We develop an algorithm to compute pCO2 in the Scotian Shelf region (NW Atlantic) from satellite-based estimates of chlorophyll-a concentration, sea-surface temperature, and observed wind speed. This algorithm is based on a high-resolution time-series of pCO2 observations from an autonomous mooring. At the mooring location (44.3° N and 63.3° W), the surface waters act as a source of CO2 to the atmosphere over the annual scale, with an outgassing of -1.1 mol C m-2 yr-1 in 2007/2008. A hindcast of air-sea CO2 fluxes from 1999 to 2008 reveals significant variability both spatially and from year to year. Over the decade, the shelf-wide annual air-sea fluxes range from an outgassing of -1.70 mol C m-2 yr-1 in 2002, to -0.02 mol C m-2 yr-1 in 2006. There is a gradient in the air-sea CO2 flux between the northeastern Cabot Strait region which acts as a net sink of CO 2 with an annual uptake of 0.50 to 1.00 mol C m-2 yr -1, and the southwestern Gulf of Maine region which acts as a source ranging from -0.80 to -2.50 mol C m-2 yr-1. There is a decline, or a negative trend, in the air-sea pCO2 gradient of 23 μatm over the decade, which can be explained by a cooling of 1.3 °C over the same period. Regional conditions govern spatial, seasonal, and interannual variability on the Scotian Shelf, while multi-annual trends appear to be influenced by larger scale processes. © Author(s) 2010.
CITATION STYLE
Shadwick, E. H., Thomas, H., Comeau, A., Craig, S. E., Hunt, C. W., & Salisbury, J. E. (2010). Air-sea CO2 fluxes on the Scotian Shelf: Seasonal to multi-annual variability. Biogeosciences, 7(11), 3851–3867. https://doi.org/10.5194/bg-7-3851-2010
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