Overview

PIRCS is a community-based project, organized under the auspices of Iowa State University, to intercompare regional models run in climate mode. PIRCS consists of a series of collaborative intercomparison experiments using different mesoscale models to simulate the climate of the Central US for a 60-day period beginning 15 May during the drought year of 1988 (Exp. 1a) and a follow-on 60-day experiment for the Midwest flood period beginning 1 June 1993 (Exp. 1b). These are periods and a region that the GEWEX Numerical Experimentation Panel has targeted for simulation by regional-scale models. These simulations provide an opportunity to evaluate local and remote influences on the water cycle of the Central US. In addition, Expt. 1a emphasizes thermal and dynamical processes and is intended to provide an initial comparison of how well regional models represent aggregate characteristics of weather events in a simulation long enough to include many such events (i.e., to simulate regional climate) during a period when surface thermal forcing within the domain is large and precipitation and latent-heat effects are minimal. Expt. 1b emphasizes processes of the water cycle and will examine strengths and weaknesses of parameterizations of precipitation.

Model simulations are performed by the participating research groups at their own expense. PIRCS provides management of datasets, including initial conditions, boundary conditions, and simulated results, using procedures and protocols consistent with other large intercomparison projects.