A Comparison of P- and L-Band PolInSAR 3-D Forest Structure Estimates: A Study Case in the Traunstein Forest

Transcription

1 A Comparison of P- and L-Band PolInSAR 3-D Forest Structure Estimates: A Study Case in the Traunstein Forest M. Pardini, M. Tello Alonso, A. Toraño Caicoya, M. Heym 2, K. Papathanassiou Microwaves and Radar Institute (DLR-HR) German Aerospace Center (DLR) 2 Technische Universität München (TUM)

2 The Traunstein forest (TempoSAR 09 campaign, DLR E-SAR) Bürgerwald Traunstein Temperate mixed managed forest Height Range (H00): 0-40m Biomass Range: 40 ~ 450 t/ha Moderate Slopes April 27, 28 May 5,, 2 October 28 November 5 # of acquisition: 4 to 7 each flight Max k z : 0.3 to mid range

3 Forest vertical reflectivity: L- vs 0 Intensity Lidar H00 Lidar DTM HH HH HH+ HH- HH+ HH- Slant range (~Km) Slant range (~Km) Traunstein site (Germany), 4 tracks L / 5 tracks P, E-SAR, Capon

4 Forest vertical reflectivity: L- vs 0 Intensity Lidar H00 Lidar DTM HH HH HH+ HH- HH+ HH- Slant range (~Km) Slant range (~Km) Traunstein site (Germany), 4 tracks L / 5 tracks P, E-SAR, Capon

5 Ground / Volume separation Dirac-δ ground after topography compensation z Baseline 2 Baseline Reflectivity profile (2-layer+RVoG) Baseline K Volume Ground Multibaseline-polarimetric cov. matrix Algebraic solution based on SVD Any ambiguity can be removed by assuming a rank-deficient ground (Dirac-δ hyp.) + knowledge of the ground height Maximum ground / volume coherences Ground / volume search segments Ground / volume only coherences after ambiguity solution [Tebaldini, 200 Ferro-Famil, et al. 203]

6 Ground / Volume separation Ground Volume HH Ground Volume HH

7 Ground-to-Volume power ratios (db) (db) L, HH P, HH 0 Ground-to-volume ratio, HH Growth stages (db) LIDAR H00-0dB G2V power ratio L, P, 0dB 0 Ground-to-volume ratio, 5 0 0m (db)

8 Min / max Ground-to-Volume power ratios Growth stages L, min P, min 7.5dB 4.5dB LIDAR H00-0dB G2V power ratio L, max P, max 0dB Ground-to-volume ratio, db 0m 45

9 Ground topography & Forest height Ground topography Forest height SAR Height, m SAR Height, m Phase center of the ground-only Fourier profile Model-based inversion from volume-only coherences (exp. profile) 50 LiDAR RMSE = 2m H00 40 ρ = LiDAR H00, m RMSE = 2.5m ρ = LiDAR H00, m -5m Est. error 5 0m 50

10 [-] [-] Vertical structure discrimination 0 MB Entropy MB Entropy Calculated from the eigenvalues λ of the MB covariance matrix 3 Normalized histogram 2 K: # of images Growth stages Volume only MB Entropy, H Normalized histogram Young Growing Mature Regen. Plenter Volume only MB Entropy, H 20m x 20m multilook (slant) for both P- / L- band

11 Temporal variations at (Capon) HH HH Slant range (~0.6Km) Slant range (~0.6Km) Slant range (~0.6Km) HH HH Slant range (~0.6Km) Slant range (~0.6Km) Slant range (~0.6Km)

12 Summary provides: Increased sensitivity to larger forest structures relevant to forest biomass Reduced attenuation through the vegetation: higher visibility of lower vegetation layers as well as of the underlying ground provides: scattering on smaller forest structures (branches,..), thus sensitivity to forest structures of ecological relevance increased attenuation through the vegetation that provides a reduced visibility of the underlying ground shows a reduced temporal stability Increased sensitivity to vegetation / ground moisture conditions and seasonality Potentially higher amount of information but at the same time it may increase interpretation ambiguities: to be discussed with respect to specific applications and robust information extraction

13 A Comparison of P- and L-Band PolInSAR 3-D Forest Structure Estimates: A Study Case in the Traunstein Forest M. Pardini, M. Tello Alonso, A. Toraño Caicoya, M. Heym 2, K. Papathanassiou Microwaves and Radar Institute (DLR-HR) German Aerospace Center (DLR) 2 Technische Universität München (TUM)