Sensitivity of convective overturning and turbulent mixing of dissolved gases in the Labrador Sea to modes of atmospheric variability

Deep oceanic convection occurs in few locations around the globe. One such location is found in the Labrador Sea where dense waters subside to depths in excess of 2km below the surface. The weak stratification preconditions the water column for deep convection, triggered by wintertime surface cooling associated with high wind speed events. The convected water brings with it dissolved gases, such as Carbon Dioxide, which are in constant flux between ocean and atmosphere. It is thought that this process of turbulent boundary layer interactions coupled with deep convection is responsible for mixing these gases into the deep ocean, making the ocean the largest sink of anthropogenic carbon. The convective overturning process depends on the temperature and salinity profiles which, together dictate density and thus the static stability of the water column. We have adapted a widely used one-dimensional mixed-layer model, to include a parameterization of the air-sea flux of gases such as Oxygen and Carbon Dioxide. With the model, we investigate the sensitivity of deep-water formation and the vertical profile of these gases to various atmospheric forcing parameters. The large temperature gradients and strong winds during the winter months favour turbulent fluxes of heat. In addition to the model, we investigate the impact of large-scale atmospheric circulation patterns such as the North Atlantic Oscillation and the Icelandic Low on air-sea fluxes over the Labrador Sea and thus convective overturning.