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This study investigates the potentialities offered by active and passive simultaneous acquisitions at L band for monitoring of soil moisture in forested areas. Airborne data, acquired over the moderately dense Gillenbah forest in the framework of SMAPEx-3 project, have been analyzed to derive the sensitivity of emissivity and backscattering coefficient to soil moisture variations during the campaign,...
This paper shows results obtained by using the SMOS retrieval algorithm over forests at the prototype level. In each SMOS node, the algorithm estimates the soil moisture and the vegetation optical depth. For the optical depth, values retrieved in July 2011 in all forests of the American continent are shown and compared against forest height estimated by GLAS LIDAR of ICESAT satellite. A significant...
This paper introduces a revised version of the forward model adopted by the SMOS SM algorithm to represent forest emission. The forward model is tested against multitemporal measurements of brightness temperature obtained over a US forest. World map of retrieved optical depth and soil moisture are also presented.
The Argentine pampas is a wide plain with more than 40 million ha of land suitable for cattle rearing and cropping. Several watersheds with different hydrological characteristics and agricultural practices cover this huge region. Last decades have shown an increase in extreme conditions (droughts and floods) and the need for improving prediction models. This work is part of an ongoing project related...
Using Microwave Remote Sensing techniques represents an important contribution to forecasting skill of regional scale flooding events occurring over time scales of days to weeks. Furthermore, it could add skills to predictions of flood peak timing and magnitude, besides climatic change predictions. In this paper, the temporal trends of Polarization Ratio at some AMSR-E bands (C, X, and Ka) will be...
Over the past two decades, orbital passive microwave systems have proven to be sensitive to flood condition in large floodplains. This sensitivity is rooted in the well differentiated emission properties of calm water with respect to non-flooded land of any kind. In this paper, AMSR-E observations of an herbaceous wetland area on the Paraná River sub-basin were analyzed during the 2009-10 timeframe...
The synergy between active and passive observations is becoming an attractive subject, particularly stimulated by the SMAP program. This paper investigates the potential advantage of the synergy related to the decoupling between the influence of soil and vegetation variables. If both the emissivity e and the backscattering coefficient σ° are available, the ratio between σ° and the reflectivity 1-e...
This work analyzes AMSR-E signatures collected in two sites of La Plata basin, in South America. Within the wide Chaco forest, an area close to Las Lomitas meteorological station was selected. Here the forest is uniform, but not very dense, with biomass values in the range 70-120 t/ha. After strong rain events, appreciable variations of polarization index at C and X band were observed. As expected,...
This paper analyzes the L-band radiometric signatures collected over a Eucalyptus forest with moderate biomass, and compares the results with simulations of a theoretical model and a simple model. Due to the limited biomass and the thin litter layer, some sensitivity to variations of soil moisture is observed. Simulations of the theoretical model are in general agreement with measurements, with an...
This paper reviews the steps of a work aimed at modeling forest emission at L band. The first step consists in the development of a discrete multiple scattering model, which was tested against experimental data collected in a variety of forest types and conditions. The main tests are summarized. The approximate relationships adopted to generate a complete input data set are described. Then, the physical...
This paper shows model simulations of forest emissivity at L-band and at global scale. The electromagnetic model developed at Tor Vergata University has been combined with information available from forest literature. Using allometric equations and auxiliary information, the geometric and dielectric inputs required by the model have been related to global variables available at large scale, such as...
This paper describes a microwave model which simulates the emissivity of forests, including litter effects. Detailed input data about forest geometry are obtained by direct measurements and/or by allometric equations. Model outputs have been compared with multifrequency measurements carried out over five broadleaf forests in Italy. Fundamental information about forest properties was available. A general...
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