Synergy between ground-based remote sensing instruments: a new approach to better understand the transport and dispersion process of aerosols in the atmospheric boundary layer

Nocturnal Low-Level Jets (NLLJ) are known to be a crucial process in the long-range transport of atmospheric pollutants with a positive or negative impact on air quality. In recent years, the study of NLLJ that occur usually at the top of the atmospheric boundary layer (ABL) has been greatly enhanced by recent technological and methodological advances in ground-based remote sensing instruments. They are now able to provide continuously high-quality profiles of ABL parameters that can be obtained from automatic LIDAR-ceilometers (ALC) providing information about clouds, precipitations, aerosols (including aerosol characteristics and types with depolarization measurements) and from wind Doppler LIDAR (WDL) providing information about wind profile characteristics.

At the Royal Meteorological Institute of Belgium (RMI), we have been developing a new pioneering algorithm (CONIOPOL: CONIOlogy + POLarization) based only on ALC measurements with a depolarization function (VAISALA CL61) to provide in real-time automatic identification of cloud phase, precipitation type and aerosol type. By combining the output of CONIOPOL based on measurements from a CL61 installed in Uccle (Brussels) with measurements from a WDL located at Brussels Airport (15km away from the CL61), it is possible to monitor continuously the transport of aerosols by NLLJ.

The synergy between both instruments will be illustrated by an interesting case study, showing the transport of marine aerosols by NLLJ into the ABL characterized in the presence of dust. The characteristic and the evolution of the synoptic situation will be used to highlight the geographical origin of aerosols. In order to better characterize the type identification of aerosols by CONIOPOL, ground measurements concerning the physical properties of aerosols carried out close to the CL61 will also be presented.