Finnish lidar network for atmospheric aerosols was assessed for the first time

For the first-time, long-term capability of the HALO Doppler lidar network across Finland has been assessed. It shows a tremendous potential in continuous monitoring of atmospheric aerosol up to the cloud base. This opens new possibilities to support air quality and the safety of aviation especially in case of volcanic eruptions.

Photo: Antonin Halas

In the study, data from a network of four HALO Doppler lidars in Utö, Hyytiälä, Vehmasmäki and Sodankylä were analyzed. These instruments can continuously observe and provide information of the atmosphere up to 9 kilometers or below the cloud base.

For all the instruments, the noise level shows stable performance but clear differences among them. The analysis also shows that all the instruments have an adequate long-term performance in measuring aerosol depolarization ratio.

Scientists developed a background correction method and constructed an algorithm to distinguish aerosol particles from other constituents in the atmosphere. This methodology could be applied to other stand-alone HALO Doppler lidars and thus expand the capability of observing atmospheric aerosol around the world.

Atmospheric aerosol was observed up to the cloud base

All the four measurement sites have low values of depolarization ratio of aerosol in the winter months and higher values in the summer months. This is attributed to the frequent presence of irregular-shaped pollen particles in relatively clean background air in the summer.

An elevated layer of aerosol with high depolarization ratio was observed on top of the boundary layer aerosol by the HALO Doppler lidars in Hyytiälä and Utö. Analysis from simulation and satellite measurement further suggests this layer is a long-range-transport dust from western Sahara. The detection of this layer demonstrates the potential of the HALO Doppler lidar network in providing timely warning for aviation and for air quality authorities.

Further information:

Doctoral researcher Viet Le, Finnish Meteorological Institute, viet.le@fmi.fi

The scientific article is highlighted by the Atmospheric Measurement Techniques journal and available at https://amt.copernicus.org/articles/17/921/2024/

Reference: Le, V., Lobo, H., O'Connor, E. J., & Vakkari, V.: Long-term aerosol particle depolarization ratio measurements with HALO Photonics Doppler lidar. Atmospheric Measurement Techniques, 17(3), 921-941, https://doi.org/10.5194/amt-17-921-2024, 2024

ResearchAtmospheric aerosols