Researchers investigated the influence of air mass origin on clouds in the Finnish subarctic

In the study, clear connection between air mass origin and clouds in the Finnish subarctic region was observed. To researcher’s knowledge, this is the first study that was performed in a subarctic environment and connects extensive in situ cloud measurements to air mass origin.

The Pallas Global Atmospheric Watch station in northern Finland is one of the few sites that enables long-term in situ observations of cloud and aerosol properties in Arctic and subarctic air masses. Photo: Konstantinos Doulgeris.

An analysis was performed to investigate how different long-range transport air masses can affect the microphysical properties of low-level clouds in a clean subarctic environment. The cloud measurements included in situ and remote sensing ground-based techniques and were conducted during eight Pallas Cloud Experiments held in the autumn between 2004 and 2019. The Pallas Global Atmospheric Watch station in northern Finland is one of the few sites that enables long-term in situ observations of cloud and aerosol properties in Arctic and subarctic air masses.

Clear differences were observed in the cloud microphysical properties for the air mass source regions. Arctic air masses were characterized by low liquid water content, low cloud droplet number concentration and comparatively large effective droplet diameter while continental air masses led to the highest cloud droplet number concentration.

The differences that were observed in cloud microphysical properties when the air masses were related to different regions show the need to investigate how the aerosol loading and meteorology of different air masses along with local meteorological parameters change the cloud microphysics and to what scale. Thus, all-year-round in situ cloud measurements in the area are considered of high importance.

Further information:

Researcher Konstantinos Doulgeris, Finnish Meteorological Institute, konstantinos.doulgeris@fmi.fi

Scientific article is available onAtmospheric Chemistry and Physics.

Reference: Doulgeris, K. M., Vakkari, V., O'Connor, E. J., Kerminen, V.-M., Lihavainen, H., and Brus, D.: Influence of air mass origin on microphysical properties of low-level clouds in a subarctic environment, Atmos. Chem. Phys., 23, 2483–2498, https://doi.org/10.5194/acp-23-2483-2023, 2023.

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