4.2.2. Variability in Surface Distribution and Sea-Air Fluxes
The positive F CO2 densities during winter shows that inner shelf of Kunene and Walvis Bay acts as a remarkable source of CO2 to the atmosphere. We computed a significant F CO2 density in winter within the inner shelf of Kunene, representing the highest daily average of F CO2; ± σM: 120.11 ± 3.54 mmol m-2d-1 relative to moderate ( ± σM: 54.20 ± 3.23 mmol m-2d-1) F CO2 density in the inner shelf off Walvis Bay. In contrast, the BUS was a small source of CO2 or almost in equilibrium relative to the atmosphere during summer (F CO2(Kunene ): ± σM: 0.08 ± 0.01 mmol m-2d-1 and F CO2(Walvis Bay ): ± σM: 0.13 ± 0.14 mmol m-2d-1) (Figure 6). Our results were in line with the previous report of higher f CO2 and fluxes off Cape Frio and the Kunene Estuary in winter and spring (May to December) linked to the regional formation of upwelling filaments and eddies relative to an oceanic-atmospheric equilibrium state in central Namibia (Santana-Casiano et al., 2009).