Abstract:Abstract. Ice-nucleating particles (INPs) can initiate ice formation in clouds at temperatures above −38 ∘C through heterogeneous ice nucleation. As a result, INPs affect cloud microphysical and radiative properties, cloud lifetime, and precipitation behavior and thereby ultimately the Earth's climate. Yet, little is known regarding the sources, abundance and properties of INPs, especially in remote regions such as the Arctic. In this study, 2-year-long INP measurements (from July 2018 to September 2020) at Vi… Show more
“…The proteinaceous fraction reached values greater than 90% in summer and ranged between 50% and 85% even in winter. This implies that even in months with little biological activity, most high-temperature INPs were still driven by biological sources, in agreement with previous studies 33 , 53 . Fig.…”
Section: Resultssupporting
confidence: 92%
“…PBAP types II, III and IV correlated with INP concentrations for activation temperatures −10 to −17.5 ° C. The highest correlations were found for INP activated at T = −15 ° C ( R = 0.57, R = 0.55 and R = 0.64 for types II–IV, respectively). This INP activation temperature was previously found to be associated with primary biological activity in the Arctic 33 , 53 . Our analysis strengthens the identification of PBAP by the MBS and links them to high-temperature INP.…”
Section: Resultssupporting
confidence: 53%
“…It is likely that PBAP dominated the contribution to high-temperature INP, even in winter. Sze et al observed a similar seasonal cycle of high-temperature INP for northern Greenland 53 . For three years, the proteinaceous fraction of high-temperature INP was always above 50% and peaked in summer 53 .…”
Section: Resultsmentioning
confidence: 63%
“…Sze et al observed a similar seasonal cycle of high-temperature INP for northern Greenland 53 . For three years, the proteinaceous fraction of high-temperature INP was always above 50% and peaked in summer 53 . The same seasonal cycle was also observed near the ice edge 33 .…”
Primary biological aerosol particles (PBAP) play an important role in the climate system, facilitating the formation of ice within clouds, consequently PBAP may be important in understanding the rapidly changing Arctic. Within this work, we use single-particle fluorescence spectroscopy to identify and quantify PBAP at an Arctic mountain site, with transmission electronic microscopy analysis supporting the presence of PBAP. We find that PBAP concentrations range between 10−3–10−1 L−1 and peak in summer. Evidences suggest that the terrestrial Arctic biosphere is an important regional source of PBAP, given the high correlation to air temperature, surface albedo, surface vegetation and PBAP tracers. PBAP clearly correlate with high-temperature ice nucleating particles (INP) (>-15 °C), of which a high a fraction (>90%) are proteinaceous in summer, implying biological origin. These findings will contribute to an improved understanding of sources and characteristics of Arctic PBAP and their links to INP.
“…The proteinaceous fraction reached values greater than 90% in summer and ranged between 50% and 85% even in winter. This implies that even in months with little biological activity, most high-temperature INPs were still driven by biological sources, in agreement with previous studies 33 , 53 . Fig.…”
Section: Resultssupporting
confidence: 92%
“…PBAP types II, III and IV correlated with INP concentrations for activation temperatures −10 to −17.5 ° C. The highest correlations were found for INP activated at T = −15 ° C ( R = 0.57, R = 0.55 and R = 0.64 for types II–IV, respectively). This INP activation temperature was previously found to be associated with primary biological activity in the Arctic 33 , 53 . Our analysis strengthens the identification of PBAP by the MBS and links them to high-temperature INP.…”
Section: Resultssupporting
confidence: 53%
“…It is likely that PBAP dominated the contribution to high-temperature INP, even in winter. Sze et al observed a similar seasonal cycle of high-temperature INP for northern Greenland 53 . For three years, the proteinaceous fraction of high-temperature INP was always above 50% and peaked in summer 53 .…”
Section: Resultsmentioning
confidence: 63%
“…Sze et al observed a similar seasonal cycle of high-temperature INP for northern Greenland 53 . For three years, the proteinaceous fraction of high-temperature INP was always above 50% and peaked in summer 53 . The same seasonal cycle was also observed near the ice edge 33 .…”
Primary biological aerosol particles (PBAP) play an important role in the climate system, facilitating the formation of ice within clouds, consequently PBAP may be important in understanding the rapidly changing Arctic. Within this work, we use single-particle fluorescence spectroscopy to identify and quantify PBAP at an Arctic mountain site, with transmission electronic microscopy analysis supporting the presence of PBAP. We find that PBAP concentrations range between 10−3–10−1 L−1 and peak in summer. Evidences suggest that the terrestrial Arctic biosphere is an important regional source of PBAP, given the high correlation to air temperature, surface albedo, surface vegetation and PBAP tracers. PBAP clearly correlate with high-temperature ice nucleating particles (INP) (>-15 °C), of which a high a fraction (>90%) are proteinaceous in summer, implying biological origin. These findings will contribute to an improved understanding of sources and characteristics of Arctic PBAP and their links to INP.
“…Tobo et al, 2020), but on a similar order of magnitude to the INPC on other days during the NASCENT campaign (Li et al, 2022) as well as results from field campaigns in other Arctic and remote coastal sites (e.g. Hartmann et al, 2020;McCluskey et al, 2018;DeMott et al, 2016;Sze et al, 2023).…”
Abstract. The Arctic is the fastest warming environment on Earth and the role of clouds in this warming is undisputed. The representation of Arctic clouds and their phase distribution, i.e. the amount of ice and supercooled water, influences predictions of future Arctic warming. Therefore, it is essential that cloud phase is correctly captured by models in order to accurately predict the future Arctic climate. Ice crystal formation in clouds happens through ice nucleation (primary ice production) and ice multiplication (secondary ice production). In common weather and climate models, rime-splintering is the only secondary ice production process included. In addition, prescribed number concentrations of cloud condensation nuclei or cloud droplets and ice-nucleating particles are often overestimated in Arctic environments by standard model configurations. This can lead to a misrepresentation of the phase distribution and precipitation formation in Arctic mixed-phase clouds, with important implications for the Arctic surface energy budget. During the Ny-Ålesund Aerosol Cloud Experiment (NASCENT) a holographic probe mounted on a tethered balloon took in-situ measurements of ice crystal and cloud droplet number and mass concentrations in Svalbard, Norway, during fall 2019 and spring 2020. In this study, we choose one case study from this campaign showing evidence of strong secondary ice production and use the Weather Research and Forecasting (WRF) model to simulate it at a high vertical and spatial resolution. We test the performance of different microphysical parametrizations and apply a new state-of-the-art secondary ice parametrization. We find that the agreement with observations highly depends on the prescribed cloud condensation nuclei/cloud droplet and ice-nucleating particle concentration and requires an enhancement of secondary ice production processes. Lowering mass mixing ratio thresholds for rime splintering inside the Morrison microphysics scheme is crucial for enabling secondary ice production and thereby matching observations for the right reasons. The latter is a prerequisite for reliable simulations of Arctic mixed-phase cloud responses to future temperature- or aerosol perturbations.
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