consistent forest change maps 1981 2000 from the avhrr ...€¦ · lc-cci 2000 1990 lc map 1980 –...
TRANSCRIPT
Consistent Forest Change Maps 1981 –
2000 from the AVHRR Time Series
Case Studies for South America and Indonesia
23-07-15 J. Eberenz1, M. Herold1, J. Verbesselt1, A. Wijaya2,
E. Linquist3, P. Defourny4, H. Gibbs5, O. Arino6
1) Wageningen University, 2) CIFOR, 3) FAO, 4) Université Catholique de Louvain, 5) University of Wisconsin , 6) ESA
ESA Climate Change Initiative
Land Cover Consortium
Motivation
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MODIS / SPOT VGT -
Landsat -
AVHRR -
Satellite Series
Global LC maps
AVHRR data
Daily global coverage 1982 – 2011
4 Channels (R, NIR, 2xIR)
Many known issues for LC mapping
Different pre-processed datasets (GIMMS, LTDR)
3
Stable Forest
Sample
Stable
Non-Forest
Deforested
1990 - 2000
Training Data: FRA Remote Sensing Survey
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Example FRA RSS tile data: % Forest 1990: 0.90 % Forest loss 90 – 00: 0.16
Methods: Exploration
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Dataset
LTDR V4
GIMMS V3
Sub setting & aggregation
Cloud flags (LTDR)
Season:
• dry Season
• Full year
Viewing Angle:
• Nadir ± 22
• All data
Monthly aggregation (max NDVI)
Time series metrics
Statistics
•Full ts
•Segments
•Yearly
Linear trends
•Full ts
•sgements
•Yearly
structural breaks, trends
(BFAST)
Classification
Classifier or regression +
threshold
Prediction Model:
•Random Forest
•ctree
•Gen. boosted regression
•SVM
Response
• FC
• FCC
Methods
6
30 yr AVHRR Timeseries
Metrics (full time series & segments) Quantiles Linear trend
Random Forest
regression
Training data: FRA RSS
Def 1990-2000
Predicted Deforestation
LC-CCI 2000
1990 LC map 1980 – 1990
AVHRR model (De Fries 2004)
1980 LC map
Calibration
Results: Pan-Tropical prediction
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Results: South America
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Training area Ref. data Response OA PA NF UA NF PA Def UA Def
Global Prodes Forest Loss (%) 1990-2000 0.881 0.911 0.901 0.830 0.846
Results: South America
Reduced training data
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• Effects of reducing training data
• show requirements for extending training dataset back to 1980s
Cross validation R2
Accuracy Assessment Results
Results: Indonesia
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Training area Ref. data Response OA PA NF UA NF PA Def UA Def
Area Def
Area NF
Global Indonesia Forest Loss 90-00 (%)
0.802 0.903 0.871 0.202 0.258 73% 104 %
Discussion
Good results for Brazil
Pan-tropical pattern look reasonable
Indonesia issues:
LC of non forest area: mosaic cropland / tree cover
Geolocation of AVHRR data
Quality of reference data
Orbital drift
Training data for 1980s requires effort
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