Comments On Gavin Schmidt’s Statement Regarding The Paper Klotzbach Et Al 2009

FINAL UPDATE November 13 2009

Gavin Schmidt at Real Climate has, unfortunately, continued to repeat his misinterpretations of our paper.  Therefore, we look forward to his submission of a formal Comment to JGR on our article, where we can complete a formal Reply to refute his erroneous claims. 

Further UPDATE   November 12 2009 pm

Here is Gavin’s response to my first UPDATE:

[Response: I’m sorry but I don’t follow this at all. The relationship between radiative forcing and surface temperature defines climate sensitivity. You don’t come up with climate sensitivity independently of that definition and then redefine what Ts means. Please read Hansen et al (2005) for discussions of the various issues in that definition and the potential variation in that definition (or rather the definition of the effective forcing) dependent on different forcings. There is nowhere in that paper, or any other, that relies on some assumption about atmospheric heat content anomalies. Not a single one. The quote from the NRC report is, frankly, a little odd, since it is bizarre that anyone would attempt to calculate the surface temperature (which is well observed) using the atmospheric heat content and climate sensitivity (which are not). So can you point me to an independent study that has attempted to do this? – gavin]

To return to the finding of our paper, are you concluding, in contrast to our finding, that there are no statistically significant differences in the lower tropospheric and surface temperature trends?

[Response: Of course there are, but this has been known for years. The issue is whether those differences are important or expected as has been stated in multiple papers prior to this one. Half of your paper using an incorrect expectation (based on the McKitricks’ inadvertently mistaken calculation) and the other half doesn’t address the issue at all (since no real physical process in the PBL can cause a bias in the surface temperature records). At best, you could be arguing that improvements to the realism of the PBL physics in the models would change the expectation of the difference in MSU and surface trends, but this is not something you address at all. – gavin]

 With respect to your statement that “No one calculates the surface temperature (which is well observed) using the atmospheric heat content“. I do not know how you made this bizzare interpretation of the quotes from the reports I provided to you! In your  original post, you wrote

“Please point me to one study anywhere in the literature which has used the surface temperature record to infer changes in the heat content of the atmosphere”. 

I have done that in the NRC (2005) report and the CCSP report which is in the chapter that Ben Santer authored. 

Now that I have answered your challenge to the question in your original post, you have changed the question to ““No one calculates the surface temperature (which is well observed) using the atmospheric heat content“. Of course, we don’t and no one has claimed this! You have mis-represented what I wrote with this later claim.

The authors of the [with the”odd” quote] NRC report, besides myself, were Daniel Jacob, Roni Avissar, Gerald Bond, Stuart Gaffin, Jeff Kiehl, Judith Lean, Ulricke Lohmann, Michael Mann, V. Ramanthan and Lynn Russell.  For you then to state that the “quote from the NRC report is, frankly, a little odd” simply means you disagree with it. The peer reviewed NRC report assessed the climate communities perspective on the surface temperature anomaly and what this metric means in terms of radiative forcing and climate system heat changes. Your disagreement with the statement in that report is with a wider community than just the authors of the Klotzbach et al 2009 paper.

On your statement that “Half of your paper using an incorrect expectation (based on the McKitricks’ inadvertently mistaken calculation) and the other half doesn’t address the issue at all (since no real physical process in the PBL can cause a bias in the surface temperature records)”

indicates that you still do not accurately report on (or understand) our paper. First, Ross McKitrick’s calculations were not mistaken but used a set of data from your GISS model output. Moreover, to state that “half” of our paper depends on that calculation is  wrong. Our results are robust even without using an amplification.

Second, the bias in using the surface temperature trends is in its interpretation as a metric of temperature trends above the surface. We have clearly shown (in several of our papers) that a systematic warm bias exists when the surface temperature measurements are in a stably stratified boundary layer, and the lower troposphere warms.  The Klotzbach et al 2009 paper examined this issue and concluded this is a robust result.

As we have written before, we look forward to a formal exchange with you on this issue in the peer-reviewed literature as part of a Comment/Reply.

 

 

UPDATE November 12 2009

FROM REAL CLIMATE – My Posted Comment:

A reply to your post and comment #2

http://pielkeclimatesci.wordpress.com/2009/11/12/comments-on-gavin-schmidts-statement-regarding-the-paper-klotzbach-et-al-2009/

Gavin Schmidt’s Response

[Response: Hi Roger, Please point me to one study anywhere in the literature which has used the surface temperature record to infer changes in the heat content of the atmosphere. Just one. – gavin]

MY RESPONSE:

Hi Gavin – In response to your reply to comment #10, the issue is the vertical distribution of positive temperature trends that is used as a measure of radiative forcing. There are many papers that discuss this, including what I presented in my post this morning [http://pielkeclimatesci.wordpress.com/2009/11/12/comments-on-gavin-schmidts-statement-regarding-the-paper-klotzbach-et-al-2009/]; i.e.

“Radiative forcing [RF] can be related through a linear relationship to the global mean equilibrium temperature change at the surface (delta Ts): delta Ts = lambda * RF, where lambda is the climate sensitivity parameter (e.g.,Ramaswamy et al., 2001).

The lower troposphere is also expected to have a linear relationship to the radiative forcing although amplified relative to the surface; e.g. see Figure 5.6 for the tropics in CCSP 1.1. Chapter 5.”

As another example, the National Research Council report[http://www.nap.edu/openbook/0309095069/html/] on pages 19 has the text
“According to the radiative-convective equilibrium concept, the equation for determining global average surface temperature of the planet is

dH/dt = f – T’/lambda,

where H is the heat content of the land-ocean-atmosphere system and T′ is the change in surface temperature in response to a change in heat content….. In principle, T′ should account for changes in the temperature of the surface and the troposphere, and since the lapse rate is assumed to be known or is assumed to be a function of surface temperature, T′ can be approximated by the surface temperature.”

To return to the finding of our paper, are you concluding, in contrast to our finding, that there are no statistically significant differences in the lower tropospheric and surface temperature trends?

************************************************************************************************

Real Climate, under the authorship of Gavin Schmidt, has posted a criticism of our paper

Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr., J.R. Christy, and R.T. McNider, 2009: An alternative explanation for differential temperature trends at the surface and in the lower troposphere. J. Geophys. Res., 114, D21102, doi:10.1029/2009JD011841

in a post he titles Muddying the peer-reviewed literature.

Our response to his post [from the authors of the Klotzbach et al paper] is given at

Response to Gavin Schmidt on Klotzbach et al. 2009

Gavin responds to this post in a comment that reads

“[Response: Way to go Roger! Reduce everything to a triviality of attribution and completely ignore the substance. Just so we’re clear, ‘puzzled’ and ‘surprised’ doesn’t equal ‘angry’ and the issue is not who should get the credit but whether the answer is right. If you are happy putting your name on clearly incorrect work, go right ahead. Readers can judge your credibility accordingly. – gavin]”

Gavin, however, continues to ignore the issue that using the surface temperature measurements to diagnose heat changes through a deeper layer of the atmosphere  introduces a bias. His issue with the amplification is tangential to this concern, and, moreover, we did investigate this as part of our e-mail exchange with him, and concluded it did not significantly alter our conclusions. We sent that finding to him in August.

We discuss the bias issue in my weblog of September 28 2009 [so Gavin certainly should have read this] titled

The IPCC Claim Regarding A Linear Relationship Between The Global Average Surface Temperature Trends And Global Average Radiative Forcing Is Quantitatively Inaccurate

“We show in our paper, irrespective of the amplification used, that the surface and lower tropospheric temperature trends are diverging in time. We offer an explanation for some of this related to the use of minimum temperatures over land as part of the construction of the global average surface temperature trend. Other sources of bias and uncertainty are reported in our 2007 JGR paper [Pielke et al 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends].

This also means that the diagnosis of the radiative forcing using the surface temperature trends introduces errors. The assumption of a linear relationship between the radiative forcings and surface temperature is clearly stated in the 2007 IPCC WG1 report (e.g. see Chapter 2 page 133), where it is written

“Radiative forcing [RF] can be related through a linear relationship to the global mean equilibrium temperature change at the surface (delta Ts): delta Ts = lambda * RF, where lambda is the climate sensitivity parameter (e.g.,Ramaswamy et al., 2001).”

The lower troposphere is also expected to have a linear relationship to the radiative forcing although amplified relative to the surface; e.g. see Figure 5.6 for the tropics in CCSP 1.1. Chapter 5.

The Real Climate post by Gavin Schmidt, continues to avoid focusing on the main finding of the Klotzbach et al 2009 paper that there a bias in the use of the land surface temperature trends as an accurate diagnostic for deep layer tropospheric temperature changes [and, hence, as part of a calculation of the global average radiative forcing].

We look forward to the opportunity to prepare a Reply in the peer-reviewed literature to a Comment that Gavin must submit if he is really convinced that we have “muddied” the peer-reviewed literature.

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