The Program for Climate Model Diagnosis and Intercomparison: furthering the understanding of climate change through model and observational analysis and community leadership


PCMDI was established in 1989 at the Lawrence Livermore National Laboratory (LLNL), located in the San Francisco Bay Area, California. PCMDI participants include research and computer scientists at LLNL, other research laboratories, and universities. The Regional and Global Model Analysis (RGMA) Program Area of the United States Department of Energy’s (DOE) Earth and Environmental Systems Modeling (EESM) Program is the primary project funder. The EESM is a component of the Earth and Environmental Systems Sciences Division (EESSD) which is within the Biological and Environmental Research (BER) Program Office of the DOE’s Office of Science.

The PCMDI mission is to develop advanced methods and tools for diagnosis and intercomparison to improve Global Climate (GCMs) and Earth System Models (ESMs). The need for innovative analysis of ESM simulations is apparent as increasingly more complex models are in development. At the same time, disagreements among these simulations relative to observations and their predictions of climate change remain significant and incompletely understood. Through PCMDI’s efforts, ESMs will advance so that they are capable of addressing the critical questions that policymakers and society have about ongoing global and regional climate change.

PCMDI’s mission demands that we work on scientific projects and infrastructural tasks. Our current scientific projects focus on developing ESM performance metrics, identifying robust Cloud Feedbacks in observations and models, devising robust statistical methods for climate change Detection and Attribution, and understanding ESM errors through a model parameterization testbed. Examples of ongoing infrastructure tasks include: 1) the development of software and data standards for model intercomparison project (MIP) data management, data creation, and computation; 2) the assembly/organization of observational data sets for model validation obs4MIPs; 3) the assembly and curation of forcing data sets for ESMs input4MIPs; and 4) the consistent documentation of climate model features across the numerous eras of the Atmospheric Model Intercomparison Project (AMIP) and Coupled Model Intercomparison Project (CMIP) phases. PCMDI is also incorporating the PCMDI metrics Package (PMP) into the Coordinated Model Evaluation Capabilities (CMEC), a platform for collective use of various diagnostics packages. CMEC aims to unify model evaluation efforts across the EESM program. We describe details of PCMDI’s work in our publications and research highlights.

We are also applying our collective expertise to support modeling studies initiated by the World Climate Research Programme (WCRP) and to contribution requests for the Intergovernmental Panel on Climate Change (IPCC) Assessment Reports. PCMDI has been invited to contribute to every report from the First Assessment (FAR) in 1990 to the most recent Sixth Assessment (AR6) published in August 2021. Notably, we lead aspects of the Coupled Model Intercomparison Project, Phase 6 (CMIP6). PCMDI is responsible for leading the WCRP Working Group on Coupled Modelling (WGCM) Infrastructure Panel (WIP), which coordinates infrastructure support for CMIP. This effort includes coordination with the Earth System Grid Federation (ESGF) project, which stores and distributes petabyte-scale data sets from multiple MIP phases. Extensive analysis of the latest CMIP6 simulations by the international climate community anchored much of the scientific basis for the IPCC’s Sixth Assessment Report on Climate Change, published in 2021/22.


Document version: 21 April 2022