\documentclass[11pt]{article} \setlength{\oddsidemargin}{0.0truein} \setlength{\evensidemargin}{0.0truein} \setlength{\textwidth}{6.5truein} \setlength{\topmargin}{0.0truein} \setlength{\textheight}{9.0truein} \setlength{\headsep}{0.0truein} \setlength{\headheight}{0.0truein} \setlength{\topskip}{10.0pt} \setlength{\parskip}{5mm} \usepackage{url} \usepackage{amsmath} \usepackage{amssymb} \pagestyle{empty} \begin{document} \begin{center} \textbf{\Large{\textsc{STANFORD UNIVERSITY}}}\\[5pt] \textbf{\Large{\textsc{DEPARTMENT OF STATISTICS}}}\\[5pt] \Large{\textsc{DEPARTMENTAL SEMINAR}} \end{center} % In the following statements, replace "Time of talk", % "Weekday", and "Date of talk". An example is provided. % If you are not sure about this, just skip this part. \begin{center} 4:15 p.m., Tuesday, April 10, 2007\\ %% Example: 4:15 p.m., Tuesday, February 13, 2007\\ Sequoia Hall Room 200\\ (Cookies at 3:45 in 1st Floor Lounge) \end{center} % In the following statements, replace "Name of the speaker" with your % name, "Department Affiliation" with your department affiliation, and %"University Affiliation" with your university affiliation. \begin{center} \textsl{Claudia Tebaldi} \\ National Center for Atmospheric Research\\ Boulder, CO\\ currently visiting the Center for Environmental Science and Policy\\ Stanford University \end{center} % In the following statements, replace "Title of the talk" % with your title of the talk. \begin{center} \subsection*{Making sense of ensembles of climate models: a Bayesian approach to estimating future climate change and its uncertainty } \end{center} % In the following statements, replace "Abstract of the talk" % with your abstract. \noindent Future projections of climate change rely for the most part on the results of simulations by complex computer models, able to simulate the main climate processes at work in the Earth's atmosphere and oceans. Different climate models, however, produce different climate projections, even under the same future forcing scenario, and even on average over large-scale regions. How do we best estimate what future climate will be like, and the uncertainty associated with it, on the basis of an ensemble of these experiments? I will describe the main issues that underlie the analysis of ensembles of climate models, and briefly offer an overview of alternative lines of attack. I will then propose a Bayesian approach that treats projections from different models over different regions in an ANOVA-like setting. As a result, posterior distributions can be derived for the climate change signal and numerous parameters representing region-specific and model-specific precisions and biases. A cross-validation step addresses the need of verifying the statistical model predictive distributions, in a setting where actual validation will have to wait some! This work is in collaboration with Richard L. Smith (UNC-Chapel Hill), and Doug Nychka and Linda O. Mearns (NCAR) \end{document}