Wigneron J.P. auteur aut IRD Chanzy A. auteur aut IRD Kerr Yann auteur aut IRD Lawrence H. auteur aut IRD Shi J. C. auteur aut IRD Escorihuela M. J. auteur aut IRD Mironov V. auteur aut IRD Mialon A. auteur aut IRD Demontoux F. auteur aut IRD Rosnay P. de auteur aut IRD Saleh-Contell K. auteur aut IRD text journalArticle eng In the forward model [L-band microwave emission of the biosphere (L-MEB)] used in the Soil Moisture and Ocean Salinity level-2 retrieval algorithm, modeling of the roughness effects is based on a simple semiempirical approach using three main "roughness" model parameters: H-R, Q(R), and N-R. In many studies, the two parameters Q(R) and N-R are set to zero. However, recent results in the literature showed that this is too approximate to accurately simulate the microwave emission of the rough soil surfaces at L-band. To investigate this, a reanalysis of the PORTOS-93 data set was carried out in this paper, considering a large range of roughness conditions. First, the results confirmed that Q(R) could be set to zero. Second, a refinement of the L-MEB soil model, considering values of N-R for both polarizations (namely, N-RV and N-RH), improved the model accuracy. Furthermore, simple calibrations relating the retrieved values of the roughness model parameters H-R and (N-RH - N-RV) to the standard deviation of the surface height were developed. This new calibration of L-MEB provided a good accuracy (better than 5 K) over a large range of soil roughness and moisture conditions of the PORTOS-93 data set. Conversely, the calibrations of the roughness effects based on the Choudhury approach, which is still widely used, provided unrealistic values of surface emissivities for medium or large roughness conditions. specialized Microwave remote sensing radiometry roughness soil moisture (SM) Soil Moisture and Ocean Salinity (SMOS) soil surface 126 49 4 1177-1189 2011 0196-2892 https://www.documentation.ird.fr/hor/PAR00006830 10.1109/tgrs.2010.2075935 0196-2892 https://www.documentation.ird.fr/hor/PAR00006830 IRD - Base Horizon / Pleins textes 2011-05-02 2017-08-23 PAR00006830 fre