BASCOE Reanalysis of Aura-MLS, version 3 (BRAM3): daily zonal means

This dataset comprises on single netCDF file which was used to evaluate the seven chemical forecast experiments with IFS-COMPO Cy49R1, as described in section 3.3 and used in section 6 of
Chabrillat, S. et al.: Modelling stratospheric composition for the Copernicus Atmosphere Monitoring Service: multi-species evaluation of IFS-COMPO Cy49, Geosci. Model Dev., https://doi.org/10.5194/gmd-18-8973-2025, 2025

BRAM3 is an upgrade of BRAM2 (Errera et al., https://doi.org/10.5194/acp-19-13647-2019, 2019). Both reanalyses result from the assimilation of Aura-MLS v4.2 observations of O3, N2O, H2O, HNO3, HCl, CO, CH3Cl and ClO (Livesey et al., 2015: https://mls.jpl.nasa.gov/data/v4-2_data_quality_document.pdf) by the BASCOE chemical Data Assimilation System (DAS, https://strato.aeronomie.be/bascoe), but with different configurations.
The most notable difference is the extension of the covered period until November 2023, thanks to the replacement of the input reanalysis for dynamical fields, from ERA-Interim (Dee et al., https://doi.org/10.1002/qj.828, 2011) in BRAM2 to ERA5 (Hersbach et al., https://doi.org/10.1002/qj.3803, 2020) in BRAM3.

NOTES:

• the full BRAM3 reanalysis weighs 144 Gb/year. This is a reduced dataset obtained by keeping only the assimilated species, and averaging every day (daily means) and over all longitudes (zonal means) the instantaneous 3-D output at 00h, 06h, 12h, 18h.

• The levels below 100 hPa or above 1 hPa are not recommended for scientific use

• N2O observations were assimilated only until 2012/11/19. On later dates, the N2O output of BRAM3 is not constrained by any observations.

• See also companion dataset: https://doi.org/10.18758/fabatq6o