Articles | Volume 17, issue 22
Atmos. Chem. Phys., 17, 13573–13604, 2017

Special issue: Environmental changes and hazards in the Dead Sea region (NHESS/ACP/HESS/SE...

Atmos. Chem. Phys., 17, 13573–13604, 2017

Research article 15 Nov 2017

Research article | 15 Nov 2017

Revealing the meteorological drivers of the September 2015 severe dust event in the Eastern Mediterranean

Philipp Gasch1, Daniel Rieger1,a, Carolin Walter1, Pavel Khain2, Yoav Levi2, Peter Knippertz1, and Bernhard Vogel1 Philipp Gasch et al.
  • 1Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Karlsruhe, Germany
  • 2Israel Meteorological Service, Bet Dagan, Israel
  • anow at: Deutscher Wetterdienst, Frankfurter Str. 135, 63067 Offenbach, Germany

Abstract. In September 2015 one of the severest and most unusual dust events on record occurred in the Eastern Mediterranean. Surprisingly, operational dust transport models were unable to forecast the event. This study details the reasons for this failure and presents simulations of the event at convection-permitting resolution using the modelling system ICON-ART. The results allow for an in-depth analysis of the influence of the synoptic situation, the complex interaction of multiple driving atmospheric systems and the mineral dust radiative effect on the dust event. A comparison of the results with observations reveals the quality of the simulation results with respect to structure and timing of the dust transport. The forecast of the dust event is improved decisively. The event is triggered by the unusually early occurrence of an active Red Sea trough situation with an easterly axis over Mesopotamia. The connected sustained organized mesoscale convection produces multiple cold-pool outflows responsible for intense dust emissions. Complexity is added by the interaction with an intense heat low, the inland-penetrating Eastern Mediterranean sea breeze and the widespread occurrence of supercritical flow conditions and subsequent hydraulic jumps in the vicinity of the Dead Sea Rift Valley. The newly implemented mineral dust radiation interaction leads to systematically more intense and faster propagating cold-pool outflows.

Short summary
This paper presents simulations of a severe dust event in the Eastern Mediterranean with a weather prediction model using very high spatial resolution. Due to the high resolution, the small-scale features of the event are captured in great detail. Consequently, the previously erroneous forecast of the event is improved drastically. In addition, the interaction of mineral dust with radiation inside the model has been included as a part of this work and is presented here.
Final-revised paper