Comarison between the microwave emissivity and backscatter coefficient of crops

Modelling and Validation of Combined Active and Passive Microwave Remote Sensing of Agricultural Vegetation at L-Band

“…Emissivity (e q ) related to brightness temperature through the physical temperature of the object, is calculated by integrating the bistatic scattering coefficients over the hemispherical solid angle as given in Equation (1) [17,18] e q = 1 − 1 4π…”

“…In many studies, the analyses for radiometer and radar data were based on different models: the tau-omega model was used as a passive model [15,16], while an empirical model [15] or the watercloud model [16] was used as an active model. Ferrazzoli et al [17] and Guerriero et al [18] discussed the interrelations between emission and scattering for vegetated surfaces. In [17,18], the emissivity and backscattering coefficient were computed in a unified approach using the radiative transfer theory and the "matrix doubling" algorithm.…”

“…Ferrazzoli et al [17] and Guerriero et al [18] discussed the interrelations between emission and scattering for vegetated surfaces. In [17,18], the emissivity and backscattering coefficient were computed in a unified approach using the radiative transfer theory and the "matrix doubling" algorithm. Chauhan et al [19] used DBA to compute both the backscattering coefficient and brightness temperature for corn.…”

Microwave remote sensing for soil moisture monitoring: synergy of active and passive observations and validation of retrieved products

“…A common method to combine active and passive data entails extracting information on roughness and vegetation properties from the data acquired by active sensors and then using this information to support the soil moisture retrieval from passive data (Chauhan 1997;Lee and Anagnostou 2004;O'Neill et al 1996;Saatchi et al 1995a;Theis et al 1986;Wen et al 2003;Zhan et al 2006). By contrast, the complementary information provided by active and passive microwave observations has only been exploited in a few studies to constrain a single discrete scattering model that is capable of simulating both the emissivity and the backscattering coefficient (Chauhan and Levine 1994;Ferrazzoli et al 1989;Saatchi et al 1994). …”

“…Only few studies combined the complementary information provided by active and passive microwave observations through the application of discrete scattering models that are capable of simulating both emissivity and backscattering, given a detailed description of soil and vegetation (Chauhan and Levine 1994;Ferrazzoli et al 1989;Saatchi et al 1994). More recently, Colliander and Xu (2013) and Guerriero et al (2012) used this approach to investigate the theoretical basis of indices that combine emissivity and backscattering for satellite applications.…”