Can SMOS Data be Used Directly on the 15-km Discrete Global Grid?

摘要: Radiometric observations from the Soil Moisture and Ocean Salinity (SMOS) mission are processed to Level 1 brightness temperature (Tb) with ~ 42-km spatial resolution reported on a 15-km hexagonal Discrete Global Grid (DGG). While these data should be used at which oversampled DGG represents, this paper poses question of whether they can directly without undertaking downscaling or implementing multiscale-type procedures when in assimilation. To assess error associated using SMOS Tb resolution, study employs 1-km Australian Airborne Cal/Val Experiment for (AACES). The compares SMOS-like derived AACES values actually observed DGG. These subsequently interpolated regular 12-km model grid compared actual that resolution. results show average root mean square differences between 15- footprints 4.5 K 3.9 horizontal (H) vertical (V) polarizations, respectively, maximum difference 12.9 K. errors interpolating onto were estimated 3.3 H polarization 2.9 V under assumption independence 4.0 3.6 interpolation process alone. An evaluation assumed found no correlation vegetation based leaf area index only slight variance topographic roughness. Given noise currently exists 42 km, equivalent further degrading quality.