TEMPERATURE VARIABILITY: GLOBAL, REGIONAL AND LOCAL
Vincent Gray
Global Temperature
It is quite impossible to obtain a statistically or scientifically acceptable estimate of mean global
temperature or its variability over time, from readings on the earth’s surface, such as is claimed for the
“global annual mean temperature anomaly record”.(e.g. Brohan et al 2006) Random distribution of
measuring equipment is simply impossible. There are a number of other reasons why such a record
should be rejected..
For continuity over time, it is necessary to use the “mean daily temperature” as the basis for this record.
This quantity, which has been collected since 1850 at some weather stations, consists of the mean of the
maximum and minimum temperature over a variable 24 hour period, which does not even usually refer
to a standard day. Such a measurement gives only a biased average, of unknown accuracy, even at a
single site..
There is no quality control system for weather station and ship measurements. Hardly anything is
standardized, even within a single country. Instruments, shelter, location, distance from buildings and
vegetation, personnel, and administration, vary widely.
Attempts to “correct” for all these sources of error are largely confined to a very few countries. A recent
study in the United States has shown that even the “approved” sites are non standard. (Davey and Pielke
Srl 2005)
Weather data are considered commercial and not generally available to the public without a fee The
processing of the data is largely secret and is not available to independent observers or “peer reviewers”,
A whole host of additional difficulties have been identified in recent papers by Pielke Sr et al 2007 and
D’Aleo et al.2007 They include, the high and variable thermal gradient at the surface, the effects of
discontinuous changes in number and location of sites, instrument calibration and change, political
changes, wars, gaps in the data., and inadequate qualifications and reliability of personnel.
Despite desperate efforts to apply “corrections” to the surface data, it is admitted that there are still
“unknown unknowns” (pace Donald Rumsfeld ) (Brohan et al 2006)
The best comparatively recent measure of globally averaged temperature anomalies is that supplied by the
Microwave Sounder units on NASA satellites since 1979. The “Ocean only” record is as shown in Figure
1. This record shows no overall change between 1979 and 1997; a sudden and temporary rise in 1998
from El Niño, a reversion to 1979-97 average between 199 and 2001, and then and a small upward
climate shift from 2001 to the present with a stable temperature.
This behaviour is incompatible with a theory which expects a steady upwards “trend” in temperature.
Weather .balloon measurements in the lower atmosphere confirm this record, and they show an additional
climate shift downwards from 1960 to 1979 which is also incompatible with a supposed constant upwards
trend (Figure 2, from Thorne et al 2005)
.
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Figure 1 MSU (satellite) monthly temperature anomalies for the lower troposphere. (ocean only)
Figure 2 Global Mean time series for 500hPg lower troposphere from weather balloons (Thorne et al
2005)
Regional Temperature
“Corrected” station measurements For the USA and China, where. are combined to give a regional
temperature record confirm the general behaviour of Figures 1 and 2, with additional information back to
1900.. The Regional compilation for China, is shown in Figure 3 (Zhao et al 2005)
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Figure 3 Amalgamated, “corrected” temperature record for China (Zhao et al 2005)
This record shows that in China temperature follows a cycle, not an upwards “trend”, with a peak today
which occurred previously in1942, and with troughs in 1905 and 1970
.
.Local Temperatures
There are a few long-lived local temperature records where the local bias has remained fairly steady and
which give records that confirm the variability shown above :including the warm shift in the 1930s and
50s resembling that seen today This effect as particularly evident in the Arctic. A number of these local
records are available on John Daly’s website.
An example is shown in Figure 4. for Reykjavik and Akureyri in Iceland.
Figure 4. Weather station records from Reykjavik and Akureyri, Iceland. (Daly 2007)
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It will be seen that a cyclic behaviour of local temperature is shown, similar to Figure 1 (since 1979),
for Figure 2. (since 1958) and Figure 3 (since 1900)
Conclusion
Reliable global, regional and local temperature records show that temperatures variability is cyclic, and
does not display a distinguishable “trend”. The most reliable records show peak temperatures .around
1940 and 2005 and low temperatures around 1910 and 1970. Thesed records are incompatible with a
belief that there is a distinguishable upwards “trend’ caused by greenhouse gas emissions.
References
Brohan, P., J J Kennedy, I Harris, S F B Tett, and P D Jones. 2006, Uncertainty estimates in regional and
global observed temperature changes: A new data set from 1850. Journal of Geophysical Research 111
D12106.doi:1020/2005JD006546
Daly, J. 2007 What the Stations Say. http://www.john-daly.com/stations/stations.htm
D’Aleo, J D , M Khandekar, and R McKitrick, “Problems with the Global Thermometer Network. 2007
AR4 Analysis Series, Fraser Institute., Vancouver, Canada
Davey, C A , and Pielke,Sr., 2005. Microclimate Exposures of Surface-Based Weather Stations.
http://ccc.atmos.colostate.edu/pdfs/BAMS_Davey&Pielke_Apr05.pdf
Gray V R 2000 The Cause of Global Warming. Energy and Environment 11 613-629
Gray V R 2006 Temperature Trends in the Lower Atmosphere. Energy and Environment 17 707-714
Gray V R 2007 Climate Change 2007: The Physical Science Basis, Summary for Policymakers. Energy
and Environment 18 433-440
MSU (Microwave Sounder Unit, Channel 2) Data. http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
Pielke, R A Sr, and 12 others 2007 Unresolved Issues with the Assessment of Multi-Decadal Global
Land-Surface Temperature Trends. J Geophysical Research, submitted.
Thorne, P W , D E Parker, S F B Tett, P D Jones, M McCarthy, H Coleman and P Brohan. 2005
Revisiting radiosonde upper air temperatures from 1958 to 2002. Journal of Geophysical Research 110
D18105, doi:10.1029/2004JD005753
ZHAO, Zongci, DING Yasui, LUO, Yong and WANG Shaowu 2005. Recent Studies on Attributions of
Climate Change in China. Acta Meteorologica Sinica 19 389-400 (in English)
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