Wind synoptic activity and oxygen levels in the tropical Pacific Ocean

The mechanisms controlling the variability of oxygen levels in the ocean are poorly quantified. The focus here is on the impact of wind synoptic variability associated with tropical convective regions and extratropical storms. Removing the wind higher frequencies of variability (2 days to 1 month) in an atmosphere reanalysis used to force an ocean model decreases wind stress by up to 20% in the tropics and 50% in the midlatitudes, weakening wind‐driven ocean circulation by 20%. Oxygen levels decrease by up to 10 mmol/m³ in tropical oceans and 30 mmol/m³ in subtropical gyres mainly due to changes in advective processes. While a large part of the tropical oxygen anomaly has local origins, changes in oxygen levels in the subtropical gyres modulate tropical oxygen distribution. This study suggests that the “storminess” of the ocean is an important parameter that could determine the future evolution of poorly oxygenated regions.