**Roselena Rubino 1,\*, Nuria Du**ff**o 1, Verónica González-Gambau 2, Ignasi Corbella 1, Francesc Torres 1, Israel Durán <sup>1</sup> and Manuel Martín-Neira <sup>3</sup>**


Received: 27 March 2020; Accepted: 8 May 2020; Published: 18 May 2020

**Abstract:** In this work, a new methodology is proposed in order to derive vertical total electron content (VTEC) maps from the radiometric measurements of the Soil Moisture and Ocean Salinity (SMOS) mission as an alternative approach to those based on external databases and models. This approach uses spatiotemporal filtering techniques with optimized filters to be robust against the thermal noise and image reconstruction artifacts present in SMOS images. It is also possible to retrieve the Faraday rotation angle from the recovered VTEC maps in order to correct the effect that it causes in the SMOS brightness temperatures.

**Keywords:** faraday rotation angle (FRA); vertical total electron content (VTEC); L-band; radiometry; Interferometry; soil moisture; ocean salinity (SMOS)
