Reanalysis of Stratospheric Chemical Composition Based on Assimilation of MLS, MIPAS and SCIAMACHY Data: Early Results
ERRERA, Quentin1; Chabrillat, Simon1; Christophe, Yves1; Lefeber, Karolien1; Skachko, Sergey1; Viscardy, Sebastien1; Ménard, Richard1; Rozanov, Alexei2

BIRA-IASB is planning a reanalysis of the stratospheric chemical composition the Belgian Assimilation System for Chemical ObsErvations (BASCOE). BASCOE is a 4D-Var system based on a chemistry transport model that has 57 chemical species, 200 chemical reactions and a PSC parameterization. For this reanalysis, the model will be driven by the ECMWF ERA-Interim reanalyses with a spatial resolution of 2.5° latitude x 3.75° longitude x 37 levels (surface to 0.1 hPa). The goal of our reanalysis is to provide daily global maps of all the relevant chemical species of the stratosphere as well as total ozone. The following instruments will be assimilated: EOS Aura MLS, MIPAS and SCIAMACHY. These instruments will potentially allow us to constrain O3, H2O, OH, CH4, N2O, HNO3, NO2, N2O5, ClONO2, ClO, BrO, CFC11, CFC12 and total ozone column.

In this contribution, we will present early results obtained for the year 2008. The quality of the analyses will be discussed using comparison against ozonesondes and ACEFTS data. We will also discuss the ability of the system to produce useful analyses in the following stratospheric conditions: polar winters (i.e. denitrification, dehydration, chlorine activation and ozone destruction), polar winters perturbed by descent of mesospheric NOx, and the UTLS. This reanalysis will be made available to the community.