Several authors have claimed an alternative climate sensitivity of a magnitude of the Stefan-Boltzmann derivative: dT/dF=1/(4σT3). The publication of the homogenised De Bilt data series by Van Engelen and Nellestijn of nearly tree hundred years of monthly averaged temperature measurements is another valuable dataset to test this assumption. The first property of the dataset is that the changes in winter temperature are dominating the annual average. In fact the well known Dalton solar minimum is absent in the July and August data. What is noticeable in the summer data is an undulating temperature which can be attributed to the North Atlantic Oscillation. On top of this undulation is a slowly upward trend.
When using the CO2 data of Mauna Loa and Law Dome combined with the forcing formula of Myhre et al: F=5.35 ln (C/C0): The slowly upward moving trend for July and August is well explained by a CO2 increase with a Stefan-Boltzmann sensitivity. See for a graphical example
http://members.lycos.nl/ErrenWijlens/co2/fingerprintdb.gif
References:
A van Engelen and Nellestijn, JW, 1996: Monthly, seasonal and annual means of air temperature in tenths of centigrades in De Bilt, Netherlands, 1706-1995. KNMI report from the Climatological Services Branch
D.M. Etheridge, L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M. Barnola and V.I. Morgan. 1998. Historical CO2 records from the Law Dome DE08, DE08-2, and DSS ice cores. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A
Keeling, C.D. and T.P. Whorf. 2002. Atmospheric CO2 records from sites in the SIO air sampling network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A
Myhre, G., E.J. Highwood, K.P. Shine, and F. Stordal, 1998b: New estimates of radiative forcing due to well mixed greenhouse gases. Geophys. Res. Lett., 25, 2715-2718. |
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