A critical look at solar-climate relationships from long temperature series 1Laboratoire de Météorologie Dynamique, UMR 8539, IPSL, CNRS/ENS/UPMC/Ecole Polytechnique, Paris, France
2Ecole Nationale de la Météorologie, Météo France, and Institut de Mathématiques de Toulouse, Toulouse, France
3CEREGE, UMR 6635, CNRS/Université Aix-Marseille/IRD/Collège de France, Aix-en-Provence, France
4Laboratoire des Sciences du Climat et de l'Environnement, UMR 8212, IPSL, CEA/CNRS/UVSQ, Gif-sur-Yvette, France
Received: 17 April 2010 – Published in Clim. Past Discuss.: 11 May 2010 Abstract. A key issue of climate change is to identify the forcings and their relative
contributions. The solar-climate relationship is currently the matter of a fierce
debate. We address here the need for high quality observations and an adequate
statistical approach. A recent work by Le Mouël et al. (2010) and its companion
paper by Kossobokov et al. (2010) show spectacular correlations between solar
activity and temperature series from three European weather stations over the last two centuries.
We question both the data and the
method used in these works. We stress (1) that correlation with solar forcing
alone is meaningless unless other forcings are properly accounted for and that
sunspot counting is a poor indicator of solar irradiance, (2) that long temperature series
require homogenization to remove historical artefacts that
affect long term variability, (3) that incorrect application of statistical
tests leads to interpret as significant a signal which arises from pure
random fluctuations. As a consequence, we reject the results and the
conclusions of Le Mouël et al. (2010) and Kossobokov et al. (2010). We believe
that our contribution bears some general interest in removing confusion from
the scientific debate.
Revised: 30 August 2010 – Accepted: 29 October 2010 – Published: 12 November 2010
Citation: Legras, B., Mestre, O., Bard, E., and Yiou, P.: A critical look at solar-climate relationships from long temperature series, Clim. Past, 6, 745-758, doi:10.5194/cp-6-745-2010, 2010.