Modified SSP2-4.5 near-surface methane mixing ratios for 2015 - 2019

The original set of near-surface methane concentrations for SSP2-4.5 (Meinshausen et al., 2020) were modified to more closely follow the observed methane concentrations for 2015 - 2019. Data from the NOAA Global Monitoring Laboratory and the World Meteorological Organization (WMO) Global Atmospheric Watch (as published in the WMO Annual Greenhouse Gas Bulletin) were used. Global scaling factors were calculated to modify the values in the original files to the 2015 - 2019 observed values. Four variations of the original files of methane mixing ratio were provided through input4MIPS (https://esgf-node.llnl.gov/projects/input4mips/) with different temporal and spatial resolution. Modified versions of these same four variations have been produced following the same scaling process. Meinshausen, M., Z. R. J. Nicholls, J. Lewis, M. J. Gidden, E. Vogel, M. Freund, U. Beyerle, C. Gessner, A. Nauels, N. Bauer, J. G. Canadell, J. S. Daniel, A. John, P. B. Krummel, G. Luderer, N. Meinshausen, S. A. Montzka, P. J. Rayner, S. Reimann, S. J. Smith, M. van den Berg, G. J. M. Velders, M. K. Vollmer and R. H. J. Wang, The shared socio-economic pathway (SSP) greenhouse gas concentrations and their extensions to 2500, Geosci. Mod. Dev., 13, 3571 – 3605, doi:10.5194/gmd-13-3571-2020, 2020.