NCAR Request for New GCMD Keywords

[mcginnis]

Hello! I have a whole slew of new GCMD keywords to request, in support of upcoming publication of new CORDEX-CMIP6 simulation data. (Plus a couple I noticed were missing along the way, like CMIP3.)

Several of these use the IPCC Glossary as a reference, for which the full citation is:
IPCC, 2021: Annex VII: Glossary [Matthews, J.B.R., et al. (eds.)]. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the IPCC. Cambridge University Press. doi:10.1017/9781009157896.022
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Keyword: Projects > A - C > CMIP3

Alternate Label(s): Coupled Model Intercomparison Project Phase 3

Definition: CMIP3, the third phase of the Coupled Model Intercomparison Project, is a coordinated set of coupled atmosphere-ocean general circulation model experiments organized under the World Climate Research Programme (WCRP) Working Group on Coupled Models. Covering twentieth- and twenty-first-century climate along with idealized and commitment experiments, the CMIP3 multimodel dataset provided the basis for the IPCC Fourth Assessment Report (AR4).

Reference: Meehl, G.A., et al., 2007: The WCRP CMIP3 Multimodel Dataset: A New Era in Climate Change Research. Bulletin of the American Meteorological Society, 88(9), 1383-1394. doi:10.1175/BAMS-88-9-1383

Rationale: CMIP3 output underpins a large body of archived projection data and the IPCC AR4 assessment. A dedicated keyword distinguishes CMIP3-derived collections from the parent CMIP keyword and from later phases.
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Keyword: Projects > A - C > CMIP5

Alternate Label(s): Coupled Model Intercomparison Project Phase 5

Definition: CMIP5, the fifth phase of the Coupled Model Intercomparison Project, is a coordinated multimodel experiment framework organized under the WCRP Working Group on Coupled Models. It comprises long-term simulations of twentieth-century and future climate, near-term (decadal) predictions, and idealized experiments run with climate models and Earth system models under Representative Concentration Pathway (RCP) scenarios, and provided the multimodel basis for the IPCC Fifth Assessment Report (AR5).

Reference: Taylor, K.E., R.J. Stouffer, and G.A. Meehl, 2012: An Overview of CMIP5 and the Experiment Design. Bulletin of the American Meteorological Society, 93(4), 485-498. doi:10.1175/BAMS-D-11-00094.1

Rationale: Same as CMIP3, CMIP5 is a distinct experiment phase with its own ensemble, scenarios, and extensive archive. A dedicated keyword enables discovery of CMIP5-specific collections separate from other CMIP phases.
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Keyword: Projects > A - C > CMIP6

Alternate Label(s): Coupled Model Intercomparison Project Phase 6

Definition: CMIP6, the sixth phase of the Coupled Model Intercomparison Project, is the current generation of coordinated climate model experiments organized under the WCRP. It is structured around a set of baseline (DECK) and historical simulations plus a suite of endorsed Model Intercomparison Projects (MIPs) addressing specific scientific questions, and uses Shared Socioeconomic Pathway (SSP) scenarios. CMIP6 underpins the IPCC Sixth Assessment Report (AR6).

Reference: Eyring, V., et al., 2016: Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization. Geoscientific Model Development, 9, 1937-1958. doi:10.5194/gmd-9-1937-2016

Rationale: Like CMIP3 & CMIP5, CMIP6 introduces a distinct experiment structure (DECK, endorsed MIPs, SSP scenarios); it has a large, actively growing archive.
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Keyword: Projects > A - C > CORDEX

Alternate Label(s): Coordinated Regional Climate Downscaling Experiment

Definition: CORDEX, the COordinated Regional climate Downscaling EXperiment, is a WCRP framework for producing coordinated regional climate projections worldwide by dynamical and statistical downscaling of global climate model output. It defines common domains, resolutions, and simulation protocols to enable evaluation of downscaling methods and to provide regional climate information for vulnerability, impact, and adaptation studies.

Reference: Giorgi, F., C. Jones, and G.R. Asrar, 2009: Addressing climate information needs at the regional level: the CORDEX framework. WMO Bulletin, 58(3), 175-183.

Rationale: CORDEX is a major international source of downscaled regional climate data with its own domains and protocols.
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Keyword: Projects > A - C > CORDEX-CMIP6

Definition: CORDEX-CMIP6 is the second phase of the COordinated Regional climate Downscaling EXperiment. It downscales CMIP6 output under an updated common protocol, producing high-resolution regional climate projections consistent with, and formatted for, the CMIP6 archive.

Reference: Gutowski, W.J., Jr., et al., 2016: WCRP COordinated Regional Downscaling EXperiment (CORDEX): a diagnostic MIP for CMIP6. Geoscientific Model Development, 9, 4087-4095. doi:10.5194/gmd-9-4087-2016

Reference: CORDEX Experiment Guidelines — CORDEX-CMIP6. WCRP CORDEX. https://cordex.org/experiment-guidelines/cordex-cmip6/

Rationale: CORDEX-CMIP6 is a distinct downscaling activity tied to the CMIP6 generation, with its own protocol and data request separate from earlier CMIP5-based CORDEX simulations. A dedicated keyword distinguishes CMIP6-era downscaled collections from the general CORDEX keyword.
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Keyword: Platforms > Other > Models > RCM

Alternate Label(s): Regional Climate Model / Limited Area Model

Definition: Regional Climate Models (RCM) are limited-area numerical models that simulate atmospheric and surface climate processes at higher spatial resolution over a bounded region, driven at their lateral boundaries by output from a global climate model or reanalysis. They add fine-scale detail to coarser global simulations through explicit representation of regional processes.

Reference: IPCC, 2021: Annex VII: Glossary [full citation above].

Rationale: The Platforms hierarchy provides GCM as a model-platform keyword but no counterpart for limited-area regional models. RCM mirrors the existing GCM entry and allows regional model output to be attributed to its generating platform.
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Keyword: Earth Science Services > Models > Regional Climate Models

Definition: Numerical models that represent atmospheric and surface climate processes over a limited area of the Earth at high spatial resolution, using boundary conditions supplied by a global climate model or reanalysis to resolve regional and local features not captured by coarser global models.

Reference: IPCC, 2021: Annex VII: Glossary [full citation above].

Rationale: The Models service hierarchy describes global model capabilities (e.g., Atmospheric General Circulation Models) but lacks a term for regional climate modeling.
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Keyword: Earth Science Services > Models > Dynamical Downscaling Models

Definition: Models and methods that increase the spatial resolution of global climate model output over a region by using a higher-resolution, physically-based limited-area model / RCM driven by the global model's boundary conditions. Dynamical downscaling produces physically consistent fine-scale fields by explicitly simulating regional processes.

Reference: IPCC, 2021: Annex VII: Glossary [full citation above].

Rationale: Distinguishes the physically based downscaling approach from statistical (and possibly machine-learning) downscaling.
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Keyword: Earth Science Services > Models > Statistical Downscaling Models

Definition: Models and methods that increase the effective resolution of climate model output by applying empirical relationships between large-scale predictors and local-scale climate variables, derived from observations. Statistical downscaling infers fine-scale climate information without explicitly simulating physical processes.

Reference: IPCC, 2021: Annex VII: Glossary [full citation above].

Rationale: The counterpart to dynamical downscaling.
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Keyword: Earth Science Services > Data Transformation

Definition: Processes that alter or generate new data values in a way that can yield different information from the “raw” source data (e.g., bias correction), as opposed to translating the same information to a new frame of reference (e.g., reprojection).

Rationale: We need a place to put Bias Correction and Derived Quantities, and they don’t seem to fit under the definition of the existing Data Management / Data Handling keyword, which emphasizes data preservation.
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Keyword: Earth Science Services > Data Transformation > Bias Adjustment

Alternate Label(s): Bias Correction

Definition: The statistical adjustment of climate model output so that its distribution matches that of a reference observational dataset over a common period, in order to remove systematic model errors (biases).

Reference: IPCC, 2021: Annex VII: Glossary [full citation above].

Rationale: Bias adjustment is widely applied to climate simulations to improve their usability, and results in datasets that are distinct from the originals.
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Keyword: Earth Science Services > Data Transformation > Derived Quantities

Definition: Quantities computed from one or more measured or modeled variables to produce new geophysical information, such as indices or diagnostics, that is not directly present in the source data.

Rationale: Derived quantities can provide information that isn’t readily available from the source data, and may even add information when the derivation is complex (e.g., fire indexes). Derivation can also be applied separately from generation of the initial source data, creating a new and distinct dataset.

[GCMD - tstevens]

Thank you for your keyword request. I will review them and let you know when they are complete.

[GCMD - tstevens]

@mcginnis

In regard to ‘Earth Science Services > Data Transformation’, we currently have ‘EARTH SCIENCE SERVICES > DATA MANAGEMENT/DATA HANDLING > TRANSFORMATION/CONVERSION’ in the GCMD keywords. See https://gcmd.earthdata.nasa.gov/KeywordViewer/scheme/all/31ab3c10-1f10-4372-82d4-4c0c4be5999f?gtm_keyword=TRANSFORMATION/CONVERSION&gtm_scheme=sciencekeywords for details.

I would recommend that the new keywords you are requesting follow this structure. Are you ok with that? Thanks.