Showing papers by "Brian Brisco published in 1991"

Tillage effects on the radar backscattering coefficient of grain stubble fields

Abstract: The effect of different tillage on the microwave backscatter from grain stubble plots was investigated as a function of frequency, polarization, row direction and type of tillage implement. The Canada Centre for Remote Sensing (CCRS) truck-mounted FM-CW scatterometer was used to make the radar backscattering coefficient (σ°) measurements. Factorial analysis found the effects of row direction to be as significant as the differences between tillage implements on σ° of like polarized data. The cross-polarized data were less sensitive to row direction effects. There were no significant differences betwen the HH and VV polarizations at any frequency investigated. An airborne SAR image of an area close to the experiment site was qualitatively used to demonstrate the effects of tillage and row direction. The scatterometer results and airborne SAR interpretations indicate the necessity of accounting for row direction, as well as surface roughness, when using SAR data for soil mapping applications. Techni...

Applying the Mimics Backscattering Model in an Agricultural Context

Abstract: RESUMECet article presente les resultats preliminaires obtenus pour des applications en agriculture avec le modele MIMICS elabore a l'Universite de Michigan. Ce modele possede deux composantes principales, a savoir une composante sol, qui decrit la retrodiffusion produite par le sol, et une composante couvert forestier, qui modelise la retrodiffusion produite par la vegetation. Le modele MIMICS est un outil de recherche qui n'a pas fait l'objet d'une etude approfondie a partir de donnees experimentales. Dans le cas de champs agricoles, la retrodiffusion produite par le sol constitue une part importante de la retrodiffusion totale. Aux fins de la presente etude, nous avons examine les possibilites offertes par le modele dans le cas d'un sol nu, ce qui nous a permis de determiner les parametres d'entree de la composante sol avant de proceder a l'analyse sur des champs agricoles. Le comportement du coefficient σo dans les bandes L et C est presente pour plusieurs parametres de la composante sol. En outre, la...