arXiv subjects

Antonio Rius

Publications and source records attributed to Antonio Rius.

3 recordsLinked to original sources

arXiv2006

Technical Note on POlarimetric Phase Interferometry (POPI)

The Global Navigation Satellite Systems (GNSS), such as the American Global Positioning System (GPS), the Russian GLONASS or the imminent European Galileo, can be used as sources of opportunity for remote sensing of the Oceans. In this document, we present the approach, conceptual background and preliminary results of a novel polarimetric interferometric technique based on GPS signals rebounded off of the sea surface and collected at both Right Hand (RH) and Left Hand (LH) Circular Polarizations. We seek to obtain geophysical information out of the phase information, which could be in principle relate to the dielectric properties of the sea surface.

physics.ao-ph↗

arXiv1999

Analysis of Water Vapor spatio-temporal structure over the Madrid Area using GPS data

We have analyzed Zenith Wet Delay (ZWD) time series from an experiment over the Madrid (Spain) area obtained from 5 GPS receivers using two different techniques. In the first case a delay correlation analysis of the ZWD time-series has been carried out. We show that for this small network (with a spatial scale of less than 100 km) the correlation between the time series is very strong, and that using windowing techniques a reliable correlation delay time series can be produced for each pair of sites (10 such pairs are available). We use this delay time series together with a frozen flow model to estimate the velocity of a passing front, and compare the results to meteorological data and Numerical Weather Prediction output, showing good agreement. In the second approach, the data is analyzed using Empirical Orthogonal Functions. We demonstrate that the temporally demeaned and normalized analysis yields information about the passing of fronts, while the spatially demeaned data yields orographic information. A common second mode highlights the underlying wave behavior.

physics.ao-ph↗

arXiv1998

A PIM-aided Kalman Filter for GPS Tomography of the Ionospheric Electron Content

We develop the formalism for a PIM-based functional for stochastic tomography with a Kalman filter, in which the inversion problem associated with four-dimensional ionospheric stochastic tomography is regularized. For consistency, GPS data is used to select dynamically the best PIM parameters, in a 3DVAR fashion. We demonstrate the ingestion of GPS (IGS and GPS/MET) data into a parameterized ionospheric model, used to select the set of parameters that minimize a suitable cost functional. The resulting PIM-fitted model is compared to direct 3D voxel tomography. We demonstrate the value of this method analyzing IGS and GPS/MET GPS data, and present our results in terms of a 4D model of the ionospheric electronic density.

physics.geo-ph↗