Friday, January 28, 2011

Pielkes all the way down, revisited

Remember Pielke and Matsui 2005, Klotzbach et al 2009 and the debate over how plausible and valid their results were? You may recall my main complaint with PM05 (it wasn't my original observation, but I could see its significance) was that they had applied a large heat flux directly into the base of the atmosphere, which is not how GHGs work, but still claimed that their results were indicative of the effects of GHGs. Based on this implausible result, and some observations which were misinterpreted as supporting this theory (but which actually had the wrong sign) Klotzbach et al claimed that about 30% of the global temperature trend might be an artefact.

Well, a new paper has been published in JGR, Screen level temperature increase due to higher atmospheric carbon dioxide in calm and windy nights revisited by Steeneveld et al. (including Roger Pielke Snr as last author). It's a modelling study which investigates how long-term 2m temperature trends (due to GHG increases) should vary with wind speed. Instead of using an analytic equation and implausibly pumping heat into the base of the atmosphere, they have used a realistic atmospheric and radiative transfer model.

The second-to last sentence of their abstract reads:
We find that the screen level temperature response is surprisingly constant for a rather broad range of both geostrophic wind speed (5–15 m s−1) and 10 m wind (2–4.0 m s−1).
Thus the central claim of PM05, which underpinned this entire edifice, is refuted. No doubt this will be spun as a glorious victory, in some quarters...

15 comments:

Steve Bloom said...

"This is mostly due to land surface-vegetation-atmosphere feedbacks taken into account in the present study which were not considered by PM05." Hrm? Well, I suppose I'll have to read it now.

Why do I have the sneaking suspicion that those Dutch guys strong-armed RP Sr. in some manner, e.g. by promising to be as nice as possible if signed on? I suppose I'm a suspicious sort.

Well, being so, I can't help but also think of the time Christy and Spencer were made to toe the line in that early CCSP report, and then repudiated it a matter of weeks later (using the excuse that their yet newest data set changed everything). We'll see if this one sticks better.

I remember asking RP Sr., when he first raised this business years ago, that he should apply for funding to do a field test of his idea. It seemed like the apparatus would be pretty cheap. I wonder if he even tried. In any case I'm pretty sure his idea even then was just to keep the ball in the air for as long as possible.

Anonymous said...

The full paper is here: http://www.met.wau.nl/medewerkers/steeneveld/Steeneveld_etal2010_JGR_SBL_T2m_rise.pdf

From the conclusion:
In this paper we revisit the issue of land surface temperature trends and their dependence on wind speeds. In an earlier study, Pielke and Matsui [2005] concluded that the nighttime 2 m temperature increase due to changes in longwave flux divergence should strongly depend on wind speed. Here we conclude that the model used in that study is not sufficient for such an analysis because of the limited processes represented as well as not considering the land surface‐vegetation‐atmosphere feedback

--cycnicus

SteveF said...

The big man blogged about this late last year:

The answer to the question of whether long term temperature trends near the surface are a significant function of height is an important climate metric issue, as these trends are used in the construction of the annual average global surface temperature trend. From this new study, it appears that feedbacks mute temperature trends near the surface, however, this was for a specific situation and may not be general to other landscapes. The new McNider et al paper, that is in preparation, will examine this issue for other situations, and we will report on this weblog when this study is complete.

http://pielkeclimatesci.wordpress.com/2010/11/19/new-paper-screen-level-temperature-increase-due-to-higher-atmospheric-carbon-dioxide-in-calm-and-windy-nights-revisited-by-steeneveld-et-al-2010/

SteveF said...

Not one for short blog post titles is out Roger. Sorry, I mean weblog.

Oh and was good to see him giving a hat tip to noted climate expert Marc Morano recently.

willard said...

Hello,

Roger Pielke Jr. kindly answered there:

http://rogerpielkejr.blogspot.com/2009/08/evidence-that-global-temperature-trends.html

Here is the last sentence from his answer:

> If history is any guide, I expect that a snarky, misleading blog post is all he's got ;-)

This sentence has two very different readings. One is a concession, one is an accusation.

PS: Word Verification is Subban, which is a name of a hockey player.

Rocco said...

willard: I disagree, to me it sounds like a challenge! :)

EliRabett said...

Eli will claim victory It was pretty clear K&P was going to fail near the ground
-------------------
Drive the wind speed to zero and you end up with a zero thickness scale length, an infinite temperature difference between ground and the layer a micron up. In other words, at some point this little model fails. It probably is not too bad for the upper range of the wind scale used, but, of course, in that case the scale length will also be larger, e.g. the layer thicker and the lapse rate not as extreme.

Dirk said...

No doubt this will be spun as a glorious victory, in some quarters...

Thanks James. Not a glorious victory, but I concede that this post made my day :-)

willard said...

James,

According to Pielke Senior, you are missing the point (again!):

http://pielkeclimatesci.wordpress.com/2011/01/28/james-annan-misses-the-point-again/

Here is the rebuttal:

> [The central claim of PM05, which underpinned this entire edifice, is refuted] is a completely inaccurate characterization of the Steenveld et al paper.

And why is that, readers might ask?

Crickets.

***

A sentence of note:

> Our paper is also discussed in my post of November 19 2010 (which James does not seem to have read)

Steve Bloom said...

Thanks, SteveF, but McNider et al.? Why the switch in author order? Does anyone know these Dutch scientists?

Steve Bloom said...

That was some rather weak ink from RP Jr., Willard.

Carl C said...

I've always thought it rather pathological how RPJr has to agree with his dad on everything...

Steve Bloom said...

It's of a piece with never, ever admitting mistakes.

Steve Bloom said...

Hmm, OK, if there's such a thing as a boundary layer specialist, those guys fill the bill. S. is a brand-new ass't prof. and got his PhD at Wageningen under H. I'd still like to know the back story, but I suppose it may be nothing more complicated than an inability on RP Sr.'s part to refuse an offer of a co-authorship. Even at that, one can only imagine that one or both of them must have the patience of Job, recalling e.g. the infamous butterfly effect dispute.

willard said...

By 10:47 last morning, Roger Pielke Sr. responded:

http://pielkeclimatesci.wordpress.com/2011/01/28/james-annan-misses-the-point-again/

that

> [T]his [the claim that the central claim of PM05, which underpinned this entire edifice, is refuted] is a completely inaccurate characterization of the Steenveld et al paper.

(Why the reader may ask? Crickets.)

Notice the links at the end of the post, especially the last one.