Patrick Leinenkugel. German Aerospace Center (DLR) Vortrag > Autor > Dokumentname > Datum

Transcription

1 Characterisation of land surface phenology and land cover for the Mekong Basin on the basis of multitemporal and multispectral satellite data from the MODIS Sensor Patrick Leinenkugel German Aerospace Center (DLR) Vortrag > Autor > Dokumentname > Datum

2 Overview Introduction and objectives Compositing Land surface phenology Land cover Subpixel land cover dynamics Conclusion Slide Folie # 2 2

3 The Mekong Basin Environmental Issues Dam construction Cash crop cultivation images.nationalgeographic.com North-South Economic Corridor Deforestation socialearth.org nigeldickinson.photoshelter.com East-West Economic Corridor saigon-gpdaily.com.vn Southern Economic Corridor Infrastructure development Slide Folie # 3 3

4 Existing Land Cover Maps for the MB Regional specific product Global products Outdated Focus on forest cover only Not covering the entire Mekong Basin JRC TREES GlobCover MODIS LC Global map products No regional specific classes Less appropriate for local/basin scale Need for an updated, comprehensive, and regional specific land cover map at basin scale Slide Folie # 4 4

5 MODIS Land Cover Dynamics Stable Pixels Stable Changes Land Cover Type Pixels [%] per pixel Evergreen Broadleaf forest 80% 0,4 Grasslands 63% 0,8 Woody savannas 38% 1,3 Cropland/Natural vegetation 34% 1,4 Permanent wetlands 33% 1,8 Croplands 23% 1,8 Evergreen Needleleaf forest 22% 1,8 Mixed forest 17% 1,8 Closed shrublands 12% 2,2 Barren or sparsely vegetated 2% 2,2 Open shrublands 1% 2,3 Deciduous Needleleaf forest 0% 2,4 Deciduous Broadleaf forest 0% 2,3 Savannas 0% 2,7 Label changes not related to real land cover dynamics! Slide Folie # 5 5

6 Objectives The objectives of my thesis are: The generation of an updated and thematic comprehensive land cover map for the entire Mekong Basin The detection of land cover changes in the Mekong Basin for the period The analysis of spatio-temporal patterns of detected land cover changes in the Mekong Basin for the period Slide Folie # 6 6

7 Climatic conditions in the Mekong Basin Daily proportions of clear observations for the Mekong Basin in 2010 Global average: ~ 55-60% Dry season average: ~ 50% Wet season average: ~10% Slide Folie # 7 7

8 Temporal Compositing Combination of Aqua and Terra observations for the generation of: - 16-day composites - Monthly composites - Dry season composites By using a new cloud mask in the compositing process, ca. 15% of clear observations could be retained compared to the standard MODIS composite products. Leinenkugel et al. (2013). Comparison and enhancement of MODIS cloud mask products for Southeast Asia. International Journal of Remote Sensing, 34, p Slide Folie # 8 8

9 Extraction of phenological parameters Parameter Definition -C 1 =6 -C 2 =7.5 -L=1 -G=2.5 s e time for the start of the season time for the end of the season certain of the seasonal amplitude measured from the left minimum level decreased to a user defined level measured from the right minimum level. l length of the season time from the start to the end of the season l_s1 x_s1 a_s1 s_s1 b_s1 m_s1 i_s1 l_s2 x_s2 e_s1 s_s2 a_s2 m_s12 b_s2 i_s2 e_s2 m_s2 b base level average of the left and right minimum values x m a largest data value during the season smallest data value during the season seasonal amplitude maximum value between start and end of season minimum value between start and end of season difference between the maximum value and the base level i seasonal integral Sum of values from the season start to the season end Slide Folie # 10 10

10 Phenological characterisation of the Mekong Basin Slide Folie # 11 11

11 The MEKONG LC2010 land cover map Slide Folie # 13 13

12 Land cover comparison for the Mekong Delta MEKONG LC 2010 GlobCover 2009 MODIS Land Cover 2009 Slide Folie # 14 14

13 Subpixel land cover estimation for High resolution Satellite data Reflectance Land cover proportions Forest Woodland Classification Aggregation to subpixel land cover proportion MODIS Reflectance Phenology Regression Model Cropland Tree Density Slide Folie # 15 15

14 Detection of land cover changes Temporary forest cut (shifting cultivation) Permanent forest cut (large plantation) Slide Folie # 17 17

15 Conclusion and Outlook Clear-sky surface reflectance composites were generated by combining satellite data from two platforms and the application of enhanced cloud masks Phenology of the land surface was characterised for the entire Mekong Basin based on EVI time series for A comprehensive land cover map was derived based on spectral and temporal information for the year Subpixel land cover proportions and continuous fields of tree density was estimated for the time period Still to do: Detecting different types (temporary/permanent, gradual/abrupt) of land cover change Spatio-temporal analyses of land cover changes (relating change to population density, distance to infrastructure/settlements etc.) Introduction > Compositing > Phenology > Land Cover 2010 > Land Cover dynamics > Conclusion Slide Folie # 18 18

16 Thank you for your attention! Folie 19