Arctic Amplification and Extreme Weather

[oren]

Is there a long term chart showing the continents getting absolutely colder as the Arctic is getting warmer? Or, as El Cid has shown, that it's only the continents warming less than the Arctic?

[sark]

at this point?  probably not... I guess you'd have to help me hone in on the prediction in question and see if it's a testable hypothesis.  Is the question, will the WACC trend hold forever? 

[sark]

When those articles were published, it was true.  Now?

OK, let's just compare a 5 year average from 2000-2020 of DJF surface temperature anomalies +/- 1.5... like an autosquint function... exaggerated.  Compared to the 1979-2000 average.  We're talking about articles published back a few years ago.  in the last few years the cooler trend anywhere is pretty much annihilated.

click to run

[El Cid]

You only pick certain months, in certain years, and compare to a warm baseline (1981-2010), in order to show the signal you are looking for. This means there is no such widespread trend of WACC for the time being.

Exactly my thoughts. We must compare the last years to the "pre-globalwarming" years. The 1980-2010 "baseline" already contains many very warm years obviously.

Here is a comparison of the past 10 (no handpicking) years (springs only) vs 1950-80. NO WACC. Second pic: 2011-2020 vs  2001-2010. You can see that the pole of cold is pushed into the Hudson-S.Greenland region. This certainly shows some WACC-yness. With a constantly warm Bering and Barents the jetstream is likely becoming curvier - I agree. However let's not forget that all those cold outbreaks are less cold than they used to be, simply because the air above the Arctic is warmer. So yes, there are places where there are more cold outbreaks but the outbreaks are likely not as cold as previously could have been

And net-net, as you can see on third picture (2011-20 springs vs 2001-2010) midlatitudes ARE warmer even vs 2001-2010), so this is more a local effect

[oren]

Thank you sark and El Cid.

[kassy]

And 2020. Yikes. Very bad!

I know I sound a bit combative here but I am not trying to be rude. The blended years since 2012 do not show the WACC-y signal since it is not yet consistent EVERY year but it has been since 2017 I believe.

The picture shows a cold America. Continents is multiple and Eurasia is not that cold. Hence is does not show the signal.

[wdmn]

I'm very interested in the "cool" Spring signal in North America. Is it just noise?

In any case, it's a hurdle for educating people on climate change. People here around the Great Lakes notice it when Spring starts late, or when we get old style extremely cold winters.

[gerontocrat]

And 2020. Yikes. Very bad!

I know I sound a bit combative here but I am not trying to be rude. The blended years since 2012 do not show the WACC-y signal since it is not yet consistent EVERY year but it has been since 2017 I believe.

The picture shows a cold America. Continents is multiple and Eurasia is not that cold. Hence is does not show the signal.

https://journals.ametsoc.org/jcli/article/33/18/8069/348406/Severe-Cold-Winter-in-North-America-Linked-to
Severe Cold Winter in North America Linked to Bering Sea Ice Loss

Our study under the present climate shows that severe cold winters in North America are linked to Bering SIA loss via the negative ALO–ANA pattern. In the near future, with little or no sea ice in the Bering Sea, this negative ALO–ANA pattern may occur more frequently, or a completely different climate mode may appear. To predict severe cold winters in North America under global warming, it will be necessary to model regional and general climate systems with little or no sea ice.

[kassy]

I'm very interested in the "cool" Spring signal in North America. Is it just noise?

In any case, it's a hurdle for educating people on climate change. People here around the Great Lakes notice it when Spring starts late, or when we get old style extremely cold winters.

See the article by gerontocrat above.

And i think there is also another reason. On the ASIB wayne used to discuss things as were the cold poles went. In the old days it could be on the Arctic ice or travel over it and hop to Siberia.

The last couple of years the American side near the Arctic is always much colder and as discussed on the Melt Season thread yesterday or today it seems the arctic is leaking air cold and that is going south into America.

For climate change you should tell them about the world. But it´s hard to explain that 0,5 C global really matters. 

[El Cid]

I'm very interested in the "cool" Spring signal in North America. Is it just noise?

I think it is a temporary and local effect. I drew a very basic sketch showing probably what is going on (very unscientific, layman terms, sry for that).

On the chart we can see 2019 vs 1995 (I could have picked any earlier years as well). As the Bering/Chukchi and the Barents is much warmer and ice free for a very long time, warm air can intrude here (creating the Alaskan Ridge and European warm weather) shown by red. However, this pushes cold (blue) out of the Arctic which could go to Siberia or Canada. Unfortunately for Canadians, the shallow Siberian seas are usually also very warm lately (green) as evidenced by late freeze-ups, so the cold air is pushed into Canada.

This might not be very scientific but I think it is more or less true

[kassy]

I like that (although only a layman to so FWIW).

[gerontocrat]

As the Bering/Chukchi and the Barents is much warmer and ice free for a very long time,

The attached graphs show the (not so) gradual and continuing transformation of these seas into open water seas from icy deserts.

[El Cid]

That is great gerontocrat, as these charts underscore that the Chukchi/Bering side has fundamentally changed during the past 5-6 years.
The Barents actually changed after 2007, not lately.

thanks

[sark]

Summer polar amplification has never really been seen to this extent, as in the past 2 years.  And, in 2020, we have an appearance of the third pole of cold?

Unfortunately there is huge model variance on what is actually going on over the Tibetan Plateau this Summer, and continuing still today...

Would someone check the ERA or MERRA records to see what is being reported in this region?  surface temperature anomaly, SLP anomaly, 500mb temps & heights even...

Specifically May - August of 2020 is very interesting as there is still model variance on what is even going on here.