Atmos. Chem. Phys. Discuss., 11, C12935–C12940, 2011 www.atmos-chem-phys-discuss.net/11/C12935/2011/ © Author(s) 2011. This work is distributed under the Creative Commons Attribute 3.0 License. Atmospheric Chemistry and Physics Discussions Interactive comment on “Assimilation of IASI partial tropospheric columns with an Ensemble Kalman Filter over Europe” by A. Coman et al. R. Hanea (Referee) remus.hanea@tno.nl Received and published: 10 December 2011 [12pt]article graphicx color C12935 Review for "Assimilation of IASI partial tropospheric columns with an Ensemble Kalman Filter over Europe" Remus Hanea The presented paper deals with the problem of state estimation in air quality modeling by assimilating satellite data in an Ensemble Kalman filter (EnKF) approach to solve a inverse problem. The ozone concentrations are estimated combining the predictions of the CHIMERE atmospheric model and the measurements coming from the satellite data, both sources of information being uncertain. The EnKF was the algorithm em- ployed to solve the inverse problem. The setup of the data assimilation experiment is well constructed and after a sensitivity analysis was performed, two parameters were appointed as most influential: dimension of the ensemble and the local patch size for the localization. Results of the experiments are presented using real IASI data and the performance of the whole approach is depicted well throughout the paper. The paper is well written and well explained. The novelty of the approach is clear and well positioned in the context of other work in the same area of research. I believe that the article should be accepted with minor comments. Consequently, there are few issues that need clarification and those are discussed in the following comments: C12936