Parametric electromagnetic transfer function estimation at USArray Site MNF34

Abstract

Abstract We propose a new parametric approach to electromagnetic transfer function (EMTF) estimation which has attributes not found in the nonparametric approach most extensively used by the magentotelluric (MT) community. Firstly, parametric EMTFs are smooth by construction, which is consistent with the underlying physics. Secondly, fewer parameters are generally required to represent an EMTF by parametric means. Thirdly, our parametric approach can simplify data quality control and editing of time series because of the direct operation in the time domain. Our approach is based on the mature discipline of system identification which is concerned with parametric transfer function determination given system input and output. In this study, MT data from one USArray site are analyzed, showing a statistical advantage in reproducing measured geoelectric field time series using a parametric model EMTF versus the standard EMTF approach.