Universität zu Köln

Pasquier, Julie Therese, Henneberger, Jan, Ramelli, Fabiola, Lauber, Annika ORCID: 0000-0001-5731-2652, David, Robert Oscar, Wieder, Joerg, Carlsen, Tim ORCID: 0000-0003-0695-9047, Gierens, Rosa ORCID: 0000-0002-3879-3099, Maturilli, Marion ORCID: 0000-0001-6818-7383 and Lohmann, Ulrike ORCID: 0000-0001-8885-3785 (2022). Conditions favorable for secondary ice production in Arctic mixed-phase clouds. Atmos. Chem. Phys., 22 (23). S. 15579 - 15602. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 1680-7324

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Abstract

The Arctic is very susceptible to climate change and thus is warming much faster than the rest of the world. Clouds influence terrestrial and solar radiative fluxes and thereby impact the amplified Arctic warming. The partitioning of thermodynamic phases (i.e., ice crystals and water droplets) within mixed-phase clouds (MPCs) especially influences their radiative properties. However, the processes responsible for ice crystal formation remain only partially characterized. In particular, so-called secondary ice production (SIP) processes, which create supplementary ice crystals from primary ice crystals and the environmental conditions that they occur in, are poorly understood. The microphysical properties of Arctic MPCs were measured during the Ny-& Aring;lesund AeroSol Cloud ExperimENT (NASCENT) campaign to obtain a better understanding of the atmospheric conditions favorable for the occurrence of SIP processes. To this aim, the in situ cloud microphysical properties retrieved by a holographic cloud imager mounted on a tethered balloon system were complemented by ground-based remote sensing and ice-nucleating particle measurements. During the 6 d investigated in this study, SIP occurred during about 40 % of the in-cloud measurements, and high SIP events with number concentrations larger than 10 L-1 of small pristine ice crystals occurred in 4 % of the in-cloud measurements. This demonstrates the role of SIP for Arctic MPCs. The highest concentrations of small pristine ice crystals were produced at temperatures between -5 and -3 ?C and were related to the occurrence of supercooled large droplets freezing upon collision with ice crystals. This suggests that a large fraction of ice crystals in Arctic MPCs are produced via the droplet-shattering mechanism. From evaluating the ice crystal images, we could identify ice-ice collision as a second SIP mechanism that dominated when fragile ice crystals were observed. Moreover, SIP occurred over a large temperature range and was observed in up to 80 % of the measurements down to -24 ?C due to the occurrence of ice-ice collisions. This emphasizes the importance of SIP at temperatures below -8 ?C, which are currently not accounted for in most numerical weather models. Although ice-nucleating particles may be necessary for the initial freezing of water droplets, the ice crystal number concentration is frequently determined by secondary production mechanisms.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Pasquier, Julie Therese UNSPECIFIED UNSPECIFIED UNSPECIFIED Henneberger, Jan UNSPECIFIED UNSPECIFIED UNSPECIFIED Ramelli, Fabiola UNSPECIFIED UNSPECIFIED UNSPECIFIED Lauber, Annika UNSPECIFIED orcid.org/0000-0001-5731-2652 UNSPECIFIED David, Robert Oscar UNSPECIFIED UNSPECIFIED UNSPECIFIED Wieder, Joerg UNSPECIFIED UNSPECIFIED UNSPECIFIED Carlsen, Tim UNSPECIFIED orcid.org/0000-0003-0695-9047 UNSPECIFIED Gierens, Rosa UNSPECIFIED orcid.org/0000-0002-3879-3099 UNSPECIFIED Maturilli, Marion UNSPECIFIED orcid.org/0000-0001-6818-7383 UNSPECIFIED Lohmann, Ulrike UNSPECIFIED orcid.org/0000-0001-8885-3785 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-683654
DOI:	10.5194/acp-22-15579-2022
Journal or Publication Title:	Atmos. Chem. Phys.
Volume:	22
Number:	23
Page Range:	S. 15579 - 15602
Date:	2022
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	1680-7324
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language NUCLEATING PARTICLE CONCENTRATION; DROP SIZE DISTRIBUTION; NY-ALESUND; MICROPHYSICAL PROPERTIES; ENVIRONMENTAL-CONDITIONS; STRATIFORM CLOUDS; LEVEL CLOUDS; NUCLEI; IMPACT; MECHANISMS Multiple languages Environmental Sciences; Meteorology & Atmospheric Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/68365