Four-dimensional variational data assimilation system for the Earth ionosphere

Abstract This paper presents the developed four-dimensional variational data assimilation system for the global ionosphere model INM-IM. The first results on realistic observational total electron content data assimilation are shown. The formulation of the problem is given, numerical methods for solving the system of direct and adjoint equations are proposed. The results of preliminary numerical experiments with developed assimilation system for the unperturbed ionospheric conditions are also presented, a comparison of obtained results in vertical electron content distribution with observed diurnal evolution is given.