The Ny-Ålesund Aerosol Cloud Experiment (NASCENT): Overview and First Results

Abstract

The Arctic is warming at more than twice the rate of the global average. This warming is influenced by clouds which modulate the solar and terrestrial radiative fluxes, and thus, determine the surface energy budget. However, the interactions among clouds, aerosols, and radiative fluxes in the Arctic are still poorly understood. To address these uncertainties, the Ny-Ålesund AeroSol Cloud ExperimeNT (NASCENT) study was conducted from September 2019 to August 2020 in Ny-Ålesund Svalbard. The campaign’s primary goal was to elucidate the life cycle of aerosols in the Arctic and to determine how they modulate cloud properties throughout the year. In-situ and remote sensing observations were taken on the ground at sea-level and at a mountaintop station, and with a tethered balloon system. An overview of the meteorological and the main aerosol seasonality encountered during the NASCENT year is introduced, followed by a presentation of first scientific highlights. In particular, we present new findings on aerosol physicochemical properties which also include molecular properties. Further, the role of cloud droplet activation and ice crystal nucleation in the formation and persistence of mixed-phase clouds, and the occurrence of secondary ice processes, are discussed and compared to the representation of cloud processes within the regional Weather Research and Forecasting model. The paper concludes with research questions that are to be addressed in upcoming NASCENT publications.

Physicochemical Characterization and Source Apportionment of Arctic Ice Nucleating Particles Observed in Ny-Ålesund in Autumn 2019

“…The measurement campaign of ambient INP and aerosol properties was a part of the Ny-Ålesund AeroSol Cloud ExperimeNT (NASCENT) campaign (Pasquier et al, 2022a) from October to November 2019 at Ny-Ålesund (78.9 °N, 11.9 °E). Ny-Ålesund is located on the western coast of the Svalbard Archipelago (Fig.…”

Predicting atmospheric background number concentration of ice-nucleating particles in the Arctic

“…Under the framework of the NASCENT campaign (Pasquier et al, 2022), ambient INP measurements and aerosol characterization took place at the Arctic field site in Ny-Ålesund, Svalbard (78.9 • N, 11.9 • E) during October-November 2019 and March-April 2020. Ny-Ålesund is located on the southern coast of the Kongsfjorden in western Svalbard, and it is a well-established international site in the Arctic for scientific research.…”

Composition and mixing state of Arctic aerosol and cloud residual particles from long-term single-particle observations at Zeppelin Observatory, Svalbard

“…These cloud residual samples were classified into three categories based on ambient air temperature: above 0, 0 to −4 • C, and below −4 • C. All cloud residual particles above 0 • are liquid droplets, whereas those below 0 • are supercooled water droplets or ice crystals. Note that cloud droplets may have undergone colder temperatures than the sampling site, and the measured temperature may not be the same as the activated temperature for forming ice crystals (Carlsen and David, 2022).…”

“…In particular, INPs are a key to understanding the formations of ice crystals in Arctic mixed-phase clouds (Kanji et al, 2017;Murray et al, 2021;Carlsen and David, 2022). A comparison of the number fraction of each particle type between ambient aerosol and cloud residual samples showed that mineral dust particles in cloud residual samples were almost 18 times higher than ambient aerosol samples in winter (Fig.…”

“…This study is based on aerosol particles and cloud residual particles collected from the Zeppelin Observatory from 2017 to 2021 using impactor samplers and the CVI inlet. This period overlapped with the campaigns of the Ny-Ålesund AeroSol Cloud ExperimeNT (NASCENT) (Pasquier et al, 2022) and the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) (Shupe et al, 2022). We focused on measuring individual particles using scanning TEM coupled with EDS (STEM-EDS).…”