Dust Intrusion Events into the Mediterranean Basin

Abstract

In this study seven dust intrusion events were identified and analyzed in the central and eastern part of the Mediterranean Sea beginning August 1988 and ending September 1989. In order to locate their sources, characterize their mode, and determine atmospheric transport levels, airflow back trajectories were calculated using the Branching Atmospheric Trajectory (BAT) model for two layers (300?2000 and 1500?3000 m) in conjunction with the synoptic situations prevailing during these dust outbreak events. Aerosol mass loading and horizontal visibility were derived for each of these seven cases from optical thickness values as analyzed by visible and near infrared radiances measured with the NOAA-9 and NOAA-11 satelliteborne radiometers. Optical thickness is displayed in composite weekly charts over the Mediterranean. The analysis has shown that transport of Saharan dust occurring in the central part of the Mediterranean are usually rather intensive in the atmospheric mass-loading capacity and take place in deeper atmospheric layers for a longer duration (approximately 2?4 days) than eastern Mediterranean dust events. The eastern transport usually originates from the Arabian Desert for short periods (approximately 1 day) and is restricted to a rather shallow atmospheric transport layer featured by low optical depth values.