IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
SOIL MOISTURE EFFECTS ON MULTIFREQUENCY MICROWAVE SIGNALS OF THE BERMEJO RIVER BASIN
Autor/es:
CRISTINA VITTUCCI; LEILA GUERRIERO; RACHID RAHMOUNE; FRANCISCO MATIAS GRINGS; VERONICA BARRAZA
Lugar:
Roma
Reunión:
Congreso; Microwave Radiometry and Remote Sensing of the Environment 2012; 2012
Institución organizadora:
IEEE
Resumen:
The purpose of this work is to investigate the capability of AMSR-E and SMOS in monitoring soil moisture and flood events in the South American Bermejo Basin using temporal trends of the polarization indexes (ratio) at L, C, X and Ka bands. The Bermejo River Basin extends over some 123,000 Km2, originating in the Andes Mountains of northwestern Argentina and southern Bolivia. The river, which flows some 1,300 km, links two major geographic features: the Andean Cordillera and the Paraguay-Paranà Rivers. In the area of the Bermejo river, natural disasters have severely affected both rural and urban infrastructure and economic production systems (mainly crop and cattle areas). Microwave Remote Sensing techniques represent a key contribution to forecasting skill of regional scale flooding events occurring over time scales of days to weeks. Available space-borne data collected over the two years of SMOS activity have been analyzed, together with the corresponding AMSR-E signatures for the period between 2010 and 2011. Here we have considered areas in which the river basin is included and close to meteorological stations. We have extracted Brightness Temperatures at vertical and horizontal polarizations for C, X, Ka AMSR bands at all resolutions, and vertical and horizontal emissivity have been also considered for SMOS measurements. In order to eliminate the dependence on surface temperature, we extracted the average Polarization Index (PI). The time trend of all of the above quantities has been studied and correlated with soil moisture data provided by ECMWF and with ground measurements. Indeed, ground truth data concerning rainfall and water level measurements (available from the nearby meteo stations) have been used, and a general correlation with variations of the Polarization Index has been found. After intense flood events and local rainfalls, a clear increase of PI is observed, followed by a gradual return to its original value. The time patterns are typical of a response to inundation, or strong increase of soil moisture. The effects are observed at every frequency but, as expected, the better dynamic ranges are achieved at the lower frequencies. For some events, the correlation is limited by the high spatial variability. In addition we have extracted for the whole Bermejo Basin area PI maps immediately before, during, and after a flood event event, in order to understand the spatial properties.