Global model datasets (GA4 UM-UKCA) for timeseries of global stratospheric sulphate burden, for interactive simulations of the background stratospheric aerosol layer (pre-industrial state, impact of resolving meteoric nuclei)

These 2 timeseries datasets are from a series of Pre-industrial TimeSlice free-running interactive stratospheric aerosol simulations of the background stratospheric aerosol layer with the UM-UKCA composition-climate model. The model experiments assess the background state of the pre-industrial stratospheric aerosol layer, with sensitivity runs to assess how meteoric smoke particles affect the simulated global sulphate burden in the upper troposphere and stratosphere (UTS), and how the sulphur is distributed among different particles sizes. Specifically, the timeseries datasets, are 5 years of monthly-means (60 data-points) from a so-called “TimeSlice pre-industrial” run, that is with the model repeating monthly “climatological pre-industrial” boundary conditions and for pre-industrial anthropogenic emissions for years 7 to 11 of the 11-year model runs (xnele and xnelk). Further details on the pre-industrial conditions state can be found within the Appendix of the PhD thesis of Lauren Marshall (Marshall, 2019), these runs part of testing ahead of running the VolMIP Tambora-ISA integrations for interactive Tambora aerosol cloud, off this background pre-industrial stratospheric aerosol state. The simulations are with UM-UKCA model at GA4 (Walters et al., 2014), the aerosol scheme GLOMAP-mode upgraded to v8.2 for these runs (Dhomse et al. 2020), as applied for the “MajorVolc” datasets for Agung, El Chichon and Pinatubo, and further evaluated in Quaglia et al., 2023., These runs aligned with the BG background conditions experiment (Brodowsky et al.., 2024) within the ISA-MIP model intercomparison activity for interactive stratospheric aerosol models (Timmreck et al., 2018). The xnele is the control run, running the model as in Dhomse et al. (2020), but at this pre-industrial conditions stratosphere, and with stratospheric circulation and ozone layer spun-up for this 1850 conditions state. The xnelk is a sensitivity run, where the model has been spun-up without meteoric smoke particles (MSPs), and demonstrate the significant impact the MSP nuclei have on the interactive stratospheric aerosol simulations. The inclusion of the MSP nuclei causes a thinner simulated stratospheric aerosol layer, the heterogeneously nucleated sulphate formed on the MSP being formed within the descending air of the polar vortex each high-latitude winter, and then having reduced residence time, compared to nuclei formed in the rising air masses withint he tropical stratospheric reservoir. The datasets stored within this zenodo archive are timeseries, for the 60 monthly-mean global UTS-column mass of sulphur in the stratosphere aerosol layer, for 3 different size modes in the model: Aitken-soluble mode (labelled “AitSol”), accumulation-soluble mode (“AccSol”) and the MSP-containing accumulation-insoluble mode (AccIns). Within the netCDF file, the variable names for the global UTS-column timeseries datasets for these 3 modes are “GlobUTScolSO4_AitSol”, “GlobUTScolSO4_AccSol”, and “GlobUTScolSO4_AccIns”, These timeseries datasets are shown within Figures 3e and 3f of the manuscript “Stratospheric aerosol from above”, by Mann et al. (2026), submitted for JGR commentary article in October 2025. The commentary aligns directly to ground-breaking field measurements with the PALMS-NG laser-ablation mass spectrometer instrument installed on the WB-57 high-altitude aircraft. The JGR paper by Lawler et al. (2025) finds that ~90% of sampled stratospheric aerosol particles in deep vortex air contain a signature of meteoric metals.The findings are consistent with refractory particle measurements from European Arctic high-altitude aircraft (Curtius et al., 2005; Weigel et al., 2014), and high-latitude total stratospheric aerosol measurements from the University of Wyoming high-altitude balloon system (Campbell and Deshler, 2014; Norgren et al., 2024) which both show increasing mixing ratios of particles between altitudes of 25km and 35km. These measurements have been interpreted as indicating a source of stratospheric aerosol from above, likely of meteoric origin. References : Brodowsky, C. V., Sukhodolov, T., Chiodo, G., et al. (2024): “Analysis of the global atmospheric background sulfur budget in a multi-model framework”, Atmos. Chem. Phys., 24, 5513–5548, https://doi.org/10.5194/acp-24-5513-2024 .Campbell, P. and Deshler, T. (2014): “Condensation nuclei measurements in the midlatitude (1982–2012) and Antarctic (1986–2010) stratosphere between 20 and 35km”, J. Geophys. Res.: Atmos., vol. 119, 137–152, https://doi.org/10.1002/2013JD019710 . Curtius, J., Weigel, R., Vössing, H.-J. et al. (2005): “Observations of meteoric material and implications for aerosol nucleation in the winter Arctic lower stratosphere derived from in situ particle measurements”, Atmos. Chem. Phys., 5, 3053–3069, https://doi.org/10.5194/acp-5-3053-2005 . Dhomse S. S, Mann G.W, Antuña Marrero J.-C, et al. (2020). “Evaluating the simulated radiative forcings, aerosol properties, & stratospheric warmings from the 1963 Mt Agung, 1982 El Chichón & 1991 Pinatubo volcanic aerosol clouds”, Atmos. Chem. Phys. 20(21), 13627-13654 , https://doi.org/10.5194/acp-20-13627-2020 Lawler, M.J.,Schill, G.P, Murphy,D.M et al., (2025): “The composition and stratospheric fate of aerosol particles originating in the polar vortex”, J. Geophys. Res. Atmos.,,130, https://doi.org/10.1029/2025JD043530 . Mann, G. W., Weigel, R., Bardeen, C., Marshall, L. R., Brodowsky, C., Norgren, M. and Toon, O.B. (2026): “Stratospheric aerosol from above: Laser-ablation mass spectrometer samples polar vortex air for the first time (Commentary article on JGR in press article by Lawler et al., The composition and stratospheric fate of aerosol particles originating in the polar vortex)”, in review for publication in J. Geophys. Res., Atmos. (submitted October 2025, reviews received March 2026). Marshall, L. R.: “Effects of volcanic eruption source parameters on radiative Forcing and sulfate deposition”, PhD thesis, University of Leeds, August 2018, available at White Rose e-theses archive, https://etheses.whiterose.ac.uk/id/eprint/22551/1/Marshall_LR_Earth_and_Environment_PhD_2018.pdf (2018) Norgren, M., Kalnajs, L. and Deshler, T. (2024): “Measurements of total aerosol concentration in the stratosphere: A new balloon‐borne instrument and a report on the existing measurement record”, J. Geophys. Res., 129, e2024JD040992. https://doi.org/10.1029/2024JD040992 . Quaglia, I., Timmreck, C., Niemeier, U. et al. (2023): “Interactive stratospheric aerosol models’ response to different amounts and altitudes of SO2 injection during the 1991 Pinatubo eruption”, Atmos. Chem. Phys., 23, 921–948 https://doi.org/10.5194/acp-23-921-2023 . Timmreck, C., Mann, G. W., Aquila, V., et al. (2018): “The Interactive Stratospheric Aerosol Model Intercomparison Project: motivation and experimental design”, Geosci. Mod. Dev., 11, 2581-2608, https://doi.org/10.5194/gmd-11-2581-2018 . Walters, D. et al. (2014): “The Met Office Unified Model Global Atmosphere 4.0 and JULES Global Land 4.0 configurations”, Geosci. Model Dev., 7, 361–386, https://doi:10.5194/gmd-7-361-2014 . Weigel, R., Volk, C. M., Kandler, K. et al. (2014): “Enhancements of the refractory submicron aerosol fraction in the Arctic polar vortex: feature or exception?”, Atmos. Chem. Phys., 14, 12319–12342, https://doi.org/10.5194/acp-14-12319-2014 .