Highly Active Ice-Nucleating Particles at the Summer North Pole
Artikel i vetenskaplig tidskrift, 2022

The amount of ice versus supercooled water in clouds is important for their radiative properties and role in climate feedbacks. Hence, knowledge of the concentration of ice-nucleating particles (INPs) is needed. Generally, the concentrations of INPs are found to be very low in remote marine locations allowing cloud water to persist in a supercooled state. We had expected the concentrations of INPs at the North Pole to be very low given the distance from open ocean and terrestrial sources coupled with effective wet scavenging processes. Here we show that during summer 2018 (August and September) high concentrations of biological INPs (active at >−20°C) were sporadically present at the North Pole. In fact, INP concentrations were sometimes as high as those recorded at mid-latitude locations strongly impacted by highly active biological INPs, in strong contrast to the Southern Ocean. Furthermore, using a balloon borne sampler we demonstrated that INP concentrations were often different at the surface versus higher in the boundary layer where clouds form. Back trajectory analysis suggests strong sources of INPs near the Russian coast, possibly associated with wind-driven sea spray production, whereas the pack ice, open leads, and the marginal ice zone were not sources of highly active INPs. These findings suggest that primary ice production, and therefore Arctic climate, is sensitive to transport from locations such as the Russian coast that are already experiencing marked climate change.

ice-nucleating particles



mixed-phase clouds


Grace C.E. Porter

University of Leeds

Michael P. Adams

University of Leeds

Ian M. Brooks

University of Leeds

Luisa Ickes

Chalmers, Rymd-, geo- och miljövetenskap, Geovetenskap och fjärranalys

Linn Karlsson

Stockholms universitet

Caroline Leck

Stockholms universitet

Matthew E. Salter

Stockholms universitet

Julia Schmale

Ecole Polytechnique Federale de Lausanne (EPFL)

Karolina Siegel

Stockholms universitet

Sebastien N.F. Sikora

University of Leeds

Mark D. Tarn

University of Leeds

Jutta Vüllers

University of Leeds

Karlsruher Institut für Technologie (KIT)

Heini Wernli

Eidgenössische Technische Hochschule Zürich (ETH)

Paul Zieger

Stockholms universitet

Julika Zinke

Stockholms universitet

Benjamin J. Murray

University of Leeds

Journal of Geophysical Research: Atmospheres

2169897X (ISSN) 21698996 (eISSN)

Vol. 127 6 e2021JD036059


Meteorologi och atmosfärforskning


Multidisciplinär geovetenskap



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