500-mile minefield of unprecedented size, in a “gigantic effort to check the German submarine campaign”. (NYT, Dec. 31, 1939) A few days later it was reported: “British naval vessels are sowing some of the last mines needed to complete Great Britain’s 30,000,000-pounds protective shield for east-coast shipping. The minefield extending from Kinnairds Head , Scotland , almost to the mouth of the Thames , is the most extensive field ever laid.” (NYT, Jan. 11, 1940).

Concerning Northern Europe temperature today ( 19th April),
__SST in the North Sea and S-W Baltic are still below average, here; http://climate-ocean.com/2013/b/9_4_25b.jpg
___the air T°C anomalies are according forecast (15-22 Apr) above normal,
here: http://climate-ocean.com/2013/b/9_4_24b.jpg , and --
___ the Baltic Sea ice is below average,
here: http://climate-ocean.com/2013/9_4.html & here: http://climate-ocean.com/2013/b/9_4_27b.jpg

R. Gates

Paul Beckwith,

Thanks for your feedback, and I expect much more feedback from you and others after Monday's post. (as I live in Colorado, USA I will actually be putting this up late Sunday night my time)

You ask why do a blog post? Well, consider it a public e-publication. No one can dispute when or by whom the ideas were presented (much like my claim to the naming of the Great Arctic Cyclone of 2012).

Actually though, I think since the ideas will be presented with all the custom graphics and years of reanalysis data, that will be proof enough of the overall originality of the concept. Most of all, I really would like feedback and crowd-review. If I'm correct in all the dimensions of my overall concepts and theory, there'll still be a ton of corroborative testing and field research to do, but the the "mystery" of SSW's in the Northern Hemisphere might essentially be solved...

Chris Reynolds

Don't know if this one's been linked to previously here, but it's worth a read:

Tang et al 2013, Cold winter extremes in northern continents linked to Arctic sea ice loss. Open Access paper.

R. Gates

Just a quick update to my upcoming post on SSW's. I'm on a very good track to complete this post by my self-imposed Monday, April 22nd deadline. It is long, but I think will be well worth your time. Currently it is approaching 2800 words with 16 different graphs, charts, animations, etc. I think I'm about 75-80% complete, possibly more.

Remko Kampen

Arnd Bernaerts | April 19, 2013 at 20:22

With respect but your theory is nonsense.

I deliberately chose the cold spell in the winter 1938-39 for just a cold spell - but December 1933 was MUCH colder.

During the so-called 'Phony War' there was virtually no warfare. None on the oceans. The mining of the few drops of water called the North Sea doesn't matter. In fact last Thursday's little gale will have churned the entire North Sea more than all the battles of history fought there combined.

You cannot explain why the winter 39-40 during the Phony War was so severe; why the winter of 40-41 when fighting was on in earnest was cold but much less severe. You may be granted 41-42, but you cannot explain why the four successive winters, two of which during the thickest of fighting the world has ever seen and two after WW II, were mild. You cannot explain why during low economic and warfare activity winter 46-47 was more severe than any winter in almost 100 years preceding it (it is still the coldest since 1845 except for 1963).

Besides, actually shipping in the North Sea during most of the war was very slack indeed. Because of the war, we can say. Merchant shipping was all but gone. Large military fleets did not roam the North Sea precisely because of mines and respective air forces. During these conditions both very mild and very cold winters emerged. As you can see, they had no relation to what happened in our little seas at all.

Please explain to me how a blocking event spanning an area of like 100 times our little mud puddles can be related to those puddles. Please explain to me how such an event caused cold spells over almost all of Europe (an area vastly larger than North/Baltic Seas combined) and at the same time caused very mild spells over the Hudson/Baffin/Greenland region (an area vastly greater than N, B Seas combined, and ten times distant from here as the length of the North Sea while being the result of the exact same blocking event).

SST's in North Sea and Baltic Sea are below average because of the prolonged cold easterlies of March and this linger for a couple weeks. But so what?

Chris Reynolds


"With respect but your theory is nonsense."

Phew, somebody said it at last!

Now I can say what I've been thinking all along. It's old, but it's a classic.

Piracy as a preventer of Tropical Cyclones.

Arnd Bernaerts

@ Remko Kampen | April 20, 2013 at 22:10

__You raised as an example Dec.1938 about an extreme cold spell, which was easy to indicate as one without any impact on the winter 1938/40, which was one of the warmest since the end of the LIA !
Each war winter can be perfectly explained based on the most pronounced naval sea area activities!

__As you do not want to take note of the rich information and in-depth discussion of naval war activities in World War II at http://www.seaclimate.com/ , or reply to events mentioned, here a few excerpts:
___War winter 1939/40:
• An example from early November 1939: “Gales have loosened several hundred mines in the German mine fields… drifting mines exploded on the coast near the suburbs (of Copenhagen ), breaking windows and with their terrific detonations frightening citizens. Naval crews have destroyed no fewer than forty-three mines from Koege Bay up to Amager Island , where 100,000 Copenhagen residents live in a district comparable to Brooklyn . Along the whole southern coast mine alarms often make it necessary to evacuate villages while experts discharge or explode the mines. So many mines are floating around that it is impossible to destroy all of them in the bad weather” (NYT, Nov 06 1939).”
• On 8th of March 1940 the Baltic was entirely covered with sea ice for the first time since 1883!
---extreme ice years 1720 to 1942: http://www.seaclimate.com/b/images/buch/big/B-16_iccover.png
¬¬---Baltic ice cover on 8 March 1940 : http://www.seaclimate.com/c/c7/images/rand/big/_1.png
• AND: have you ever heard of the Russian /Finnish war in the E-Baltic? See Chapter C6, p.75 f: http://www.seaclimate.com/c/c6/c6.html

___War winter 1940/41 raised record low temperature around the Skagerrak region, after the German Navy sailed and operated in Norwegain waters since April 1940; see Ch. 6: here http://www.seaclimate.com/d/d.html with record low T°C in
o Denmark : http://www.seaclimate.com/d/images/buch/big/D-7-.png
o in S-Norway _ http://www.seaclimate.com/d/images/buch/big/D-8.png

___War winter 1941/42: After six month naval war in the eastern Baltic the temperatures plunge to record low:
o Eastern Baltic 1880-1990 : http://www.seaclimate.com/e/e1/images/buch/big/e1-1.png
o Tallinn 1880 to 2005: http://www.seaclimate.com/e/e3/images/buch/big/e3-6.png
o The fighting in the Baltic Sea generated a so early and severe cold that the German Army abandoned to reach Moscow as planned; Ch. E1: “Nazis give up idea of Moscow in 1941. Winter forces abandoning big drives in the north until spring, Berlin says” (NYT, Dec. 09, 1941).” http://www.seaclimate.com/e/e1.html

INDEED the biggest naval war fighting took place since Dec. 1941 in the North Atlantic and the Western Pacific; which propelled the global climate into a global cooling process for about three decades, actually form winter 1940 to the mid of the 1970s. See G (http://www.seaclimate.com/g/g1.html ) & H (http://www.seaclimate.com/h/h.html )

Concerning blocking in Europe one only need to reckon that the colder the N&BS are, the more they act ‘continentally’, and more easily support the processing of a blocking situation. For autumn 1939 see Ch. 5: “Jet stream blocked by naval combat?” http://www.seaclimate.com/c/c5/c5.html

Permanent activities in the marine environment of the N&BS have significant impact on temperature and salinity (at least in the NS), but science does not care and does not know.


Remko Kampen, you've made a valiant effort, but it's probably about time to let this one be. there's eccentric, there's weird, and there's batshit crazy. it's not possible to reason productively with a true believer

Steve Bloom

Neven, I'm going to suggest placing AB in moderation and deleting his comments from the moment he launched into the warfare-climate business. It's an old internet trope, from before your time I suspect. In any event it's the sort of thing that destroys the value of comment threads if allowed to continue, so please put a stop to it now.


I'm sorry, I wasn't reading Arnd Bernaerts' comments, as I don't have any time for long-winded not-to-the-point texts. It looked harmless to me, but it's getting a bit boring now.

Arnd Bernaerts, could you please stop what you're doing? Keep things on-topic and to the point.

Espen Olsen

Completely unrelated but big, at least the cracks are, the cracks are appearing across the GIS!!!! See more:


Peter Ellis

Aircraft contrail.

Espen Olsen


Aircraft contrail.Nope!




Arnd Bernaerts may have got one point right about March temperature anomalies.

Having lived through a number of decades myself, having heard ancestors tell about the WW-II winters, and having spent some time studying palæo-climatology, I can state the following:

1) March mean temperatures in Copenhagen in the 1780ies and 1840ies were as low as -5 degrees C – devastating cold periods according to all contemporary sources.
2) March mean temperature in Copenhagen in 1942 was -3.5 degrees C – a bitterly cold period leading to frost bites occasionally.
3) Copenhagen this year in March had average temperature around -0.5 degrees C, despite the fierce easterly winds – no frostbite at all , no sea ice in the Baltic and no war in the North sea.

These numbers just make the point, that despite roughly similar circulation patterns in those years, we have changed the climate system in such a way, that not even the Government believes in a renaissance of cold anomalies anymore - see


Let’s try to keep the perspective on this blog in the Arctic and stick to the current calamities.

R. Gates

SSW post update. I'm just doing spell checking and some minor clean up. I hope to actually post this Sunday evening (Colorado time).


Sorry guys

That link should have been to a story about a government trying to sell three ice-breakers...

try http://www.maritimedenmark.dk/?Id=16383

and search for icebreaker Dec 12, if you wish.

Shared Humanity

Arnd Bernaerts | April 19, 2013 at 20:22

With respect but your theory is nonsense.

At five years old, I did not like to take a bath. Mom got me a bunch of toy boats as encouragement. I would swirl them around in the tub and the water got noticeably cooler. So there is that.

Artful Dodger

Hi folks, let's move on.

Shared Humanity - Please DNFTT. :^)

Peter, LOL. Are you HAARP'ing about Aircraft contrails again? ;^)

Cheers, and have fun!

Remko Kampen

"Remko Kampen, you've made a valiant effort, but it's probably about time to let this one be."
Said Sofouuk, for which I thank him.
I give a benefit of the doubt at first with some, that's what the effort was for. Only once.

Meantime the discussion was, imho, more or less on topic. If we are to identify 'weather weirdness' re the Arctic and it's evolution of climate/sea ice, then differential analysis must be done, too. The winters of the 1940's are very important material to compare recent events with. In fact, last year I at first dismissed work of Francis et al for reasons of absence of such comparison (this dismissal is totally over, though).

Chris Reynolds


It was on topic, Ardnt's claims were just b_____ks.


It looks like there's going to be a meeting at the White House about arctic sea ice as well:


Shared Humanity

The forecasters are beginning to get it. What is particularly interesting about this forecast for the U.S. is that it mentions the blocking patterns they expect to see.



New paper in GRL collaborating link between cold winters in Europe and Sea Ice melt:


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