Mapping forests in Monsoon Asia with ALOS PALSAR and MODIS imagery in 2010

Abstract:

Spatial distribution and temporal dynamics of forests are important to climate change, carbon cycle, and biodiversity. An accurate forest map is required in monsoon Asia where extensive forest changes occurred. An algorithm was developed to map the distribution of forests in Monsoon Asia in 2010, with the integration of structure information from the Advanced Land Observation System (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) mosaic dataset, and phenology information from MOD13Q1 NDVI, and MOD09A1 land surface reflectance products. The PALSAR-based forest map was generated based on a decision tree classification, and assessed with the randomly selected ground truth samples from high spatial resolution images in Google Earth. The spatial and area comparison were performed between our forest map (OU/Fudan F/NF) and other forest maps generated by Japanese Space Exploration Agency (JAXA F/NF), European Space Agency (ESA F/NF), Boston University (MCD12Q1 F/NF), Food and Agricultural Organization (FAO FRA), and University of Maryland (Landsat forests). Then we investigate the reasons for the large uncertainties among these typical forest maps in 2010. This study could provide a way to monitor the dynamics of forests using the Synthetic Aperture Radar (SAR) and optical satellite images, and the resultant F/NF datasets can be used to analyze the impacts of changes in forests on climate and ecosystems.