A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...
A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...
A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...
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Regrowth Biomass Estim<strong>at</strong>ion in <strong>the</strong> <strong>Amazon</strong>using JERS/RADARSAT SAR CompositesLeland Pierce, Pan Liang, M. Craig DobsonRadi<strong>at</strong>ion Labor<strong>at</strong>oryDepartment of Electrical Engineering and Computer ScienceUniversity of MichiganAnn Arbor, MI 48109-2122Phone: (734) 763-3157,FAX: (734) 647-2106E-mail: lep@eecs.umich.eduAbstractSyn<strong>the</strong>tic Aperture Radar is known to have a response th<strong>at</strong> is directly rel<strong>at</strong>ed to<strong>the</strong> amount of living m<strong>at</strong>erial th<strong>at</strong> it interacts <strong>with</strong>. It is thisproperty th<strong>at</strong> our research seeks to exploit in order to better understand Carbon <strong>Dynamics</strong>in <strong>the</strong> <strong>Amazon</strong>. Complic<strong>at</strong>ing factors include adependency on veget<strong>at</strong>ion moisture, veget<strong>at</strong>ion species, and veget<strong>at</strong>ion density.Geometry, due to species diversity, causes subtledifferences th<strong>at</strong> can be exploited for monocultures, but in <strong>the</strong> case of <strong>the</strong> <strong>Amazon</strong> is asource of noise. The veget<strong>at</strong>ion density causes <strong>the</strong>radar response to s<strong>at</strong>ur<strong>at</strong>e such th<strong>at</strong> veget<strong>at</strong>ion th<strong>at</strong> is more dense than some threshhold isindistinguishable from each o<strong>the</strong>r. Wh<strong>at</strong> thismeans for this study is th<strong>at</strong> <strong>the</strong> undisturbed forest will likely fall in this s<strong>at</strong>ur<strong>at</strong>ed region,and hence radar cannot be used to assess <strong>the</strong>biomass of those regions, beyond classifying it as large. However, <strong>the</strong> areas of regrowthare likely to have a low enough biomass during<strong>the</strong> first 10 years of regrowth to be accur<strong>at</strong>ely assessed using radar. It is in this area wherewe expect our study to be useful.Our efforts involve obtaining appropri<strong>at</strong>e pairs of radar images from several sitesand for both seasons. These d<strong>at</strong>a are <strong>the</strong>n orthorectifiedusing a map and elev<strong>at</strong>ion d<strong>at</strong>a of <strong>the</strong> area. Once orthorectified, <strong>the</strong> d<strong>at</strong>a overlay oneano<strong>the</strong>r sufficiently accur<strong>at</strong>ely to allow accur<strong>at</strong>ecalibr<strong>at</strong>ion and incidence angle correction. Without <strong>the</strong>se corrections <strong>the</strong> terrain effectswould make our analysis too noisy and inaccur<strong>at</strong>eto be useful. The seasonality of <strong>the</strong> d<strong>at</strong>a is used to deal <strong>with</strong> <strong>the</strong> moisture sensitivity of <strong>the</strong>d<strong>at</strong>a, and <strong>the</strong> different frequency d<strong>at</strong>a is used tohelp classify <strong>the</strong> d<strong>at</strong>a into several classes for use in class-specific biomass estim<strong>at</strong>es.We have chosen <strong>the</strong> following sites in Brazil for our study: Manaus, Rio Branco,Tapajos, Rondonia. In order to classify, as a first step tobiomass estim<strong>at</strong>ion, we use <strong>the</strong> JERS (L-band) and RADARSAT (C-band) d<strong>at</strong>a <strong>at</strong> <strong>the</strong> 2different seasons to cre<strong>at</strong>e a 4-channel
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