[en] The attenuation of microwave emissions through the canopy is quantified by the vegetation optical depth (VOD), which is related to the amount of water, the biomass and the structure of vegetation. To provide microwave-derived plant water estimates, one must account for biomass/structure contributions in order to extract the water component from the VOD. This study uses Aquarius scatterometer data to build an L-band global seasonality of vegetation volume fraction (d), representative of biomass/structure dynamics. The dynamic range of d is adapted for its application in a gravimetric moisture (Mg) retrieval model. Results show that d ranging from 0 to 3.35·10-4 is needed for modelling physically reasonable Mg values. The global average of d shows consistent spatial patterns across vegetation distributions, and d seasonality is coherent with the phenology of the studied vegetation types. These findings enable the separation of information on vegetation water and biomass/structure inherent within VOD.
Jagdhuber, Thomas; German Aerospace Center, Microwaves and Radar Institute, Weßling, Germany ; University of Augsburg, Institute of Geography, Augsburg, Germany
Entekhabi, Dara; Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, United States
Jonard, François ; Université de Liège - ULiège > Département de géographie ; Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, Germany
Fluhrer, Anke; German Aerospace Center, Microwaves and Radar Institute, Weßling, Germany ; University of Augsburg, Institute of Geography, Augsburg, Germany
Feldman, Andrew; Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, United States
The Institute of Electrical and Electronics Engineers Geoscience and Remote Sensing Society (GRSS)
Funding text :
This work was supported by “la Caixa” Foundation (ID 100010434), under agreement LCF/PR/MIT19/51840001 (MIT-Spain Seed Fund), and by the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund (ERDF, EU) through projects ESP2017-89463-C3-3-R, RTI2018-096765-A-100, CAS19/00264 and MDM-2016-0600. Also, the authors are grateful to MIT for supporting this research with the MIT-Germany Seed Fund (D. Entekhabi, T. Jagdhuber).
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