Using satellite data to estimate partial pressure of CO₂ in the Baltic Sea

Gaëlle Parard (1) , Anastase Alexandre Charantonis (2) , Anna Rutgersson (1)

1 Department of Earth Sciences [Uppsala]
2 PARVATI - Processus de la variabilité climatique tropicale et impacts

In this study we focused on estimating the pressure partial of CO₂ (pCO₂) in the entire Baltic Sea which can be considered a coastal area in its entirety. We used the self-organizing multiple linear output (SOMLO) method to estimate the ocean surface pCO₂ in the Baltic Sea from the remotely sensed sea surface temperature, chlorophyll a, colored dissolved organic matter, net primary production, and mixed-layer depth. Uncertainties in the estimates include sparsity of in situ data used to train the algorithms, in particular, for some sectors and seasons. For this application we divided the Baltic Sea in four basins. When comparing the results obtained with this division to those obtained in previous studies, we notice a decrease in the root-mean-square error (<40 μatm) between the reconstruction of the pCO₂ and their corresponding in situ measurements, as well as an increase of the correlation coefficient (> 0.96) between them. The outputs of this research have a horizontal resolution of 4 km and cover the 1998–2011 period. For the first time, a climatological mean distribution of surface water pCO₂ over the Baltic Sea was calculated based on the SOMLO method with a mean pCO₂ of 368.3±100 μatm, and a range of 234–514 μatm. The seasonal variability is similar throughout the Baltic Sea, being high in winter and low in summer.

Domaines: Géophysique [physics.geo-ph]

Gaëlle Parard, Anastase Alexandre Charantonis, Anna Rutgersson. Using satellite data to estimate partial pressure of CO₂ in the Baltic Sea. Journal of Geophysical Research: Biogeosciences, 2016, 121 (3), pp.1002 - 1015. ⟨10.1002/2015jg003064⟩. ⟨hal-01497840⟩