Publication Abstracts

Franke et al. 2020, submitted

Franke, J., C. Müller, J. Elliott, A.C. Ruane, J. Jägermeyr, A. Snyder, M. Dury, P. Falloon, C. Folberth, L. François, T. Hank, R.C. Izaurralde, I. Jacquemin, C. Jones, M. Li, W. Liu, S. Olin, M. Phillips, T.A.M. Pugh, A. Reddy, K. Williams, Z. Wang, F. Zabel, and E. Moyer, 2020: The GGCMI phase II emulators: Global gridded crop model responses to changes in CO2, temperature, water, and nitrogen (version 1.0). Geosci. Model Dev., submitted, doi:10.5194/gmd-2019-365.

Statistical emulation allows combining advantageous features of statistical and process-based crop models for understanding the effects of future climate changes on crop yields. We describe here the development of emulators for nine process-based crop models and five crops using output from the Global Gridded Model Intercomparison Project (GGCMI) Phase II. The GGCMI Phase II experiment is designed with the explicit goal of producing a structured training dataset for emulator development that samples across four dimensions relevant to crop yields: atmospheric carbon dioxide (CO2) concentrations, temperature, water supply, and nitrogen inputs (CTWN). Simulations are run under two different adaptation assumptions: that growing seasons shorten in warmer climates, and that cultivar choice allows growing seasons to remain fixed. The dataset allows emulating the climatological mean yield response without relying on interannual variations; we show that these are quantitatively different. Climatological mean yield responses can be readily captured with a simple polynomial in nearly all locations, with errors significant only in some marginal lands where crops are not currently grown. In general, emulation errors are negligible relative to differences across crop models or even across climate model scenarios. We demonstrate that the resulting GGCMI emulators can reproduce yields under realistic future climate simulations, even though the GGCMI Phase II dataset is constructed with uniform CTWN offsets, suggesting that effects of changes in temperature and precipitation distributions are small relative to those of changing means. The resulting emulators therefore capture relevant crop model responses in a lightweight, computationally tractable form, providing a tool that can facilitate model comparison, diagnosis of interacting factors affecting yields, and integrated assessment of climate impacts.

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BibTeX Citation

  author={Franke, J. and Müller, C. and Elliott, J. and Ruane, A. C. and Jägermeyr, J. and Snyder, A. and Dury, M. and Falloon, P. and Folberth, C. and François, L. and Hank, T. and Izaurralde, R. C. and Jacquemin, I. and Jones, C. and Li, M. and Liu, W. and Olin, S. and Phillips, M. and Pugh, T. A. M. and Reddy, A. and Williams, K. and Wang, Z. and Zabel, F. and Moyer, E.},
  title={The GGCMI phase II emulators: Global gridded crop model responses to changes in CO2, temperature, water, and nitrogen (version 1.0)},
  journal={Geosci. Model Dev.},
  note={Manuscript submitted for publication}

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RIS Citation

ID  - fr08300m
AU  - Franke, J.
AU  - Müller, C.
AU  - Elliott, J.
AU  - Ruane, A. C.
AU  - Jägermeyr, J.
AU  - Snyder, A.
AU  - Dury, M.
AU  - Falloon, P.
AU  - Folberth, C.
AU  - François, L.
AU  - Hank, T.
AU  - Izaurralde, R. C.
AU  - Jacquemin, I.
AU  - Jones, C.
AU  - Li, M.
AU  - Liu, W.
AU  - Olin, S.
AU  - Phillips, M.
AU  - Pugh, T. A. M.
AU  - Reddy, A.
AU  - Williams, K.
AU  - Wang, Z.
AU  - Zabel, F.
AU  - Moyer, E.
PY  - 2020
TI  - The GGCMI phase II emulators: Global gridded crop model responses to changes in CO2, temperature, water, and nitrogen (version 1.0)
JA  - Geosci. Model Dev.
DO  - 10.5194/gmd-2019-365
ER  -

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