Meteorological Conditions Leading To The Saharan Dust Events Observed Over South Florida In July 2012
The meteorological conditions that occurred during July 2012 from West Africa to South Florida were compared to climatological averages to determine any relationship with the large frequency of dust events. The daily averaged conditions were analyzed to identify the transport mechanism for the dust to reach South Florida. The position of the subtropical ridge during periods of active dust transport, and a prolonged period of inactivity, were noted. Neither the time the dust spent aloft, nor the location where the dust originated, was indicative of the concentration when it reached Miami. Dust lifting occurred in two major locations: the Libya/Algeria border, and another in Niger, with event 2 outlying in western Mauritania . The Nigerien events were all similar in strength (0.325 to 0.375 AOD), but the far North African origins ranged from the strongest to weakest events. The 850mb flow best represented dust transport. The orientation of the subtropical ridge was found to be crucial for transporting dust to South Florida, with southerly and westerly maxima and an east to west elongation of the ridge most conducive for transport. The fastest movements of dust across the Atlantic came during a westward expansion of the subtropical ridge. Forecasters at the NWS Miami forecast office can use the results of this study to increase their situational awareness concerning Saharan dust events. This is expected to increase the accuracy of dust forecasting over South Florida.