Wednesday, August 10, 2011

New paper finds some Antarctic temperature measurements show false warming of up to 10°C (18°F)

A paper published today in the Journal of Atmospheric and Oceanic Technology finds that temperature measurements on the Antarctic plateau "are shown to be significantly warm biased by solar radiation," resulting in temperature measurements up to 10°C (18°F) warmer than actual temperatures. The authors find that the summer Sun heats the housing for the electronic thermometers causing the warming bias during summer, which is also exacerbated by low wind conditions. Surface temperature measurements are particularly important at the poles, because satellite measurements of temperature do not include data poleward of 82.5° North and 70° South and the only available measurements in these areas are from surface temperature stations. Considering the tiny change in global temperature over the past 161 years of only 0.7°C, this newly-discovered large warming bias of up to 10°C calls into question data from areas critical to the AGW debate.

Atmospheric temperature measurements biases on the Antarctic plateau

Christophe Genthon1, Delphine Six, Vincent Favier
Laboratoire de Glaciologie et Géophysique de l'Environnement, CNRS/UJF, Saint Martin, d'Hères, France
Matthew Lazzara, Linda Keller
Antarctic Meteorological Research Center, University of Wisconsin-Madison, Madison, USA
Observations of atmospheric temperature made on the Antarctic plateau with thermistors housed in naturally (wind) ventilated radiation shields are shown to be significantly warm biased by solar radiation. High incoming solar flux and high surface albedo result in radiation biases in Gill (multiplate) styled shields that can occasionally exceed 10°C in summer in case of low wind speed. Although stronger and more frequent when incoming solar radiation is high, biases exceeding 8°C are found even when solar is less than 200 Wm−2. Comparing with sonic thermometers, which are not affected by radiation but which are too complex to be routinely used for mean temperature monitoring, commercially available aspirated shields are shown to efficiently protect thermistor measurements from solar radiation biases. Most of the available in situ reports of atmospheric temperature on the Antarctic plateau are from automatic weather stations that use passive shields and are thus likely warm biased in the summer. In spite of low power consumption, deploying aspirated shields at remote locations in such a difficult environment may be a challenge. Bias correction formulae are not easily derived and are obviously shield dependent. On the other hand, because of a strong dependence of bias to wind speed, filtering out temperature reports for wind speed less than a given threshold (about 4–6 ms−1 for the shields tested here) may be an efficient way to quality control the data, albeit at the cost of significant data loss and records biased towards high wind speed cases.


  1. Owww, that's got to hurt!

    Isn't it amazing that we do not hear of anybody mistakenly collecting temperature data that erred toward cooling?

    Checking the methodology, regardless of whether the data matches your expectations, is what scientists are supposed to do, are expected to do, and should be demanded to do.

  2. How did you get a copy of this paper to read? It is embargoed online ahead of its printing date. Why are you promoting a study which you can't have possibly read and dissected?

  3. But does this result suggests an INCREASE over years? That's the interesting question, and I'm doubt it does. (There is however a temp bias due to UHI, poor maintenance of weather stations etc; up to half the temp increase since 19th century; Michaels and McKitrick). So this may cause a small over all bias. Globally an 0.005 C bias? ;)

    And "bias" compared to What? Interesting here is that land temperature change is consistent with two satellite temperature measurements.

    I'm a "climate skeptics". Of course CO2 affects the temperature on Earth, with maybe +0.2 C or +0.4 C in 100 years. The methodology and presumptions in IPCC's climate models make them inaccurate for their purpose. This most climate scientists think, due to Hans von Storch's and Dennis Bray's well performed and large study of the opinions of climate scientists. Due to other very credible "mainstream" climate-, and atmosphere scientists, several years ago, the climate sensitivity (at double concentration CO2 in the atmosphere) is between +1 C and +2 C, but different studies suggest negative feedback (strong negative feedback) so that we might get +0.5 C.

    The media behave like they are a propaganda tool, when they say that a study asking scientists if CO2 is a greenhouse gas proves that 98 percent of the scientists believe in IPCC's climate catastrophe prediction. This is also what blogs like Real Climate (where all my comments has been stopped or removed) says.

    AGW is a propaganda movement because it acts like one, presenting reports in erroneous ways and silencing facts. We patiently must reveal this.

  4. Mmm, 10 degrees higher, can't be much as water freezes at 0 degrees!!!