Reyes-Mendoza, O.; Mariño-Tapia, I.; Herrera-Silveira, J.; Ruiz-Martínez, G.; Enriquez, C., and Largier, J.L., 2016. The effects of wind on upwelling off Cabo Catoche.

Upwelling of cold, nutrient-rich waters at the NE corner of the Yucatan Peninsula is known to enhance productivity over the Yucatan Shelf, fueling fisheries and harboring the largest global aggregation of whale sharks. Nevertheless, the physical processes that control this upwelling and the spreading of upwelled waters onto the Yucatan Shelf are not well known, particularly near the coast. In this study, upwelling behavior close to the coast was characterized, and the contribution of wind was assessed. Time series of wind, air and ocean temperatures, sea level, and current velocities from two moorings were analyzed. Wavelet transforms showed cold-water pulses with timescales that vary across the seasons and also between the shallower site (8 m) and the deeper site (12 m), with a broader range of periodicities observed further offshore. These upwelling pulses do not correlate simply with wind-driven Ekman transport, suggesting that the process is not locally controlled. Temperature covaried with horizontal currents, suggesting an advective mechanism, which is related to the wind. Although local winds may at times enhance the nearshore intrusion of upwelled waters along the northern shore of the Yucatan Peninsula, more important in these data was the disappearance of cold waters during northerly winds. This appears as an interruption of upwelling, which was highly coherent at periods of 7 to 16 days. These northerly winds are typical from October to February, but can occur at other times as well, for example during an intensive field campaign in April 2012.