P-BAND TOMOGRAPHY IMAGING OF TROPICAL FOREST AT 6 MHZ BANDWIDTH: CAPABILITIES FOR FOREST BIOMASS AND HEIGHT ESTIMATION

摘要

The objective of this paper is to provide a better understandingrnof BIOMASS capabilities concerning the estimation of forestrnbiomass and height by means of tomographic techniques. Thernanalysis presented in this paper is carried out on airborne datarnacquired by ONERA over the site of Paracou, French Guiana,rnduring the ESA campaign TropiSAR. Those data have beenrnreprocessed in order to generate a new data stack consistentrnwith BIOMASS as for bandwidth and carrier frequency. Torndo this, two different processing approaches have been considered.rnOne consisted in degrading the resolution of airbornerndata through linear filtering. The other approach consisted inrnrecovering the 3D distribution of the scatterers at high resolution,rnwhich was then reprojected onto BIOMASS geometryrnaccounting for the available radiofrequency bandwidth.rnThe connection to forest biomass has been examined in bothrncases, by investigating the correlation between backscatteredrnpower at different forest heights and above ground biomassrn(AGB) values from in-situ data. As expected, the reductionrnof system bandwidth to 6 MHz resulted in significant verticalrnresolution losses compared to the original airborne data (125rnMHz). Nevertheless, it was possible to retrieve forest heightrnto within an accuracy of less than 4 m, whereas the backscatteredrnpower at volume height (say 30 m above the ground)rnexhibited a correlation higher than 0.8 with in-situ data andrnno bias phenomena over AGB values ranging from 250 t/harnto 450 t/ha 1.