Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Forest Height Estimation with X- Band InSAR: Phase Centre Location versus RVoGFlorian Kugler, Irena Hajnsek, Seung-Kuk Lee & Konstantinos PapathanassiouGerman Aerospace Center (DLR)Microwaves and Radar Institute (HR)
2Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Lineout
Test Sites:
FinSAR CampaignINDREX II: MawasKobernausser WaldTempoSAR Campaign: TraunsteinBiosar II Campaign: Krycklan
Issues:
Phase Centre HeightForest HeightExtinctionComparision/Combination of different baselines
3Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
0
0
0
0
Height Validation X band vs L band boreal forest Southern Finnland
X band validated against Scatterometer
4Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
• Peat swamp forest
• Forest Height: 15m – 25m
• Biomass around 100-350t/ha
• Uniform structure
• Open canopy
• Flat Topography
INDREX-II: Mawas Test Site
5Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Mawas X band Validation with Lidar
Lidar Strip was divided into100 equal samples
Phase Center Height
Inversion I using φ0 fromunvegetatedarea
Inversion IIusing σ0.3 d B/m(mean ExtinctionInversion I)
Lidar StripReference Height: Top Canopy height 100(100 tallest tree per hectar)
6Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Test Site Kobernausser Wald
Kobernausser Wald: • Upper Austria• Temperate managed forest• Hilly Topography• Inhomogenous Composition• Stands of different Heights
from 4 to 35m and different age and differentbiomass
• Domintated by Coniferous trees• Canopy mainly closed
7Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
KobernausserWaldDataset
X Band Polarisation VVSingle PassBaseline :0.8m
Lidar StripInSAR Coherence Amplitude Image
8Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Kobernausser Wald X band Validation with LidarPhase Center
Lidarh100
InversionHeights
InversionHeights
Phase Center
Reference Height: Top Canopy height h100(100 tallest tree per hectar)
Inversion Iusing φ0 from Lidar
9Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Kobernausser Wald X band Extinction Estimation
Extinctionfrom heightestimation
Extinctionfrom LidarInversion
2dB/m
1dB/m
0dB/m
Stand:Mean Extinction from
Inversion: 0.79dB/mMean Extinction from
Lidar h100: 0.82dB/mMean Ground to Volume Ratio: 0.05
Mean forest Height, 25.7m
10Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Traunstein Test Site
Forest type Temperate Topography Moderate slopes
25 ~ 35mN. Spruce, E. Beech, White Fir
40 ~ 450 t/ha
HeightSpeciesBiomass
11Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Temposar dataFull Baseline Half Baseline
Coherence 0 to 1 Coherence 0 to 1Phase -π to π Phase -π to π
12Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Estimated Forest Heights Full Baseline
Inversion height Scattering Centre40m
20m
0m
Inversion using external ground phase
Tends to underestimate high forests
Scattering Centre clearly below estimated forest height
13Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Estimated Forest Heights Half Baseline
40m
20m
0m
Inversion height Scattering Centre
Inversion using external ground phaseTends to underestimate high forests
Scattering Centre clearly below estimated forest height
Good Inversion Performance in near range
14Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Estimated Extinction Full Baseline Half Baseline
Estimated with Reference Height
Estimated with Reference Height
Estimated from Height Inversion
Estimated from Height Inversion
15Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Lidar Tree Vegetation height
40m
20m
0m
16Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Biosar II Test Site Krycklan Sweden
Krycklan forest:Location:• middle Sweden• boreal forest• high topography
Composition• stands of different Height• maximum forest height: ~ 30m• mean forest height: 17m
• stands of different age and different biomass
• domintated by Coniferoustrees
17Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Biosar data Full Baseline Half Baseline
Coherence 0 to 1 Coherence 0 to 1Phase -π to π Phase -π to π
18Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Biosar dual Baseline Inversion results
Extinction Forest Height
2dB/m
1dB/m
0dB/m
40m
20m
0m
19Microwaves and Radar Institute / Microwaves and Radar Institute / PolPol -- InSAR Research Group InSAR Research Group
Summary Forest Height Inversion using X-Band
Forest height estimation using X band provides prommissing results fortropical as well as for temperate & boreal forest conditiions
X band Phase Center is significantly lower than Pol-InSAR forest height
Especially in less dense forest conditions as can be found in boreal forests X band could provide good results
Limitting factor for X band is forest density
If there is an external DEM available we can go even further
The results show a high potential of TanDEMX for forest height estimation in certain ecosystems, even if Quad or Dual Pol data are available