A Multiscale Parametrization for Refractivity Estimation in the Troposphere

Abstract : This paper presents the idea of multiscale parametrization for tropospheric refractivity inversion using gradient-based optimization method. Our motivation is to improve the accuracy of inversion without the use of apriori information. We retrieve the details of the refractivity distribution progressively from large to smaller scales using hierarchical multiscale strategies in the admissible parameter space. The proposed formulation for multiscale adjoint tomography is validated and is confronted to a numerical test. This study shows that such strategies can potentially resolve complex ducting conditions which would otherwise fail a plain gradient-based inversion.