Long-term deposition and condensation ice-nucleating particle measurements from four stations across the globe

  • Ice particle activation and evolution have important atmospheric implications for cloud formation, initiation of precipitation and radiative interactions. The initial formation of atmospheric ice by heterogeneous ice nucleation requires the presence of a nucleating seed, an ice-nucleating particle (INP), to facilitate its first emergence. Unfortunately, only a few long-term measurements of INPs exist, and as a result, knowledge about geographic and seasonal variations of INP concentrations is sparse. Here we present data from nearly 2 years of INP measurements from four stations in different regions of the world: the Amazon (Brazil), the Caribbean (Martinique), central Europe (Germany) and the Arctic (Svalbard). The sites feature diverse geographical climates and ecosystems that are associated with dissimilar transport patterns, aerosol characteristics and levels of anthropogenic impact (ranging from near pristine to mostly rural). Interestingly, observed INP concentrations, which represent measurements in the deposition and condensation freezing modes, do not differ greatly from site to site but usually fall well within the same order of magnitude. Moreover, short-term variability overwhelms all long-term trends and/or seasonality in the INP concentration at all locations. An analysis of the frequency distributions of INP concentrations suggests that INPs tend to be well mixed and reflective of large-scale air mass movements. No universal physical or chemical parameter could be identified to be a causal link driving INP climatology, highlighting the complex nature of the ice nucleation process. Amazonian INP concentrations were mostly unaffected by the biomass burning season, even though aerosol concentrations increase by a factor of 10 from the wet to dry season. Caribbean INPs were positively correlated to parameters related to transported mineral dust, which is known to increase during the Northern Hemisphere summer. A wind sector analysis revealed the absence of an anthropogenic impact on average INP concentrations at the site in central Europe. Likewise, no Arctic haze influence was observed on INPs at the Arctic site, where low concentrations were generally measured. We consider the collected data to be a unique resource for the community that illustrates some of the challenges and knowledge gaps of the field in general, while specifically highlighting the need for more long-term observations of INPs worldwide.

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Author:Jann Erik SchrodORCiDGND, Erik S. Thomson, Daniel WeberGND, Jens Koßmann, Christopher Pöhlker, Jorge Saturno, Florian DitasORCiDGND, Paulo Artaxo, Valérie Clouard, Jean-Marie Saurel, Martin EbertGND, Joachim CurtiusORCiD, Heinz BingemerGND
Parent Title (English):Atmospheric Chemistry and Physics
Publisher:European Geosciences Union
Place of publication:Katlenburg-Lindau
Document Type:Article
Date of Publication (online):2020/12/22
Date of first Publication:2020/12/22
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2021/08/23
Page Number:24
First Page:15983
Last Page:16006
This research has been supported by the Seventh Framework Programme (BACCHUS (grant no. 603445)). This open-access publication was funded by the Goethe University Frankfurt.
Institutes:Geowissenschaften / Geographie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Licence (German):License LogoCreative Commons - Namensnennung 4.0