NORA3 atmosphere hindcast data

The atmospheric component of NORA3 is produced by running the non-hydrostatic HARMONIE-AROME model (Seity et al., 2011, Bengtsson et al., 2017, Muller et al., 2017) with 3km horizontal resolution and 65 vertical levels. The model runs 9-hourly forecasts four times a day. Each forecast starts from an assimilated state of the last forecast adapted to surface observations. Model levels are forced with the global ERA-5 data (https://climate.copernicus.eu/climate-reanalysis). A continuous historical time series, i.e. the hindcast, is then compiled from hour 4-9 of each forecast.