Climate Change and Cold Outbreaks in North America

[pazzo83]

All, I don't often post in here but I find the study and analysis of climate fascinating.  The recent "POLAR VORTEX OMG" cold outbreak in southern Canada and the eastern US and its attendant unwarranted (IMO) media hype prompted me to get into a few lengthy discussions with a friend on Facebook. He was posting articles that essentially were claiming that climate change has been making and will continue to make more severe the cold outbreaks we experience here in North America and elsewhere.  The articles and his commentary were touting this most recent outbreak as evidence of this.  I countered saying that the outbreak, while somewhat extreme, represents the type of cold that used to be more typical in the region a couple decades ago.  I also argued that a warming climate pushes forward the means, meaning that by definition future cold outbreaks will be both less severe and shorter in duration.  Well, he would have none of it.  If you guys don't mind, I'd like to post some of his claims so that I might get some feedback from those on here much more knowledgeable than me.  Am I way off here?

 

 

Let me explain something

 

It only requires a knowledge of ordinal numbers.

 

If the earth is getting warmer...

 

and storms are "just as cold" as they were years ago.

 

doesn't it mean the storms are MORE intense?

 

you say it's exxageration

 

i say you are wrong.

 

storms are much more intense than ever

 

and while Tower MN has similar extreme readings

 

the wind speed

 

and size of storms is MUCH more in tense

 

 

 

With warming ocean temps, ocean air is warmer

 

and hence the intensity of storms that come ashore is greater

 

no MATTER WHAT the surface temp

hence

 

if the surface temp remains the same

and the storm is stronger

 

it means only one thing: The cold snap is stronger

 

period.

 

 

 

but in lock-step with intensifying storms? not at all. ESPECIALLY if a polar vortex enters the jet stream

 

you and i both know that

 

Historically warm ocean temps = Historically intense storms

 

PLUS polar vortex

 

equals = Historic prediction for cold

 

 

Not sure now to explain that stronger wind makes for more intense storms. And when it's cold out, that means a cold snap.

 

it's pretty self-explanatory

 

And when you take historically warm ocean temps + an average winter + a (piece of the) polar vortex, it's 100% responsible for journalists to call it 'historic"

 

 

 

I never made any claims on future cold. My only claim is that wind speeds and areas of storm coverage are increasing. And that wind velocity intensifies cold.

 

[ORH_wxman]

CONUS cold extremes (defined by 4 day outbreaks that climatologically occur less frequent than 1 in 5 years) peaked in the 1980s...likely due to natural variability in the north Pacific blocking regimes. Overall the trend has been downward as the underlying mean temperature has increased.

 

 

Here is the figure from Peterson et al (2013) that defines heat waves and cold waves of minimum 4 days and less than 1 in 5 year threshold through the 2000-2010 decade:

 

 

 

 

 

 

 

 

You can see how the 2000s decade had the least number of anomalous cold waves. If climate change were responsible for increased anomalous cold outbreaks, then you would expect the 2000s to have the most or at least near the most....especially considering it has had the most sea ice loss than previous decades which some papers have tried to link to increased blocking.

 

 

However that hasn't been the case. U.S. cold waves are tied very heavily to blocking over the North Pacific region we often call the "EPO" or the "East Pacific Oscillation". The 1980s had a maximum in height anomalies in this region during the cold season, so it is no surprise that the 1980s had the highest number of anomalous cold waves.

[ORH_wxman]

In addition to the graphic above, here is another one from the same paper that shows the trend in daily extremes (not a minimum of 4 day outbreaks) for beyond the 99th percentile in either direction. You can see the greatest warming trend in the tails of extremes beyond the 99th percentile is clearly in the coldest minimum temperatures across the CONUS.

 

[Vandy]

Just to add to the good info posted above, from a theory standpoint it wouldn't really make sense for climate change to increase the severity or rate of cold air outbreaks, though an argument could be made that when they do occur, they could last longer. Changes in temperature are felt most strongly at the poles, so you are warming the source region for the outbreaks. In addition, you are decreasing the equator-to-pole temperature gradient, which on average should reduce the amplitude of Rossby waves resulting in less southward excursions of cold air from high latitudes. On the other hand, a weaker gradient would likely slow down zonal motions on average, so you could see longer heat/cold waves when they occur.

 

Of course, the big question is how much high latitude warming is necessary until such effects would become apparent in average weather patterns.

[bluewave]

The only thing that we can say is that record cold during the winter really fell off after the 70's into 80's.

 

 

[ORH_wxman]

This was a quick rundown by NCDC, NOAA and NC State at a 2012 seminar of the trend in extremes in the U.S.

 

[pazzo83]

Thanks for the responses guys.  It seems pretty intuitive that a warming climate would necessarily lead to fewer severe cold outbreaks, but it's good to see the data back that up.

[Jonger]

Thanks for the responses guys.  It seems pretty intuitive that a warming climate would necessarily lead to fewer severe cold outbreaks, but it's good to see the data back that up.

 

Jeff Masters posted a graph showing the decrease in Detroits sub-zero nights. 

 

Jeff Masters: " For example, in Detroit during the 1970s, there were an average of 7.9 nights with temperatures below zero. But this decade, that number has been closer to two nights.

 

 

So I got interested and wanted to find out what happened from 1959-1969: 2 nights per year on average.

 

The 1965-1980 period was a cold anomaly over the lower 48.

 

I don't have the data to show what constitutes as a 'Cold Outbreak", but for much of the 1930's to 1960's, it was pretty much on par with today in my location. 

[ORH_wxman]

Jeff Masters posted a graph showing the decrease in Detroits sub-zero nights. 

 

Jeff Masters: " For example, in Detroit during the 1970s, there were an average of 7.9 nights with temperatures below zero. But this decade, that number has been closer to two nights.

 

 

 

So I got interested and wanted to find out what happened from 1959-1969: 2 nights per year on average.

 

The 1965-1980 period was a cold anomaly over the lower 48.

 

I don't have the data to show what constitutes as a 'Cold Outbreak", but for much of the 1930's to 1960's, it was pretty much on par with today in my location. 

 

 

The '40s and '50s had a low number of cold outbreaks in the U.S. Not as low as the 2000s...but both decades were lower than the 1990s.

[skierinvermont]

The number of cold outbreaks and cold records has clearly been decreasing and will continue to decrease. On the other hand, there is some reasonable but inconclusive evidence that the NAO will trend negative in a warming world as the jet stream slows and meanders more. So you might see more blocking patterns but because of the warmer background state you still won't be breaking cold records frequently.

 

Your friend also talks about increasing storm intensity. More frequent blocking patterns could play some role in that (you're probably pretty familiar with what a -NAO pattern does). On the other hand, the automatic assumption that more water vapor and warmer SSTs will cause more intense storms isn't correct. Storms are caused by gradients vertically and by latitude. Climate change is supposed to warm high latitude and high altitudes faster, reducing these gradients and making the atmosphere more stable. But when you do get gradients, there will be more downpours. Basically, Brazil gets more downpours than New York, and as the climate shifts northwards, New york's climate becomes more brazil-like. 

[blizzard1024]

The number of cold outbreaks and cold records has clearly been decreasing and will continue to decrease. On the other hand, there is some reasonable but inconclusive evidence that the NAO will trend negative in a warming world as the jet stream slows and meanders more. So you might see more blocking patterns but because of the warmer background state you still won't be breaking cold records frequently.

 

Your friend also talks about increasing storm intensity. More frequent blocking patterns could play some role in that (you're probably pretty familiar with what a -NAO pattern does). On the other hand, the automatic assumption that more water vapor and warmer SSTs will cause more intense storms isn't correct. Storms are caused by gradients vertically and by latitude. Climate change is supposed to warm high latitude and high altitudes faster, reducing these gradients and making the atmosphere more stable. But when you do get gradients, there will be more downpours. Basically, Brazil gets more downpours than New York, and as the climate shifts northwards, New york's climate becomes more brazil-like. 

 

I don't buy this idea that there will be more blocking patterns in a warmer world. The 1960s and 70s winters were full of epic blocking patterns that led to extreme cold and very snowy winters in the mid latitudes. I have read the literature related to less sea ice and more blocking and the evidence is weak IMO.  Just look at the NAO and AO charts and you can see they were predominately negative in the colder time frame of the 1960s and 70s when there was more late summer sea ice in the Arctic. 

[skierinvermont]

I don't buy this idea that there will be more blocking patterns in a warmer world. The 1960s and 70s winters were full of epic blocking patterns that led to extreme cold and very snowy winters in the mid latitudes. I have read the literature related to less sea ice and more blocking and the evidence is weak IMO.  Just look at the NAO and AO charts and you can see they were predominately negative in the colder time frame of the 1960s and 70s when there was more late summer sea ice in the Arctic. 

 

 Again, you are making huge logical leaps of faith. Nobody said -NAO can't occur in a cold world. Sorry -- blizzard1024 vs peer reviewed science and I will pick the latter 100% of the time. 

[ORH_wxman]

The idea that less sea ice is leading to more blocking is very debatable. There is peer reviewed evidence supporting either case. A paper that just came out supports the idea that blocking is not getting more anomalous

 

http://barnes.atmos.colostate.edu/FILES/MANUSCRIPTS/Barnes_DunnSigouin_etal_2014_GRL_wsupp.pdf

 

 

 

The key idea they stress in how their results differ from those of other papers

 

One possible explanation is the index used - they identify a block by persistent Z500 anomalies which can be influenced by large-scale changes in the Z500 field (e.g. by the general increase in Z500 due to high-latitude warming over the last decade). Our indices avoid this potential issue by requiring a reversal of the full Z500 field which equates to easterly winds and likely irreversibly deformed flow contours.

 

 

This is the same idea we had brought up months ago when talking about "record blocks" in the arctic. You cannot just use 5H height anomalies by themselves since general warming in the atmospehre will cause the the 5H heights to rise. You need to look at the actual flow to see if it is blocked. These blocked flows are what actually cause the "wavey jet stream" or whatever term some of the media is trying to use to explain "weird" weather or, for example, a Hurricane Sady type block.

 

 

There isn't anything close to a consensus regarding the attribution of blocking to a reduction in sea ice...at least not yet.

[The_Global_Warmer]

[ORH_wxman]

Yep that is the Franics and Vavrus paper that the newer paper above discusses...and why they think their results are not robust for claiming that blocking has increased.

[blizzard1024]

 Again, you are making huge logical leaps of faith. Nobody said -NAO can't occur in a cold world. Sorry -- blizzard1024 vs peer reviewed science and I will pick the latter 100% of the time. 

 

I would be very wary of peer review climate science too. Just because something is peer reviewed does not make it automatically true. This does not prove anything in itself. To say that I make leaps of faith is your opinion. Thats OK. Its your opinion. But I can tell you that I am not making any leaps of faith.  It called watching and studying the atmosphere for over 30 years and studying reanalysis data and atmopheric flow patterns in detail back to the late 1940s.  There is also a tendency for climate scientists to try to tie in current weather extremes to global warming. Go back to the late 1990s, when there was less blocking and more positive NAO/AO patterns. Climate studies suggested that a warming Earth would lead to more positive NAO/AO patterns and less blocking because the upper tropical troposphere hotspot increases the subtropical highs and the geopotential heights in the subtropics which in effect makes for faster westerly flow and less blocking. Now since we have seen more blocking of late...global warming now leads to blocking.  Just like the idea that global warming = more and stronger el ninos was the mantra of the 1990s when El Ninos predominated. Now with the PDO shift, La Ninas have been more dominate and el ninos fewer and weaker. This was all peer reviewed literature. I am not saying that blocking won't increase from global warming. I just don't see enough evidence to boldly make this claim.

[The_Global_Warmer]

Isn't this quintessentially the definition of blocking?  Did they go back on this?  I don't have time to research it further right now so if anyone can give me a quick explanation that would be great.

 

FWIW if it's even a tiny bit more blocking it means more blocking.  Doesn't mean it's a big difference maker though. 

 

 

[ORH_wxman]

Isn't this quintessentially the definition of blocking?  Did they go back on this?  I don't have time to research it further right now so if anyone can give me a quick explanation that would be great.

 

FWIW if it's even a tiny bit more blocking it means more blocking.  Doesn't mean it's a big difference maker though. 

 

 

 

 

 

No, it is not blocking just because the overall 500mb wind speeds are slower. Any block actually requires a reversal in the wind field whether you are talking omega blocks or rex blocks.

[skierinvermont]

Well I'm not the one overly invested in one single paper. I'm proposing the opposite. That the weight of peer-reviewed evidence points to a more -NAO when there is less sea ice. It would be the opposing side of the argument putting too much weight on one paper that claims there is no statistically significant correlation at present but also doesn't specifically rule out the possibility of one in the future. 

 

 

Branstator and Selten 2009

Barnes and Polvani 2013

Strong et al. 2009

Wu and Zhang 2010

Kvamsto et al. 2004

Magnusdottir et al. 2004

Seierstad and Bader 2009

Deser et al. 2010

Screen et al. 2012

 

 

Reviews in 

Budikova 2009

Bader et al. 2011

[ORH_wxman]

Well I'm not the one overly invested in one single paper. I'm proposing the opposite. That the weight of peer-reviewed evidence points to a more -NAO in a warmer world. It would be the opposing side of the argument putting to much weight on one paper that claims there is no statistically significant correlation at present but also doesn't specifically rule out the possibility of one in the future. 

 

 

The traditional peer review consensus was a +NAO in the future as the westerlies constrict northward....only the sea ice theory supports the -NAO argument, which was much more recent, but still has opposing viewpoints in the literature.

 

I think it is very difficult to oppose either view at this point. Climate models (both Hadgem and CMIP5) have been notoriously horrendous at simulating the NAO on decadal timescales. I know the Hadgem predicts a positive NAO as we warm...in pretty recent literature.

 

I think your statement is not really supported.

[skierinvermont]

The traditional peer review consensus was a +NAO in the future as the westerlies constrict northward....only the sea ice theory supports the -NAO argument, which was much more recent, but still has opposing viewpoints in the literature.

 

I think it is very difficult to oppose either view at this point. Climate models (both Hadgem and CMIP5) have been notoriously horrendous at simulating the NAO on decadal timescales. I know the Hadgem predicts a positive NAO as we warm...in pretty recent literature.

 

I think your statement is not really supported.

 

You caught me before my edit. I switched it to 'less sea ice.' The literature in the AR5 is essentially 50/50 split on the NAO in a warmer world. 

[bluewave]

I think that the reason that some of the studies called for a more positive NAO/AO and others a

negative is that they are both correct. Studies involving coral found that the NAO/AO becomes

more variable as the climate warms. The record seems to bear this finding out with the lowest

readings and highest all occurring since 1990. We are also seeing stronger ENSO swings

as the climate warms.

 

http://www.whoi.edu/page.do?pid=7545&tid=3622&cid=54686

 

 

 

Study links swings in North Atlantic Oscillation variability to climate warming

 

FOR IMMEDIATE RELEASE

Media Relations Office

[email protected]

January 13, 2009

(508) 289-3340

Using a 218-year-long temperature record from a Bermuda brain coral, researchers at the Woods Hole Oceanographic Institution (WHOI) have created the first marine-based reconstruction showing the long-term behavior of one of the most important drivers of climate fluctuations in the North Atlantic.

The North Atlantic Oscillation (NAO) is a wide-ranging pressure seesaw that drives winter climate over much of North America, Europe and North Africa. Past reconstructions of the NAO have relied mainly on terrestrial, or land-based records, such as tree ring chronologies combined with ice cores and historical climate data. Those records do not fully capture oceanic processes linked to NAO variability, and short instrumental records from relatively few locations limit the understanding of ocean–atmosphere dynamics with regard to NAO behavior.

“By analyzing the coral, we were able to look at changes in the ocean relative to changes on land,” said Nathalie Goodkin, lead author of the study published in the December issue of the journal Nature Geoscience.“Because they are slow growing and have long life-spans, corals can provide high resolution records that are well dated and centuries long.”

As they grow, corals accrete seasonal and annual growth layers, similar to tree rings.  The proportions of trace elements versus the major element (calcium) found in the layers of the skeleton largely depend on the temperature of the seawater in which it was formed.  By analyzing the strontium to calcium ratio in the Bermuda brain coral, Goodkin and colleagues — WHOI scientists Konrad Hughen, Scott Doney and William Curry — were able to reconstruct monthly changes in ocean temperatures and evaluate variability of the NAO during both cold and warm periods from the Little Ice Age (1800–1850) to modern day.  

The research team found the variability of the NAO decade-to-decade (multi-decadal scale) has been larger, swinging more wildly, during the late twentieth century than in the early 1800s, suggesting that variability is linked to the mean temperature of the Northern Hemisphere. This confirms variability previously reported in past terrestrial reconstructions. 

“When the Industrial Revolution begins and atmospheric temperature becomes warmer, the NAO takes on a much stronger pattern in longer-term behavior,” said Goodkin. “That was suspected before in the instrumental records, but this is the first time it has been documented in records from both the ocean and the atmosphere.” 

The North Atlantic Oscillation is described by the NAO index, calculated as a weighted difference between the polar low and the subtropical high during the winter season. (For more information about the NAO index, seeanimation.) In a positive phase, both the low-pressure zone over Iceland and high pressure over the Azores are intensified, resulting in changes in the strength, incidence, and pathway of winter storms crossing the Atlantic. In a negative phase, a weak subtropical high and a weak Icelandic low results in fewer and weaker winter storms crossing on a more west-east pathway. 

The NAO index varies from year to year, but also exhibits a tendency to remain in one phase for intervals lasting more than a decade. An unusually long period of positive phase between 1970-2000 led to the suggestion that global warming was affecting the behavior of the NAO. 

“Anthropogenic (human-related) warming does not appear to be altering whether the NAO is in a positive or negative phase at multi-decadal time scales,” said WHOI paleoclimatologist Konrad Hughen. “It does seem to be increasing variability. Clearly, this has implications for the future.”

“As temperatures get warmer, there’s potential for more violent swings of the NAO — the phases becoming even more positive and even more negative,” Hughen added. “If the NAO locks more into these patterns, intense storms will become more intense and droughts will become more severe.” 

The climatic influence of the NAO extends from the eastern United States to Western Europe, impacting human activities such as shipping, oil drilling, fisheries, hydroelectric power generation and coastal management. Improving the ability to predict shifts in the phase and intensity of the NAO is a prerequisite to mitigating the economic impacts of future climate change.

While additional modeling and palaeoclimatic studies are needed, a broad distribution of marine records could advance our knowledge of NAO variability and serve to improve future projections, said Goodkin, now an assistant professor in the Department of Earth Sciences at the University of Hong Kong. 

A WHOI Ocean and Climate Change Institute Fellowship, and grants from the National Science Foundation and Woods Hole Oceanographic Institution supported this work. 


The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans’ role in the changing global environment.

 

 

 

 

 

Monday, October 28, 2013: New research shows El Niño Southern Oscillation (ENSO) phenomena have been more active and intense during the 30-year period between 1979-2009 than at any time during the past 600 years.

At the same time, this result suggests that the intensity and activity of El Niño and La Ninas appears to increase as global average temperatures increase.

The results of this new research, published in Climate of the Past, is a significant step towards understanding where current ENSO activity sits in the context of the past according to researchers from UNSW’s Centre of Excellence for Climate System Science, the University of Hawaii International Pacific Research Centre and the NOAA Geophysical Fluid Dynamics Laboratory.

 “Our research suggests in a warming world we are likely to see more extreme El Niño and La Nina events, which over the past decade in Australia have been related to extreme flooding, persistent droughts and dangerous fire seasons,” said lead author Dr Shayne McGregor from UNSW

“Importantly, this study not only tells us how ENSO activity has behaved in the past in relation to global average temperature, it also opens the window for climate models to be able to estimate more accurately how this activity will change in the future."

The researchers used a newly defined method they had developed and measurements from lake sediment and old coral cores along with tree rings across a wide variety of locations to determine how ENSO events had changed across the Pacific over hundreds of years. From these proxies, the researchers were able to determine the state of the climate over a wide area at the same time, revealing changes in ENSO activity. 

As part of the research, the team brought together the different proxy reconstructions of past climate and, where the time periods of these proxies overlapped with current instrumental data, used these periods to determine how accurately they represented contemporary ENSO activity.

Once the effectiveness of the proxies was confirmed the researchers used this information to extrapolate the climate and activity of ENSO over the past 600 years.

They then further tested the robustness of this approach by comparing their real-world data with that produced by two multi-century-long climate model simulations.

“By applying these observations and finding which climate models reproduce past changes, we will have a better idea of which climate models are more likely to reproduce the ENSO response to climate change in the future," said co-author Prof Matt England from the ARC Centre of Excellence for Climate System Science.

While the research shows how external warming factors have impacted ENSO cycles, one important question remains.

“We still don't know why. Understanding this relationship will be vital to help us get a clear idea of the future changes to global climate," said Dr McGregor.

Paper: Inferred changes in El Niño–Southern Oscillation variance over the past six centuries

[blizzard1024]

I think that the reason that some of the studies called for a more positive NAO/AO and others a

negative is that they are both correct. Studies involving coral found that the NAO/AO becomes

more variable as the climate warms. The record seems to bear this finding out with the lowest

readings and highest all occurring since 1990. We are also seeing stronger ENSO swings

as the climate warms.

 

http://www.whoi.edu/page.do?pid=7545&tid=3622&cid=54686

 

 

 

Study links swings in North Atlantic Oscillation variability to climate warming

 

FOR IMMEDIATE RELEASE

Media Relations Office

[email protected]

January 13, 2009

(508) 289-3340

Using a 218-year-long temperature record from a Bermuda brain coral, researchers at the Woods Hole Oceanographic Institution (WHOI) have created the first marine-based reconstruction showing the long-term behavior of one of the most important drivers of climate fluctuations in the North Atlantic.

The North Atlantic Oscillation (NAO) is a wide-ranging pressure seesaw that drives winter climate over much of North America, Europe and North Africa. Past reconstructions of the NAO have relied mainly on terrestrial, or land-based records, such as tree ring chronologies combined with ice cores and historical climate data. Those records do not fully capture oceanic processes linked to NAO variability, and short instrumental records from relatively few locations limit the understanding of ocean–atmosphere dynamics with regard to NAO behavior.

“By analyzing the coral, we were able to look at changes in the ocean relative to changes on land,” said Nathalie Goodkin, lead author of the study published in the December issue of the journal Nature Geoscience.“Because they are slow growing and have long life-spans, corals can provide high resolution records that are well dated and centuries long.”

As they grow, corals accrete seasonal and annual growth layers, similar to tree rings.  The proportions of trace elements versus the major element (calcium) found in the layers of the skeleton largely depend on the temperature of the seawater in which it was formed.  By analyzing the strontium to calcium ratio in the Bermuda brain coral, Goodkin and colleagues — WHOI scientists Konrad Hughen, Scott Doney and William Curry — were able to reconstruct monthly changes in ocean temperatures and evaluate variability of the NAO during both cold and warm periods from the Little Ice Age (1800–1850) to modern day.  

The research team found the variability of the NAO decade-to-decade (multi-decadal scale) has been larger, swinging more wildly, during the late twentieth century than in the early 1800s, suggesting that variability is linked to the mean temperature of the Northern Hemisphere. This confirms variability previously reported in past terrestrial reconstructions. 

“When the Industrial Revolution begins and atmospheric temperature becomes warmer, the NAO takes on a much stronger pattern in longer-term behavior,” said Goodkin. “That was suspected before in the instrumental records, but this is the first time it has been documented in records from both the ocean and the atmosphere.” 

The North Atlantic Oscillation is described by the NAO index, calculated as a weighted difference between the polar low and the subtropical high during the winter season. (For more information about the NAO index, seeanimation.) In a positive phase, both the low-pressure zone over Iceland and high pressure over the Azores are intensified, resulting in changes in the strength, incidence, and pathway of winter storms crossing the Atlantic. In a negative phase, a weak subtropical high and a weak Icelandic low results in fewer and weaker winter storms crossing on a more west-east pathway. 

The NAO index varies from year to year, but also exhibits a tendency to remain in one phase for intervals lasting more than a decade. An unusually long period of positive phase between 1970-2000 led to the suggestion that global warming was affecting the behavior of the NAO. 

“Anthropogenic (human-related) warming does not appear to be altering whether the NAO is in a positive or negative phase at multi-decadal time scales,” said WHOI paleoclimatologist Konrad Hughen. “It does seem to be increasing variability. Clearly, this has implications for the future.”

“As temperatures get warmer, there’s potential for more violent swings of the NAO — the phases becoming even more positive and even more negative,” Hughen added. “If the NAO locks more into these patterns, intense storms will become more intense and droughts will become more severe.” 

The climatic influence of the NAO extends from the eastern United States to Western Europe, impacting human activities such as shipping, oil drilling, fisheries, hydroelectric power generation and coastal management. Improving the ability to predict shifts in the phase and intensity of the NAO is a prerequisite to mitigating the economic impacts of future climate change.

While additional modeling and palaeoclimatic studies are needed, a broad distribution of marine records could advance our knowledge of NAO variability and serve to improve future projections, said Goodkin, now an assistant professor in the Department of Earth Sciences at the University of Hong Kong. 

A WHOI Ocean and Climate Change Institute Fellowship, and grants from the National Science Foundation and Woods Hole Oceanographic Institution supported this work. 

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans’ role in the changing global environment.

 

Arctic Oscillation Index.png

 

DecAO.png

 

 

 

Monday, October 28, 2013: New research shows El Niño Southern Oscillation (ENSO) phenomena have been more active and intense during the 30-year period between 1979-2009 than at any time during the past 600 years.

At the same time, this result suggests that the intensity and activity of El Niño and La Ninas appears to increase as global average temperatures increase.

The results of this new research, published in Climate of the Past, is a significant step towards understanding where current ENSO activity sits in the context of the past according to researchers from UNSW’s Centre of Excellence for Climate System Science, the University of Hawaii International Pacific Research Centre and the NOAA Geophysical Fluid Dynamics Laboratory.

 “Our research suggests in a warming world we are likely to see more extreme El Niño and La Nina events, which over the past decade in Australia have been related to extreme flooding, persistent droughts and dangerous fire seasons,” said lead author Dr Shayne McGregor from UNSW

“Importantly, this study not only tells us how ENSO activity has behaved in the past in relation to global average temperature, it also opens the window for climate models to be able to estimate more accurately how this activity will change in the future."

The researchers used a newly defined method they had developed and measurements from lake sediment and old coral cores along with tree rings across a wide variety of locations to determine how ENSO events had changed across the Pacific over hundreds of years. From these proxies, the researchers were able to determine the state of the climate over a wide area at the same time, revealing changes in ENSO activity. 

As part of the research, the team brought together the different proxy reconstructions of past climate and, where the time periods of these proxies overlapped with current instrumental data, used these periods to determine how accurately they represented contemporary ENSO activity.

Once the effectiveness of the proxies was confirmed the researchers used this information to extrapolate the climate and activity of ENSO over the past 600 years.

They then further tested the robustness of this approach by comparing their real-world data with that produced by two multi-century-long climate model simulations.

“By applying these observations and finding which climate models reproduce past changes, we will have a better idea of which climate models are more likely to reproduce the ENSO response to climate change in the future," said co-author Prof Matt England from the ARC Centre of Excellence for Climate System Science.

While the research shows how external warming factors have impacted ENSO cycles, one important question remains.

“We still don't know why. Understanding this relationship will be vital to help us get a clear idea of the future changes to global climate," said Dr McGregor.

Paper: Inferred changes in El Niño–Southern Oscillation variance over the past six centuries

is there any way we can see the actual papers without having to pay?  I much rather read the paper than a press release or just an abstract. This always irks me. Tax papers fund the research. Its cost the researchers a lot of money to publish in that journal. Then you have to subscribe. What a racket! Never liked the way this works. Interesting papers but again, would like to actually analyze the "meat" of them. Thanks for posting.  

[Jonger]

Soon the piratesbay will have science publications.... Just wait.

[michsnowfreak]

Jeff Masters posted a graph showing the decrease in Detroits sub-zero nights. 

 

Jeff Masters: " For example, in Detroit during the 1970s, there were an average of 7.9 nights with temperatures below zero. But this decade, that number has been closer to two nights.

 

 

So I got interested and wanted to find out what happened from 1959-1969: 2 nights per year on average.

 

The 1965-1980 period was a cold anomaly over the lower 48.

 

I don't have the data to show what constitutes as a 'Cold Outbreak", but for much of the 1930's to 1960's, it was pretty much on par with today in my location. 

LOL. I guess the earth was created in 1970 (this is FAR from the first graph/chart/etc I have seen that has used 1970 as a starting point to show a warming trend). The 1970s not only featured well-documented anamolously cold winters, but at that time, DTW was a radiating MAGNET (usually the coldest in SE MI on clear, calm nights) and in the late 80s/early 90s UHI quickly took over. Noted local weather historican, retired met Bill Deedler (worked at DTX 1974-2010) will tell you plenty about the UHI/radiating effect at DTW then and now.

 

Days below zero at the official reporting station for Detroit:

1930s- 39.......................avg 3.9 days

1940s- 15.......................avg 1.5 days

1950s- 12.......................avg 1.2 days

1960s- 28.......................avg 2.8 days

1970s- 87.......................avg 8.7 days

1980s- 77.......................avg 7.7 days

1990s- 29.......................avg 2.9 days

2000s- 27.......................avg 2.7 days

2010s- 8 thru 1/12/14.....avg approx 2 days

[Jonger]

Jeff Masters posted a graph showing the decrease in Detroits sub-zero nights.

Jeff Masters: " For example, in Detroit during the 1970s, there were an average of 7.9 nights with temperatures below zero. But this decade, that number has been closer to two nights.

So I got interested and wanted to find out what happened from 1959-1969: 2 nights per year on average.

The 1965-1980 period was a cold anomaly over the lower 48.

I don't have the data to show what constitutes as a 'Cold Outbreak", but for much of the 1930's to 1960's, it was pretty much on par with today in my location.

LOL. I guess the earth was created in 1970 (this is FAR from the first graph/chart/etc I have seen that has used 1970 as a starting point to show a warming trend). The 1970s not only featured well-documented anamolously cold winters, but at that time, DTW was a radiating MAGNET (usually the coldest in SE MI on clear, calm nights) and in the late 80s/early 90s UHI quickly took over. Noted local weather historican, retired met Bill Deedler (worked at DTX 1974-2010) will tell you plenty about the UHI/radiating effect at DTW then and now.

Days below zero at the official reporting station for Detroit:

1930s- 39.......................avg 3.9 days

1940s- 15.......................avg 1.5 days

1950s- 12.......................avg 1.2 days

1960s- 28.......................avg 2.8 days

1970s- 87.......................avg 8.7 days

1980s- 77.......................avg 7.7 days

1990s- 29.......................avg 2.9 days

2000s- 27.......................avg 2.7 days

2010s- 8 thru 1/12/14.....avg approx 2 days

I only did 1960-1970, much appreciated work Josh.

[The_Global_Warmer]

NCDC show February warming the most in Michigan with January slightly cooling since 1895.  Can't emphasis the slightly enough.

 

December warming but less than November and March.  But Feb had the highest rate of change.

[AvantHiatus]

NCDC show February warming the most in Michigan with January slightly cooling since 1895.  Can't emphasis the slightly enough.

 

December warming but less than November and March.  But Feb had the highest rate of change.

Ties in somewhat with the trend of decreasing snowcover in the spring. The lesser warming trend in December and cooling in January makes sense considering some locations are experiencing more snowfall in recent decades.

[bluewave]

is there any way we can see the actual papers without having to pay?  I much rather read the paper than a press release or just an abstract. This always irks me. Tax papers fund the research. Its cost the researchers a lot of money to publish in that journal. Then you have to subscribe. What a racket! Never liked the way this works. Interesting papers but again, would like to actually analyze the "meat" of them. Thanks for posting.  

 

The interesting thing is that the record AO plunge occurred in in the years after the paper was published in late 2008.

I was able to find a link below of the full paper showing an increase in positive and negative extremes compared

the the earlier years in the record of the study.

 

http://www.whoi.edu/science/GG/people/wcurry/Curry_pdf_files/Goodkin_et_al_2008.pdf

 

 

Increased multidecadal variability of the North Atlantic Oscillation since 1781

 

The North Atlantic Oscillation is a meridional oscillation of atmospheric mass measured between Iceland and the Ac ̧ores1,2, which drives winter climate variability in eastern North America and Europe. A prolonged period of the positive phase during the 1990s led to the suggestion that anthropogenic warming was affecting the behaviour of the North Atlantic Oscillation3,4. However, instrumental records1,5 are too short to compare observations during periods of extended warm and cold hemispheric temperatures, and existing palaeoclimate reconstructions6,7 primarily capture terrestrial variability. Here we present a record of Sr/Ca, a sea surface temperature proxy, from a Bermuda coral from 1781 to 1999. We use this monthly resolved record to reconstruct past variability of the North Atlantic Oscillation at multiple frequencies. Our record shows enhanced multidecadal scale variability during the late twentieth century compared with the end of the Little Ice Age (1800–1850). We suggest that variability within the North Atlantic Oscillation is linked to the mean temperature of the Northern Hemisphere, which must be considered in any long-term predictions.

 

 

The new coral Sr/Ca marine record shows that at multidecadal frequencies NAO behaviour is correlated to shifts in hemispheric mean temperature, with greatly increasing power in both marine and atmospheric NAO records with increasing temperatures (Fig. 3). Intervals of both positive- and negative-phase NAO occur both during the LIA and the late twentieth century. Anthropogenic warming does not therefore seem to be altering whether the NAOI is positive or negative at multidecadal timescales, but rather it seems to be acting to increase NAO multidecadal variability, suggesting that prolonged intervals of extreme positive and negative NAO index will probably continue if temperatures continue to rise.

[wildweatherman179]

LOL. I guess the earth was created in 1970 (this is FAR from the first graph/chart/etc I have seen that. as used 1970 as a starting point to show a warming trend). The 1970s not only featured well-documented anamolously cold winters, but at that time, DTW was a radiating MAGNET (usually the coldest in SE MI on clear, calm nights) and in the late 80s/early 90s UHI quickly took over. Noted local weather historican, retired met Bill Deedler (worked at DTX 1974-2010) will tell you plenty about the UHI/radiating effect at DTW then and now.

Days below zero at the official reporting station for Detroit:

1930s- 39.......................avg 3.9 days

1940s- 15.......................avg 1.5 days

1950s- 12.......................avg 1.2 days

1960s- 28.......................avg 2.8 days

1970s- 87.......................avg 8.7 days

1980s- 77.......................avg 7.7 days

1990s- 29.......................avg 2.9 days

2000s- 27.......................avg 2.7 days

2010s- 8 thru 1/12/14.....avg approx 2 days

I have a question as well. I hear and see all the things stated that show climate to 1900, 1920, etc. At the same time I read where people have research dating to mid 1800s (article above) or pre 1800 yet I never see the data. Also, why do we continually shift climate averages in 30 year intervals but still use standing records from as far back as weather has been recorded. Thanks.