Estimation of the L-Band effective scattering albedo of tropical forests using SMOS observations

This letter aims to estimate the effective scattering albedo ( $\omega _{p}$ ) over the tropical forests using L-band (1.4 GHz) microwave remote sensing. It is carried out using Soil Moisture and Ocean Salinity (SMOS) mission data over five years (2011–2015). We find similar values of $\omega _{p}$ computed over the Congo and Amazon forests. The $\omega _{p }$ values depend slightly on the polarization. The values of $\omega _{p }$ at H-polarization and at 52° ± 5° (40° ± 5°) of incidence angle are within the range 0.064 – 0.069 ± 0.01 (0.061 – 0.067 ± 0.012). At V-polarization, the values of $\omega _{p }$ are slightly lower (0.060 – 0.061 ± 0.013 at 52° ± 5° of incidence angle and 0.052 – 0.055 ± 0.013 at 40° ± 5° of incidence angle). These findings should contribute to a better calibration of the value of $\omega _{p }$ over the tropical forests in both the SMOS and SM active and passive retrieval algorithms, leading to increase the SM retrieval accuracy over heterogeneous pixels.