Mercury in the free troposphere and bidirectional atmosphere-vegetation exchanges - Insights from Maïdo mountain observatory in the Southern Hemisphere tropics
Koenig, Alkuin M.; Magand, Olivier; Verreyken, Bertet al.
2023 • In Atmospheric Chemistry and Physics, 23 (2), p. 1309 - 1328
[en] Atmospheric mercury (Hg) observations in the lower free troposphere (LFT) can give important insights into Hg redox chemistry and can help constrain Hg background concentrations on a regional level. Relatively continuous sampling of LFT air, inaccessible to most ground-based stations, can be achieved at high-altitude observatories. However, such high-altitude observatories are rare, especially in the Southern Hemisphere (SH), and atmospheric Hg in the SH LFT is unconstrained. To fill this gap, we continuously measured gaseous elemental mercury (GEM; hourly) and reactive mercury (RM; integrated over g1/4g6-14gd) for 9 months at Maïdo mountain observatory (2160gmga.s.l.) on remote Reunion Island (21.1g gS, 55.5g gE) in the tropical Indian Ocean. GEM exhibits a marked diurnal variation characterized by a midday peak (mean: 0.95gnggm-3; SD: 0.08gnggm-3) and a nighttime low (mean: 0.78gnggm-3; SD: 0.11gnggm-3). We find that this diurnal variation is likely driven by the interplay of important GEM photo-reemission from the islands' vegetated surfaces (i.e. vegetationg+gsoil) during daylight hours (8-22gnggm-2gh-1), boundary layer influences during the day, and predominant LFT influences at night. We estimate GEM in the LFT based on nighttime observations in particularly dry air masses and find a notable seasonal variation, with LFT GEM being lowest from December to March (mean 0.66gnggm-3; SD: 0.07gnggm-3) and highest from September to November (mean: 0.79gnggm-3; SD: 0.09gnggm-3). Such a clear GEM seasonality contrasts with the weak seasonal variation reported for the SH marine boundary layer but is in line with modeling results, highlighting the added value of continuous Hg observations in the LFT. Maïdo RM is 10.6gpggm-3 (SD: 5.9gpggm-3) on average, but RM in the cloud-free LFT might be about twice as high, as weekly-biweekly sampled RM observations are likely diluted by low-RM contributions from the boundary layer and clouds.
Disciplines :
Chemistry
Author, co-author :
Koenig, Alkuin M.; Institut des Geosciences de l'Environnement, Universite Grenoble Alpes, CNRS, INRAE, IRD, Grenoble, France
Magand, Olivier; Institut des Geosciences de l'Environnement, Universite Grenoble Alpes, CNRS, INRAE, IRD, Grenoble, France
Verreyken, Bert ; Université de Liège - ULiège > Département GxABT > Biosystems Dynamics and Exchanges (BIODYNE) ; Royal Belgian Institute for Space Aeronomy, BIRA-IASB, Brussels, Belgium ; Department of Chemistry, Ghent University, Ghent, Belgium ; Laboratoire de l'Atmosphère et des Cyclones, UMR 8105, CNRS, Universite de la Reunion, La Reunion, France ; NOAA Chemical Sciences Laboratory, Boulder, United States
Brioude, Jerome ; Laboratoire de l'Atmosphère et des Cyclones, UMR 8105, CNRS, Universite de la Reunion, La Reunion, France
Amelynck, Crist; Royal Belgian Institute for Space Aeronomy, BIRA-IASB, Brussels, Belgium ; Department of Chemistry, Ghent University, Ghent, Belgium
Schoon, Niels; Royal Belgian Institute for Space Aeronomy, BIRA-IASB, Brussels, Belgium
Colomb, Aurelie; Laboratoire de Meteorologie Physique, UMR6016, CNRS, Universite Clermont Auvergne, Aubière, France
Ferreira Araujo, Beatriz; Geosciences Environnement Toulouse, CNRS/IRD/Universite Paul Sabatier Toulouse 3, Toulouse, France
Ramonet, Michel ; Laboratoire des Sciences du Climat et de l'Environnement, Universite Paris-Saclay, CEA-CNRS-UVSQ, UMR8212, Gif-sur-Yvette, France
Sha, Mahesh K. ; Laboratoire des Sciences du Climat et de l'Environnement, Universite Paris-Saclay, CEA-CNRS-UVSQ, UMR8212, Gif-sur-Yvette, France
Cammas, Jean-Pierre; Observatoire des Sciences de l'Univers À la Reunion (OSU-R), UAR 3365, CNRS, Universite de la Reunion, La Reunion, France
Sonke, Jeroen E.; Geosciences Environnement Toulouse, CNRS/IRD/Universite Paul Sabatier Toulouse 3, Toulouse, France
Dommergue, Aurelien ; Institut des Geosciences de l'Environnement, Universite Grenoble Alpes, CNRS, INRAE, IRD, Grenoble, France
Mercury in the free troposphere and bidirectional atmosphere-vegetation exchanges - Insights from Maïdo mountain observatory in the Southern Hemisphere tropics
H2020 - 654109 - ACTRIS-2 - Aerosols, Clouds, and Trace gases Research InfraStructure
Funders :
EU - European Union BELSPO - Belgian Federal Science Policy Office
Funding text :
The PTR-MS data from BIRA-IASB were obtained in the framework of the OCTAVE project, funded by the Belgian Federal Science Policy Office (grant no. BR/175/A2/OCTAVE) with additional support for deploying the instrument at Maïdo from Horizon 2020 (ACTRIS-2, grant no. 654109).This publication is part of the GMOS-Train project that has received funding from the European Union's Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement no. 860497.We thank OPAR (Observatoire de Physique de l'Atmosphère à La Réunion), funded by CNRS-INSU and Université de La Réunion and managed by OSU-R (Observatoire des Sciences de l'Univers à La Réunion, UMS 3365). Jean-Marc Metzger, from OSU-R, and Christelle Barthe, from LACy and Météo-France, are particularly thanked for their support in the implementation of OPAR's instrumentation and the provision of meteorological data.This research has been supported by Horizon 2020 in the framework of GMOS-Train (grant no. 860497) and ERA-PLANET (grant no. 689443), the Belgian Federal Science Policy Office (grant no. BR/175/A2/OCTAVE), and the French national LEFECHAT CNRS/INSU program (TOPMMODEL project, grant no. AO2017-984931 to Olivier Magand).
Agnan, Y., Le Dantec, T., Moore, C. W., Edwards, G. C., and Obrist, D.: New Constraints on Terrestrial Surface- Atmosphere Fluxes of Gaseous Elemental Mercury Using a Global Database, Environ. Sci. Technol., 50, 507-524, https://doi.org/10.1021/acs.est.5b04013, 2016.
Aliaga, D., Sinclair, V. A., Andrade, M., Artaxo, P., Carbone, S., Kadantsev, E., Laj, P.,Wiedensohler, A., Krejci, R., and Bianchi, F.: Identifying source regions of air masses sampled at the tropical high-Altitude site of Chacaltaya using WRF-FLEXPART and cluster analysis, Atmos. Chem. Phys., 21, 16453-16477, https://doi.org/10.5194/acp-21-16453-2021, 2021.
Almeida, M. D., Marins, R. V., Paraquetti, H. H. M., Bastos, W. R., and Lacerda, L. D.: Mercury degassing from forested and open field soils in Rondônia, Western Amazon, Brazil, Chemosphere, 77, 60-66, https://doi.org/10.1016/j.chemosphere.2009.05.018, 2009.
Amelynck, C., Schoon, N., and Verreyken, B.: Long-Term in situ (O)VOC measurements at the Maïdo Observatory (Reunion Island), Royal Belgian Institute for Space Aeronomy (BIRAIASB) [data set], https://doi.org/10.18758/71021061, 2021 Angot, H., Barret, M., Magand, O., Ramonet, M., and Dommergue, A.: A 2-year record of atmospheric mercury species at a background Southern Hemisphere station on Amsterdam Island, Atmos. Chem. Phys., 14, 11461-11473, https://doi.org/10.5194/acp-14-11461-2014, 2014.
Angot, H., Dion, I., Vogel, N., Legrand, M., Magand, O., and Dommergue, A.: Multi-year record of atmospheric mercury at Dumont d-Urville, East Antarcticcoast: continental outflow and oceanic influences, Atmos. Chem. Phys., 16, 8265-8279, https://doi.org/10.5194/acp-16-8265-2016, 2016a.
Angot, H., Magand, O., Helmig, D., Ricaud, P., Quennehen, B., Gallée, H., Del Guasta, M., Sprovieri, F., Pirrone, N., Savarino, J., and Dommergue, A.: New insights into the atmospheric mercury cycling in central Antarctica and implications on a continental scale, Atmos. Chem. Phys., 16, 8249-8264, https://doi.org/10.5194/acp-16-8249-2016, 2016b.
Archer, D., Eby, M., Brovkin, V., Ridgwell, A., Cao, L., Mikolajewicz, U., Caldeira, K., Matsumoto, K., Munhoven, G., Montenegro, A., and Tokos, K.: Atmospheric Lifetime of Fossil Fuel Carbon Dioxide, Annu. Rev. Earth Pl. Sc., 37, 117-134, https://doi.org/10.1146/annurev.earth.031208.100206, 2009.
Ariya, P. A., Skov, H., Grage, M. M.-L., and Goodsite, M. E.: Gaseous Elemental Mercury in the Ambient Atmosphere: Review of the Application of Theoretical Calculations and Experimental Studies for Determination of Reaction Coefficients and Mechanisms with Halogens and Other Reactants, in: Advances in Quantum Chemistry, Vol. 55, Elsevier, 43-55, https://doi.org/10.1016/S0065-3276(07)00204-3, 2008.
Ariya, P. A., Amyot, M., Dastoor, A., Deeds, D., Feinberg, A., Kos, G., Poulain, A., Ryjkov, A., Semeniuk, K., Subir, M., and Toyota, K.: Mercury Physicochemical and Biogeochemical Transformation in the Atmosphere and at Atmospheric Interfaces: A Review and Future Directions, Chem. Rev., 115, 3760-3802, https://doi.org/10.1021/cr500667e, 2015.
Baray, J.-L., Courcoux, Y., Keckhut, P., Portafaix, T., Tulet, P., Cammas, J.-P., Hauchecorne, A., Godin Beekmann, S., De Mazière, M., Hermans, C., Desmet, F., Sellegri, K., Colomb, A., Ramonet, M., Sciare, J., Vuillemin, C., Hoareau, C., Dionisi, D., Duflot, V., Vérèmes, H., Porteneuve, J., Gabarrot, F., Gaudo, T., Metzger, J.-M., Payen, G., Leclair de Bellevue, J., Barthe, C., Posny, F., Ricaud, P., Abchiche, A., and Delmas, R.: Maïdo observatory: A new high-Altitude station facility at Reunion Island (21_ S, 55_ E) for long-Term atmospheric remote sensing and in situ measurements, Atmos. Meas. Tech., 6, 2865-2877, https://doi.org/10.5194/amt-6-2865-2013, 2013.
Black Jr., C. C.: Photosynthetic carbon fixation in relation to net CO2 uptake, Ann. Rev. Plant Physio., 24, 253-286, 1973.
Brioude, J., Arnold, D., Stohl, A., Cassiani, M., Morton, D., Seibert, P., Angevine, W., Evan, S., Dingwell, A., Fast, J. D., Easter, R. C., Pisso, I., Burkhart, J., and Wotawa, G.: The Lagrangian particle dispersion model FLEXPART-WRF version 3.1, Geosci. Model Dev., 6, 1889-1904, https://doi.org/10.5194/gmd-6-1889-2013, 2013.
Callewaert, S., Brioude, J., Langerock, B., Duflot, V., Fonteyn, D., Möller, J.-F., Metzger, J.-M., Hermans, C., Kumps, N., Ramonet, M., Lopez, M., Mahieu, E., and De Mazière, M.: Analysis of CO2, CH4, and CO surface and column concentrations observed at Réunion Island by assessing WRF-Chem simulations, Atmos. Chem. Phys., 22, 7763-7792, https://doi.org/10.5194/acp-22-7763-2022, 2022.
Calvert, J. and Lindberg, S.: Mechanisms of mercury removal by O and OH in the atmosphere, Atmos. Environ., 39, 3355-3367, https://doi.org/10.1016/j.atmosenv.2005.01.055, 2005.
Carbone, F., Landis, M. S., Gencarelli, C. N., Naccarato, A., Sprovieri, F., De Simone, F., Hedgecock, I. M., and Pirrone, N.: Sea surface temperature variation linked to elemental mercury concentrations measured on Mauna Loa: SST AND HG(0) CONCENTRATION ON MAUNA LOA, Geophys. Res. Lett., 43, 7751-7757, https://doi.org/10.1002/2016GL069252, 2016.
Chen, Q., Sherwen, T., Evans, M., and Alexander, B.: DMS oxidation and sulfur aerosol formation in the marine troposphere: A focus on reactive halogen and multiphase chemistry, Atmos. Chem. Phys., 18, 13617-13637, https://doi.org/10.5194/acp-18-13617-2018, 2018.
Collaud Coen, M., Weingartner, E., Furger, M., Nyeki, S., Prévôt, A. S. H., Steinbacher, M., and Baltensperger, U.: Aerosol climatology and planetary boundary influence at the Jungfraujoch analyzed by synoptic weather types, Atmos. Chem. Phys., 11, 5931-5944, https://doi.org/10.5194/acp-11-5931-2011, 2011.
Converse, A. D., Riscassi, A. L., and Scanlon, T. M.: Seasonal variability in gaseous mercury fluxes measured in a high-elevation meadow, Atmos. Environ., 44, 2176-2185, https://doi.org/10.1016/j.atmosenv.2010.03.024, 2010.
D-Amore, F., Bencardino, M., Cinnirella, S., Sprovieri, F., and Pirrone, N.: Data quality through a web-based QA/QC system: implementation for atmospheric mercury data from the global mercury observation system, Environ. Sci. Proc. Imp., 17, 1482- 1491, https://doi.org/10.1039/C5EM00205B, 2015.
De Mazière, M., Sha, M. K., Ramonet, M., and ICOS RI: ICOS Atmosphere Level 2 data, La Réunion [data set], https://doi.org/10.18160/10QG-6RP6, 2022.
Denzler, B., Bogdal, C., Henne, S., Obrist, D., Steinbacher, M., and Hungerböhler, K.: Inversion Approach to Vali date Mercury Emissions Based on Background Air Monitoring at the High Altitude Research Station Jungfraujoch (3580 m), Environ. Sci. Technol., 51, 2846-2853, https://doi.org/10.1021/acs.est.6b05630, 2017.
Dibble, T. S., Tetu, H. L., Jiao, Y., Thackray, C. P., and Jacob, D. J.: Modeling the OH-Initiated Oxidation of Mercury in the Global Atmosphere without Violating Physical Laws, J. Phys. Chem. A, 124, 444-453, https://doi.org/10.1021/acs.jpca.9b10121, 2020.
Diéguez, M. C., Bencardino, M., García, P. E., D-Amore, F., Castagna, J., De Simone, F., Soto Cárdenas, C., Ribeiro Guevara, S., Pirrone, N., and Sprovieri, F.: A multi-year record of atmospheric mercury species at a background mountain station in Andean Patagonia (Argentina): Temporal trends and meteorological influence, Atmos. Environ., 214, 116819, https://doi.org/10.1016/j.atmosenv.2019.116819, 2019.
Doelsch, E., Van de Kerchove, V., and Saint Macary, H.: Heavy metal content in soils of Réunion (Indian Ocean), Geoderma, 134, 119-134, https://doi.org/10.1016/j.geoderma.2005.09.003, 2006.
Duflot, V., Tulet, P., Flores, O., Barthe, C., Colomb, A., Deguillaume, L., Vaïtilingom, M., Perring, A., Huffman, A., Hernandez, M. T., Sellegri, K., Robinson, E., O-Connor, D. J., Gomez, O. M., Burnet, F., Bourrianne, T., Strasberg, D., Rocco, M., Bertram, A. K., Chazette, P., Totems, J., Fournel, J., Stamenoff, P., Metzger, J.-M., Chabasset, M., Rousseau, C., Bourrianne, E., Sancelme, M., Delort, A.-M., Wegener, R. E., Chou, C., and Elizondo, P.: Preliminary results from the FARCE 2015 campaign: multidisciplinary study of the forest-gas-aerosol?cloud system on the tropical island of La Réunion, Atmos. Chem. Phys., 19, 10591? 10618, https://doi.org/10.5194/acp-19-10591-2019, 2019.
Dunham-Cheatham, S. M., Lyman, S., and Gustin, M. S.: Evaluation of sorption surface materials for reactive mercury compounds, Atmos. Environ., 242, 117836, https://doi.org/10.1016/j.atmosenv.2020.117836, 2020.
Edwards, D. P., Emmons, L. K., Gille, J. C., Chu, A., Attié, J.-L., Giglio, L., Wood, S. W., Haywood, J., Deeter, M. N., Massie, S. T., Ziskin, D. C., and Drummond, J. R.: Satellite-observed pollution from Southern Hemisphere biomass burning, J. Geophys. Res., 111, D14312, https://doi.org/10.1029/2005JD006655, 2006.
Fain, X., Obrist, D., Hallar, A. G., Mccubbin, I., and Rahn, T.: High levels of reactive gaseous mercury observed at a high elevation research laboratory in the Rocky Mountains, Atmos. Chem. Phys., 9, 8049-8060, https://doi.org/10.5194/acp-9-8049-2009, 2009.
Feinberg, A., Dlamini, T., Jiskra, M., Shah, V., and Selin, N. E.: Evaluating atmospheric mercury (Hg) uptake by vegetation in a chemistry-Transport model, Environ. Sci. Proc. Imp., 24, 1303- 1318, https://doi.org/10.1039/D2EM00032F, 2022.
Forrer, J., Röttimann, R., Schneiter, D., Fischer, A., Buchmann, B., and Hofer, P.: Variability of trace gases at the high-Alpine site Jungfraujoch caused by meteorological transport processes, J. Geophys. Res., 105, 12241-12251, https://doi.org/10.1029/1999JD901178, 2000.
Foucart, B., Sellegri, K., Tulet, P., Rose, C., Metzger, J.-M., and Picard, D.: High occurrence of new particle formation events at the Maïdo high-Altitude observatory (2150 m), Réunion (Indian Ocean), Atmos. Chem. Phys., 18, 9243-9261, https://doi.org/10.5194/acp-18-9243-2018, 2018.
Fu, X., Feng, X., Zhang, H., Yu, B., and Chen, L.: Mercury emissions from natural surfaces highly impacted by human activities in Guangzhou province, South China, Atmos. Environ., 54, 185- 193, https://doi.org/10.1016/j.atmosenv.2012.02.008, 2012.
Fu, X., Marusczak, N., Heimbörger, L.-E., Sauvage, B., Gheusi, F., Prestbo, E. M., and Sonke, J. E.: Atmospheric mercury speciation dynamics at the high-Altitude Pic du Midi Observatory, southern France, Atmos. Chem. Phys., 16, 5623-5639, https://doi.org/10.5194/acp-16-5623-2016, 2016a.
Fu, X., Zhu, W., Zhang, H., Sommar, J., Yu, B., Yang, X., Wang, X., Lin, C.-J., and Feng, X.: Depletion of atmospheric gaseous elemental mercury by plant uptake at Mt.Changbai, Northeast China, Atmos. Chem. Phys., 16, 12861-12873, https://doi.org/10.5194/acp-16-12861-2016, 2016b.
Fu, X., Marusczak, N., Wang, X., Gheusi, F., and Sonke, J. E.: Isotopic Composition of Gaseous Elemental Mercury in the Free Troposphere of the Pic du Midi Observatory, France, Environ. Sci. Technol., 50, 5641-5650, https://doi.org/10.1021/acs.est.6b00033, 2016c.
Gillot, P.-Y. and Nativel, P.: Eruptive history of the Piton de la Fournaise volcano, Reunion Island, Indian Ocean, J. Volcanol. Geoth. Res., 36, 53-65, https://doi.org/10.1016/0377-0273(89)90005-X, 1989.
Guenther, A. B., Zimmerman, P. R., Harley, P. C., Monson, R. K., and Fall, R.: Isoprene and monoterpene emission rate variability: Model evaluations and sensitivity analyses, J. Geophys. Res., 98, 12609, https://doi.org/10.1029/93JD00527, 1993.
Guilpart, E., Vimeux, F., Evan, S., Brioude, J., Metzger, J.-M., Barthe, C., Risi, C., and Cattani, O.: The isotopic composition of near-surface water vapor at the Maïdo observatory (Reunion Island, southwestern Indian Ocean) documents the controls of the humidity of the subtropical troposphere: Water Vapor Isotopes in Reunion Island, J. Geophys. Res.-Atmos., 122, 9628-9650, https://doi.org/10.1002/2017JD026791, 2017.
Gustin, M. S., Amos, H. M., Huang, J., Miller, M. B., and Heidecorn, K.: Measuring and modeling mercury in the atmosphere: A critical review, Atmos. Chem. Phys., 15, 5697-5713, https://doi.org/10.5194/acp-15-5697-2015, 2015.
Gustin, M. S., Dunham-Cheatham, S. M., and Zhang, L.: Comparison of 4 Methods for Measurement of Reactive, Gaseous Oxidized, and Particulate Bound Mercury, Environ. Sci. Technol., 53, 14489-14495, https://doi.org/10.1021/acs.est.9b04648, 2019.
Gustin, M. S., Dunham-Cheatham, S. M., Huang, J., Lindberg, S., and Lyman, S. N.: Development of an Understanding of Reactive Mercury in Ambient Air: A Review, Atmosphere, 12, 73, https://doi.org/10.3390/atmos12010073, 2021.
Hahn, C. J., Merrill, J. T., and Mendonca, B. G.: Meteorological influences during MLOPEX, J. Geophys. Res., 97, 10291, https://doi.org/10.1029/91JD02299, 1992.
Hazan, L., Tarniewicz, J., Ramonet, M., Laurent, O., and Abbaris, A.: Automatic processing of atmospheric CO2 and CH4 mole fractions at the ICOS Atmosphere Thematic Centre, Atmos. Meas. Tech., 9, 4719-4736, https://doi.org/10.5194/amt-9-4719-2016, 2016.
Heiskanen, J., Brömmer, C., Buchmann, N., Calfapietra, C., Chen, H., Gielen, B., Gkritzalis, T., Hammer, S., Hartman, S., Herbst, M., Janssens, I. A., Jordan, A., Juurola, E., Karstens, U., Kasurinen, V., Kruijt, B., Lankreijer, H., Levin, I., Linderson, M.-L., Loustau, D., Merbold, L., Myhre, C. L., Papale, D., Pavelka, M., Pilegaard, K., Ramonet, M., Rebmann, C., Rinne, J., Rivier, L., Saltikoff, E., Sanders, R., Steinbacher, M., Steinhoff, T., Watson, A., Vermeulen, A. T., Vesala, T., Vítková, G., and Kutsch, W.: The Integrated Carbon Observation System in Europe, Bulletin of the American Meteorological Society, 103, E855-E872, https://doi.org/10.1175/BAMS-D-19-0364.1, 2022.
Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz-Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmons, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., Chiara, G., Dahlgren, P., Dee, D., Diamantakis, M., Dragani, R., Flemming, J., Forbes, R., Fuentes, M., Geer, A., Haimberger, L., Healy, S., Hogan, R. J., Hólm, E., Janisková, M., Keeley, S., Laloyaux, P., Lopez, P., Lupu, C., Radnoti, G., Rosnay, P., Rozum, I., Vamborg, F., Villaume, S., and Thépaut, J.: The ERA5 global reanalysis, Q. J. Roy. Meteorol. Soc., 146, 1999-2049, https://doi.org/10.1002/qj.3803, 2020.
Horowitz, H. M., Jacob, D. J., Zhang, Y., Dibble, T. S., Slemr, F., Amos, H. M., Schmidt, J. A., Corbitt, E. S., Marais, E. A., and Sunderland, E. M.: A new mechanism for atmospheric mercury redox chemistry: implications for the global mercury budget, Atmos. Chem. Phys., 17, 6353-6371, https://doi.org/10.5194/acp-17-6353-2017, 2017.
Howard, D., Nelson, P. F., Edwards, G. C., Morrison, A. L., Fisher, J. A., Ward, J., Harnwell, J., van der Schoot, M., Atkinson, B., Chambers, S. D., Griffiths, A. D., Werczynski, S., and Williams, A. G.: Atmospheric mercury in the Southern Hemisphere tropics: seasonal and diurnal variations and influence of inter-hemispheric transport, Atmos. Chem. Phys., 17, 11623- 11636, https://doi.org/10.5194/acp-17-11623-2017, 2017.
Inkscape Project: Inkscape, version 0.92.5 [software], https:// inkscape.org (last access: 18 January 2023), 2022.
Janssen, H.: Monte-Carlo based uncertainty analysis: Sampling efficiency and sampling convergence, Reliab. Eng. Syst. Safe., 109, 123-132, https://doi.org/10.1016/j.ress.2012.08.003, 2013.
Jarvis, A., Guevara, E., Reuter, H. I., and Nelson, A. D.: Hole-filled SRTM for the globe: version 4: data grid, web publication/site, CGIAR Consortium for Spatial Information [data set], https://research.utwente.nl/en/publications/ hole-filled-srtm-for-The-globe-version-4-data-grid (last access: 18 January 2023) 2008.
Jiskra, M., Sonke, J. E., Obrist, D., Bieser, J., Ebinghaus, R., Myhre, C. L., Pfaffhuber, K. A., Wängberg, I., Kyllönen, K., Worthy, D., Martin, L. G., Labuschagne, C., Mkololo, T., Ramonet, M., Magand, O., and Dommergue, A.: A vegetation control on seasonal variations in global atmospheric mercury concentrations, Nat. Geosci., 11, 244-250, https://doi.org/10.1038/s41561-018-0078-8, 2018.
Khalil, M. A. K. and Rasmussen, R. A.: Sources, sinks, and seasonal cycles of atmospheric methane, J. Geophys. Res., 88, 5131- 5144, https://doi.org/10.1029/JC088iC09p05131, 1983.
Kleissl, J., Honrath, R. E., Dziobak, M. P., Tanner, D., Val Martín, M., Owen, R. C., and Helmig, D.: Occurrence of upslope flows at the Pico mountaintop observatory: A case study of orographic flows on a small, volcanic island: upslope flow at the pico-nare station, J. Geophys. Res., 112, D10S35, https://doi.org/10.1029/2006JD007565, 2007.
Kloster, S., Feichter, J., Maier-Reimer, E., Six, K. D., Stier, P., and Wetzel, P.: DMS cycle in the marine ocean-Atmosphere system - a global model study, Biogeosciences, 3, 29-51, https://doi.org/10.5194/bg-3-29-2006, 2006.
Koenig, A. M., Magand, O., Laj, P., Andrade, M., Moreno, I., Velarde, F., Salvatierra, G., Gutierrez, R., Blacutt, L., Aliaga, D., Reichler, T., Sellegri, K., Laurent, O., Ramonet, M., and Dommergue, A.: Seasonal patterns of atmospheric mercury in tropical South America as inferred by a continuous total gaseous mercury record at Chacaltaya station (5240 m) in Bolivia, Atmos. Chem. Phys., 21, 3447-3472, https://doi.org/10.5194/acp-21-3447-2021, 2021.
Koenig, A. M., Sonke, J. E., Magand, O., Andrade, M., Moreno, I., Velarde, F., Forno, R., Gutierrez, R., Blacutt, L., Laj, P., Ginot, P., Bieser, J., Zahn, A., Slemr, F., and Dommergue, A.: Evidence for Interhemispheric Mercury Exchange in the Pacific Ocean Upper Troposphere, J. Geophys Res.-Atmos., 127, e2021JD036283, https://doi.org/10.1029/2021JD036283, 2022.
Kurz, A. Y., Blum, J. D., Gratz, L. E., and Jaffe, D. A.: Contrasting Controls on the Diel Isotopic Variation of Hg 0 at Two High Elevation Sites in the Western United States, Environ. Sci. Technol., 54, 10502-10513, https://doi.org/10.1021/acs.est.0c01918, 2020.
Laurent, O.: ICOS Atmosphere Monitoring Station Assembly, ICOS Atmosphere Thematic Centre (ATC), Report, ICOS Atmospheric Station Specifications v1.3, ICOS-ERIC, https://doi.org/10.18160/SDW6-BX90, 2017.
Lesouëf, D., Gheusi, F., Delmas, R., and Escobar, J.: Numerical simulations of local circulations and pollution transport over Reunion Island, Ann. Geophys., 29, 53-69, https://doi.org/10.5194/angeo-29-53-2011, 2011.
Lesouëf, D., Gheusi, F., Chazette, P., Delmas, R., and Sanak, J.: Low Tropospheric Layers Over Reunion Island in Lidar-Derived Observations and a High-Resolution Model, Bound.-Lay. Meteorol., 149, 425-453, https://doi.org/10.1007/s10546-013-9851-9, 2013.
Lim, A. G., Jiskra, M., Sonke, J. E., Loiko, S. V., Kosykh, N., and Pokrovsky, O. S.: A revised pan-Arctic permafrost soil Hg pool based on Western Siberian peat Hg and carbon observations, Biogeosciences, 17, 3083-3097, https://doi.org/10.5194/bg-17-3083-2020, 2020.
Lin, C. J.: Atmospheric Chemistry of Mercury, in: Environmental Chemistry and Toxicology of Mercury: Liu/Toxicology of Mercury, edited by: Liu, G., Cai, Y., and O-Driscoll, N., John Wiley & Sons, Inc., Hoboken, NJ, USA, https://doi.org/10.1002/9781118146644, 2011.
Lindberg, S., Bullock, R., Ebinghaus, R., Engstrom, D., Feng, X., Fitzgerald, W., Pirrone, N., Prestbo, E., and Seigneur, C.: A Synthesis of Progress and Uncertainties in Attributing the Sources of Mercury in Deposition, AMBIO, 36, 19-33, https://doi.org/10.1579/0044-7447(2007)36[19:ASOPAU]2.0.CO;2, 2007.
Lindqvist, O. and Rodhe, H.: Atmospheric mercury-A review, Tellus B, 37, 136-159, https://doi.org/10.1111/j.1600-0889.1985.tb00062.x, 1985.
Luippold, A., Gustin, M. S., Dunham-Cheatham, S. M., Castro, M., Luke, W., Lyman, S., and Zhang, L.: Use of Multiple Lines of Evidence to Understand Reactive Mercury Concentrations and Chemistry in Hawai-i, Nevada, Mary land, and Utah, USA, Environ. Sci. Technol., 54, 7922-7931, https://doi.org/10.1021/acs.est.0c02283, 2020.
Luo, Y., Duan, L., Driscoll, C. T., Xu, G., Shao, M., Taylor, M., Wang, S., and Hao, J.: Foliage/atmosphere exchange of mercury in a subtropical coniferous forest in south China: Foliage Atmosphere Hg Exchange, J. Geophys. Res.-Biogeo., 121, 2006- 2016, https://doi.org/10.1002/2016JG003388, 2016.
Lyman, S. N., Jaffe, D. A., and Gustin, M. S.: Release of mercury halides from KCl denuders in the presence of ozone, Atmos. Chem. Phys., 10, 8197-8204, https://doi.org/10.5194/acp-10-8197-2010, 2010.
Magand, O. and Dommergue, A.: Continuous measurements of atmospheric mercury at Maido Observatory (L2), Global Mercury Observation System [data set], https://doi.org/10.25326/352, 2022.
Marusczak, N., Sonke, J. E., Fu, X., and Jiskra, M.: Tropospheric GOM at the Pic du Midi Observatory - Correcting Bias in Denuder Based Observations, Environ. Sci. Technol., 51, 863-869, https://doi.org/10.1021/acs.est.6b04999, 2017.
McClure, C. D., Jaffe, D. A., and Edgerton, E. S.: Evaluation of the KCl Denuder Method for Gaseous Oxidized Mercury using HgBr 2 at an In-Service AMNet Site, Environ. Sci. Technol., 48, 11437-11444, https://doi.org/10.1021/es502545k, 2014.
Metropolis, N. and Ulam, S.: The Monte Carlo Method, J. Am. Stat. Assoc., 44, 335-341, https://doi.org/10.1080/01621459.1949.10483310, 1949.
Miller, M. B., Howard, D. A., Pierce, A. M., Cook, K. R., Keywood, M., Powell, J., Gustin, M. S., and Edwards, G. C.: Atmospheric reactive mercury concentrations in coastal Australia and the Southern Ocean, Sci. Total Environ., 751, 141681, https://doi.org/10.1016/j.scitotenv.2020.141681, 2021.
Munthe, J., Sprovieri, F., Horvat, M., and Ebinghaus, R.: SOPs and QA/QC protocols regarding measurements of TGM, GEM, RGM, TPM and mercury in precipitation in cooperation with WP3, WP4 and WP5, GMOS deliverable 6.1, CNR-IIA, IVL, http://www.gmos.eu (last access: 18 January 2023), 2011.
Nair, U. S., Wu, Y., Holmes, C. D., Ter Schure, A., Kallos, G., and Walters, J. T.: Cloud-resolving simulations of mercury scavenging and deposition in thunderstorms, Atmos. Chem. Phys., 13, 10143-10157, https://doi.org/10.5194/acp-13-10143-2013, 2013.
Nguyen, L. S. P., Sheu, G.-R., Lin, D.-W., and Lin, N.-H.: Temporal changes in atmospheric mercury concentrations at a background mountain site downwind of the East Asia continent in 2006-2016, Sci. Total Environ., 686, 1049-1056, https://doi.org/10.1016/j.scitotenv.2019.05.425, 2019.
Nguyen, L. S. P., Sheu, G.-R., Chang, S.-C., and Lin, N.-H.: Effects of temperature and relative humidity on the partitioning of atmospheric oxidized mercury at a high-Altitude mountain background site in Taiwan, Atmos. Environ., 261, 118572, https://doi.org/10.1016/j.atmosenv.2021.118572, 2021.
Nguyen, L. S. P., Nguyen, K. T., Griffith, S. M., Sheu, G.-R., Yen, M.-C., Chang, S.-C., and Lin, N.-H.: Multiscale Temporal Variations of Atmospheric Mercury Distinguished by the Hilbert-Huang Transform Analysis Reveals Multiple El Niño- Southern Oscillation Links, Environ. Sci. Technol., 56, 1423- 1432, https://doi.org/10.1021/acs.est.1c03819, 2022.
Obrist, D., Hallar, A. G., McCubbin, I., Stephens, B. B., and Rahn, T.: Atmospheric mercury concentrations at Storm Peak Laboratory in the Rocky Mountains: Evidence for long-range transport from Asia, boundary layer contributions, and plant mercury uptake, Atmos. Environ., 42, 7579-7589, https://doi.org/10.1016/j.atmosenv.2008.06.051, 2008.
Osterwalder, S., Bishop, K., Alewell, C., Fritsche, J., Laudon, H., Akerblom, S., and Nilsson, M. B.: Mercury evasion from a boreal peatland shortens the timeline for recovery from legacy pollution, Sci. Rep., 7, 16022, https://doi.org/10.1038/s41598-017-16141-7, 2017.
Pacifico, F., Harrison, S. P., Jones, C. D., and Sitch, S.: Isoprene emissions and climate, Atmos. Environ., 43, 6121-6135, https://doi.org/10.1016/j.atmosenv.2009.09.002, 2009.
Panagos, P., Jiskra, M., Borrelli, P., Liakos, L., and Ballabio, C.: Mercury in European topsoils: Anthropogenic sources, stocks and fluxes, Environ. Res., 201, 111556, https://doi.org/10.1016/j.envres.2021.111556, 2021.
Pisso, I., Sollum, E., Grythe, H., Kristiansen, N. I., Cassiani, M., Eckhardt, S., Arnold, D., Morton, D., Thompson, R. L., Groot Zwaaftink, C. D., Evangeliou, N., Sodemann, H., Haimberger, L., Henne, S., Brunner, D., Burkhart, J. F., Fouilloux, A., Brioude, J., Philipp, A., Seibert, P., and Stohl, A.: The Lagrangian particle dispersion model FLEXPART version 10.4, Geosci. Model Dev., 12, 4955-4997, https://doi.org/10.5194/gmd-12-4955-2019, 2019.
Pohl, B., Morel, B., Barthe, C., and Bousquet, O.: Regionalizing Rainfall at Very High Resolution over La Réunion Island: A Case Study for Tropical Cyclone Ando, Mon.Weather Rev., 144, 4081-4099, https://doi.org/10.1175/MWR-D-15-0404.1, 2016.
QGIS Development Team: QGIS Geographic Information System, QGIS Association [software], https://www.qgis.org (last access: 18 January 2023), 2022.
R Core Team: R: A Language and Environment for Statistical Computing, R Foundation for Statistical Computing [software], Vienna, Austria, https://www.R-project.org/ (last access: 18 January 2023), 2019.
Reidmiller, D. R., Jaffe, D. A., Fischer, E. V., and Finley, B.: Nitrogen oxides in the boundary layer and free troposphere at the Mt. Bachelor Observatory, Atmos. Chem. Phys., 10, 6043-6062, https://doi.org/10.5194/acp-10-6043-2010, 2010.
Rocco, M., Colomb, A., Baray, J.-L., Amelynck, C., Verreyken, B., Borbon, A., Pichon, J.-M., Bouvier, L., Schoon, N., Gros, V., Sarda-Esteve, R., Tulet, P., Metzger, J.-M., Duflot, V., Guadagno, C., Peris, G., and Brioude, J.: Analysis of Volatile Organic Compounds during the OCTAVE Campaign: Sources and Distributions of Formaldehyde on Reunion Island, Atmosphere, 11, 140, https://doi.org/10.3390/atmos11020140, 2020.
Roelfsema, M. R. G. and Hedrich, R.: In the light of stomatal opening: new insights into "the Watergate", New Phytol., 167, 665- 691, https://doi.org/10.1111/j.1469-8137.2005.01460.x, 2005.
Rohatgi, A.: WebPlotDigitize, Version 4.5 [software], https:// automeris.io/WebPlotDigitizer (last access: 18 January 2023), 2021.
Rose, C., Foucart, B., Picard, D., Colomb, A., Metzger, J.-M., Tulet, P., and Sellegri, K.: New particle formation in the volcanic eruption plume of the Piton de la Fournaise: specific features from a long-Term dataset, Atmos. Chem. Phys., 19, 13243-13265, https://doi.org/10.5194/acp-19-13243-2019, 2019.
Schroeder, W. H. and Munthe, J.: Atmospheric mercury - An overview, Atmos. Environ., 32, 809-822, https://doi.org/10.1016/S1352-2310(97)00293-8, 1998.
Schroeder,W. H., Anlauf, K. G., Barrie, L. A., Lu, J. Y., Steffen, A., Schneeberger, D. R., and Berg, T.: Arctic springtime depletion of mercury, Nature, 394, 331-332, https://doi.org/10.1038/28530, 1998.
Seibert, P. and Frank, A.: Source-receptor matrix calculation with a Lagrangian particle dispersion model in backward mode, Atmos. Chem. Phys., 4, 51-63, https://doi.org/10.5194/acp-4-51-2004, 2004.
Selin, N. E., Jacob, D. J., Park, R. J., Yantosca, R. M., Strode, S., Jaeglé, L., and Jaffe, D.: Chemical cycling and deposition of atmospheric mercury: Global constraints from observations, J. Geophys. Res., 112, D02308, https://doi.org/10.1029/2006JD007450, 2007.
Shah, V., Jacob, D. J., Thackray, C. P., Wang, X., Sunderland, E. M., Dibble, T. S., Saiz-Lopez, A., C- ernušák, I., Kellö, V., Castro, P. J., Wu, R., and Wang, C.: Improved Mechanistic Model of the Atmospheric Redox Chemistry of Mercury, Environ. Sci. Technol., 55, 14445-14456, https://doi.org/10.1021/acs.est.1c03160, 2021.
Sheu, G.-R., Lin, N.-H., Wang, J.-L., Lee, C.-T., Ou Yang, C.-F., and Wang, S.-H.: Temporal distribution and potential sources of atmospheric mercury measured at a high-elevation background station in Taiwan, Atmos. Environ., 44, 2393-2400, https://doi.org/10.1016/j.atmosenv.2010.04.009, 2010.
Slemr, F., Angot, H., Dommergue, A., Magand, O., Barret, M., Weigelt, A., Ebinghaus, R., Brunke, E.-G., Pfaffhuber, K. A., Edwards, G., Howard, D., Powell, J., Keywood, M., and Wang, F.: Comparison of mercury concentrations measured at several sites in the Southern Hemisphere, Atmos. Chem. Phys., 15, 3125- 3133, https://doi.org/10.5194/acp-15-3125-2015, 2015.
Slemr, F., Martin, L., Labuschagne, C., Mkololo, T., Angot, H., Magand, O., Dommergue, A., Garat, P., Ramonet, M., and Bieser, J.: Atmospheric mercury in the Southern Hemisphere - Part 1: Trend and inter-Annual variations in atmospheric mercury at Cape Point, South Africa, in 2007-2017, and on Amsterdam Island in 2012-2017, Atmos. Chem. Phys., 20, 7683-7692, https://doi.org/10.5194/acp-20-7683-2020, 2020.
Song, S., Angot, H., Selin, N. E., Gallée, H., Sprovieri, F., Pirrone, N., Helmig, D., Savarino, J., Magand, O., and Dommergue, A.: Understanding mercury oxidation and air-snow exchange on the East Antarctic Plateau: A modeling study, Atmos. Chem. Phys., 18, 15825-15840, https://doi.org/10.5194/acp-18-15825-2018, 2018.
Sprovieri, F., Pirrone, N., Bencardino, M., D'Amore, F., Carbone, F., Cinnirella, S., Mannarino, V., Landis, M., Ebinghaus, R., Weigelt, A., Brunke, E.-G., Labuschagne, C., Martin, L., Munthe, J., Wängberg, I., Artaxo, P., Morais, F., Barbosa, H. de M. J., Brito, J., Cairns, W., Barbante, C., Diéguez, M. del C., Garcia, P. E., Dommergue, A., Angot, H., Magand, O., Skov, H., Horvat, M., Kotnik, J., Read, K. A., Neves, L. M., Gawlik, B. M., Sena, F., Mashyanov, N., Obolkin, V., Wip, D., Feng, X. B., Zhang, H., Fu, X., Ramachandran, R., Cossa, D., Knoery, J., Marusczak, N., Nerentorp, M., and Norstrom, C.: Atmospheric mercury concentrations observed at groundbased monitoring sites globally distributed in the framework of the GMOS network, Atmos. Chem. Phys., 16, 11915-11935, https://doi.org/10.5194/acp-16-11915-2016, 2016.
Stefels, J., Steinke, M., Turner, S., Malin, G., and Belviso, S.: Environmental constraints on the production and removal of the climatically active gas dimethylsulphide (DMS) and implications for ecosystem modelling, Biogeochemistry, 83, 245-275, https://doi.org/10.1007/s10533-007-9091-5, 2007.
Stieltjes, L. and Moutou, P.: A statistical and probabilistic study of the historic activity of Piton de la Fournaise, Reunion Island, Indian Ocean, J. Volcanol. Geoth. Res., 36, 67-86, https://doi.org/10.1016/0377-0273(89)90006-1, 1989.
Stohl, A., Forster, C., Frank, A., Seibert, P., and Wotawa, G.: Technical note: The Lagrangian particle dispersion model FLEXPART version 6.2, Atmos. Chem. Phys., 5, 2461-2474, https://doi.org/10.5194/acp-5-2461-2005, 2005.
Sun, S., Ma, M., He, X., Obrist, D., Zhang, Q., Yin, X., Sun, T., Huang, J., Guo, J., Kang, S., and Qin, D.: Vegetation Mediated Mercury Flux and Atmospheric Mercury in the Alpine Permafrost Region of the Central Tibetan Plateau, Environ. Sci. Technol., 54, 6043-6052, https://doi.org/10.1021/acs.est.9b06636, 2020.
Swartzendruber, P. C., Jaffe, D. A., Prestbo, E. M., Weiss-Penzias, P., Selin, N. E., Park, R., Jacob, D. J., Strode, S., and Jaeglé, L.: Observations of reactive gaseous mercury in the free troposphere at the Mount Bachelor Observatory, J. Geophys. Res., 111, D24301, https://doi.org/10.1029/2006JD007415, 2006.
Swinehart, D. F.: The Beer-Lambert Law, J. Chem. Educ., 39, 333, https://doi.org/10.1021/ed039p333, 1962.
Travnikov, O.: Atmospheric Transport of Mercury, in: Environmental Chemistry and Toxicology of Mercury: Liu/-Toxicology of Mercury, edited by: Liu, G., Cai, Y., and O-Driscoll, N., John Wiley & Sons, Inc., Hoboken, NJ, USA, https://doi.org/10.1002/9781118146644, 2011.
Tulet, P., Di Muro, A., Colomb, A., Denjean, C., Duflot, V., Arellano, S., Foucart, B., Brioude, J., Sellegri, K., Peltier, A., Aiuppa, A., Barthe, C., Bhugwant, C., Bielli, S., Boissier, P., Boudoire, G., Bourrianne, T., Brunet, C., Burnet, F., Cammas, J.-P., Gabarrot, F., Galle, B., Giudice, G., Guadagno, C., Jeamblu, F., Kowalski, P., Leclair de Bellevue, J., Marquestaut, N., Mékies, D., Metzger, J.-M., Pianezze, J., Portafaix, T., Sciare, J., Tournigand, A., and Villeneuve, N.: First results of the Piton de la Fournaise STRAP 2015 experiment: multidisciplinary tracking of a volcanic gas and aerosol plume, Atmos. Chem. Phys., 17, 5355- 5378, https://doi.org/10.5194/acp-17-5355-2017, 2017.
Tulet, P., Aunay, B., Barruol, G., Barthe, C., Belon, R., Bielli, S., Bonnardot, F., Bousquet, O., Cammas, J.-P., Cattiaux, J., Chauvin, F., Fontaine, I., Fontaine, F. R., Gabarrot, F., Garabedian, S., Gonzalez, A., Join, J.-L., Jouvenot, F., Nortes-Martinez, D., Mékiès, D., Mouquet, P., Payen, G., Pennober, G., Pianezze, J., Rault, C., Revillion, C., Rindraharisaona, E. J., Samyn, K., Thompson, C., and Vérèmes, H.: ReNovRisk: A multidisciplinary programme to study the cyclonic risks in the South-West Indian Ocean, Nat. Hazards, 107, 1191-1223, https://doi.org/10.1007/s11069-021-04624-w, 2021.
Verreyken, B., Brioude, J., and Evan, S.: Development of turbulent scheme in the FLEXPART-AROME v1.2.1 Lagrangian par ticle dispersion model, Geosci. Model Dev., 12, 4245-4259, https://doi.org/10.5194/gmd-12-4245-2019, 2019.
Verreyken, B., Amelynck, C., Brioude, J., Möller, J.-F., Schoon, N., Kumps, N., Colomb, A., Metzger, J.-M., Lee, C. F., Koenig, T. K., Volkamer, R., and Stavrakou, T.: Characterisation of African biomass burning plumes and impacts on the atmospheric composition over the south-west Indian Ocean, Atmos. Chem. Phys., 20, 14821-14845, https://doi.org/10.5194/acp-20-14821-2020, 2020.
Verreyken, B., Amelynck, C., Schoon, N., Möller, J.-F., Brioude, J., Kumps, N., Hermans, C., Metzger, J.-M., Colomb, A., and Stavrakou, T.: Measurement report: Source apportionment of volatile organic compounds at the remote high-Altitude Maïdo observatory, Atmos. Chem. Phys., 21, 12965-12988, https://doi.org/10.5194/acp-21-12965-2021, 2021.
Villeneuve, N. and Bachèlery, P.: Revue de la typologie des éruptions au Piton de La Fournaise, processus et risques volcaniques associés, cybergeo, Europ. J. Geogr., https://doi.org/10.4000/cybergeo.2536, 2006.
Wang, Y., Anderegg, W. R. L., Venturas, M. D., Trugman, A. T., Yu, K., and Frankenberg, C.: Optimization theory explains nighttime stomatal responses, New Phytol., 230, 1550-1561, https://doi.org/10.1111/nph.17267, 2021.
Weisspenzias, P., Jaffe, D., Swartzendruber, P., Hafner, W., Chand, D., and Prestbo, E.: Quantifying Asian and biomass burning sources of mercury using the Hg =CO ratio in pollution plumes observed at the Mount Bachelor observatory, Atmos. Environ., 41, 4366-4379, https://doi.org/10.1016/j.atmosenv.2007.01.058, 2007.
Wickham, H.: ggplot2: Elegant Graphics for Data Analysis, 2nd Edn., Springer International Publishing, Imprint, Springer, Cham, https://doi.org/10.1007/978-3-319-24277-4, 2016.
Wickham, H., Averick, M., Bryan, J., Chang, W., McGowan, L., François, R., Grolemund, G., Hayes, A., Henry, L., Hester, J., Kuhn, M., Pedersen, T., Miller, E., Bache, S., Möller, K., Ooms, J., Robinson, D., Seidel, D., Spinu, V., Takahashi, K., Vaughan, D., Wilke, C., Woo, K., and Yutani, H.: Welcome to the Tidyverse, J. Open Source Softw., 4, 1686, https://doi.org/10.21105/joss.01686, 2019.
Yu, Q., Luo, Y.,Wang, S.,Wang, Z., Hao, J., and Duan, L.: Gaseous elemental mercury (GEM) fluxes over canopy of two typical subtropical forests in south China, Atmos. Chem. Phys., 18, 495- 509, https://doi.org/10.5194/acp-18-495-2018, 2018.
Yu, Q., Luo, Y., Xu, G., Wu, Q., Wang, S., Hao, J., and Duan, L.: Subtropical Forests Act as Mercury Sinks but as Net Sources of Gaseous Elemental Mercury in South China, Environ. Sci. Technol., 54, 2772-2779, https://doi.org/10.1021/acs.est.9b06715, 2020.
Yuan, W., Sommar, J., Lin, C.-J., Wang, X., Li, K., Liu, Y., Zhang, H., Lu, Z.,Wu, C., and Feng, X.: Stable Isotope Evidence Shows Re-emission of Elemental Mercury Vapor Occurring after Reductive Loss from Foliage, Environ. Sci. Technol., 53, 651-660, https://doi.org/10.1021/acs.est.8b04865, 2019.
Yver-Kwok, C., Philippon, C., Bergamaschi, P., Biermann, T., Calzolari, F., Chen, H., Conil, S., Cristofanelli, P., Delmotte, M., Hatakka, J., Heliasz, M., Hermansen, O., Komínková, K., Kubistin, D., Kumps, N., Laurent, O., Laurila, T., Lehner, I., Levula, J., Lindauer, M., Lopez, M., Mammarella, I., Manca, G., Marklund, P., Metzger, J.-M., Mölder, M., Platt, S. M., Ramonet, M., Rivier, L., Scheeren, B., Sha, M. K., Smith, P., Steinbacher, M., Vítková, G., and Wyss, S.: Evaluation and optimization of ICOS atmosphere station data as part of the labeling process, Atmos. Meas. Tech., 14, 89-116, https://doi.org/10.5194/amt-14-89-2021, 2021.
Zhang, P. and Zhang, Y.: Earth system modeling of mercury using CESM2 - Part 1: Atmospheric model CAM6-Chem/Hg v1.0, Geosci. Model Dev., 15, 3587-3601, https://doi.org/10.5194/gmd-15-3587-2022, 2022.
Zhou, J. and Obrist, D.: Global Mercury Assimilation by Vegetation, Environ. Sci. Technol., 55, 14245-14257, https://doi.org/10.1021/acs.est.1c03530, 2021.
Zhou, M., Langerock, B., Vigouroux, C., Sha, M. K., Ramonet, M., Delmotte, M., Mahieu, E., Bader, W., Hermans, C., Kumps, N., Metzger, J.-M., Duflot, V., Wang, Z., Palm, M., and De Mazière, M.: Atmospheric CO and CH4 time series and seasonal variations on Reunion Island from ground-based in situ and FTIR (NDACC and TCCON) measurements, Atmos. Chem. Phys., 18, 13881-13901, https://doi.org/10.5194/acp-18-13881-2018, 2018.
