Abstract

Numerical models have been employed in understanding and capturing spatiotemporal CO₂ trends, inter seasonal to decadal variability, and the characterization of thermal (pCO₂-T) and non-thermal (pCO₂-nonT) components of surface ocean pCO₂ and air-sea CO₂ flux variability. We employed the MIT Ocean General Circulation Model and available data from two sub polar North Atlantic observatories at 49°N, 16.5°W and 56.5°N, 52.6°W to capture in situ pCO₂ observations and deconvolute bio-physical controlling processes. The model suggests that the pCCO₂ cycle is marked by a summertime minimum and wintertime maximum. The physical-chemical and biological response pattern of the model is in good accordance with the observed pCO₂, pCO₂-T and pCO₂-nonT trends. Model outputs suggest that the CO₂ cycle is governed by contrasting effects of seasonal cooling and warming on one side and spring and summer net biology activities on the other side. It also predicts year-round under saturation, indicating that the region is a weak to moderate sink for CO₂.

Keywords: Ocean modeling; Sea surface temperature; Biogeochemistry; Carbon dioxide; North Atlantic ocean