Mialon A., Wigneron J.P., De Rosnay P., Escorihuela M.J., Kerr Yann. (2012). Evaluating the l-meb model from long-term microwave measurements over a rough field, SMOSREX 2006. IEEE Transactions on Geoscience and Remote Sensing, 50 (5), p. 1458-1467. ISSN 0196-2892.
Titre du document
Evaluating the l-meb model from long-term microwave measurements over a rough field, SMOSREX 2006
Mialon A., Wigneron J.P., De Rosnay P., Escorihuela M.J., Kerr Yann
Source
IEEE Transactions on Geoscience and Remote Sensing, 2012,
50 (5), p. 1458-1467 ISSN 0196-2892
The present paper analyzes the effects of roughness on the surface emission at L-band based on observations acquired during a long-term experiment. At the Surface Monitoring of the Soil Reservoir Experiment site near Toulouse, France, a bare soil was plowed and monitored over more than a year by means of an L-band radiometer, profile soil moisture and temperature sensors, and a local weather station, accompanied by 12 roughness campaigns. The aims of this paper are the following: 1) to present this unique database and 2) to use this data set to investigate the semiempirical parameters for the roughness in L-band Microwave Emission of the Biosphere, which is the forward model used in the Soil Moisture and Ocean Salinity soil moisture retrieval algorithm. In particular, we studied the link between these semiempirical parameters and the soil roughness characteristics expressed in terms of standard deviation of surface height (sigma) and the correlation length (LC). The data set verifies that roughness effects decrease the sensitivity of surface emission to soil moisture, an effect which is most pronounced at high incidence angles and soil moisture and at horizontal polarization. Contradictory to previous studies, the semiempirical parameter Qr was not found to be equal to 0 for rough conditions. A linear relationship between the semiempirical parameters N and sigma was established, while N-H and N-V appeared to be lower for a rough (N-H similar to 0.59 and N-V similar to -0.3) than for a quasi-smooth surface. This paper reveals the complexity of roughness effects and demonstrates the great value of a sound long-term data set of rough L-band surface emissions to improve our understanding on the matter.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Bioclimatologie [072]
;
Télédétection [126]
