Research article - Peer-reviewed, 2021
Upscaling Northern Peatland CO2 Fluxes Using Satellite Remote Sensing Data
Junttila, Sofia; Kelly, Julia; Kljun, Natascha; Aurela, Mika; Klemedtsson, Leif; Lohila, Annalea; Nilsson, Mats B.; Rinne, Janne; Tuittila, Eeva-Stiina; Vestin, Patrik; Weslien, Per; Eklundh, LarsAbstract
Peatlands play an important role in the global carbon cycle as they contain a large soil carbon stock. However, current climate change could potentially shift peatlands from being carbon sinks to carbon sources. Remote sensing methods provide an opportunity to monitor carbon dioxide (CO2) exchange in peatland ecosystems at large scales under these changing conditions. In this study, we developed empirical models of the CO2 balance (net ecosystem exchange, NEE), gross primary production (GPP), and ecosystem respiration (ER) that could be used for upscaling CO2 fluxes with remotely sensed data. Two to three years of eddy covariance (EC) data from five peatlands in Sweden and Finland were compared to modelled NEE, GPP and ER based on vegetation indices from 10 m resolution Sentinel-2 MSI and land surface temperature from 1 km resolution MODIS data. To ensure a precise match between the EC data and the Sentinel-2 observations, a footprint model was applied to derive footprint-weighted daily means of the vegetation indices. Average model parameters for all sites were acquired with a leave-one-out-cross-validation procedure. Both the GPP and the ER models gave high agreement with the EC-derived fluxes (R-2 = 0.70 and 0.56, NRMSE = 14% and 15%, respectively). The performance of the NEE model was weaker (average R-2 = 0.36 and NRMSE = 13%). Our findings demonstrate that using optical and thermal satellite sensor data is a feasible method for upscaling the GPP and ER of northern boreal peatlands, although further studies are needed to investigate the sources of the unexplained spatial and temporal variation of the CO2 fluxes.Keywords
ecosystem respiration (ER); footprint analysis; gross primary production (GPP); net ecosystem exchange (NEE); peatland; Sentinel-2; upscalingPublished in
Remote Sensing2021, volume: 13, number: 4, article number: 818
Publisher: MDPI
Authors' information
Junttila, Sofia
Lund University
Kelly, Julia
Lund University
Kljun, Natascha
Lund University
Aurela, Mika
Finnish Meteorological Institute
Klemedtsson, Leif
University of Gothenburg
Lohila, Annalea
Finnish Meteorological Institute
Lohila, Annalea
University of Helsinki
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Rinne, Janne
Lund University
Tuittila, Eeva-Stiina
University of Eastern Finland
Vestin, Patrik
Lund University
Weslien, Per
University of Gothenburg
Eklundh, Lars
Lund University
UKÄ Subject classification
Climate Research
Remote Sensing
Publication Identifiers
DOI: https://doi.org/10.3390/rs13040818
URI (permanent link to this page)
https://res.slu.se/id/publ/111351