Aerosol variability and interaction with ambient conditions based on small-scale vertical and horizontal distribution of Arctic measurements (AIDA)

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In the Arctic climate system, aerosol particles play a crucial role in understanding the rapid warming. With predominantly low background aerosol concentrations, local new particle formation events are an important source of aerosol particles, and can contribute significantly to cloud condensation nuclei. Due to the difficult accessibility, particularly vertical measurements in Arctic areas are rare. However, the aerosol concentration is highly variable in space and time and therefore difficult to implement in models. In particular, the spatial distribution and temporal variability on small scales strongly depends on ambient conditions, like atmospheric stratification, clouds, orography and surface properties. Therefore, the project AIDA (Aerosol variability and interaction with ambient conditions based on small-scale vertical and horizontal distribution of Arctic measurements) studies the small-scale variability at the site Ny-Alesund in Svalbard, a natural laboratory of small-scale contrasting environmental conditions, with simultaneous vertical measurements of a tethered balloon and horizontal and vertical measurements of a fixed-wing drone in addition to the existing continuously measuring ground-based observatories at Ny-Alesund and the Zeppelin Mountain. Measurements are planned for the transition time from the Arctic haze season in spring with predominantly remote transport to local aerosol formation in summer. The drone and the tethered balloon are equipped with similar aerosol instrumentation: The key instruments are two condensation particle counters of different lower detection threshold operated in parallel on each measurement platform to identify very small particles in the size range of 3-20 nm, which are an indicator of new particle formation. A new light-weight aerosol size spectrometer will be implemented to the balloon system for this campaign for the first time and measure the aerosol size distribution between 8 and 300 nm. In addition, sensors for larger aerosol particles are implemented to study the formation of new particles in dependence on pre-existing aerosol concentrations and the contribution of long-range transport of anthropogenic pollution. Temperature and humidity are recorded with high temporal resolution to investigate atmospheric stability and mixing. The three-dimensional wind vector is also measured, as the local wind field is strongly influenced by local orography. The small scale-variability of thermodynamic conditions is expected to have a significant influence on the formation and growth of new, small aerosol particles. All these in-situ data from vertical and horizontal measurements will be analysed afterwards in cooperation with partners, who operate complementary measurement systems in Ny-Alesund, on Zeppelin Mountain and other Arctic sites. The results will lead to a better understanding of the small-scale distribution of aerosol particles, their formation, growth and vertical transport processes.