Publications des scientifiques de l'IRD

Lawrence H., Wigneron J. P., Richaume P., Novello N., Grant J., Mialon A., Al Bitar A., Merlin Olivier, Guyon D., Leroux D., Bircher S., Kerr Yann. (2014). Comparison between SMOS Vegetation Optical Depth products and MODIS vegetation indices over crop zones of the USA. Remote Sensing of Environment, 140, p. 396-406. ISSN 0034-4257.

Titre du document
Comparison between SMOS Vegetation Optical Depth products and MODIS vegetation indices over crop zones of the USA
Année de publication
2014
Type de document
Article référencé dans le Web of Science WOS:000329766200033
Auteurs
Lawrence H., Wigneron J. P., Richaume P., Novello N., Grant J., Mialon A., Al Bitar A., Merlin Olivier, Guyon D., Leroux D., Bircher S., Kerr Yann
Source
Remote Sensing of Environment, 2014, 140, p. 396-406 ISSN 0034-4257
The Soil Moisture and Ocean Salinity (SMOS) mission provides multi-angular, dual-polarised brightness temperatures at 1.4 GHz, from which global soil moisture and vegetation optical depth (tau) products are retrieved. This paper presents a study of SMOS' tau product in 2010 and 2011 for crop zones of the USA. Retrieved tau values for 504 crop nodes were compared to optical/IR vegetation indices from the MODES (Moderate Resolution Imaging Spectroradiometer) satellite sensor, including the Normalised Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVE), Leaf Area Index (LAI), and a Normalised Difference Water Index (NOW!) product. tau values were observed to increase during the growing season and decrease during senescence in these areas, as did MODIS vegetation indices. SMOS' tau values generally peaked later than MODES LAI values, with an estimated time difference of about 19 days. A linear regression between tau and the MODIS products was carried out for each node and values of the determination coefficient, R-2, slope, b' and intercept, b ' were found. The average R-2 value varied from 0.32 to 035 for the different vegetation indices. The linear regression between LAI and tau produced an average slope of b' = 0.06, and an average intercept of b ' = 0.14. The effects of crop fraction and dominant crop type were investigated and crop fraction was found to have a low effect on R-2 values. R-2 values appeared to be lower for wheat and hay and higher for corn. b' and b ' values had higher standard deviations for wheat but were generally close to the mean values for corn, soybean and hay.
Plan de classement
Bioclimatologie [072] ; Télédétection [126]
Description Géographique
ETATS UNIS
Localisation
Fonds IRD
Identifiant IRD
PAR00011390
 DOI
Contact