Aboveground biomass estimation of mangrove species using ALOS-2 PALSAR imagery in Hai Phong City, Vietnam

摘要

This study examined the potential of using the HH and HV backscatter from the Advanced Land Observing Satellite 2 (ALOS-2) with enhanced phased array L-band synthetic aperture radar (PALSAR) in high sensitive mode to estimate the above-ground biomass (AGB) of the two mangrove species of Hai Phong city, Vietnam. A positive correlation was observed between the mean backscattering coefficients of the dominant mangrove species at dual polarizations HH and HV and various biophysical parameters. In contrast, low correlations were observed between those coefficients and the tree densities for the two mangrove species. The AGB of the mangrove species were estimated at between 2.8 and 161.5 Mg ha~(-1) with an average of about 39 Mg ha~(-1) for Sonneratia caseolaris and between 27.6 and 209.2 Mg ha~(-1) with an average of ～100 Mg ha~(-1) for Kandelia obovata. The main indicators used for the selection of the best potential models in estimating the AGB of different species were R~2 and the rootmean-square error (RMSE). The results showed a satisfactory correlation between model estimation and field-based measurements with R~2 = 0.51, RMSE = 35.5 Mg ha~(-1) for S. caseolaris and R~2 = 0.64, RMSE = 41.3 Mg ha~(-1) for K. obovata. This research has illustrated the potential use of ALOS-2 PALSAR data in estimating the AGB of mangrove species in the tropics.