Monitoring soil moisture in the Pampas plains of Argentina using spaceborne radiometers and SAR: Evaluation of products

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 to mapping and monitoring flooding events in La Plata Basin using spaceborne instruments, including SACD/Aquarius. Measurements of AMSR-E, SMOS, and ENVISAT/ASAR over several locations of the Pampas were analyzed. Precipitations, NDVI, PR (polarization ratios for L, C and X band), as well as both SMOS and AMSR-E soil moisture (SM) products trends were evaluated. The sensitivity and the correlation of the different trends were studied. When comparing between frequencies, the measured PRs present trends which agree with theoretical results. SMOS PRs present both higher sensitivity and dynamic range. SMOS optical depth is also shown. Finally Envisat ASAR images collected during the period analyzed are discussed.