Fldgen v1.0: An Emulator with Internal Variability and Space-Time Correlation for Earth System Models

TitleFldgen v1.0: An Emulator with Internal Variability and Space-Time Correlation for Earth System Models
Publication TypeJournal Article
Year of Publication2019
JournalGeoscientific Model Development
Volume12
Pages1477-1489
Date Published04/2019
Abstract / Summary

Earth system models (ESMs) are the gold standard for producing future projections of climate change, but running them is difficult and costly, and thus researchers are generally limited to a small selection of scenarios. This paper presents a technique for detailed emulation of the Earth system model (ESM) temperature output, based on the construction of a deterministic model for the mean response to global temperature. The residuals between the mean response and the ESM output temperature fields are used to construct variability fields that are added to the mean response to produce the final product. The method produces grid-level output with spatially and temporally coherent variability. Output fields include random components, so the system may be run as many times as necessary to produce large ensembles of fields for applications that require them. We describe the method, show example outputs, and present statistical verification that it reproduces the ESM properties it is intended to capture. This method, available as an open-source R package, should be useful in the study of climate variability and its contribution to uncertainties in the interactions between human and Earth systems.

URLhttps://www.geosci-model-dev.net/12/1477/2019/
DOI10.5194/gmd-12-1477-2019
Funding Program: 
Journal: Geoscientific Model Development
Year of Publication: 2019
Volume: 12
Pages: 1477-1489
Date Published: 04/2019

Earth system models (ESMs) are the gold standard for producing future projections of climate change, but running them is difficult and costly, and thus researchers are generally limited to a small selection of scenarios. This paper presents a technique for detailed emulation of the Earth system model (ESM) temperature output, based on the construction of a deterministic model for the mean response to global temperature. The residuals between the mean response and the ESM output temperature fields are used to construct variability fields that are added to the mean response to produce the final product. The method produces grid-level output with spatially and temporally coherent variability. Output fields include random components, so the system may be run as many times as necessary to produce large ensembles of fields for applications that require them. We describe the method, show example outputs, and present statistical verification that it reproduces the ESM properties it is intended to capture. This method, available as an open-source R package, should be useful in the study of climate variability and its contribution to uncertainties in the interactions between human and Earth systems.

DOI: 10.5194/gmd-12-1477-2019
Citation:
Link, R, A Snyder, C Lynch, C Hartin, B Kravitz, and B Bond-Lamberty.  2019.  "Fldgen v1.0: An Emulator with Internal Variability and Space-Time Correlation for Earth System Models."  Geoscientific Model Development 12: 1477-1489.  https://doi.org/10.5194/gmd-12-1477-2019.