Airborne S-band SAR for forest biophysical retrieval in temperate mixed forests of the UK

Ningthoujam, Ramesh K.; Balzter, Heiko; Tansey, Kevin; Morrison, Keith; Johnson, Sarah C.M.; Gerard, France; George, Charles; Malhi, Yadvinder; Burbidge, Geoff; Doody, Sam; Veck, Nick; Llewellyn, Gary M.; Blythe, Thomas; Rodriguez-Veiga, Pedro; van Beijma, Sybrand; Spies, Bernard; Barnes, Chloe; Padilla-Parellada, Marc; Wheeler, James E.M.; Louis, Valentin; Potter, Tom; Edwards-Smith, Alexander; Polo Bermejo, Jaime. 2016 Airborne S-band SAR for forest biophysical retrieval in temperate mixed forests of the UK [in special issue: Remote sensing of vegetation structure and dynamics] Remote Sensing, 8 (7), 609. 22, pp. https://doi.org/10.3390/rs8070609

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Official URL: http://dx.doi.org/10.3390/rs8070609

Abstract/Summary

Radar backscatter from forest canopies is related to forest cover, canopy structure and aboveground biomass (AGB). The S-band frequency (3.1–3.3 GHz) lies between the longer L-band (1–2 GHz) and the shorter C-band (5–6 GHz) and has been insufficiently studied for forest applications due to limited data availability. In anticipation of the British built NovaSAR-S satellite mission, this study evaluates the benefits of polarimetric S-band SAR for forest biophysical properties. To understand the scattering mechanisms in forest canopies at S-band the Michigan Microwave Canopy Scattering (MIMICS-I) radiative transfer model was used. S-band backscatter was found to have high sensitivity to the forest canopy characteristics across all polarisations and incidence angles. This sensitivity originates from ground/trunk interaction as the dominant scattering mechanism related to broadleaved species for co-polarised mode and specific incidence angles. The study was carried out in the temperate mixed forest at Savernake Forest and Wytham Woods in southern England, where airborne S-band SAR imagery and field data are available from the recent AirSAR campaign. Field data from the test sites revealed wide ranges of forest parameters, including average canopy height (6–23 m), diameter at breast-height (7–42 cm), basal area (0.2–56 m2/ha), stem density (20–350 trees/ha) and woody biomass density (31–520 t/ha). S-band backscatter-biomass relationships suggest increasing backscatter sensitivity to forest AGB with least error between 90.63 and 99.39 t/ha and coefficient of determination (r2) between 0.42 and 0.47 for the co- polarised channel at 0.25 ha resolution. The conclusion is that S-band SAR data such as from NovaSAR-S is suitable for monitoring forest aboveground biomass less than 100 t/ha at 25 m resolution in low to medium incidence angle range.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.3390/rs8070609
UKCEH and CEH Sections/Science Areas:	Reynard
ISSN:	2072-4292
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	SAR, S-band SAR, remote sensing, aboveground biomass, MIMICS-I model, Savernake Forest, Wytham Woods
NORA Subject Terms:	Ecology and Environment Electronics, Engineering and Technology
Date made live:	03 Aug 2016 13:19 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/514129

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.3390/rs8070609

UKCEH and CEH Sections/Science Areas:

Reynard

ISSN:

2072-4292

Additional Information. Not used in RCUK Gateway to Research.:

Open Access paper - full text available via Official URL link.

Additional Keywords:

SAR, S-band SAR, remote sensing, aboveground biomass, MIMICS-I model, Savernake Forest, Wytham Woods