Combining Climate Model Output for Assessments of Climate Change

• Activity Number: 19
• Type: Topic Contributed
• Date/Time: Sunday, August 7, 2005 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics and the Environment
• Author(s): Stephan Sain*+ and Reinhard Furrer and Douglas Nychka
• Companies: University of Colorado, DHSC and National Center for Atmospheric Research and National Center for Atmospheric Research
• Keywords: Climate Change ; Climate Models ; Multivariate Hierarchical Spatial Model

Abstract

The U.S. Climate Change Science Program Strategic Plan has recognized the need for regional climate modeling to assess climate impacts. This is the focus of the newly formed North American Regional Climate Change Assessment Program that seeks to examine a number of regional climate-change scenarios based on a collection of regional climate models (RCMs) with boundary conditions defined by atmosphere ocean general circulation models (GCMs). Over the next several years, this program will use as many as four GCMs and six RCMs to produce a range of model output over a region of North America. We propose a general framework for synthesizing this model output to obtain estimates of climate change and examine sources of variation attributable to RCM, the GCM, and the downscaling from the GCM to the RCM. This framework involves the specification of a multivariate (temperature and precipitation) spatial hierarchical model structure with a process model that can be decomposed into terms involving the underlying climate, model bias, and internal model variation.