......

[bluewave]

.....

 

 

 

 

 

[nflwxman]

http://web.mit.edu/jlcohen/www/papers/Cohenetal_GRL2012.pdf

 

 

] Current consensus on global climate change predicts warming trends driven by anthropogenic forcing, with maximum temperature changes projected in the Northern Hemisphere (NH) high latitudes during winter. Yet, global temperature trends show little warming over the most recent decade or so. For longer time periods appropriate to the assessment of trends, however, global temperatures have experienced significant warming trends for all seasons except winter, when cooling trends exist instead across large stretches of eastern North America and northern Eurasia. Hence, the most recent lapse in global warming is a seasonal phenomenon, prevalent only in boreal winter. Additionally, we show that the largest regional contributor to global temperature trends over the past two decades is land surface temperatures in the NH extratropics. Therefore, proposed mechanisms explaining the fluctuations in global annual temperatures should address this apparent seasonal asymmetry. Citation: Cohen, J. L., J. C. Furtado, M. Barlow, V. A. Alexeev, and J. E. Cherry (2012), Asymmetric seasonal tem- perature trends, Geophys. Res. Lett., 39, L04705, doi:10.1029/ 2011GL050582.

 

 

Screen shot 2013-09-13 at 10.48.58 AM.png

Thanks for posting bluewave.  Tamino had a post on this which I outlined in the 2013 global temperature thread.

 

Tamino had a very interesting post about the seasonal impact of ENSO on global and particularly northern hemispheric temperatures.  His analysis is based on the findings of  Kosaka and Xie (2013, Nature, doi:10.1038/nature12534), where scientists ran a model (GFDL) that simulated the recent hiatus using the widely estimated climate forcings.  However, the model even took it a step further and correctly estimated the seasonal impact of ENSO on global temperatures (focusing mostly on the N. Hemisphere).  As you can see, winter temperatures were far more impacted by changes in ENSO.  They go on to note that the Foster and Romhstorf paper from 2011 could be improved by including a more robust seasonal model with ENSO (I know a few people noticed there was quite a bit of ENSO resididual in their original analysis). Here is a note from the paper..

 

"We examined regional climate change associated with the hiatus. Although models project a slowdown of the Walker circulation in global warming¹⁵, the Pacific Walker cell intensified during the past decade (Fig. 2c). POGA-H captures this circulation change, forced by the SST cooling across the tropical Pacific (Fig. 2d). As in interannual ENSO, the tropical Pacific cooling excites global teleconnections in December, January and February (DJF; the season is denoted by the first letters of the months). SST changes in POGA-H are in broad agreement with observations over the Indian, South Atlantic and Pacific oceans outside the restoring domain (Fig. 2a, . The model reproduces the weakening of the Aleutian low as the response of the Pacific–North American pattern to tropical Pacific cooling¹¹ (Fig. 2c, d). As a result, the SAT change over North America is well reproduced, including a pronounced cooling in the northwest of the continent. The model fails to simulate the SAT and sea-level presure (SLP) changes over Eurasia, suggesting that they are due to internal variability unrelated to tropical forcing (Extended Data Fig. 5a and c)."

 

 

 

 

 

 

http://tamino.wordpr...nino/#more-6769

[ORH_wxman]

This is a pretty interesting read.

 

Their study mentions what I had been thinking when I saw it....that climate models and AGW predict that the highest positive temperature trends would occur in the northern hemisphere winter at extra-tropical latitudes....which is precisely the opposite of what has actually been occurring.

 

The study then goes on with how the AO may be a large factor...and mentions how AGW theory also predicts a positive trend in the AO, not negative:

 

 

Studies like this are good for tackling research inside the problems with GCMs.

[The_Global_Warmer]

Probably the Barents/Kara High pressure cell to some extent.

 

The OHC like 70N from the Atlantic towards the  Kara has increased a ton. I haven't seen data for the last couple years but obviously we have all watched tremendous amounts of heat get dumped into water there.

 

 

 

This is just the in the most recent years though.

 

 

 

[TerryM]

Canadian temperatures might be indicative for the western hemisphere.

Terry

[tacoman25]

Canadian temperatures might be indicative for the western hemisphere.

Terry

 

 

That's annual temps though, not winter, which this thread is focused on.

[tacoman25]

As far as the other seasons go, I believe that spring overall has followed winter's trends more (cooler), and fall has followed summer (warmer).

[TerryM]

Taco

The graph is winter temps. link to page is below.

http://www.ec.gc.ca/adsc-cmda/default.asp?lang=En&n=8C03D32A-1

Apologize for not noticing that the graph in question didn't mention the season it was depicting.

Terry

[tacoman25]

Taco

The graph is winter temps. link to page is below.

http://www.ec.gc.ca/adsc-cmda/default.asp?lang=En&n=8C03D32A-1

Apologize for not noticing that the graph in question didn't mention the season it was depicting.

Terry

 

Ah, ok. Well Canada has apparently had warmer winters overall the past 5-6 years compared to Europe/Asia/U.S. Clearly warmer than the NH mean.

[ORH_wxman]

Ah, ok. Well Canada has apparently had warmer winters overall the past 5-6 years compared to Europe/Asia/U.S. Clearly warmer than the NH mean.

 

 

Western Canada up through Alaska has cooled in the means in winter...but northeast Canada has torched...particularly the further NE you go into the NAO domain. We've had incredible blocking there in recent winters which has meant very mild temps in that region.

[TerryM]

Western Canada up through Alaska has cooled in the means in winter...but northeast Canada has torched...particularly the further NE you go into the NAO domain. We've had incredible blocking there in recent winters which has meant very mild temps in that region.

Actually a small area in the far north west cooled slightly but almost all of the country warmed, some considerably, which is undoubtedly what lead to the ~5 1/2F increase over the last 60 years. Bearing in mind that Canada is approximately as large as the contiguous US AND Mexico temperatures there account for about 40% of the temperatures over land in the northern hemisphere.

Terry

[The_Global_Warmer]

How have Central America/Mexico temps changed?

[TerryM]

Alaska apparently followed Canada in having warmer winters going forward in time.

Terry

[ORH_wxman]

 

Actually a small area in the far north west cooled slightly but almost all of the country warmed, some considerably, which is undoubtedly what lead to the ~5 1/2F increase over the last 60 years. Bearing in mind that Canada is approximately as large as the contiguous US AND Mexico temperatures there account for about 40% of the temperatures over land in the northern hemisphere.

 

Terry

 

 

The study focuses on the last 15-25 years. Almost everyone has warmed in the past 60 years.

 

 

 

[TerryM]

"The study focuses on the last 15-25 years. Almost everyone has warmed in the past 60 years."

 

The chart I posted seems to show an increased rate of warming over the last 25 winters.

 

Friv

Mexico seems to be warming faster in winter than in summer as well..

"For the summer the trend is 0.17 oC per decade (5th to 95th percentile of slopes: 0.10 to 0.24 oC per decade) and for the winter the trend is 0.26 oC per decade (5th to 95th percentile of slopes: 0.16 to 0.36 oC per decade"

according to

http://www.metoffice.gov.uk/media/pdf/c/6/Mexico.pdf

[tacoman25]

Actually a small area in the far north west cooled slightly but almost all of the country warmed, some considerably, which is undoubtedly what lead to the ~5 1/2F increase over the last 60 years. Bearing in mind that Canada is approximately as large as the contiguous US AND Mexico temperatures there account for about 40% of the temperatures over land in the northern hemisphere.

Terry

 

 

What is the time frame for that map? Will was only talking about the past 5-6 years, when much of the NH has been cooler during winter than Canada, including the U.S., Europe, and much of Asia. When I say cooler, I mean cooler than the 30 year mean. Of course anomalies have still been warmer overall for the NH than 60 years ago.

 

Which is why the 1987-2013 and 1997-2013 maps he posted above show a lot of winter cooling for the NH, with notable exceptions in far northern Russia and northeastern Canada, which have seen warming.

[ORH_wxman]

"The study focuses on the last 15-25 years. Almost everyone has warmed in the past 60 years."

 

The chart I posted seems to show an increased rate of warming over the last 25 winters.

 

Friv

Mexico seems to be warming faster in winter than in summer as well..

"For the summer the trend is 0.17 oC per decade (5th to 95th percentile of slopes: 0.10 to 0.24 oC per decade) and for the winter the trend is 0.26 oC per decade (5th to 95th percentile of slopes: 0.16 to 0.36 oC per decade"

according to

http://www.metoffice.gov.uk/media/pdf/c/6/Mexico.pdf

 

 

That is because it has. Only western Canada has cooled and the magnitude of the cooling is not enough to offset the extreme warmth in Northeast Canada. You can see from the maps I posted that the majority of the cooling in winter since the mid-late 1980s has been in Siberia and Europe....the U.S. joins the steeper cooling trend once we move up to the past 16-18 years.

 

Canada's warming trend has slowed down only since the mid 2000s.

[tacoman25]

Another way to illustrate what's been going on:

 

 

[TerryM]

Taco

The map I posted was ave. 2012-2013 vs avg. 1961-1990.

It's a strange pattern we're seeing, particularly the 1987/2013 scenario. Is it possible to graph an avg, of the post 2007 years against an ave. of say the 1980's? Another graph that might add light would be one showing an avg. of the lowest ice years against the highest ice years (since 2007). If WACC is the culprit it might be easier to spot.

Terry

[ORH_wxman]

 

Is it possible to graph an avg, of the post 2007 years against an ave. of say the 1980's? Terry

 

 

Yes.

 

 

 

[tacoman25]

Taco

The map I posted was ave. 2012-2013 vs avg. 1961-1990.

It's a strange pattern we're seeing, particularly the 1987/2013 scenario. Is it possible to graph an avg, of the post 2007 years against an ave. of say the 1980's? Another graph that might add light would be one showing an avg. of the lowest ice years against the highest ice years (since 2007). If WACC is the culprit it might be easier to spot.

Terry

 

 

Sure, here's the past 5 winters vs. 1980-1990. Still shows winter cooling over large parts of the NH mid latitudes. The overall picture is that winter warming peaked in many NH regions during the 1990-2006 era, and has since cooled...in some areas to below 1980s levels.

 

EDIT: I see Will beat me to the map.

[nflwxman]

 

 

 

Yes.

 

 

 

That some serious Siberia cold.  Which year was it that many parts of eastern europe/russia saw like 6 feet of snowcover?

 

Also, the difference between the last 5 years and the 80s ENSO is really apparent in that map.

[tacoman25]

That some serious Siberia cold.  Which year was it that many parts of eastern europe/russia saw like 6 feet of snowcover?

 

Also, the difference between the last 5 years and the 80s ENSO is really apparent in that map.

 

As well as vs. 1980s +PDO and -AMO.

[Jonger]

That's annual temps though, not winter, which this thread is focused on.

 

That chart is probably heavily influenced by the arctic, plus its baseline is against the coolest period in the last 100 years.

[Jonger]

Actually a small area in the far north west cooled slightly but almost all of the country warmed, some considerably, which is undoubtedly what lead to the ~5 1/2F increase over the last 60 years. Bearing in mind that Canada is approximately as large as the contiguous US AND Mexico temperatures there account for about 40% of the temperatures over land in the northern hemisphere.

Terry

 

5 1/2F?

 

No way does that average out that high, looks like 2.5F tops.

 

I

[TerryM]

Thanks for the new maps!

I have to run but will post comments when I get back.

Terry

[ORH_wxman]

5 1/2F?

 

No way does that average out that high, looks like 2.5F tops.

 

I

 

 

Its near 3C according to the graph....which is right around 5.5F...learn to convert celsius into fahrenheit.

[Jonger]

5 1/2F?

 

No way does that average out that high, looks like 2.5F tops.

 

I

 

 

Its near 3C according to the graph....which is right around 5.5F...learn to convert celsius into fahrenheit.

I know the calculation, but look at that map.... No way is that higher than 2.5C.... Half the map is zero or less.