Air-sea exchange of nitrous oxide and methane in the Arabian Sea: A simple model of the seasonal variability

77-83With a simple box model the seasonal variability of N₂O and CH₄ were simulated in surface layers in the central and western Arabian Sea. The model was able to reproduce the N₂O measurements except for times when cold water filaments occur (i.e., during the SW monsoon). Based on the comparison of model results and measurements, it is concluded that the saturation of N₂O in the surface layer of the Arabian Sea is mainly controlled by (i) the wind-driven air-sea exchange during the SW monsoon, (ii) entrainment of N₂O from the subsurface layer, and (iii) sea surface temperature variability. However, the contribution of the factors listed above to the seasonality of the N₂O saturations is different in the selected areas. The overall good agreement of model results and the majority of N₂O measurements suggest that N₂O formation in the surface layer of the Arabian Sea is negligible. The comparison of model’s results and CH₄ measurements revealed a more complex situation, partly due to considerable inconsistencies in the available CH₄ data. Thus, the situation for CH₄ remains unresolved and inconclusive