High-Resolution classification of South Patagonian peat bog microforms reveals potential gaps in up-scaled CH4 fluxes by use of unmanned aerial system (UAS) and CIR imagery

MÜNCHBERGER W, ; NIEBERDING F, ; KLEINEBECKER T; LEHMANN JRK, ; BLODAU C, ; PANCOTTO VA, AND ; KNOTH C, ; PRINZ T,

Remote Sensing

MDPI AG

Año: 2016

SouthPatagonian peat bogs are little studied sources of methane (CH4). Since CH4 fluxes can vary greatly on a small scale of meters,high-quality maps are needed to accurately quantify CH4fluxes from bogs. We used high-resolution color infrared(CIR) images captured by an Unmanned Aerial System (UAS) to investigatepotential uncertainties in total ecosystem CH4 fluxes introduced by the classification of the surface area.An object-based approach was used to classify vegetation both on species andmicroform level. We achieved an overall Kappa Index of Agreement (KIA) of 0.90for the species- and 0.83 for the microform-level classification, respectively. CH4fluxes were determined by closed chamber measurements onfour predominant microforms ofthe studied bog. Both classification approaches were employed to up-scale CH4closed chamber measurementsin a total area of around 1.8 hectares. Including proportions of the surfacearea where no chamber  measurements were conducted, we estimated a potentialuncertainty in ecosystem CH4 fluxes introduced by the classification of the surface area.This potential uncertainty ranged from 14.2 mg_m_2_day_1 to 26.8 mg_m_2_day_1. Our results show that a simple classification with only fewclasses potentially leads to pronounced bias in total ecosystem CH4fluxes when plot-scale fluxes are up-scaled.