Robert Kaufmann
Center for Energy & Environmental Studies
Boston University
675 Commonwealth Avenue
Boston, MA 02215
Tel: 617-353-3940
Fax: 617-353-5986
E-mail: kaufmann@crsa.bu.edu
I have published several papers that use statistical techniques to analyze the relation between radiative forcing and surface temperature [Kaufmann et al., in review; Kaufmann and Stern, 2002; Stern and Kaufmann, 2000; Kaufmann and Stern, 1997]. In several, I have used the regression results to estimate temperature sensitivity. These estimates have elicited a variety of comments from physical scientists. Among the most frequent is the question, what is the physical interpretation of the statistical estimate of temperature sensitivity? That is, do the regression coefficients measure a short run effect, the transient climate response, the equilibrium response, or some intermediate effect?
I propose to answer this question by analyzing the CMIP2 experiments with the same statistical techniques used in the aforementioned papers. Specifically, I will estimate the relation between radiative forcing and surface temperature for the full sample period and sub-samples that include the period during which radiative forcing increases and and is stable. I will use these regression results to calculate temperature sensitivity. I will then compare them to the known temperature sensitivities from the climate models. I hope this comparison will help interpret the physical meaning of the temperature sensitivities calculated from regression coefficients.
Towards this end, I request data on the CMIP2 experiments in which radiative forcing is increased at about 1 percent per year until radiative forcing doubles and then is simulated until temperature reaches equilibrium. These data are equivalent to the data plot in Figure 9.1 (in Chapter 9) of the TAR. Ideally, I would analyze results from many simulations.
I understand that the simulations available are for about 80 years only. Although this is not the time-span I described in my original e-mail, I would still like to analyze them using the techniques I described in my pre-proposal.
Kaufmann, R.K. H. Kauppi and J.H. Stock. Emissions, concentrations, and temperature: a time series analysis. Journal of Geophysical Research.
Kaufmann, R.K. and D.I. Stern. 2002 Cointegration analysis of hemispheric temperature relations. Journal of Geophysical Research. 107 D2 10.1029, 2000JD000174.
Kaufmann, R.K. and D.I. Stern. 1997. Evidence for human influence on climate from hemispheric temperature relations. Nature 388:39-44.
Stern, D.I. and R.K. Kaufmann. 2000. Is there a global warming signal in hemispheric temperature series: a structural time series approach Climatic Change. 47:411-438.