Climate Science: Roger Pielke Sr. Research Group News

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.

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.

This paper documents that landscape change is a regional first oder climate forcing in the United States. For more recent studies on this subject from our research group (see).

Copeland, J.H., R.A. Pielke, and T.G.F. Kittel, 1996: Potential climatic impacts of vegetation change: A regional modeling study. J. Geophys. Res., 101, 7409-7418.

The abstract reads

“The human species has been modifying the landscape long before the development of modern agrarian techniques. Much of the land area of the conterminous United States is currently used for agricultural production. In certain regions this change in vegetative cover from its natural state may have led to local climatic change. A regional climate version of the Colorado State University Regional Atmospheric Modeling System was used to assess the impact of a natural versus current vegetation distribution on the weather and climate of July 1989. The results indicate that coherent regions of substantial changes, of both positive and negative sign, in screen height temperature, humidity, wind speed, and precipitation are a possible consequence of land use change throughout the United States. The simulated changes in the screen height quantities were closely related to changes in the vegetation parameters of albedo, roughness length, leaf area index, and fractional coverage.”

This paper provides observational examples of the interaction between the atmosphere and the landscape which was discussed in yesterday’s weblog. 

Stohlgren, T.J., T.N. Chase, R.A. Pielke, T.G.F. Kittel, and J. Baron, 1998: Evidence that local land use practices influence regional climate and vegetation patterns in adjacent natural areas. Global Change Biology, 4, 495-504.

The abstract reads

“We present evidence that land use practices in the plains of Colorado influence regional climate and vegetation in adjacent natural areas in the Rocky Mountains in predictable ways. Mesoscale climate model simulations using the Colorado State University Regional Atmospheric Modelling System (RAMS) projected that modifications to natural vegetation in the plains, primarily due to agriculture and urbanization, could produce lower summer temperatures in the mountains. We corroborate the RAMS simulations with three independent sets of data: (i) climate records from 16 weather stations, which showed significant trends of decreasing July temperatures in recent decades; (ii) the distribution of seedlings of five dominant conifer species in Rocky Mountain National Park, Colorado, which suggested that cooler, wetter conditions occurred over roughly the same time period; and (iii) increased stream flow, normalized for changes in precipitation, during the summer months in four river basins, which also indicates cooler summer temperatures and lower transpiration at landscape scales. Combined, the mesoscale atmospheric/land-surface model, short-term trends in regional temperatures, forest distribution changes, and hydrology data indicate that the effects of land use practices on regional climate may overshadow larger-scale temperature changes commonly associated with observed increases in CO₂ and other greenhouse gases.”

Today’s weblog reviews how the atmosphere and landscape are coupled together, and that the climate system is an interactive nonlinear system.

Pielke, R.A., R. Avissar, M. Raupach, H. Dolman, X. Zeng, and S. Denning, 1998: Interactions between the atmosphere and terrestrial ecosystems: Influence on weather and climate. Global Change Biology, 4, 461-475.

The abstract reads

“This paper overviews the short-term (biophysical) and long-term out to around 100 year timescales; biogeochemical and biogeographical) influences of the land surface on weather and climate. From our review of the literature, the evidence is convincing that terrestrial ecosystem dynamics on these timescales significantly influence atmospheric processes. In studies of past and possible future climate change, terrestrial ecosystem dynamics are as important as changes in atmospheric dynamics and composition, ocean circulation, ice sheet extent, and orbit perturbations.”

Yesterday’s paper discussed how  adjacent snow and snow free areas could generate mesoscale circulations. Today’s post (and yesterday’s as well) shows that not only does this affect air quality, but temperatures near the ground (such as used to monitor long term temperature trends) are very significantly affected. Even if the atmosphere above was not warming over time, a series of winters with less snow in a region would report  higher surface air temperatures.

Segal, M., J.R. Garratt, R.A. Pielke, P. Hildebrand, F.A. Rogers, and J. Cramer, 1991: On the impact of snow cover on daytime pollution dispersion. Atmos. Environ., 25B, 177-192.

The abstract reads

“A preliminary evaluation of the impact of snow cover on daytime pollutant dispersion conditions is made by using conceptual, scaling, and observational analyses. For uniform snow cover and synoptically unperturbed sunny conditions, observations indicate a considerable suppression of the surface sensible heat flux, the turbulence, and the development of the daytime atmospheric boundary layer (ABL) when compared to snow-free conditions. However, under conditions of non-uniform snow cover, as in urban areas, or associated with vegetated areas or bare ground patches, a milder effect on pollutant dispersion conditions would be expected. Observed concentrations of atmospheric particles within the ABL, and surface pollutant concentrations in urban areas, reflect the impact of snow cover on the modification of ABL characteristics.”

Today’s weblog documents that the areas of snow and adjacent snow free areas can result in signifcant mesoscale circulations. This is yet another example of a the role of landscape within the climate system.

Segal, M., J.H. Cramer, R.A. Pielke, J.R. Garratt, and P. Hildebrand, 1991: Observational evaluation of the snow-breeze. Mon. Wea. Rev., 119, 412-424.

The abstract reads

“An observational evaluation of the daytime thermally induced flow between the snow and snow-free areas (termed snow breeze) has been carded out. Aircraft measurements within the lower atmosphere made in the winter of 1988 reveal large temperature reductions over the snow cover relative to the bare ground implying the potential for snow-breeze generation. The aircraft flights were generally made under unfavorable synoptic conditions although in one particular case with a moderate synoptic flow, a snow breeze was clearly identified. A less distinctive snow breeze was indicated in a second case. Observed features and a scaling analysis of relevance to snow breezes are presented.”

The weblogs of our research papers present observational and modeling evidence of the significant role of landscape processes on weather and climate Today’s paper summarizes why these effects have significant consequences on local and regional climate.

Pielke, R.A. and R. Avissar, 1990: Influence of landscape structure on local and regional climate. Landscape Ecology, 4, 133-155.

The abstract reads

“This paper discusses the physical linkage between the surface and the atmosphere, and demonstrates how even slight changes in surface conditions can have a pronounced effect on weather and climate. Observational and modeling evidence are presented to demonstrate the influence of landscape type on the overlying atmospheric conditions. The albedo, and the fractional partitioning of atmospheric turbulent heat flux into sensible and latent fluxes is shown to be particularly important in directly affecting local and regional weather and climate. It is concluded that adequate assessment of global climate and climate change cannot be achieved unless mesoscale landscape characteristics and their changes over time can be accurately determined.”

The weblog for today shows how the presence of irrigated landscapes in semiarid regions can result in a substantial alteration in the intensity of thunderstorms.

Pielke, R.A. and X. Zeng, 1989: Influence on severe storm development of irrigated land. Natl. Wea. Dig., 14, 16-17.

The abstract reads

“Using radiosonde sounding data collected over an irrigated area and over an adjacent natural grassland region in northeast Colorado, it is documented that larger available buoyant energy exists in the lower troposphere over the irrigated land. This enhanced energy, a result of evopotranspiration from the crops, is suggested as a mechanism for potentially enhanced thunderstorm severity over and near irrigated locations. Low-level convergence that develops as a result of the differential turbulent sensible heating between the two land surfaces can further enhance available buoyant energy.”

Today’s paper documents with observational data the major role of irrigated crops on the surface and boundary layer temperatures and moisture in a semi arid region.

Segal, M., W. Schreiber, G. Kallos, R.A. Pielke, J.R. Garratt, J. Weaver, A. Rodi, and J. Wilson, 1989: The impact of crop areas in northeast Colorado on midsummer mesoscale thermal circulations. Mon. Wea. Rev., 117, 809-825.

The abstract reads

“The present study provides a preliminary evaluation of mesoscale circulations forced by surface gradients of heating arising from irrigated areas adjacent to dry land, utilizing a combination of satellite, observational, and modeling approaches. The irrigated crop areas of northeast Colorado were chosen for the study. For the cases studied satellite surface infrared temperature data indicated a typical temperature contrast of approximately 10 K at noon, between the irrigated area and the adjacent dry land. Surface observations and aircraft measurements within the lower region of the atmospheric boundary layer indicated, in general, a significant temperature contrast and moisture difference, thereby implying a potential thermally driven circulation. The anticipated thermally induced flows, however, were reflected in the measurements only by modest changes in the wind speed and wind direction across the contrast location. It is suggested that the daytime, elevated, terrain-forced flow in the area, and the synoptic flow, combined to mask to varying degrees the thermally induced circulation due to the irrigated land-dry land area effect. Numerical model simulations which were carried out over the studied area support this hypothesis. In addition, the impact of the irrigated areas on the moisture within the boundary layer, as well as on potential convective cloud developments is discussed.”

The paper for today documents how landscape patterning, such as presented in yesterday’s weblog, result in the generation of mesoscale circulations.

Segal, M., R. Avissar, M.C. McCumber, and R.A. Pielke, 1988: Evaluation of vegetation effects on the generation and modification of mesoscale circulations. J. Atmos. Sci., 45, 2268-2292.

The abstract is

“The purpose of the present study is to evaluate (i) the effect of vegetated surfaces on modifying sea breeze and daytime thermally induced upslope flows, and (ii) the generation of thermally induced flow by vegetated areas contrasted by bare soil area. In order to address these objectives, the following tasks were carried out: 1) previous documented studies with implication for (i) and (ii) are reviewed; 2) the main features of the thermal balance of vegetated surfaces are outlined qualitatively; 3) a quantitative evaluation of the various components in the thermal balance based on documented observational studies is provided; and 4) scale analyses and numerical model simulations are used to provide quantitative evaluations of the circulations involved with (i) and (ii) for several illustrative cases.

The study suggests that the impact of vegetated surfaces in those cases is highly dependent on the environmental conditions as well as vegetation characteristics. For ideal environmental conditions resulting in high evapotranspiration rates over extended dense vegetated areas, it is shown that the circulation types listed in (i) are substantially reduced. For the situation described by (ii), circulations with an intensity close to that of a sea breeze can develop when the vegetation is very dense, and covers an extended area, and under favorable environmental conditions. The reduction in these impacts for more frequent real world situations involved with less favorable environmental conditions as well as with relatively sparse vegetated areas is also evaluated.”