DOI: 10.5281/zenodo.4744686
title: SMURPHS/ACSIS Agung volcanic forcing dataset (mapped to UM wavebands) -- from HErSEA ensemble of interactive strat-aerosol GA4 UM-UKCA runs (Dhomse et al., 2020, ACP)

description: The netCDF file uploaded here is a volcanic forcing dataset for the Agung aerosol cloud for use in climate model simulations, produced equivalently to the CMIP6-AER2D volcanic forcing dataset (Arfeuille et al., 2014; Luo, 2016), generated for use within the post-industrial historical integrations for CMIP6 (Eyring et al., 2016).<br> <br> The dataset is specific to UKESM (e.g. Sellar et al., 2019), with waveband-averaged extinction, absorption and asymmetry parameter mapped to the SW & LW wavebands within the SOCRATES radiative transfer module (Edwards and Slingo, 1996; Manners et al., 2017).<br> <br> Whereas the Agung period within the CMIP6-AER2D volcanic forcing dataset (Arfeuille et al., 2014; Luo, 2016) was generated from aerosol microphysics simulations from a 2D model, this SMURPHS/ACSIS dataset is from the ensemble of interactive stratospheric aerosol simulations of the Agung aerosol cloud with the 3D composition-climate model UM-UKCA (see Dhomse et al., 2020). The main forcing dataset is that from the 3-member mean of the 6Tg @ 20-22km UM-UKCA simulations, matching the "lower SO2 emission, shallow-medium injection height" eruption source parameters realisation within the ISA-MIP HErSEA experiment (Timmreck et al., 2018), found to best match with the benchmark observational datasets compared to in the Dhomse et al. (2020) ACP study.<br> <br> A control stratospheric aerosol dataset is also provided, based on the corresponding 3 "no-SO2-emission control" integrations from the Dhomse et al. (2020) simulations, then representing the quiescent stratospheric aerosol layer for 1963-1966 (different then from the "average volcanism" background dataset provided for use in the CMIP6 pre-industrial control).<br> <br> The original 3D-monthly-mean data from the UM-UKCA interactive stratospheric aerosol simulations has been zonally-averaged for this dataset, to match the same structure as for the CMIP6-AER2D dataset. The latitude resolution of the dataset is 1.25 degrees with 85 hybrid-height vertical levels (see Sellar et al., 2019). The aerosol optical properties are averaged across the usual 6 UM wavebands in the SW and the 9 wavebands in the LW.<br> <br> The 1.25 degree resolution matches the ENDGAME N96E horizontal grid for UKESM1 (re-gridded from New Dynamics grid in GA4).<br> <br> The L85 vertical resolution of the dataset is the same vertical model grid used in the GA4 UM-UKCA N96L85 simulations,<br> as also required identically for use within UKESM1.<br> <br> <strong>References</strong> Arfeuille, F., Weisenstein, D., Mack, H., Rozanov, E., Peter, T. and Broenimann, S.<br> "Volcanic forcing for climate modeling: a new microphysics-based data set covering years 1600-present",<br> Clim. Past, 10, 359-375, 2014, https://doi.org/10.5194/cp-10-359-2014<br> <br> Dhomse, S. S., Mann, G. W., Antuna Marrero, J.-C., Shallcross, S. E., Chipperfield, M. P., Carslaw, K. S. et al. (2020):<br> "Evaluating the simulated radiative forcings, aerosol properties, and stratospheric warmings from the 1963 Mt Agung, 1982 El Chichón, and 1991 Mt Pinatubo volcanic aerosol clouds", <br> <em>Atmos. Chem. Phys.</em>, <strong>20</strong>, 13627–13654, https://doi.org/10.5194/acp-20-13627-2020 Edwards, J. M. and Slingo, A. (1996): <br> "Studies with a flexible new radiation code. I: Choosing a configuration for a large-scale model",<br> <em>Quart. J. Roy. Meteor. Soc.</em>, <strong>122</strong> <strong>, </strong>689–719, https://doi.org/10.1002/qj.49712253107 Eyring, V., Bony, S., Meehl, G. A., Senior, C. A., Stevens, B., Stouffer, R. J. and Taylor, K. E. (2016):<br> "Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization",<br> <em>Geosci. Mod. Dev.</em>, <strong>9</strong>, 1937–1958, https://doi.org/10.5194/gmd-9-1937-2016 Luo, B.: Stratospheric aerosol data for use in CMIP6 models, available at: ftp://iacftp.ethz.ch/pub_read/luo/CMIP6/Readme_Data_Description.pdf, 2016.<br> <br> Manners, J., Edwards, J. M., Hill, P. and Thelen, J.-C. (2017):<br> "SOCRATES Technical Guide -- Suite Of Community RAdiative Transfer codes based on Edwards and Slingo"<br> <em>Technical Guide. Met Office, UK</em>. Available at: https://code.metoffice.gov.uk/trac/socrates. Sellar, A., Jones, C. G., Mulcahy, J. P., Tang, Y., Yool, A., Wiltshire, A., O'Connor, F. M., Stringer, M. et al. (2019):<br> "UKESM1: Description and Evaluation of the U.K. Earth System Model"<br> <em>J. Adv. in Modelling Earth Systems</em>, https://doi.org/10.1029/2019MS001739 Timmreck, C. E., Mann, G. W., Aquila, V., Hommel, R., Lee, L. A., Schmidt, A., Bruehl, C., Carn, S. et al. (2018):<br> "The Interactive Stratospheric Aerosol Model Intercomparison Project (ISA-MIP): motivation and experimental design"<br> Geosci. Model Dev., 11, 2581-2608, https://doi.org/10.5194/gmd-11-2581-2018