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© 2019. This work is published under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Sunlit snow is highly photochemically active and plays a key role in the exchange of gas phase species between the cryosphere and the atmosphere. Here, we investigate the behaviour of two selected species in surface snow: mercury (Hg) and iodine (I). Hg can deposit year-round and accumulate in the snowpack. However, photo-induced re-emission of gas phase Hg from the surface has been widely reported. Iodine is active in atmospheric new particle formation, especially in the marine boundary layer, and in the destruction of atmospheric ozone. It can also undergo photochemical re-emission. Although previous studies indicate possible post-depositional processes, little is known about the diurnal behaviour of these two species and their interaction in surface snow. The mechanisms are still poorly constrained, and no field experiments have been performed in different seasons to investigate the magnitude of re-emission processes Three sampling campaigns conducted at an hourly resolution for 3 d each were carried out near Ny-Ålesund (Svalbard) to study the behaviour of mercury and iodine in surface snow under different sunlight and environmental conditions (24 h darkness, 24 h sunlight and day–night cycles). Our results indicate a different behaviour of mercury and iodine in surface snow during the different campaigns. The day–night experiments demonstrate the existence of a diurnal cycle in surface snow for Hg and iodine, indicating that these species are indeed influenced by the daily solar radiation cycle. Differently, bromine did not show any diurnal cycle. The diurnal cycle also disappeared for Hg and iodine during the 24 h sunlight period and during 24 h darkness experiments supporting the idea of the occurrence (absence) of a continuous recycling or exchange at the snow–air interface. These results demonstrate that this surface snow recycling is seasonally dependent, through sunlight. They also highlight the non-negligible role that snowpack emissions have on ambient air concentrations and potentially on iodine-induced atmospheric nucleation processes.

Details

Title
Diurnal cycle of iodine, bromine, and mercury concentrations in Svalbard surface snow
Author
Spolaor, Andrea 1   VIAFID ORCID Logo  ; Barbaro, Elena 1 ; Cappelletti, David 2 ; Turetta, Clara 1   VIAFID ORCID Logo  ; Mazzola, Mauro 3   VIAFID ORCID Logo  ; Giardi, Fabio 4 ; Björkman, Mats P 5   VIAFID ORCID Logo  ; Lucchetta, Federico 6 ; Dallo, Federico 1   VIAFID ORCID Logo  ; Pfaffhuber, Katrine Aspmo 7 ; Angot, Hélène 8   VIAFID ORCID Logo  ; Dommergue, Aurelien 9   VIAFID ORCID Logo  ; Maturilli, Marion 10   VIAFID ORCID Logo  ; Saiz-Lopez, Alfonso 11   VIAFID ORCID Logo  ; Barbante, Carlo 12   VIAFID ORCID Logo  ; Cairns, Warren R L 1   VIAFID ORCID Logo 

 Institute of Polar Science, ISP-CNR, Campus Scientifico Via Torino 155, 30172 Mestre, Venice, Italy 
 Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy 
 Institute of Polar Science, ISP-CNR, Via P. Gobetti 101, Bologna, Italy 
 Chemistry Department – Analytical Chemistry, Scientific Pole, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (Florence) Italy 
 Department of Earth Sciences, University of Gothenburg, P.O. Box 460, 40530 Gothenburg, Sweden 
 Department of Environmental Sciences, Informatics and Statistics, Ca' Foscari University of Venice, Santa Marta – Dorsoduro 2137, 30123 Venice, Italy 
 NILU – Norwegian Institute for Air Research, Kjeller, Norway 
 Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder, USA 
 Institut des Géosciences de l'Environnement, Univ. Grenoble Alpes, CNRS, IRD, Grenoble INP, 38000 Grenoble, France 
10  Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany 
11  Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain 
12  Department of Environmental Sciences, Informatics and Statistics, Ca' Foscari University of Venice, Santa Marta – Dorsoduro 2137, 30123 Venice, Italy; Institute of Polar Science, ISP-CNR, Campus Scientifico Via Torino 155, 30172 Mestre, Venice, Italy 
Pages
13325-13339
Publication year
2019
Publication date
2019
Publisher
Copernicus GmbH
ISSN
16807316
e-ISSN
16807324
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2309748590
Copyright
© 2019. This work is published under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.