Assimilation of ozone data in the context of observation system simulation experiments

Observation System Simulation Experiments (OSSEs) have been performed as part of a satellite based ozone lidar project feasibility study. The Ozone Research with Advanced Co-operative Lidar Experiment (ORACLE) project should provide ozone vertical profiles with an horizontal resolution of 100km and a vertical resolution of 1km. OSSEs that we have performed consist in one-month ozone assimilation cycles with ORACLE "observations". Our assimilation cycles are based on the Canadian Meteorological Centre 3D-var assimilation system coupled to the CMC Global Environmental Multiscale (GEM) model with a lid at 1mb. ORACLE profiles are built from a nature run obtained with the CMC global spectral model (SEF) associated to an ozone chemical package of 47 species. Methodology of experiments will be presented along with results of the OSSEs. These experiments allowed us to investigate several aspects of ozone data assimilation: the impact of the number of ozone profiles, the comparison between assimilation of total ozone observations and ozone profile observations and the effect of adding ozone chemistry with different complexities to our assimilation cycle.