ESG has had a significant impact upon the national and international climate community by enabling broad dissemination of important data holdings, including the Community Climate System Model (CCSM) data archive, the Intergovernmental Panel on Climate Change (IPCC) 4th Assessment Report (AR4) data archive, and now the CCSM BGC Carbon-Land Model Intercomparison Project (C-LAMP)¹² data archive. All three archives are well known to the user community and, since ESG’s official release, the community has downloaded well over 300 TB of data, well over 1 million files, and reported over 300 journal articles,¹³ all in a short time span.

The ESG team works closely with the CCSM community to publish CCSM model data into the ESG archives. Collaborating with CCSM scientists and data providers, the ESG team developed and utilized Grid technology that interfaces into the ESG metadata database allowing the CCSM community to view and manage all information related to generating, defining, and archiving CCSM model simulation runs. This interface allows scientists to impose selective access control on project runs, to sort information by any type, and to enter data collaboratively. The long-term goal is to tie the metadata ingestion process to the actual CCSM run workflow, so that model simulation metadata can be added automatically into the ESG data holdings.

The ESG user base comprises climate scientists, analysts, educators, governments (both domestic and abroad), private industry, and many others. CCSM data, along with other important datasets accessible via ESG, such as those produced by the Parallel Climate Model (PCM)¹⁴ and the Parallel Ocean Program (POP),¹⁵ have been used in numerous scientific papers, impact analyses, urban planning and ecosystem monitoring studies, education, and other activities. By allowing access, ESG enables scientists, hardware and software engineers, universities and others to examine and learn how a state-of-the-art climate model works, and to provide suggestions and enhancements for its scientific accuracy, portability, and performance. We even receive occasional queries from the general public, asking how they can use data published in ESG to better understand climate change issues or local impacts.

ESG was thrust into international collaboration when it was asked in late 2003 to support the IPCC/Working Group on Coupled Models (WGCM) need to distribute data to the international climate community. The IPCC, which was jointly established by the World Meteorological Organisation (WMO) and the United Nations Environment Programme, carries out periodic assessments of the science of climate change. Fundamental to this effort is the production, collection and analysis of data from climate model simulations carried out by major international research centers. Analysis of a set of standard climate-change simulations from many modelling centers provides comprehensive understanding of the strengths and weaknesses of climate models, as well as which aspects of the simulation results may be due to characteristics of specific models and which are generally observed across multiple models. The IPCC and WGCM requested that PCMDI at LLNL collect model output data from these IPCC simulations and distribute these to the community via ESG. Since this effort began, IPCC model runs published to the climate community via the CMIP3 (IPCC AR4) ESG portal total just over 35 TB (78,158 files), and some 1,400 users have registered to receive IPCC data for analysis. Figure 2 shows the daily download rate over time.

New to ESG is the dissemination of C-LAMP¹² biogeochemistry data. This model inter-comparison project has two terrestrial BGC modules linked to the same set of prescribed ocean BGC fluxes, together with the CCSM’s interactive atmosphere and interactive land surface modules. The C-LAMP effort involves two separate experiments: one in which atmospheric data comes from observations, the other in which it is calculated by CAM3, the current atmospheric component of the CCSM. The first experiment will determine how well land-air fluxes of CO2 are simulated by the two BGC modules, given the observed climate. The second will determine the effect of the atmospheric model’s climate bias (notably in precipitation) on the simulated CO2 fluxes. The C-LAMP experimental output is now being archived and disseminated on an ESG C-LAMP site modelled after the ESG CMIP3 (IPCC AR4). This archive will initially be open only to members of the BGC Working Group, but ultimately the working group will open up the data to any interested researcher.

Knowledge and expertise gained from ESG have helped the climate community plan effective strategies to manage a rapidly growing data environment. Approaches and technologies developed under the ESG project have also impacted data-simulation integration in other disciplines, such as astrophysics, molecular biology, and materials science.