Monday, 12 January 2009
A Study of the Impacts of a Saharan Air Layer Plume over the Florida Keys
Hall 5 (Phoenix Convention Center)
A large Saharan air layer plume moved westward across the northern Atlantic Ocean from 20 to 25 June 2008, arriving over the Florida Keys on 26 June and departing by 29 June. A thick layer of haze aloft (composed of suspended mineral dust from the Sahara) scattered sunlight and cast an eerie gray celestial veil over the Florida Keys and adjacent coastal waters. In addition, the plume, containing very warm and dry air in the lower troposphere, suppressed cumulus convection for three days (26—28 June). Horizontal surface visibility was unrestricted throughout this event, suggesting that the dry, dusty air from the Sahara remained elevated above the moist layer. An examination of the trajectory of the Saharan air layer across the Atlantic Ocean and subsequent impact on weather in the Florida Keys will be presented, utilizing satellite and rawinsonde observations. This event over the Florida Keys was compared with Saharan air layer outbreaks over the Atlantic Ocean and Caribbean Sea analyzed in previous studies. A unique look at the Saharan air layer will be offered from the perspective of a subtropical field forecasting operation located in the western part of the Atlantic Basin, over 4000 miles from the Sahara Desert.