Roger A. Pielke Sr. Comments On The NCDC Talking Point Response To The Report “Is The U.S. Surface Temperature Record Reliable?” By Anthony Watts

The National Climate Data Center (NCDC) has responded to the excellent report

Watts, A. 2009: Is the U.S. Surface Temperature Record Reliable? 28 pages, March 2009 The Heartland Institute [hard copies available from The Heartland Institute 19 South LaSalle Street #903 Chicago Illinois 60603]

which I weblogged on at  “Is The U.S. Surface Temperature Record Reliable?” By Anthony Watts.

The NCDC “Talking Points” released on June 9, 2009  are available at

Talking Points related to: Is the U.S. Temperature Record Reliable?

Unfortunately, the author of the NCDC Talking Points cavalierly and poorly responded to Anthony Watts report. They did not even have the courtesy to cite the report! {UPDATE 7/3/09: They have now cited Anthony’s report, but retained the original date of the Talking Points of June 9 2009).

Below, I comment on their response.

NCDC Talking Point #1

Q. Do many U.S. stations have poor siting by being placed inappropriately close to trees, buildings, parking lots, etc.?


A. Yes. The National Weather Service has station siting criteria, but they were not always followed. That is one reason why NOAA created the Climate Reference Network, with excellent siting and redundant sensors. It is a network designed specifically for assessing climate change. http://www.ncdc.noaa.gov/oa/climate/uscrn/. Additionally, an effort is underway to modernize the Historical Climatology Network, though funds are currently available only to modernize and maintain stations in the Southwest. Managers of both of these networks work diligently to put their stations in locations not only with excellent current siting, but also where the site characteristics are unlikely to change very much over the coming decades.

Climate Science Response

Their answer confirms what Anthony Watts and colleagues have carefully documented.  An obvious question is why did not NCDC elevate this as a priority sooner? Moreover, if the current sites can be “adjusted” to be regionally representative, why does NOAA even need the new Climate Reference Network? The answer to that is that they have recognized for years that there is a problem with the siting of the surface stations, but deliberately attempted to bury this issue until Anthony Watts and colleagues confronted NCDC with the issue.

 NCDC Talking Point #2

Q. How has the poor siting biased local temperatures trends?

A. At the present time (June 2009), to the best of our knowledge, there has only been one published peer-reviewed study that specifically quantified the potential bias in trends caused by poor station siting: Peterson, Thomas C., 2006: Examination of Potential Biases in Air Temperature Caused by Poor Station Locations. Bulletin of the American Meteorological Society, 87, 1073-1080. Written by a NOAA National Climatic Data Center scientist, it examined only a small subset of stations – all that had their siting checked at that time – and found no bias in long-term trends. The linear trend in adjusted temperature series over the period examined was nearly identical between the stations with good siting and the stations with poor siting, with the stations having poor siting showing slightly less warming. The following questions address implications from that paper.

Climate Science Response

This is blatantly untrue and the author of these talking points know that. Tom Peterson, for example, was even a reviewer of the Pielke 2007a and 2007b papers, and was aware of the Pielke et al 2002 paper.

Pielke Sr., R.A., T. Stohlgren, L. Schell, W. Parton, N. Doesken, K. Redmond, J. Moeny, T. McKee, and T.G.F. Kittel, 2002: Problems in evaluating regional and local trends in temperature: An example from eastern Colorado, USA. Int. J. Climatol., 22, 421-434.

Pielke Sr., R.A. J. Nielsen-Gammon, C. Davey, J. Angel, O. Bliss, N. Doesken, M. Cai., S.  Fall, D. Niyogi, K. Gallo, R. Hale, K.G. Hubbard, X. Lin, H. Li, and S. Raman, 2007a: Documentation of uncertainties and biases associated with surface temperature measurement sites for climate change assessment. Bull. Amer. Meteor. Soc., 88:6, 913-928.

Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007b: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229.

In the second paper, we wrote

“Peterson’s approach and conclusions, therefore, provide a false sense of confidence with these data for temperature change studies by seeming to indicate that the errors can be corrected.”

The decision of the NCDC Talking Points to ignore these papers illustrates the state that NCDC is in with respect to Climate Science. NCDC, as led by Tom Karl, is not interested in an inclusive assessment of climate science issues (in this case the multi-decadal surface temperature trends), but are only interested in promoting their particular agenda and in protecting their particular data set.

NCDC Talking Point #3

Q. Does a station with poor siting read warmer than a station with good siting?

Not necessarily. A station too close to a parking lot would be expected to read warmer than a station situated over grass far from any human influence other natural obstructions. But a station too close to a large tree to the west, so that the station was shaded in the afternoon, would be expected to make the afternoon maximum temperature read a bit cooler than a station in full sunlight. Many local factors influence the observed temperature: whether a station is in a valley with cold air drainage, whether the station is a liquid-in-glass thermometer in a standard wooden shelter or an electronic thermometer in the new smaller and more open plastic shelters, whether the station reads and resets its maximum and minimum thermometers in the coolest time of the day in early morning or in the warmest time of the day in the afternoon, etc. But for detecting climate change, the concern is not the absolute temperature – whether a station is reading warmer or cooler than a nearby station over grass – but how that temperature changes over time.

Climate Science Response

The answer correctly reports on the variety of issues that affect surface temperatures. However, where we disagree is that the multi-decadal surface temperature trends and anomalies also depend on the details of the observing sites and how these details change over time.

This can be illustrated from our 2007 BAMS paper, where the set of relatively closely spaced stations shown in Figure 10 (reproduced belw) have significantly different long term trends, as summarized in Table 5 (reproduced below) from that paper. Despite being relatively close together, the variations in both the local enviroment and the station exposure result in distinctly different trends [Using the categories in the Watts, 2009 report, the stations had the following Trinidad (3); Cheyenne Wells (1); Las Animas (5); Eads (4) and Lamar (4)]. 

Even sites that are locally in a category 1 class, such as Cheyenne Wells, however, also have issues with the landscape in their local surroundings, as we documented for locations in northeastern Colorado in Figures 5, 7, 9, 10 and 12 of

Hanamean, J.R. Jr., R.A. Pielke Sr., C.L. Castro, D.S. Ojima, B.C. Reed, and Z. Gao, 2003: Vegetation impacts on maximum and minimum temperatures in northeast Colorado. Meteorological Applications, 10, 203-215.

Depending on wind direction, the air that reaches the observing site can have a different temperature. Changes in the wind directions over time can result in temperature trends that are due to this effect alone.

This local landscape variation as a function of azimith can be seen in the photographs for the Cheyenne Wells site in

Davey, C.A., and R.A. Pielke Sr., 2005: Microclimate exposures of surface-based weather stations – implications for the assessment of long-term temperature trends. Bull. Amer. Meteor. Soc., Vol. 86, No. 4, 497–504,

where depending on the wind direction and time of year, the air that the temperature sensor monitors may transit a dirt road, crops, or other land surface varations, each with a different surface heat budget., before reaching the temperature observing site.

The NCDC Talking Points ignore informing us why all of these local landscape effects on multi-decadal surface temperature trends would be random and average out.

NCDC Talking Point #4

Q. So a station moving from a location with good siting to a location with poor siting could cause a bias in the temperature record. Can that bias be adjusted out of the record?

A. A great dealof work has gone into efforts to account for a wide variety of biases in the climate record, both in NOAA and at sister agencies around the world. Since the 1980s, scientists at NOAA’s NationalClimatic Data Center are at the forefront of this effort developing techniques to detect and quantify biases in station time series. When a bias associated with any change is detected, it is removed so that the time series is homogeneous with respect to its current instrumentation and siting. The latest peer-reviewed paper which provides an overview the sources of bias and their removal (Menne et al., 2009 in press), including urbanization and nonstandard siting. At the time that paper was written, station site evaluations were too incomplete to conduct a thorough investigation (that analysis is forthcoming). However, they could evaluate urban bias and found that once the data were fully adjusted the 30% most urban stations had about the same trend as the remaining more rural stations.

Climate Science Response

The failure of NCDC to correct for all of the recognized biases has been documented in

Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229;

a paper NCDC has chosen to ignore [another surface temperature analysis group has been open to scientific debate, however; see]. 

NCDC has also ignored

Lin, X., R.A. Pielke Sr., K.G. Hubbard, K.C. Crawford, M. A. Shafer, and T. Matsui, 2007: An examination of 1997-2007 surface layer temperature trends at two heights in Oklahoma. Geophys. Res. Letts., 34, L24705, doi:10.1029/2007GL031652,

where we document a bias in the use of a single level surface temperature (the minimum temperature, in particular) to monitor multi-decadal surface temperature trends.  

The NCDC talking points also mention the Menne et al (2009) paper, which, unfortunately, perpetuates the NCDC failure to adequately consider all of the biases and uncertainties in the surface temperature record. The Menne et al paper was weblogged in

Comments On The New Paper “The United States Historical Climatology Network Monthly Temperature Data – Version 2 By Menne Et Al 2009

Finally, we have several other papers in the review process, and look forward to communicating them to you when accepted for publication.

NCDC Talking Point #5

Q. What can we say about poor siting’s impact on national temperature trends?


A. We are limited in what we can say due to limited information about station siting. Surfacestations.org has examined about 70% of the 1221 stations in NOAA’s Historical Climatology Network (USHCN). According to their web site of early June 2009, they classified 70 USHCN version 2 stations as good or best (class 1 or 2). The criteria used to make that classification is based on NOAA’s Climate Reference Network Site Handbook so the criteria are clear. But, as many different individuals participated in the site evaluations, with varying levels of expertise, the degree of standardization and reproducibility of this process is unknown.

However, at the present time this is the only large scale site evaluation information available so we conducted a preliminary analysis.

Two national time series were made using the same gridding and area averaging technique. One analysis was for the full data set. The other used only the 70 stations that surfacestations.org classified as good or best. We would expect some differences simply due to the different area covered: the 70 stations only covered 43% of the country with no stations in, for example, New Mexico, Kansas, Nebraska, Iowa, Illinois, Ohio, West Virginia, Kentucky, Tennessee or North Carolina. Yetthe two time series, shown below as both annual data and smooth data, are remarkably similar. Clearly there is no indication for this analysis that poor current siting is imparting a bias in the U.S. temperature trends.

Climate Science Response

This is a cavalier response.  In order to show that there is little effect on surface temperature anomalies due to station siting, they need to assess the anomalies over time in the same region for each category of station siting. A national average which includes includes large regional variations (e.g. see Figure 20a in Pielke et al 2007a ) tells us little about the quality of the data.

They also do not provide the details of how (or even if) they “homogenized” their data using other surface temperature information. As we wrote in Pielke et al 2007b
“….attempting to correct the errors with existing adjustment methods artificially forces toward regional representativeness and cannot be expected to recover all of the trend information that would have been obtained locally from a well-sited station.”
   NCDC Talking Point #6

Q. Is there any question that surface temperatures in the United States have been rising rapidly during the last 50 years?

A. None at all. Even if NOAA did not have weather observing stations across the length and breadth of the United States the impacts of the warming are unmistakable. For example, lake and river ice is melting earlier in the spring and forming later in the fall. Plants are blooming earlier
in the spring. Mountain glaciers are melting. And a multitude of species of birds, fish, mammals and plants are extending their ranges northward and, in mountainous areas, upward as well.

Menne, Matthew J., Claude N. Williams, Jr. and Russell S. Vose, 2009: The United States Historical Climatology Network Monthly Temperature Data – Version 2. Bulletin of the American Meteorological Society, in press.


Peterson, Thomas C., 2006: Examination of Potential Biases in Air Temperature Caused by Poor Station Locations. Bulletin of the American Meteorological Society, 87, 1073-1080. It is available from
http://ams.allenpress.com/archive/1520-0477/87/8/pdf/i1520-0477-87-8-1073.pdf.

Climate Science Response

Their claim that temperatures have been “rising rapidly” over the past 50 years is based on the surface temperature record in which there are reported warm biases; e.g. see

Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229.

NCDC also is misinformed with respect to the other climate metrics. For example, they write

Plants are blooming earlier in the spring.”  

However, a new paper in press (see)

White, M.A., K.M. de Beurs, K. Didan, D.W. Inouye, A.D. Richardson, O.P. Jensen, J. O’Keefe, G. Zhang, R.R. Nemani, W.J.D. van Leeuwen, J.F. Brown, A. de Wit, M. Schaepman, X. Lin, M. Dettinger, A. Bailey, J. Kimball, M.D. Schwartz, D.D. Baldocchi, J.T. Lee, W.K. Lauenroth. Intercomparison, interpretation, and assessment of spring phenology in North America estimated from remote sensing for 1982 to 2006. Global Change Biology (in press),

writes

“Trend estimates from the SOS [Start of Spring] methods as well as measured and modeled plant phenologystrongly suggest either no or very geographically limited trends towards earlier spring arrival, although we caution that, for an event such as SOS with high interannual variability, a 25-year SOS record is short for detecting robust trends.”

IN CONCLUSION

NCDC would be a much more valuable resource in the climate community if they worked to be inclusive in presenting all peer reviewed perspectives in climate science. Currently, they are only reporting on information that supports their agenda and not communicating real world observational data that conflicts with that agenda. The fault for this failure in leadership is with Tom Karl who is Director of NCDC.







 

 

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