An algorithm for pre-operational high resolution soil moisture mapping using Synthetic Aperture Radar (SAR) data is presented. It has been conceived to be inserted in the operational weather alert system of the Italian Department of Civil Protection. The Maximum A Posteriori (MAP) probability criterion is applied to retrieve soil moisture by inverting a forward backscattering model, and ancillary data such as optical images and land cover maps are also used to identify areas in which the retrieval can be carried out. The well-established semiempirical water cloud model is adopted to correct for the effect of vegetation on SAR data. In anticipation of the use of the algorithm in an operational system, in which the SAR-derived high resolution soil moisture product can be assimilated within weather prediction models or hydrological ones, an uncertainty index is associated to each estimate. The algorithm has been tested on a dataset consisting of ground data gathered for seven years (2003-2010) on an agricultural test site in Northern Italy and radar data provided by the C-band ENVISAT/ASAR instrument. A comparison, performed at field scale, between estimated and in situ soil moisture data has shown that, by discarding the estimates with the largest uncertainty, the correlation coefficient can exceed 0.80 and the root mean square estimation error is less than 0.05 m(3)/m(3). Moreover, the uncertainty index has turned out to be fairly correlated to the actual estimation error
A study on the electromagnetic propagation in various\ud
models of the Martian subsurface is performed with a relevance\ud
to ground penetrating radar (GPR) operating onboard\ud
rover missions. Measurements of the electromagnetic properties of\ud
Mars soil simulants are obtained; on this basis, the attenuation\ud
features of the GPR signals are estimated, including both electric\ud
and magnetic losses. The effect on propagation of inhomogeneities\ud
inside the soil is also taken into account by means of a specific\ud
model with randomly distributed scatterers. The GPR performance\ud
in terms of resolution and maximum penetration depth\ud
is evaluated in the considered scenarios for different operating\ud
frequencies, thus providing a basic information for the design of\ud
systems for future subsurface sounding investigations on Mars
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