Requirements for a global data infrastructure in support of CMIP6

Abstract

The World Climate Research Programme (WCRP)'s Working Group on Climate Modelling (WGCM) Infrastructure Panel (WIP) was formed in 2014 in response to the explosive growth in size and complexity of Coupled Model Intercomparison Projects (CMIPs) between CMIP3 (2005)(2006) and CMIP5 (2011CMIP5 ( -2012. This article presents the WIP recommendations for the global data infrastructure needed to support CMIP design, future growth, and evolution. Developed in close coordination with those who build and run the existing infrastructure (the Earth System Grid Federation; ESGF), the recommendations are based on several principles beginning with the need to separate requirements, implementation, and operations. Other important principles include the consideration of the diversity of community needs around data -a data ecosystem -the importance of provenance, the need for automation, and the obligation to measure costs and benefits.This paper concentrates on requirements, recognizing the diversity of communities involved (modelers, analysts, software developers, and downstream users). Such requirements include the need for scientific reproducibility and account-ability alongside the need to record and track data usage. One key element is to generate a dataset-centric rather than system-centric focus, with an aim to making the infrastructure less prone to systemic failure.With these overarching principles and requirements, the WIP has produced a set of position papers, which are summarized in the latter pages of this document. They provide specifications for managing and delivering model output, including strategies for replication and versioning, licensing, data quality assurance, citation, long-term archiving, and dataset tracking. They also describe a new and more formal approach for specifying what data, and associated metadata, should be saved, which enables future data volumes to be estimated, particularly for well-defined projects such as CMIP6.The paper concludes with a future facing consideration of the global data infrastructure evolution that follows from the blurring of boundaries between climate and weather, and the changing nature of published scientific results in the digital age.

The penultimate deglaciation: protocol for Paleoclimate Modelling Intercomparison Project (PMIP) phase 4 transient numerical simulations between 140 and 127 ka, version 1.0

“…Direct evidence for constraining the evolution of the global sea level during the time interval 140-127 ka remains sparse. Although the LR04 benthic δ 18 O stack (Lisiecki and Raymo, 2005) is sometimes used to approximate sea-level change on glacial-interglacial timescales, in the case of the PDG, the timing of the LR04 benthic δ 18 O stack is fixed by reference to a handful of U-series coral dates from Huon Peninsula with relatively high analytical uncertainties and questionable preservation (Bard et al, 1990;Stein et al, 1993). Tying the MIS 5e peak to the average age of these coral dates results in a benthic δ 18 O minimum that is roughly centred on the main phase of coral growth during this interglacial period (122-129 ka) (Stirling et al, 1998) rather than having the onset of the interglacial aligned with the timing of the onset of the sea-level highstand at far-field sites (∼ 129 ka) (e.g.…”

“…Depending on the spatial resolution of the different model components, storage of data outputs can become an issue. We therefore suggest a list of variables that absolutely needs to be uploaded to the Earth System Grid Federation (ESGF) database (Balaji et al, 2018) to understand the results and perform inter-model and modeldata comparisons. The CMIP6 conventions should be used for all the variable names and units.…”

“…While the Barbados coral record suggests that a second phase of rapid sea-level rise occurred at about 11.3 ka (MWP-1B) (e.g. Bard et al, 1990), data from Tahiti boreholes (Bard et al, 2010) and from a compilation of sea-level data (Lambeck et al, 2014) provide no evidence of a particularly rapid sea-level rise during that period.…”

Data Distribution Centre Support for the IPCC Sixth Assessment

“…The planned application of the ESMVal tool on the source data to be archived in the Reference Data Archive for AR6 at WDCC/DKRZ will add important information on model and therefore data quality of the AR6 data archived in the IPCC DDC. The TSU is also investigating other resources to access and process stored data, for example Jupyter notebook systems being developed as part of the WGI Atlas or data-centric infrastructure projects (Balaji et al, 2018) such as the Pangeo Environment (https://pangeo.io/). Ultimately, the AR6 cycle will make the analysis and visualization scripts public on a platform like GitHub with the details on how to recreate the figure or table and datasets used.…”

Designing and Documenting Experiments in CMIP6

“…Such difficulties resulted in documentation generally arriving too late to be of use to the target audience: scientists analysing the data. The Metafor project has been superseded by the ES-DOC project (https://es-doc.org) which provides a much improved tool chain, and ES-DOC use is now 10 required for the documentation of CMIP6 simulations (Balaji et al, 2018).…”