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Southeast Asia

GLC 2000 Project Results from Southeast Asia Stibig H-J., Upik R.W., Beuchle R., Mubareka, S., Hildanus, Giri C. Southeast Asia. Continental Southeast Asia: Monsoon Climate Wet Season: May – November Dry Season: December – April Variable conidtions over Vietnam

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Southeast Asia

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  1. GLC 2000 ProjectResults from Southeast Asia Stibig H-J., Upik R.W., Beuchle R., Mubareka, S., Hildanus, Giri C.

  2. Southeast Asia Continental Southeast Asia: Monsoon Climate Wet Season: May – November Dry Season: December – April Variable conidtions over Vietnam Mix of evergreen and seasonal / dry vegetation Reasonably cloud-free images : end Dec – middle of March Insular Southeast Asia: Moist tropical climateall year: short ‘less humid’ periods (hemisphere, spec. island, spec. loc.) Evergreen vegetation No cloud & haze free images all year

  3. Example for good quality 10 - day mosaic: February 1999

  4. Example: Typical 10 - day mosaic from May 2000

  5. Main challenges for mosaic generation and mapping • Continental Southeast Asia • obtain good differentiation between seasonal and evergreen vegetation formations • to cope with the mixed pattern of cropland, shrub, re-growth, & forest (active and abandoned shifting cultivation) • get sufficient haze and cloud free data over Vietnam • Insular Southeast Asia • cope with persistent haze and cloud cover

  6. Test with S1 Data from the year 2000 (S. Mubareka) • Continental SE-Asia: S1-images for Jan-Feb 2000 • Insular SE-Asia: S1-Images full year 2000 • SWIR line error mask • Cloud mask threshold: blue < 720; SWIR < 320 • Filter for angle Φ<45º and hot spots (Φ,φ) • Water mask Mosaic Generation • Selecting from the top15 percent of NDVI values Minimum value in the red channel

  7. Test with S1 data from 2000 (S. Mubareka) Contin. Se-Asia: Jan-Feb 2000 Insular SE-Asia: Year 2000 acceptable result – more images to be included - remaining holes and mosaic effects - separation evergreen / deciduous limited - low quality over parts of Vietnam insufficient for removal of cloud & haze

  8. Mosaic generation from S10 data: year 1998 to early 2000 • Cont. SE-Asia: S10 composites of dry seasons 1999 & 2000 (Jan-Mar) • Ins. SE-Asia: S10 composites Mar-Nov 1998-1999, Jan-Mar 2000 • Threshold for SWIR line errors (>5% in the SWIR band) • Cloud-haze threshold ( <10% in the blue band) • Cloud-shadow masks by unsupervised classification Mosaic Generation in 2 Steps: • Monthly Mosaics: Pixel selection by minimum in SWIR (good contrast for forest, reduction of atmospheric & angular effects, line errors) • Annual Mosaics: Pixel selection by minimum in NIR (further enhancement of contrast between evergreen and deciduous vegetation)

  9. Mosaic detail: Continental SE-Asia

  10. Mosaic detail: Insular SE-Asia

  11. Mapping Approach for SE-Asia • Unsupervised clustering and maximum likelihood classification 70 clusters cont. SEA, 60 clusters ins SEA • Cluster labeling and grouping to land cover classes supported by interpretation from available TM scenes, maps, field records • Specific for continental SE-Asia: • Splitting up of clusters for different bioclimatic zones • Correction of errors for selected AOIs • Specific for Ins. SE-Asia: • mapping of formerly burnt areas and of irrigated cropland supported by a rough stratification of vegetation and non-vegetation from the S1 Mosaic

  12. GLC2000 Map Continental SE-Asia Evergreen forest Deciduous forest & woodland Shifting cultivation mosaics Cropland inundated Cropland Evergreen forest Deciduous forest & woodland

  13. GLC2000 Map Insular SE-Asia Cropland annual Shrub & re-growth, burnt 1997/98 Evergreen forest Mix of thickets, shrubs, perennial cropland (oil palm, rubber plantations)

  14. Legend SE-Asia • incl. degraded forests, shrub cover • transitions to shrubs • differentiation closed –open not possible Natural Vegetation / Cropland & shifting cultivation ] • other land cover components partly unknown • includes cropland mosaics

  15. Map comparison for the Lower Mekong Basin MRC Map from interpretation of 1997 TM Scenes GLC2000

  16. Forest Cover Map of Peninsular Malaysia National Forest Inventory Map 92 GLC2000 Map

  17. The End…

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