Physical Marine Climate Projections for the North West European Shelf Seas: EnsStats

Ensemble statistics are calculated from the North West Shelf Perturbed Parameter Ensemble (NWSPPE) climatologies. The NWSPPE (https://catalogue.ceda.ac.uk/uuid/edf66239c70c426e9e9f19da1ac8ba87) provides climatological mean and climatological standard deviations for an early-century period (2000-2019) and a late-century period (2079-2098) for each of the 12 NWSPPE ensemble members, for the annual means, and for each month and season of the year. These have been processed into ensemble statistics, for each period (2000-2019, 2079-2098, and the difference 2079-2098minus2000-2019), and for each season and month and for annual means. For the early-century and late-century climatology periods, these ensemble statistics include the ensemble mean, ensemble variance, ensemble standard deviation and interannual variance. These describe the behaviour of the ensemble, including any present day ensemble spread. For the statistics of the difference between the periods (2079-2098minus2000-2019), we simply provide the difference between the ensemble statistics calculated in the near present and end of century period. To allow the user to simply use these data to provide projections, with the associated uncertainty, we also provide two additional statistics, the projected ensemble mean (projensmean) and the projected ensemble standard deviation (projensstd). We remove the early-century climatological mean from the late-century climatological mean, for each ensemble member of the NWEPPE to give an anomaly ensemble. We then calculate the resulting ensemble mean (projensmean) and its standard deviation (projensstd). Nucleus for European Modelling of the Ocean (NEMO) has three model grids, the T, U and V grids, and we output variables in three files, respecting their native model grid. In practice, all our variables are on the T grid, apart from the Eastward and Northward components of the depth mean velocities (DMU, DMV), which are in the U and V grid files respectively. The T grid files have Sea Surface, Near Bed, and the Difference between the surface and bed Temperature and Salinity (SST, NBT, DFT, SSS, NBS, DFS), Potential Energy Anomaly (PEA), Mixed Layer Depth (MLD), the barotropic current magnitude interpolated onto the T grid (DMUV).