This might put a kink in the RC posited “polar amplification of temperature” that is expected from AGW. A previous paper published in Nature (Screen & Simmonds 2010) said:
The ERA-40 reanalysis has been used to show that Arctic warming trends aloft were of equal or greater magnitude than those at the surface, leading to the conclusion that atmospheric circulation changes were a more important cause of recent Arctic amplification than retreating snow and sea ice cover.
But even then they started to question the data:
The findings of ref. 8 have been contested, and concerns have been expressed over the validity of trends in ERA-40 that may reflect inhomogeneities or artefacts in the reanalysis rather than true climate signals.
Of course “Skeptical science” ignored all that, and pushed the conclusion they liked.
WUWT readers are familiar with this DMI Arctic temperature analysis of temperatures at 80°N and above from the WUWT sea ice reference page:
ERA40 is used as the baseline normal, now that may be in question.
Dr. Roger Pielke Sr. writes:
Indictment Of The ERA-40 Reanalysis In A New Paper “Erroneous Arctic Temperature Trends in the ERA-40 Reanalysis: A Closer Look” By Screen and Simmonds 2011
There is a new paper which is critical of the ERA-40 Reanalysis. This is an important issue as this data set has been used in long-term climate studies; e.g. see which has over 2000 citations in the peer-reviewed literature according to google scholar. The new paper is
The abstract reads [highlight added]
“Atmospheric reanalyses can be useful tools for examining climate variability and change; however, they must be used cautiously because of time-varying biases that can induce artificial trends. This study explicitly documents a discontinuity in the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) that leads to significantly exaggerated warming in the Arctic mid- to lower troposphere, and demonstrates that the continuing use of ERA-40 to study Arctic temperature trends is problematic.
The discontinuity occurs in 1997 in response to refined processing of satellite radiances prior to their assimilation into the reanalysis model. It is clearly apparent in comparisons of ERA-40 output against satellite-derived air temperatures, in situ observations, and alternative reanalyses. Decadal or multidecadal Arctic temperature trends calculated over periods that include 1997 are highly inaccurate, particularly below 600 hPa. It is shown that ERA-40 is poorly suited to studying Arctic temperature trends and their vertical profile, and conclusions based upon them must be viewed with extreme caution. Consequently, its future use for this purpose is discouraged. In the context of the wider scientific debate on the suitability of reanalyses for trend analyses, the results show that a series of alternative reanalyses are in broad-scale agreement with observations. Thus, the authors encourage their discerning use instead of ERA-40 for examining Arctic climate change while also reaffirming the importance of verifying reanalyses with observations whenever possible.”
Text in the paper includes
“ERA-40 has been recently used to assess Arctic temperature trends and their vertical structure. Most notably, ERA-40 formed the basis of a now-controversial examination of central Arctic temperature trends by Graversen et al. (2008). The results of that study have been strongly contested, mainly because of concerns about the accuracy of trends calculated from ERA-40 temperatures (Bitz and Fu 2008; Grant et al. 2008; Thorne 2008; Screen and Simmonds 2010b). Yet, ERA-40 continues to be used for Arctic temperature trend analysis (e.g., Yang et al. 2010). In light of this, we show here—explicitly and more thoroughly than previous studies—that inhomogeneities in ERA-40 lead to a poor representation of Arctic temperature trends, particularly in the mid- to lower troposphere, and we demonstrate that its continued use for this purpose is problematic.”
Such an error not only affects the Arctic troposphere, but necessarily must effect the entire northern hemisphere jet stream. It is the poleward to equatorward layer average temperature gradient which causes this wind, as we discuss, for example, in
Pielke, R.A. Sr., T.N. Chase, T.G.F. Kittel, J. Knaff, and J. Eastman, 2001: Analysis of 200 mbar zonal wind for the period 1958-1997. J. Geophys. Res., 106, D21, 27287-27290 [we used the NCEP Reanalysis in our study]
and
Christy, J.R., B. Herman, R. Pielke, Sr., P. Klotzbach, R.T. McNider, J.J. Hnilo, R.W. Spencer, T. Chase and D. Douglass, 2010: What do observational datasets say about modeled tropospheric temperature trends since 1979? Remote Sensing, 2(9), 2148-2169.
The authors of the Journal of Climate paper [Screen and Simmonds] are commended for alerting everyone to this serious error.
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Ouch. That’s gonna leave a mark.
Of course, “the team” will stop at nothing to explain away how “this means nothing.”
Highly inaccurate data? Shurely a great chance for the Team to ADJUST the values (upwards, of course)?
I’d like to point out that the 2001 paper by Pielke, Chase, Kittle, Knaff and Eastman was funded by 2 Evil Big Oil Fossil Fuel organizations……NOAA and NASA. They laundered the funding through another Fossil Fuel shill, NCAR. /sarc
(I’m still bitter about UCS saying anyone who disagrees with them is funded by big oil)
But seriously,
The Screen/Simmonds’ paper came out of the Earth Sciences section of The University of Melbourne…..which receives funding from the Australian gov’t, which generates a significant portion of its revenue from the export of coal. Oh, the irony??
This raises the question of what can replace the ERA-40? And what does this mean for all the studies that used it, and the whole idea of Polar Amplification? I would really like to hear someone knowledgeable about this weigh in, as the implications of this are too big for me to fully distill with the limited knowledge I have of the ERA-40.
tabula rosa … trust no data older than today … start over …
From the Skeptical Science response to this paper:
“Another potential contributor to amplified warming that’s investigated is changes in cloud cover. Spring is the only season that exhibits significant trends in Arctic average cloudiness and the trend is negative. However, decreased cloud cover is expected to cause surface cooling because clouds have a warming influence in spring. Thus no evidence is found of cloud cover changes contributing to recent near-surface Arctic warming.”
WTF? There are less clouds in the spring but it gets cooler. And the sun does shine between March 21 and June 21 right up to the north pole, in fact the specific north pole gets 24 hours of sun after the between the equinoxes, with the 24-hour period sliding down to 66* on June 21st.. And, okay … where there is night during spring, night cloud cover does keep the ground warmer that cloudless nights. But I’ve been from the Tropics and the high Arctic, and I can tell you that the physics is the same when the sun shines – the ground warms up.
Perhaps a story from the North explains this : Years ago an Inuit boy didn’t want to leave the hilltop where we were eating lunch when I saw a lightning-dancing thundercloud approaching across the tundra. He explained that in his town (then called Coppermine) lightning struck the metal jungle gym he was standing by one recess time. There was a huge flash of light, he said, and he fell down, but he was unhurt. “Maybe lightning kills you down south,” he said, “but not up here.” I insisted we seek lower ground and he agreed, though he thought I was just silly, as all southerners are.
So maybe physics does work differently in different parts of the world. Perhaps that is Hansen and Gore’s “problem-that-is-no-problem”. In their world or part there-of, CO2 has different properties. And Skeptical Science takes rooms (or at least rent from) there.
Obviously, the data has not been properly adjusted.
Hmm… Curious that you should link to an RC article on polar amplification by Cecilia Bitz and then go on to say that this was in jeopardy because “ref 8” (Graversen et al, Nature) had been challenged. It’s curious because the challenge was from Cecilia Bitz (and others):
http://www.nature.com/nature/journal/v455/n7210/full/nature07258.html
So Bitz is wrong because she was right? Very confusing….
Typo alert. This might put a kink in the RC posited “polar amplification of temperature” that is expected from AGW. A previous paper published in Nature (Screen & Simmons 2010) said:
should be “(Screen & Simmonds 2010)”—according to the PDF that was linked.
[Thanks. Robt]
The response will be “Of course this doesn’t really affect the general results”. In fact nothing ever does. Because the general result is the desired result and doesn’t require data, only computer models.
Interesting…. though this brings up many questions. Anthony, I think you may have supplied us too many papers for a focused discussion.
What I find strange here is a couple of things….. one, “(ERA-40) that leads to significantly exaggerated warming in the Arctic mid- to lower troposphere,” Ok, so ERA-40 is too high. So, what’s this? (Giss’ June temp anomaly map for the arctic) Supererly duperly too high temps?
And the two, are we really using RSS satellites to determine the validity of ERA-40? My understanding is that both RSS and UAH satellites don’t have the orbit to accurately tell us what the temps are up there.
I’m not trying to be a wet blanket, but I’m trying to understand what sort of precision were demanding from DMI while looking at our sources of data(GISS, UAH, RSS….), we are even more exaggerated than ERA-40. I mean, fine, if ERA-40 is wrong, its wrong, but….. this doesn’t seem kosher.
James
Above 70 north, the “accepted approximations and assumptions” that are made about the sun’s radiation, clouds, atmospheric absorption and open-water/ice-covered reflectivity are – most often- simply dead wrong.
1. Greatly increased absorbtion of light energy into the atmosphere.
At the equator, air mass (the atmosphere’s “thickness”) is (obviously) 1.0 Between the equator and about 60 north, air mass can be closely approximated by 1.0/(sin(latitude) ) … But that formula fails up higher because it doesn’t include the curvature of the earth, and it doesn’t include the swing of each position on the sea’s surface position back around the north pole.
In the high Arctic, air mass over most of the hours of each day over most of the month’s of the year when the sun is actually visible range from 4.5 as high as 11.0 and 15.0 Thus, little light actually reaches the surface –even on a clear day. So, when I calculate that only 25% of the sun’s radiation (on that hypothetical perfectly clear day in the Arctic in the summer), that means that 85% of the sun’s light is absorbed in the atmosphere. It never reaches the ocean’s surface (regardless of ice-covered or open water) to be-reradiated at any wavelength.
2. High Reflectivity off of both sea-ice and open water – in the regions where sea ice actually exists.
Keep looking at radiation in the high Arctic – that region above 80 north latitudes. Currently, very little sea ice remains below 80 north latitude at the September minimum of 4.5 to 5.0 million km square. Thus, ANY consideration of sea-ice albedo feedback MUST be limited to looking at the today’s present conditions of a September sea ice minimum and at conditions above 80 north. Now, what “CAGW theory” – as taught by the CAGW-centric world’s universities – uses is open water albedo’s of 0.06 for water, and 0.85 for ice – as if (1) all of the the “Arctic Ocean” were sea ice and (2) all of that sea ice was floating at the Equator while (3) subjected to 24 hours per day of Equatorial sunshine. Am I exaggerating? No – I’ve read the on-line curriculums and course papers and the research papers and course exams and have these “equatorial” values endlessly repeated at every “university” and college. Actual Arctic values are simply not used. Only “global averages” and equatorial absolutes.
What all this means is that, of what little bit of the sun’s is actually delivered to the surface, between 65% to 90% of it is immediately reflected back off of either sea ice, melt water ponds or open ocean (doesn’t matter which, they all reflect nearly identically in the Arctic latitudes) and returns to the sky at that same low incidence angle that the rays appear to come in at. General ambient background radiation WILL come in at high incident angles (because it is is being re-radiated from the sky and clouds) and WILL be more strongly absorbed by the open water and melt ponds. But that general background radiation is a small percent of the direct radiation that will be reflected.
So, now having bounced off of the Arctic surfaces, and now still at the same wavelength that the incoming solar energy was delivered, the atmosphere now can absorb more of the remaining energy. And that energy will be at the same visible light frequencies that are “invisible” to the CO2 molecules that are so greatly feared by the CAGW equations.
The only radiation that can be affected by changes in CO2 levels is that 10% to 15% of the direct radiation that is actually absorbed by the water (or sea ice) up north, then is re-radiated into the skies at lower energies (longer wavelengths) that can be absorbed by CO2 at any concentration. And today’s CAGW-induced global circulation models don’t “model” this real-world value.
Very interesting.
Potentially, it gives rise to very large (and significant) implications. Should the data set be replaced, and if so with what? If it is to be replaced, will there be any agreement/consensus as to the replacement data set? Will all past papers that relied upon the data set require re-evaluation and who will do this or should they simply be ignored? .
RACookPE1978 says:
August 18, 2011 at 10:08 am
Above 70 north, the “accepted approximations and assumptions” that are made about the sun’s radiation, clouds, atmospheric absorption and open-water/ice-covered reflectivity are – most often- simply dead wrong……….
What all this means is that, of what little bit of the sun’s is actually delivered to the surface, between 65% to 90% of it is immediately reflected back off of either sea ice, melt water ponds or open ocean (doesn’t matter which, they all reflect nearly identically in the Arctic latitudes) and returns to the sky at that same low incidence angle that the rays appear to come in at. General ambient background radiation WILL come in at high incident angles (because it is is being re-radiated from the sky and clouds) and WILL be more strongly absorbed by the open water and melt ponds. But that general background radiation is a small percent of the direct radiation that will be reflected. ……….
The only radiation that can be affected by changes in CO2 levels is that 10% to 15% of the direct radiation that is actually absorbed by the water (or sea ice) up north, then is re-radiated into the skies at lower energies (longer wavelengths) that can be absorbed by CO2 at any concentration. And today’s CAGW-induced global circulation models don’t “model” this real-world value.”
///////////////////////////////////////////////////////////////////////
No surprise there then!!!
I have long been saying, it is the tropics that drive the system and understanding the tropics is the key to understanding how the climate/weather systems work. This is the source of the heat pump. Other areas of the globe are of far less significance and changes in the Artic whilst these may have real visible effect in practice, make little difference and often work in a manner reverse to what one may expect (may be this is mother nature’s in built self regulator eg., melting ice allows the globe to lose more heat and is therefore a brake on runaway warming).
Ged says:
August 18, 2011 at 9:37 am
This raises the question of what can replace the ERA-40? And what does this mean for all the studies that used it, and the whole idea of Polar Amplification?
As I understand the term – as it is most commonly used in most cases – is that Polar Amplification is caused by:
(1) the “assumed” 24-hour day in the high Arctic. (It’s not really 24-hours of daylight, every day between the March and Sept Equinox at all points above the Arctic circle… The sun is visible at midnight above that point during SOME days of the year (depending on the latitude, the further north you go, the more days the sun is visible) at certain (very low) angles above the horizon. Right at the Arctic circle, the sun will “kiss” the horizon at midnight only one day, and will be much higher at noon. Right at the exact pole, the sun will be up all the time , swinging in a low circle all around the horizon. But there are only a few tens of thousand of sq km’s between 89 north and the pole. As you go further south towards the Arctic circle, the number of days the sun shines for 24 hours decreases significantly, and the sun’s angle at midnight averages lower and lower – which means less and less energy can be absorbed into the surface.
(2) The amount of water vapor (90+% of the total greenhouse gas concentration near the equator) in the Arctic (and Antarctic) is limited by the very low temperatures up there. Thus, assuming CO2 is evenly distributed around the globe, the relative amounts of CO2 as a greenhouse gas increases at the poles, and thus, the assumed effect of an increase in CO2 is greater at the poles than anywhere else on the globe.
(3) Positive sea-ice albedo feedback. If the sun is shining “straight down” onto open water, 6-7% is reflected, and the remaining (93-94%) is absorbed into the water, where is available to be re-radiated and absorbed by the CO2 in the atmosphere. (per conventional CAGW theory.) Thus, if I melt any sea ice up north, there is more open “dark” ocean water to absorb more radiation, which then heats the ocean, which re-radiates more radiation, which is absorbed by CO2 which heats the little remaining sea ice, which melts that sea ice faster, which absorbs more solar radiation, which melts the sea ice faster ….
This concept fails when actual reflectivity at actual sea ice locations is checked. Both sea ice and open water have nearly identical indices at 1.33 and 1.31, and thus have nearly the same amounts of reflected energy – regardless of “color” of the open water compared to sea ice – in the high Arctic.
Radiation of both sea ice and open water are even more identical (to three decimal places) so the 24-hour per day radiation of heat energy in the Arctic does not change with ice-covered water or open water.
RACookPE1978 says:
August 18, 2011 at 10:08 am
– as taught by the CAGW-centric world’s universities – uses is open water albedo’s of 0.06 for water, and 0.85 for ice –
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Thanks, man, I’ve been looking for that…… it is hilarious, but if that’s what they’re applying in the arctic, then yes, their models will be wrong. You wouldn’t happen to have a link that shows those assumptions?
Great post.
Thanks to RACook for an interesting lesson.
James Sexton says:
August 18, 2011 at 10:42 am
RACookPE1978 says:
August 18, 2011 at 10:08 am
– as taught by the CAGW-centric world’s universities – uses is open water albedo’s of 0.06 for water, and 0.85 for ice –
===========================================================
Thanks, man, I’ve been looking for that…… it is hilarious, but if that’s what they’re applying in the arctic, then yes, their models will be wrong. You wouldn’t happen to have a link that shows those assumptions?
===========================================================
For “jest” one problem with how climate “science” is being graded – not taught, mind you, but what today’s students are being graded on – see the “answers” to problem 4 in this mid-term exam:
http://isnap.nd.edu/Lectures/phys20054/midterm_exam_solution.pdf
Now, can you count the errors and omissions and assumptions being made … by the person who wrote the “answer” to this mid-term question?
” Thus, the authors encourage their discerning use instead of ERA-40 for examining Arctic climate change while also reaffirming the importance of verifying reanalyses with observations whenever possible.”
Now that will never work.
RACookPE1978 says:
August 18, 2011 at 11:26 am
Now, can you count the errors and omissions and assumptions being made … by the person who wrote the “answer” to this mid-term question?
=======================================================================
lol, thanks again….. especially for the link! But, to avoid displaying my ignorance, I’ll abstain from trying to count the errors, omissions and assumptions……. mostly because my views on climate energy forcings are self-taught, so I’ve got to interpret the colloquial vernacular. For instance, what do the epsilon represent? The alpha obviously is the albedo…..that’s funny…. they assume equal incoming solar forcing…..
Well, ERA-40, flawed as it may be, is becoming increasingly fashionable among mainstream climate scientists.
This is the number of articles by year on Google scholar containing the terms both “Arctic” & “ERA-40” (Articles excluding patents – at least summaries):
1995 0
1996 1
1997 8
1998 13
1999 10
2000 23
2001 25
2002 28
2003 52
2004 71
2005 142
2006 221
2007 280
2008 355
2009 377
2010 501
Clearly, it is increasing exponentially, with a doubling time of ~2 years. If it goes on like this, by the end of this century the annual number of papers connecting the Arctic to the ERA-40 reanalysis product is projected to be 17,592,186,044,416,000 (17.6 quadrillion). It is certainly worse than we thought.
1910-1940 Arctic warming was several times more “amplified” as 1975-2005 allegedly anthropogenic warming.
http://climexp.knmi.nl/data/tsicrutem3_hadsst2_0-360E_70-90N_n_suseason.png
Winter temperatures are as “warm” as in 1940s and those should be affected by CO2 most due to dry and cold air up there. This single chart falsifies the whole pseudo scientific AGW theory.
Temperature in Arctic is a function of Atlantic SST anyway, which goes 30 years up and 30 years down.
Epsilon (the greek “e”) as used in the “solution” to problem 4 of that mid-term exam is approximately the “emissivity” of pure ice and pure water, rounded to 2 decimal places. If so, then “1-e” is (I assume) supposed to be the proportion of absorbed energy not “re-radiated” from either substance. I think. 8<)
“that leads to significantly exaggerated warming in the Arctic mid- to lower troposphere,”
================================================================
and one person is going to argue that the Arctic is even more sensitive, because temps were lower and more ice melted….
…..another person is going to argue that less ice lets more heat escape
now what…………….LOL
But don’t the models show most of the warming is coming from the poles? Don’t we have a lack of sensors in this region and plug estimates into the climate models?