Comparison of PolSAR and PolInSAR Method to Estimate Mangrove Carbon Stocks in Southeast Sulawesi Indonesia, using ALOS PALSAR Dual-Polarizationsin the Perspective of Climate Change Mitigation

Abstract

This paper was aimed to compare Polarimetric Synthetic Aperture Radar (PolSAR) and Polarimetric Interferometry Synthetic Aperture Radar (PolInSAR) for estimation of mangrove carbon stocks ini Southeast Sulawesi, Indonesia. Mangrove carbon stocks becomes one of key parameter to study climate change and its impact to human being and environment due to its ability to sink carbon from atmosphere more than the land forest. The method of the research is conducting carbon volume analysis from backscatter coefficient of PolSARand comparing the result to carbon volume obtained from PolInSAR method. Random Volume over Ground was used to model tree biophysical aspect which established from PolInSAR method. We used two images of ALOS PALSAR dual-polarization(HH+HV) with 46 days temporal baseline. Field survey conducted to measure Diameter at Breast Height (DBH) and mangrove tree height to obtain actual carbon stocks. The result showed the PolSAR method which indicated by HV polarization is suitable for mangrove up to 40 t ha-1 (R2=0.8982) while using PolInSAR, carbon stockscan be estimated up to 60 t ha-1 (R2=0.6606). However, the PolSAR method indicated saturation of backscatter correlation to carbon stocks.Using the PolInSAR, based on the RVoG model, the tree height distributed from 0 to 25 meters which less than 20 meters heights dominated the study area. This research has confirmed the usage of dual-pol ALOS PALSAR for carbon mapping particularly for mangrove. From PolSAR and PolInSAR method, mangrove carbon stocks estimated in thestudy arearange between 40 to 60 t Ha-1.