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README for DATASET "Data from: Seasonally Modulated Stratospheric Aerosol Geoengineering Alters the Climate Outcomes"
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This readme file describes the dataset used in the following GRL paper: Visioni, D., MacMartin, D. G., Kravitz, B., Richter, J. H., Tilmes, S., & Mills, M. J. (2020). Seasonally modulated stratospheric aerosol geoengineering alters the climate outcomes. Geophysical Research Letters, 47, e2020GL088337. https://doi.org/10.1029/2020GL088337.

Please cite this dataset as: Visioni, Daniele; MacMartin, Douglas; Kravitz, Ben; Richter, Yaga; Tilmes, Simone; Mills, Michael (2020) Data from: Seasonally modulated stratospheric aerosol geoengineering alters the climate outcomes. [Dataset] Cornell University eCommons Digital Repository. https://doi.org/10.7298/c92j-2p46

This dataset is shared under a Attribution 4.0 International (CC BY 4.0) license (https://creativecommons.org/licenses/by/4.0/). The material can be shared and built upon, but attribution to the original authors and a statement of changes made is required.


All files in the dataset are NetCDF (Network Common Data Form) and can be easily read in common programming languages (python, Matlab, R, NCL, C++, and others).

Variables are grouped into .tar.gz files of the same name for easier download.

The single files are described as follow: 
[Variable name]_[Simulation name]_[ensemble member]_[type of spatial average]_monthly.nc 
and contains the variable (with a short description) and the spatial and temporal coordinates (i.e. latitude, longitude (when applicable) and vertical levels (when applicable, in hPa)). All associated coordinates  are described in each file.


The variables shared are:
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Variable name		dimensions		long name						units				
AODVISstdn 		2D-zm			Stratospheric aerosol optical depth 550 nm day night	unitless		
ICEFRAC 		2D-map			Fraction of sfc area covered by sea-ice			unitless
PRECT 			2D-map			Precipitation rate					m/s
QFLX			2D-map			Surface water flux (evapotranspiration rate)		kg/m2/s
so4_a1			3D-zm			so4 concentration in Accumulation mode			kg/kg
so4_a2			3D-zm			so4 concentration in Aitken mode			kg/kg
so4_a3			3D-zm			so4 concentration in Coarse mode			kg/kg
T			3D-zm			Air temperature						K
TLAI			2D-map			Total projected leaf area index				unitless
TREFHT			2D-map			Reference height temperature				K

All data spans the 2070-2089 period. 

The simulations names describe the SO2 injection period in the two hemispheres.
The equivalence with the simulation name used in the GRL paper is described below

N_DJF_S_JJA = iWINTER (1 ensemble member)
N_MAM_S_SON = iSPRING (3 ensemble member)
N_JJA_S_DJF = iSUMMER (1 ensemble member)
N_SON_S_MAM = iAUTUMN (3 ensemble member)


For the iANNUAL case described in the paper, and for the Control data, please refer to https://doi.org/10.5065/D6JH3JXX


Acknowledgments
We would like to acknowledge high-performance computing support from Cheyenne (doi:10.5065/D6RX99HX) provided by NCAR's Computational and Information Systems Laboratory, sponsored by the National Science Foundation. Support for D. V. and D. G. M. was provided by the Atkinson Center for a Sustainable Future at Cornell University and by the National Science Foundation through agreement CBET-1818759. This  research was supported in part by the Indiana University Environmental Resilience Institute and the Prepared for Environmental Change grand challenge initiative. The Pacific Northwest National Laboratory is operated for the U.S. Department of Energy by Battelle Memorial Institute under contract DE-AC05-76RL01830. The CESM project is supported primarily by the National Science Foundation. This work was supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation under Cooperative Agreement No. 1852977.