Remotely sensed land surface temperature is a proxy of ecosystem
respiration in intact and disturbed northern peatlands
Abstract
Remotely sensed land surface temperature (LST) enables global modelling
and monitoring carbon dioxide (CO2) fluxes from peatlands. We aimed to
provide the first overview of the LST potential for monitoring ecosystem
respiration (Reco) in disturbed (drained and extracted) peatlands. We
used chamber measured data (2017–2020) from five disturbed and two
intact northern peatlands and LST data from Landsat 7, 8, and MODIS
missions. First, we studied the strength of relationships between fluxes
and their in-situ drivers: thermal and moisture conditions. Second, we
examined the association between LST and in-situ temperatures. Third, we
compared chamber measured Reco with the modelled Reco based on (i)
in-situ measured surface temperature and (ii) MODIS LST. In-situ
temperatures were a stronger driver of CO2 fluxes in disturbed sites
(Spearman correlation R=0.8–0.9) than in intact ones (R=0.5–0.7). LST
had a higher association with in-situ measured temperatures (mean R=0.74
for MODIS) in disturbed sites and weaker in the intact peatlands (mean
R=0.34 for Landsat and 0.36 for MODIS). Reco models driven by MODIS LST
and in-situ surface temperature yielded similar accuracy: R-squared was
0.26, 0.64, 0.65 and 0.28, 0.68, 0.58 for intact, drained and extracted
sites, correspondingly. Therefore, LST has a great potential to be
utilized in Reco models as a proxy of thermal regime in disturbed and
intact northern peatlands.