DOI: 10.5281/zenodo.11061150
title: CMIP6 scenarios' radiative forcing of non-CO2 greenhouse gases and aerosols for UVic ESCM simulations (1850-2500)

description: Overview

This repository contains the input files for the UVic Earth System Climate Model (ESCM) that are required to simulate the historical period (1850-2014) and the extended CMIP6 SSP-RCP scenarios SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP4-3.4, SSP4-6.0, SSP5-3.4, SSP5-8.5 (2015-2500).

For simulations of these scenarios, the model is forced with aggregated non-CO2 greenhouse gas radiative forcing, land use cover, aerosol radiative forcing, and either CO2 concentration or CO2 emissions. The radiative forcing of CO2 is calculated internally by the UVic ESCM.

The following files are included in this repository:

CO2 concentrations  (for concentration-driven simulations)

A_co2_hist.nc

A_co2_119.nc

A_co2_126.nc

A_co2_245.nc

A_co2_370.nc

A_co2_434.nc

A_co2_460.nc

A_co2_534.nc

A_co2_585.nc

 

CO2 emissions (for emission-driven simulations)

F_co2emit_119.nc

F_co2emit_126.nc

F_co2emit_245.nc

F_co2emit_370.nc

F_co2emit_434.nc

F_co2emit_460.nc

F_co2emit_534.nc

F_co2emit_585.nc

 

Land use cover fractions (pasture and crops)

L_agricfra_hist_and_ssp119.nc

L_agricfra_hist_and_ssp126.nc

L_agricfra_hist_and_ssp245.nc

L_agricfra_hist_and_ssp370.nc

L_agricfra_hist_and_ssp434.nc

L_agricfra_hist_and_ssp460.nc

L_agricfra_hist_and_ssp534.nc

L_agricfra_hist_and_ssp585.nc

 

Aggregated non-CO2 greenhouse gas forcing

A_aggfor_hist.nc

A_aggfor_119.nc

A_aggfor_126.nc

A_aggfor_245.nc

A_aggfor_370.nc

A_aggfor_434.nc

A_aggfor_460.nc

A_aggfor_534.nc

A_aggfor_585.nc

 

Aerosol optical depth

A_sulphod_hist.nc

A_sulphod_119.nc

A_sulphod_126.nc

A_sulphod_245.nc

A_sulphod_370.nc

A_sulphod_434.nc

A_sulphod_460.nc

A_sulphod_534.nc

A_sulphod_585.nc

 

Detailed description

1.  CO2 concentrations

The CO2 concentrations are provided here as the annual global mean mole fraction of CO2 in ppm and identical with the CMIP6 input data available at https://esgf-node.llnl.gov/search/input4mips/.

2.  CO2 emissions

The CO2 emissions are the same as provided by RCMIP (Meinshausen et al., 2020). Here the Agriculture, Forestry and Other Land Use (AFOLU) emissions are represented as “F_co2eland” emissions. Also, the sector based emissions from Aircraft, the Industrial Sector, International Shipping, Residential Commercial Other, Solvents Production and Application, the Transportation Sector, and Waste are aggregated into the Fossil and Industrial emissions and represented as “F_co2efuel” emissions. Both the F_co2eland and F_co2efuel emissions are finally aggregated into total CO2 emissions represented as “F_co2emit”. These aggregated CO2 emissions are likewise identical to globally averaged CMIP6 input data available at https://esgf-node.llnl.gov/search/input4mips/. All three CO2 emission variables are included in the “F_co2emit*.nc” files. In addition to the SSP-RCP-scenario CO2 emissions also the historical CO2 emissions are included in all files (starting in year 1750).

3.  Land use cover

The land-use forcing is provided as the pasture and cropland grid cell fraction (variable names: “L_cropfra” and “L_pastfra”; in file: “L_agricfra.nc”). The UVic ESCM translates pasture and cropland fractions internally into C3 grass or C4 grass fractions, depending on the local conditions. The land-use cover is based on LUH2v2f “states.nc” data (available at https://luh.umd.edu/data.shtml) and has been regridded and reaggregated for the UVic ESCM. The cropland fraction of the UVic ESCM input (“L_cropfra”) is the sum of all crop types given by LUH2v2f (“c3ann”, “c3nfxc”, “c3per”, “c4ann”, “C4per”), whereas the pasture fraction (“L_pastfra”) is the sum of LUH2v2f’s pasture fraction and rangeland fraction (“pastr”, “range”). The land-use forcing covers the period 850-2100.

4.  Non-CO2 greenhouse gas radiative forcing

The aggregated radiative forcing of 44 non-CO2 greenhouse gases (GHG) was calculated from the respective atmospheric GHG concentrations (provided by RCMIP for CMIP6, see References), following the approach of Meinshausen et al. 2020 and Etminan et al. 2016. Radiative forcing of tropospheric ozone, stratospheric ozone, and stratospheric water vapor from methane oxidation was calculated as described in Smith et al. 2018.

The following non-CO2 GHG are accounted for in the aggregated forcing files (“A_aggfor.nc”):

N2O; CH4; CFC11; CFC12; HFC134a; C2F6; C6F14; CF4; HFC23; HFC32; HFC43_10; HFC125; HFC143a; HFC227ea; HFC245fa; SF6; CFC113; CFC114; CFC115; HCFC22; HCFC142B; HCFC141B; HALON1211; HALON1301; HALON2402; CH3BR; CH3CL; CCL4; CH2CL2; CH3CCL3; NF3; HFC365mfc; C3F8; C4F10; HFC236fa; C5F12; CHCL3; cC4F8; HFC152a; SO2F2; C7F16; C8F18; stratospheric and  tropospheric O3; water vapor from CH4 oxidation.

5.  Aerosol radiative forcing

Aerosol optical depth (AOD) 2D input data for the UVic ESCM was created using a UVic grid with the scripts and data provided by Stevens et al. (2017). The data provided describes nine different plumes globally which are scaled with time to produce monthly aerosol optical depth forcing for the years 1850-2018 (Stevens et al., 2017). For the future projection of the years 2018-2100, the same scripts were run with input data from Fiedler et al. (2019). To extend aerosol optical depth data from 2100 to 2500, the last year of available data (i.e. 2100) was repeated. 

Since the AOD input caused too great a negative forcing in the historical period, a scaling factor was implemented into the UVic ESCM, which allows to scale aerosol forcing from AOD data. The scaling factor was set to 0.7, which gives a globally averaged forcing of -1.03 Wm-2 in 2011.

Note that the file "A_sulphod_hist.nc" contains not only the data of the historical period (1850-2014) but also the data of the scenario SSP5-8.5 (extended until 2500).

 

References

Fiedler, S., Stevens, B., Gidden, M., Smith, S. J., Riahi, K., & van Vuuren, D. (2019). First forcing estimates from the future CMIP6 scenarios of anthropogenic aerosol optical properties and an associated Twomey effect. Geoscientific Model Development, 12(3), 989-1007.Etminan, M., Myhre, G., Highwood, E., and Shine, K.: Radiative forcing of carbon dioxide, methane, and nitrous oxide: A significant revision of the methane radiative forcing, Geophys. Res. Lett., 43, 12614–12623, https://doi.org/10.1002/2016GL071930, 2016.

Meinshausen, M., Nicholls, Z. R., Lewis, J., Gidden, M. J., Vogel, E., Freund, M., ... & Wang, R. H. (2020). The shared socio-economic pathway (SSP) greenhouse gas concentrations and their extensions to 2500. Geoscientific Model Development, 13(8), 3571-3605.

Smith, C. J., Forster, P. M., Allen, M., Leach, N., Millar, R. J., Passerello, G. A., & Regayre, L. A. (2018). FAIR v1. 3: a simple emissions-based impulse response and carbon cycle model. Geoscientific Model Development, 11(6), 2273-2297.

Stevens, B., Fiedler, S., Kinne, S., Peters, K., Rast, S., Müsse, J., Smith, S. J., and Mauritsen, T.: MACv2-SP: a parameterization of anthropogenic aerosol optical properties and an associated Twomey effect for use in CMIP6, Geosci. Model Dev., 10, 433-452, https://doi.org/10.5194/gmd-10-433-2017, 2017

RCMIP GHG concentration data: https://zenodo.org/record/4589756/files/rcmip-concentrations-annual-means-v5-1-0.csv

RCMIP Emissions data:

https://rcmip-protocols-au.s3-ap-southeast-2.amazonaws.com/v5.1.0/rcmip-emissions-annual-means-v5-1-0.csv

Input4mips CO2 concentration data: https://esgf-node.llnl.gov/search/input4mips/

LUH2 land-use cover data: https://luh.umd.edu/data.shtml