Global Gridded Crop Model Evaluation Tool

By Jaewoo Shin1, Christoph Müller (contributor)2, Joshua Elliott (contributor)3

1. Purdue University 2. Potsdam Institute for Climate Impact Research, Potsdam, Germany 3. University of Chicago and Argonne National Laboratory Computation Institute, Chicago, IL, USA

GGCM Evaluation Tool

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Version 1.0 - published on 31 Mar 2017

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The GGCMI Evaluation Tool allows users to evaluate their own model simulation results against different reference data sets at global, national and grid cell level for the four major crops maize, wheat, rice and soybean as well as against an ensemble of 14 global gridded crop models (GGCMs) that contributed data to first stage the GGCM Intercomparison (GGCMI) of the Agricultural Model Intercomparison and Improvement Project (AgMIP), as described by Elliott et al. (2015).

This tool reproduces the central figures of the GGCMI evaluation paper (Müller et al., 2016) and adds a new data point/set for the model results that are supplied by the user. These extended figure reproductions can then be used by the user to evaluate and demonstrate their model performance against observational data and other models.

Data upload instructions

Data has to be supplied in two netCDF4 files (one for rainfed and one for irrigated simulations), following the instructions in Elliott et al. (2015). A sample file is available here for download. If rainfed and irrigated simulations are not conducted separately, the same file should be uploaded twice.

The single variable in the NetCDF file should be named 'yield_[crop]', where [crop] is one of the four crop name abbreviations 'mai', 'whe', 'ric' or 'soy' respectively.

In order to facilitate the analysis of your simulation results, gridded data should be returned in NetCDF Version 4 format with the formatting specified below. Data are to be submitted for the ranges -89.75 to 89.75 degrees latitude, and -179.75 to 179.75 degrees longitude, i.e. 360 rows and 720 columns, or 259200 grid cells total, though obviously it is unnecessary to simulate Greenland and Antarctica. Some groups are choosing to simulate only latitude 67N to 60S, but even so it is important to submit output completely filled for the entire range from 89.75S to 89.75N. Please report the output data row-wise starting at 89.75 and -179.75, and ending at -89.75 and 179.75. Latitude, longitude and time should be included as individual variables in each file.

Dimension Name Unit
x lon degrees east, -179.75…179.75
y lat degrees north, -89.75…89.75
t time “growing seasons since YYYY-01-01 00:00:00”
missing value 1.e+20f

There will be a quality check, that reports possible errors in dimension definitions and or meta-data issues. Please follow the advise and fix the files for upload accordingly, if any errors are reported.

A sample NetCDF file is attached here, to give some guidance.


Elliott J, Müller C, Deryng D, Chryssanthacopoulos J, Boote KJ, Büchner M, Foster I, Glotter M, Heinke J, Iizumi T, Izaurralde RC, Mueller ND, Ray DK, Rosenzweig C, Ruane AC, Sheffield J (2015): The Global Gridded Crop Model intercomparison: data and modeling protocols for Phase 1 (v1.0). Geosci. Model Dev. 8, 261-277, doi:10.5194/gmd-8-261-2015

Müller C, Elliott J, Chryssanthacopoulos J, Arneth A, Balkovic J, Ciais P, Deryng D, Folberth C, Glotter M, Hoek S, Iizumi T, Izaurralde RC, Jones C, Khabarov N, Lawrence P, Liu W, Olin S, Pugh TAM, Ray D, Reddy A, Rosenzweig C, Ruane AC, Sakurai G, Schmid E, Skalsky R, Song CX, Wang X, de Wit A, and Yang H. 2016, Global Gridded Crop Model evaluation: benchmarking, skills, deficiencies and implications, Geosci. Model Dev. Discuss., 2016, 1-39, doi: 10.5194/gmd-2016-207

Cite this work

Researchers should cite this work as follows:

  • Jaewoo Shin; Christoph Müller; Joshua Elliott (2017), "Global Gridded Crop Model Evaluation Tool,"

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