Tropical peatland identification using ALOS PALSAR imageries: A case study in Kahayan River catchment area, Central Kalimantan, Indonesia

Rapid economic development has led to intensive logging, drainage, and conversion of tropical peatlands to commercial plantations such as oil palm, which has led to large increases in carbon emissions. Therefore, proper management of tropical peatland is a necessary component in carbon emission control. The first step in realizing the management of tropical peatlands is establishment of a reliable monitoring technique. Synthetic Aperture Radar (SAR) offers cloud-free observation for tropical peatland monitoring by remote sensing. However, few studies have identified tropical peatland using L-band full polarimetric SAR data. This study was carried out to identify tropical peatland using L-band full polarimetric ALOS PALSAR data. Two study areas, 5 * 5 km in size, were selected to represent the conditions of tropical peatland in Central Kalimantan, Indonesia. Three polarimetric decompositions (PDs) and the radar vegetation index (RVI) were evaluated for their capability to identify tropical peatland characteristics from the viewpoint of L-band full polarimetric SAR. Overall, a combination of classes derived from unsupervised classification of polarimetric parameters of Freeman-Durden three-component decomposition, integrated with the broad interval class of RVI that represents the amount of vegetation cover in the scattering mechanisms, successfully identified tropical peatland. Subsequently, the tropical peatland identified in study area 1 yielded a producer accuracy of 75.8% and a user accuracy of 80.9%. Study area 2 gave accuracies of 77.6% and 76.0% for producers and users, respectively. These results indicate that L-band full polarimetric SAR is advantageous for monitoring tropical peatlands.