Comparison of X and C band satellite radar images to characterize irrigated agricultural fields

Abstract

Despite the effect of water content on radar backscattering is well known, isolating the contributions from soil, vegetation, and vegetation superficial water content (wetness) is still challenging. This work aim to characterize the backscatter response over maize crops in the Argentine pampas with differing soil and vegetation water content and wetness considering multipolarimetric X and C band radar. Two images (RADARSAT-2 and TerraSAR-X) were acquired with a 20' time difference over the same study area. Simultaneously with acquisitions, field measurements of superficial soil moisture, dry and wet vegetation biomass and height were performed over irrigated and non irrigated and standing and non emerged crop fields. Soil moisture showed high r2for backscatter and several polarimetric decompositions approaches. On the contrary low correlation was found for maize crop growth parameters. X and C band radar indexes seem to saturate at low maize biomass values but could be associated to superficial crop wetness.