PCMDI - IPCC

The Intergovernmental Panel on Climate Change (IPCC) has recently completed its Fourth Assessment Report (AR4) “Climate Change 2007”. Results from comprehensive numerical models of the climate system are fundamentally important for understanding climate processes and how climate has changed in the past and may change in the future.
Some time ago CSIRO completed its submission to the IPCC AR4 Model database a set of experiments simulating past, present and future climate with the Mk3 Climate System. The Mk3 model has been in development and used for production climate runs for the best part of a decade and is the end result of a significant commitment of financial and intellectual resources from a relatively small group of developers and stakeholders. The task of processing, deriving, validating and submitting Mk3 output provided significant computing and logistic challenges. Data requirements were substantially more demanding than ever before and the schedule for inclusion in the AR4 database was extremely tight. Particularly when several key model experiments were still underway when the call for data (from JSC/CLIVAR WGCM) came. However, the importance of contributing to the IPCC AR4 with a climate model developed in the Southern Hemisphere cannot be underestimated. This effort will provide a useful “model development” yardstick for the ACCESS climate model development program that is underway in Australia. The best indicator of the Mk3 outcome is the inclusion of its performance in hundreds of peer-reviewed scientific articles and the many contractual reports completed and underway. We briefly described the system for managing Mk3 model output based on a modern, locally developed, scripting computer language for the efficient processing of large and complex datasets. This system takes into account different Mk3 model configurations and model output inconsistencies and is able to generate a temporally, spatially and physically consistent set of data products. An essential feature is the ability to make the model results self describing (CF-compliant netCDF files) to enable efficient uptake by researchers. Experiences with data validation and quality control checking is described, an often overlooked aspect of data delivery. Our goal was to make the Mk3 model output easily accessible its to the international climate research community. In this presentation a brief history of the development and features of the CSIRO Mk3 model will be provided. The Mk3.5 version of the climate model includes many improvements over its predecessor resulting in a control climate with a relatively small drift. This new and updated archive of model outputs will provide the local and international community with a wealth of informative and sophisticated climate model experiments for completion of important institutional studies. An indication of the regional demands for Mk3 outputs will be given. Details of how to access the CSIRO Mk3.0 and Mk3.5 data will be provided.