Stratospheric Ozone Density Retrieval Using the Optimal Estimation Method (OEM) Ghazal Farhani, R. J. Sica, Sophie Godin-Beekmann and Alexander Haefele EPJ Web Conf., 176 (2018) 03006 Published online: 20 August 2018 DOI: 10.1051/epjconf/201817603006