Low ozone dry deposition rates to sea ice during the MOSAiC field campaign: Implications for the Arctic boundary layer ozone budget

• Published in: Elementa: Science of the Anthropocene
• Main Authors: Barten, Johannes, G M, Ganzeveld, Laurens, N, Steeneveld, Gert-Jan, Blomquist, Byron, W, Angot, Hélène, Archer, Stephen, D, Bariteau, Ludovic, Beck, Ivo, Boyer, Matthew, von der Gathen, Peter, Helmig, Detlev, Howard, Dean, Hueber, Jacques, Jacobi, Hans-Werner, Jokinen, Tuija, Laurila, Tiia, Posman, Kevin, M, Quéléver, Lauriane, Schmale, Julia, Shupe, Matthew, D, Krol, Maarten, C
• Other Authors: Ecole Polytechnique Fédérale de Lausanne (EPFL), University of Colorado Boulder, Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Ozone deposition; Arctic ozone; Modelling; Atmospheric boundary layer; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Arctic; Sea ice
• Online Access: https://hal.science/hal-04292739; https://hal.science/hal-04292739/document; https://hal.science/hal-04292739/file/Bartenetal_Elementa2023.pdf; https://doi.org/10.1525/elementa.2022.00086

International audience Dry deposition to the surface is one of the main removal pathways of tropospheric ozone (O3). We quantified for the first time the impact of O3 deposition to the Arctic sea ice on the planetary boundary layer (PBL) O3 concentration and budget using year-round flux and concentration observations from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) campaign and simulations with a single-column atmospheric chemistry and meteorological model (SCM). Based on eddy-covariance O3 surface flux observations, we find a median surface resistance on the order of 20,000 s m−1, resulting in a dry deposition velocity of approximately 0.005 cm s−1. This surface resistance is up to an order of magnitude larger than traditionally used values in many atmospheric chemistry and transport models. The SCM is able to accurately represent the yearly cycle, with maxima above 40 ppb in the winter and minima around 15 ppb at the end of summer. However, the observed springtime ozone depletion events are not captured by the SCM. In winter, the modelled PBL O3 budget is governed by dry deposition at the surface mostly compensated by downward turbulent transport of O3 towards the surface. Advection, which is accounted for implicitly by nudging to reanalysis data, poses a substantial, mostly negative, contribution to the simulated PBL O3 budget in summer. During episodes with low wind speed (<5 m s−1) and shallow PBL (<50 m), the 7-day mean dry deposition removal rate can reach up to 1.0 ppb h−1. Our study highlights the importance of an accurate description of dry deposition to Arctic sea ice in models to quantify the current and future O3 sink in the Arctic, impacting the tropospheric O3 budget, which has been modified in the last century largely due to anthropogenic activities.