Paper Offers Possible Link Between Climate Change & Extreme Weather

[donsutherland1]

The researchers suggested a mechanism that leads to a slowing of the progression of weather patterns, possibly allowing for more extremes.

The abstract is below:

Arctic amplification (AA) – the observed enhanced warming in high northern latitudes relative to the northern hemisphere – is evident in lower-tropospheric temperatures and in 1000-to-500 hPa thicknesses. Daily fields of 500 hPa heights from the National Centers for Environmental Prediction Reanalysis are analyzed over N. America and the N. Atlantic to assess changes in north-south (Rossby) wave characteristics associated with AA and the relaxation of poleward thickness gradients. Two effects are identified that each contribute to a slower eastward progression of Rossby waves in the upper-level flow: 1) weakened zonal winds, and 2) increased wave amplitude. These effects are particularly evident in autumn and winter consistent with sea-ice loss, but are also apparent in summer, possibly related to earlier snow melt on high-latitude land. Slower progression of upper-level waves would cause associated weather patterns in mid-latitudes to be more persistent, which may lead to an increased probability of extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.

http://www.agu.org/pubs/crossref/2012/2012GL051000.shtml

[LocoAko]

Yep. It is a good paper. For those who are interested, here is Jennifer Francis' presentation from AMS:

http://ams.confex.com/ams/92Annual/webprogram/Paper195301.html

[WeatherRusty]

The researchers suggested a mechanism that leads to a slowing of the progression of weather patterns, possibly allowing for more extremes.

The abstract is below:

Arctic amplification (AA) – the observed enhanced warming in high northern latitudes relative to the northern hemisphere – is evident in lower-tropospheric temperatures and in 1000-to-500 hPa thicknesses. Daily fields of 500 hPa heights from the National Centers for Environmental Prediction Reanalysis are analyzed over N. America and the N. Atlantic to assess changes in north-south (Rossby) wave characteristics associated with AA and the relaxation of poleward thickness gradients. Two effects are identified that each contribute to a slower eastward progression of Rossby waves in the upper-level flow: 1) weakened zonal winds, and 2) increased wave amplitude. These effects are particularly evident in autumn and winter consistent with sea-ice loss, but are also apparent in summer, possibly related to earlier snow melt on high-latitude land. Slower progression of upper-level waves would cause associated weather patterns in mid-latitudes to be more persistent, which may lead to an increased probability of extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.

http://www.agu.org/p...2GL051000.shtml

So, this negates my argument made in the other thread which is based on the idea that gradients are increasing due to changes in differential warming patterns. If in fact the larger scale general circulation is slowing down due to a decreasing tropics to pole gradient as the predominating factor then the rock solid physics I base my argument on does not really apply? Only the larger scale feature matters?

[turtlehurricane]

So, this negates my argument made in the other thread which is based on the idea that gradients are increasing due to changes in differential warming patterns. If in fact the larger scale general circulation is slowing down due to a decreasing tropics to pole gradient as the predominating factor then the rock solid physics I base my argument on does not really apply? Only the larger scale feature matters?

This is a good example of why the climate system isn't so simple as heating it up and then turbulence breaks out from increasing gradients. It makes sense that the pole-equator temperature gradients are actually decreasing since there simply isn't that much cold air to the north in the fall and spring (this spring is a great example), which reduces the westerlies since they are directly correlated to the pole-equator temperature gradient. Longwave Rossby wave energy propagation is to the west, so when you slow down the westerlies the longwaves move much slower to the east and may even retrograde, causing them to sit over the same spot for awhile. In that sort of pattern short waves are more likely to be absorbed into the longwaves amplifying the longwaves, and the more the longwave Rossby waves amplify the more they propagate to the west against the flow and end up in the same spot.

I don't think this is the entire answer behind extreme weather and climate change, but a piece of the puzzle. I think the fact that longwaves are persisting more in the same spot and amplifying is leading to more occurrences of the polar jet coinciding with the subtropical jet, which is what really leads to extreme weather as you get massive largescale uplift.

[skierinvermont]

So, this negates my argument made in the other thread which is based on the idea that gradients are increasing due to changes in differential warming patterns. If in fact the larger scale general circulation is slowing down due to a decreasing tropics to pole gradient as the predominating factor then the rock solid physics I base my argument on does not really apply? Only the larger scale feature matters?

I think this is the point I have been trying to make. If the earth was in perfect spatial and temporal thermal equilibrium, and then you applied AGW warming, equilibrium would be disrupted and weather would occur.

However, AGW is acting on a planet which is NOT in spatial or temporal equilibrium. Thus, the weather produced depends upon how AGW effects existing spatial and temporal gradients. In general, both the process of warming and the warmth itself will act to lessen those gradients. For example, the temperature gradient between surface and mid-troposphere is reduced ESPECIALLY during the period of active warming. This gradient would actually grow again slightly once warming ceased, but not return to its pre-industrial level. What we would see is something like this (completely hypothetical numbers:

pre industrial surface to mid-troposphere gradient: 30C

year 2000: 29.5C

year 2050: 29C

year 2100 (assuming CO2 levels plateaued): 29.3C

Notice how the gradient is actually smallest near the end of the period of active warming, and actually rebounds a bit after warming has ceased (and the oceans have warmed fully).

The same might even be true for the pole-tropic temperature gradient. Heat loss from the tropics to the poles is slowed dramatically during the period of active warming because the GHG effect is strongest at the poles. Once warming has ceased, gradually heat would build up in the tropics and tropical oceans and the hadley cells might re-strengthen slightly.

[WeatherRusty]

Stu Ostro over at TWC has done a great job documenting how this process has been behind the weather

extremes that we have been experiencing recently. We registered a +400m 500 mb height anomaly during

the historic March warmth last week which ties in with his study.

http://i.imwx.com/we...atestupdate.pdf

http://voices.washin...iew_of_ext.html

I got a real kick out of page 31 in the first article!

What this really boils down to is the differences in how meteorologists, climatologists and theoretical physicist look at an issue like this. I come at the problem more from the point of view of the latter two.

[LocoAko]

I got a real kick out of page 31 in the first article!

What this really boils down to is the differences in how meteorologists, climatologists and theoretical physicist look at an issue like this. I come at the problem more from the point of view of the latter two.

[turtlehurricane]

I got a real kick out of page 31 in the first article!

What this really boils down to is the differences in how meteorologists, climatologists and theoretical physicist look at an issue like this. I come at the problem more from the point of view of the latter two.

Meteorologists are overlapped with theoretical physics too. In fact, there's really not much of a difference between climatologists and meteorologists. They often have the same college degree.

There are another group of people though that aren't educated much (maybe an undergrad degree at best) that end up as forecasters. I think those are the meteorologists you're referring to.

[CoastalWx]

Stu Ostro over at TWC has done a great job documenting how this process has been behind the weather

extremes that we have been experiencing recently. We registered a +400m 500 mb height anomaly during

the historic March warmth last week which ties in with his study.

http://i.imwx.com/we...atestupdate.pdf

http://voices.washin...iew_of_ext.html

Man, I don't know how I feel about that article. If you are going to cherry pick disasters..why not go back to the 1970s or 60s? The warming is just one piece of the puzzle, but there are so many others. We've warmed little in the last 10 years, so what elso could be going on with the blocking that he notes? We've had some interesting things going on in the world of solar weather...could that be part of it? Don't think for a bit that technology hasn't added to all these reports and records from once remote second and third world countries and rural areas.

[WeatherRusty]

All he is really doing is showing how the rapid changes in the Arctic are playing out in the day to day events

which have been setting one record for extreme after another especially since 2000. It's really in the Arctic

where you can see the dramatic temperature rise which in turn is effecting our weather in the mid-latitudes.

It agrees with all of the research being done on Arctic amplification.

http://e360.yale.edu...he_arctic/2501/

http://www.nature.co...l/ngeo1285.html

http://www.wundergro...l?entrynum=1398

This is an example of what I have been trying to get across. It is the differential warming of the planet during the warming phase which disrupts the flow within the atmosphere. Once the climate is no longer in a warming mode and settles down to relative stasis, differential warming will be less of a factor. Arctic amplification is an example of differential warming.

How this physical demand for atmospheric disruption plays out in the atmosphere is open for discussion by you trained mets, but from a physical point of view it must take place during the period of active warming, and it will calm down once relative thermal equilibrium is restored at a warmer global temperature with change occurring at a more sluggish pace.

[turtlehurricane]

Before that data is detrended it can be seen that we've indeed had little actual warming in the past 15 years. Of course, increased warming from CO2 is undeniable.

Also, the solar minimum was quite long but nowhere near the longest or quietest, and we're definitely out of it now. There's been plenty of solar flares interacting with the outer layers of the atmosphere over the past few months.

[LakeEffectKing]

seriously? the last decade was the HOTTEST decade on record. after all of the info posted on this forum debunking this you're seriously asking this?

http://www.skeptical...ntermediate.htm

what are you talking about? the Sun has been at one of its lowest, if not its lowest ever, solar minimum cycles.

furthermore:

http://www.skeptical...bal-warming.htm

emphasis in original

http://www.skeptical...ts-advanced.htm

you have got to be trolling now--these are fallacies which have been debunked dozens of times in this forum.

You must have found the missing heat that Trenberth couldn't find......no more travesty!!!!!! Nice Job!

[LocoAko]

You must have found the missing heat that Trenberth couldn't find......no more travesty!!!!!! Nice Job!

I posted a paper a few months back (I think?) that showed that when natural variability is removed from the climate record, we've been warming just as fast as ever.

Edit:

[LakeEffectKing]

it's sad that the red taggers are the biggest trolls in this forum.

What's sad is your use of the troll card everytime someone calls you out....you don't seem to handle being wrong very well.

[TerryM]

it's sad that the red taggers are the biggest trolls in this forum.

Sad indeed.

From the title of the thread I'd have assumed that a skeptical/denial position would be to attempt to show that either the weather over the last decades has been normal or alternatively that there is some way to ascribe the weather extremes we have been experiencing to some other global climatic phenomena

Instead were seeing with arguments that have been debunked so many times that they each has a standardized response listed at skeptical science.

I have to assume that since no new arguments are being proffered, and since the old arguments have already been dealt with, there is no reason not to accept the paper as written.

Terry

[LakeEffectKing]

I posted a paper a few months back (I think?) that showed that when natural variability is removed from the climate record, we've been warming just as fast as ever.

Edit: http://www.americanw...-slowed-at-all/

Phil Jones has stated that over most of the time period we are referencing here, that the warming has been "insignificant".....No offense but haven't we been told to trust Dr. Jones and the consensus?

[LakeEffectKing]

Sad indeed.

From the title of the thread I'd have assumed that a skeptical/denial position would be to attempt to show that either the weather over the last decades has been normal or alternatively that there is some way to ascribe the weather extremes we have been experiencing to some other global climatic phenomena

Instead were seeing with arguments that have been debunked so many times that they each has a standardized response listed at skeptical science.

I have to assume that since no new arguments are being proffered, and since the old arguments have already been dealt with, there is no reason not to accept the paper as written.

Terry

So you have debunked Dr. Jones and Kevin Trenberth???

[ORH_wxman]

How can you say we've warmed the last decade in any meaningful sense?

My goodness, its not hard to look at the data:

[ORH_wxman]

it's sad that the red taggers are the biggest trolls in this forum.

So people that correctly point out that there is been no significant warming the past decade are now trolls?

That's a new one to me.

[CoastalWx]

Once again Trixie gets owned. Hey Tricks, why don't you read my part about the sun again. Where did I insinuate the sun as somehow being a solar max and causing warming or cooling? Who has the agenda again?

[ORH_wxman]

unfortunately it's gotten a bit tiresome to many of us.

http://www.newscient...snt-stoppe.html

Jake's link has some of the figures from the Rahmstorf and Foster paper.

Saying natural variability is causing the halt in warming is different than saying its trolling when people say we haven't warmed in a decade. Natural variability is kind of a an important variable.

[CoastalWx]

the sun's impact on global warming is very small. I'm not sure what your point is.

The point wasn't about solar insolation on this planet. The point was having the sun going to sleep and possible having a correlation to the extreme blocking we had leading to extreme events. Now, we bombard the stratosphere with charged particles and it's possible this has had an impact on the AO. So please, don't let your agenda and assumptions pollute the thread again. It's all a puzzle and these may be just part of the whole issue.

[LakeEffectKing]

I was referring to TH and LEK as the trolls as they are main red taggers who participate here.

and the Earth has warmed in the last decade. I'm not sure how saying that isn't true isn't trolling.

Phil Jones is trolling the whole planet then, when he publicly states insignificant warming.....

Didn't bring your A game today.....

[WeatherRusty]

Phil Jones is trolling the whole planet then, when he publicly states insignificant warming.....

Didn't bring your A game today.....

Jones never said 'insignificant warming'. He said statistically significant warming.

His original quote:

"Do you agree that from 1995 to the present there has been no statistically-significant global warming?"

"Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods."

Now with the passage of another year or two of data:

Another year has passed since the original BBC interview, and in a new BBC article, Jones notes that the HadCRUT warming trend since 1995 is now statistically significant.

"Basically what's changed is one more year [of data]. That period 1995-2009 was just 15 years - and because of the uncertainty in estimating trends over short periods, an extra year has made that trend significant at the 95% level which is the traditional threshold that statisticians have used for many years.

"It just shows the difficulty of achieving significance with a short time series, and that's why longer series - 20 or 30 years - would be a much better way of estimating trends and getting significance on a consistent basis."

More skeptical twisting of words to change the meaning.

[LakeEffectKing]

Jones never said 'insignificant warming'. He said statistically significant warming.

His original quote:

"Do you agree that from 1995 to the present there has been no statistically-significant global warming?"

"Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods."

Now with the passage of another year or two of data:

Another year has passed since the original BBC interview, and in a new BBC article, Jones notes that the HadCRUT warming trend since 1995 is now statistically significant.

"Basically what's changed is one more year [of data]. That period 1995-2009 was just 15 years - and because of the uncertainty in estimating trends over short periods, an extra year has made that trend significant at the 95% level which is the traditional threshold that statisticians have used for many years.

"It just shows the difficulty of achieving significance with a short time series, and that's why longer series - 20 or 30 years - would be a much better way of estimating trends and getting significance on a consistent basis."

More skeptical twisting of words to change the meaning.

Parse words much??? no statistically significant is a a very nicely spun version of insignificant....but I'll cede you your verbage if it means something to you.

[WeatherRusty]

Parse words much??? no statistically significant is a a very nicely spun version of insignificant....but I'll cede you your verbage if it means something to you.

Or you could just admit the real reason for rephrasing what Jones actually said. I know you did not invent the rephrasing, but I feel you shouldn't be using it to spread an 'untruth'.

[LakeEffectKing]

Or you could just admit the real reason for rephrasing what Jones actually said. I know you did not invent the rephrasing, but I feel you shouldn't be using it to spread an 'untruth'.

Cool! So we had no statistically significant warming....but now we have statistically significant warming.......I bet not by much and from only a few select sources....as Will has pointed out.

[LakeEffectKing]

http://www.bbc.co.uk...onment-13719510

And now another couple years later...I'm guessing we have tickled the significance value again.....

[PhillipS]

Phil Jones has stated that over most of the time period we are referencing here, that the warming has been "insignificant".....No offense but haven't we been told to trust Dr. Jones and the consensus?

Actually, you are misquoting Dr. Jones - what he said in an interview was that the warming trend was just shy of being statistically significant. "Statistically significant" has a different meaning than the common usage of the word "significant".

But then you knew that, didn't you?

oops - I now see that others have already tried to clear up your confusion

[dabize]

How can you say we've warmed the last decade in any meaningful sense?

My goodness, its not hard to look at the data:

These graphs have been used before by "skeptics" to make this case.

They look noisy because they include nonrandom variations that the eye naturally interprets as "random" noise.........

http://tamino.wordpress.com/2011/07/16/trend-and-noise/