Saharan Dust and Solar Energy Generation in Europe: Case Study of June 2019

Aeolian dust, the most dominant atmospheric aerosol by mass, decreases the solar energy reaching the Earth surface by absorbing and scattering the solar radiation. This energy loss increases mainly with the dust concentration in the atmosphere, which is controlled by the emission, transport and removal of the dust particles. All these processes can vary significantly depending on the convection treatment in the model simulations, thereby affect the solar energy forecast.

This study investigates the dust impacts on solar energy generation within convection-resolving simulations using the next-generation atmospheric modeling system ICON-ART (ICOsahedral Nonhydrostatic with Aerosols and Reactive Trace gases). The simulation set-up includes a global domain with 40 km horizontal resolution with three nests down to 5 km horizontal resolution over North Africa and Europe. The innermost nest resolves convection while other domains are based on parameterized convection. This set-up is used to simulate the period 22-27 June 2019, which is associated with a Saharan dust outbreak in clear sky conditions over North Africa and large parts of Europe. 

Compared to the global simulation, the convection-resolving simulation leads to significantly higher dust optical depth in North Africa. This is related to the elevated coarse mode concentrations due to higher vertical velocities in the convection-resolving simulation. However, dust optical depth over Europe only slightly changes as a large portion of coarse mode particles do not reached Europe due to their large sedimentation velocities. The results are compared with AERONET, ceilometer and radiation measurements.