Fennec dust forecast intercomparison over the Sahara in June 2011

摘要: In the framework of Fennec international programme , a field campaign was conducted in June 2011 over western Sahara. It led to first observational data set ever obtained that documents dynamics, thermodynam-ics and composition Saharan atmospheric boundary layer (SABL) under influence heat low. support aircraft operation, four dust forecasts were run daily at low high resolutions with convection-parameterizing convection-permitting models, respectively. The unique airborne ground-based sets allowed intercomparison At monthly scale, large aerosol optical depths (AODs) forecast Sahara, feature observed by satellite retrievals but different magnitudes. AOD intensity correctly predicted high-resolution while it underestimated low-resolution models. This partly because generation strong near-surface wind associated thunderstorm-related density currents could only be reproduced models representing con-vection explicitly. Such yield emissions mainly afternoon dominate total emission fringes Adrar des Iforas Air Mountains forecasts. Over where harmattan contributes up 80 % emission, all successful forecasting deep well-mixed SABL. Some them, however, missed concentration generated low-level winds. feature, repeatedly lidar, one model only.