Title :
About the Optimal Grid for SMOS Level 1C and Level 2 Products
Author :
Talone, M. ; Portabella, M. ; Martinez, J. ; Gonzalez-Gambau, V.
Author_Institution :
Soil Moisture & Ocean Salinity, Barcelona Expert Centre, Barcelona, Spain
Abstract :
Remotely sensed measurements acquired by the European Space Agency´s Soil Moisture and Ocean Salinity (SMOS) satellite are processed in a uniform equal-area grid, the Icosahedral Snyder Equal Area (ISEA) 4H9. Brightness temperature measurements are projected onto that grid (the so-called Level 1C), as well as sea surface salinity and soil moisture estimates (Level 2). The ISEA grid has been chosen for its characteristics of equal area and almost uniform intercell spacing. Nevertheless, when considering the SMOS viewing geometry, the measurement footprint size, and the processing applied to those measurements, this choice may be revisited. With this objective, the ISEA 4H9 grid is compared to other equal-area grids with different sizes and orientations with respect to the satellite track. The best configuration resulted to be a 25-km-width grid symmetrical with respect to satellite track. This grid appeared to be better suited for improving SMOS Level 2 retrieval algorithms as well as to serve as input for higher level data production, since it best accounts for the instrument´s viewing geometry and substantially reduces the correlation between adjacent grid cells.
Keywords :
ocean temperature; oceanographic techniques; remote sensing; soil; temperature measurement; ISEA 4H9 grid; SMOS level 1C; SMOS level 2 products; SMOS level 2 retrieval algorithm; SMOS viewing geometry; adjacent grid cells; brightness temperature measurement; higher level data production; icosahedral Snyder equal area; instrument viewing geometry; measurement footprint size; optimal grid; remote sensing measurement; satellite track; sea surface salinity; soil moisture and ocean salinity; soil moisture estimation; uniform intercell spacing; Antenna measurements; Extraterrestrial measurements; Instruments; Remote sensing; Satellite broadcasting; Satellites; Sea measurements; Grid; Icosahedral Snyder Equal Area (ISEA); Soil Moisture and Ocean Salinity (SMOS);
Journal_Title :
Geoscience and Remote Sensing Letters, IEEE
DOI :
10.1109/LGRS.2015.2416920