Reactive halogen chemistry in volcanic plumes – an overview on our current understanding Nicole Bobrowski1,2 and Ulrich Platt1 , Peter Lübcke1 Jonas Gliss3, Santiago Arellano4, Leif Vogel1,8, Florian Dinger1, Bo Galle2, Gustavo Garzón5, Julian Peña7, Zoraida Chacon7, Mathiew Yalire6, Abel Minani6, Simon Warnach1 1 Institute of Environmental Physics (IUP), Heidelberg University, INF 229, D-69120 Heidelberg, Germany 2 Institut fuer Geowissenschaften, Universitaet Mainz, Germany 3 Norwegian Institute for Air Research (NILU), Kjeller, Norway 4 Department of Earth and Space Sciences, Chalmers University of Technology, Gothenburg, Sweden 5 FISQUIM Research Group, Laboratory Division, Colombian Geological Survey, Cali, Colombia 6 Observatoire Volcanologique de Goma , Goma, DR Congo 7 Colombian Geological Survey, Manizales, Colombia 8 now at Earth Observation Science Group, Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, UK Motivation for volcanic halogen studies • Volcanic Activity Changes • Plume Chemistry, Atmospheric 2000 Chemistry, Radiation Budget,.. , • Environmental and Health Impact Robock Bobrowski et al., 2007Bobrowski Tropospheric chemistry could be influenced by volcanic halogen emission in various ways (Platt and Bobrowski 2015): 1) Bromine catalyses O3 destruction 2) Bromine inhibits the O3 production in the troposphere 3) RHS reactions interfere with the NOx reaction cycle. 4) RHS reactions enhance the OH/HO2 ratio 5) Hypohalous acids (HOBr, HOCl) contribute to the formation of sulphate in aqueous particles 6) RHS can induce secondary organic aerosol formation (shown in lab studies by Cai et al. 2008 for Cl atoms and Ofner et al. 2013 for Cl and Br) 7) Bromine can oxidize mercury, and therefore reduce its atmospheric lifetime …. There is reactive halogen chemistry in the volcanic plume: MAX-DOAS BrO and SO2 from Soufriere Hills Volcano on Montserrat, May 2002 N. Bobrowski, G. Hönninger, B. Galle, and U. Platt, (2003), Detection of bromine monoxide in a volcanic plume, Nature, 423, doi: 10.1038/nature01625 0 10 20 30 40 50 60 70 80 90 330 340 350 360 0 10 20 30 40 50 60 70 80 90 306 308 310 312 314 316 318 12.0 120 4 5 4 14.0 10 10 100 ] ] 1 2 2 4 10.0 5 SO BrO [%] Optical Density 9 12.0 9 80 5 3 8 2 8 8.0 60 [%] Optical Density 10.0 3 7 3 2 40 7 molec/cm molec/cm 17 14 6 8.0 6 1 6.0 6 20 5 6 5 0 0 6.0 4.0 4 2 7 4 2 -1 SCD[10 -20 2 4.0 7 3 2.0 -40 3 -2 SO * BrO SCD[10 BrO 1 8 1 9 2 -60 2.0 8 2 -3 10 9 0.0 10 1 -80 0.0 1 -4 0 10 20 30 40 50 60 70 80 90 306 308 310 312 314 316 318 0 10 20 30 40 50 60 70 80 90 330 340 350 360 elevation angle [°] elevation angle [°] BrO is nothing exceptional in a volcanic plume Klichuvskoi13 Eyjafjallajökull9,13 , Kizimen13 , Karymsky13 Kasatochi8,13 5 Mutnovsky Stromboli 12,18 Mt. Gorely 13,15 Redoubt Mt. Etna e.g.3,4,5,6 Sarychev13 1,5 Soufriere Hills Sakurajima2 Popocatépetl18 Pacaya11 Dallafilla, Nabro13 Masaya5 San Cristobal18 Nevado del Ruiz13 Galeras Tungurahua Ambrym7,13 Copahue 5 Villarica Nyamulagira Puyehue-Cordón Caulle17 Nyiragongo15 Mt Erebus10 >BrO detected on > 25 volcanoes -3 -6 BrO/SO2 between 10 – 10 Platt and Bobrowski, 2015 Nevado del Ruiz, Colombia BrO/SO2 time series Etna, Italy Bobrowski and Giuffrida, 2012 Giuffrida, and Bobrowski Lübcke et al., 2014 Global volcanic gas studies: NOVAC – the great opportunity Harestua Vulcano Eijafjallajökull, Stromboli Hekla Mount Etna Bárdarbunga Popocatépetl INSTRUMENT, NETWORKING, GLOBAL STUDIES Colima Santa Ana COORDINATOR: Chalmers U. (SE) Santiaguito San Miguel Heidelberg U. (DE) Fuego Institut Aerospatiale de Belgique (BE) Cambridge U. (UK) San Cristóbal IFM-GEOMAR (DE) Masaya MIT (US) Arenal Mayon Maryland U. (US) Turrialba Sierra Negra VOLCANO OBSERVATORIES Concepción Nyamuragira INGV-CT/PA (IT) Nevado del Ruiz Nyiragongo IPGP (FR) INETER (NI) Nevado del Huila Ubinas OVSICORI (CR) Galeras SGC (CO) Cotopaxi SNET (SV) Copahue OVG (CD) Tungurahua UNAM (MX) Sangay IGEPN (EC) Láscar INSIVUMEH (GT) IMO (IS) Llaima Piton de la Fournaise PHIVOLCS/EOS (PH) Villarica INGEMMET (PE) 80 stations in 31 volcanoes, 21 countries, 40 measurements per day 33 volcanoes, ~80 instruments, 21 volcanoes actively monitored today Global volcanic gas studies: NOVAC – the great opportunity BrO Harestua Vulcano Eijafjallajökull, Stromboli Hekla Mount Etna Bárdarbunga Popocatépetl INSTRUMENT, NETWORKING, GLOBAL STUDIES Colima Santa Ana COORDINATOR: Chalmers U. (SE) Santiaguito San Miguel Heidelberg U. (DE) Fuego Institut Aerospatiale de Belgique (BE) Cambridge U. (UK) San Cristóbal IFM-GEOMAR (DE) Masaya MIT (US) Arenal Mayon Maryland U. (US) Turrialba Sierra Negra VOLCANO OBSERVATORIES Concepción Nyamuragira INGV-CT/PA (IT) Nevado del Ruiz Nyiragongo IPGP (FR) INETER (NI) Nevado del Huila Ubinas OVSICORI (CR) Galeras SGC (CO) Cotopaxi SNET (SV) Copahue OVG (CD) Tungurahua UNAM (MX) Sangay IGEPN (EC) Láscar INSIVUMEH (GT) IMO (IS) Llaima Piton de la Fournaise PHIVOLCS/EOS (PH) Villarica INGEMMET (PE) 80 stations in 31 volcanoes, 21 countries, 40 measurements per day 33 volcanoes, ~80 instruments, 21 volcanoes actively monitored today Global volcanic gas studies: NOVAC – the great opportunity BrO NOVAC BrO Harestua Vulcano Eijafjallajökull, Stromboli Hekla Mount Etna Bárdarbunga Popocatépetl INSTRUMENT, NETWORKING, GLOBAL STUDIES Colima Santa Ana COORDINATOR: Chalmers U. (SE) Santiaguito San Miguel Heidelberg U. (DE) Fuego Institut Aerospatiale de Belgique (BE) Cambridge U. (UK) San Cristóbal IFM-GEOMAR (DE) Masaya MIT (US) Arenal Mayon Maryland U. (US) Turrialba Sierra Negra VOLCANO OBSERVATORIES Concepción Nyamuragira INGV-CT/PA (IT) Nevado del Ruiz Nyiragongo IPGP (FR) INETER (NI) Nevado del Huila Ubinas OVSICORI (CR) Galeras SGC (CO) Cotopaxi SNET (SV) Copahue OVG (CD) Tungurahua UNAM (MX) Sangay IGEPN (EC) Láscar INSIVUMEH (GT) IMO (IS) Llaima Piton de la Fournaise PHIVOLCS/EOS (PH) Villarica INGEMMET (PE) 80 stations in 31 volcanoes, 21 countries, 40 measurements per day 33 volcanoes, ~80 instruments, 21 volcanoes actively monitored today BrO and SO2 at different distances down- wind from the crater of Etna Bobrowski et al., 2007 Oppenheimer et al., 2006 BrO and SO2 at different distances down- wind from the crater of Etna Evolution of a passive tracer (red) and a fictious reactive component (blue) with time in the volcanic plume. By taking a ratio, atmospherheric dilution effects and temporal variations of emitted amounts are elimitated Bobrowski et al., 2007 Oppenheimer et al., 2006 BrO/SO2 ratio dependence of the distance from the source 5 Etna 2004 Etna 2005 4 -4 3 2 BrO/SO2 10 BrO/SO2 1 0 Adapted from Adaptedfrom 2005 Bobrowski etal., 0 5 10 15 20 distance km Vogel, 2010 General agreement with model data possible SO2 and BrO- spatial distribution in a volcanic plume Louban et al., 2009 What do we know about BrO in volcanic plumes? BrO is a secondary gas a bit of attention is needed when using it as volcanic activity tracer Bromine explosion HOBr(gas)→ HOBr(aq) - + HBr(gas)→ Br (aq) + H (aq) − + HOBr(aq)+ Br (aq)+ H (aq)→Br2(gas)+H2O Br2 + hν→2Br Br + O →BrO + O Bobrowski et al. 2007 3 2 BrO + BrO→2Br + O2 e.g. Bobrowski et al. 2007 Glasow et al. 2009 BrO + BrO→Br2 + O2 BrO + HO2→HOBr + O2 Is this everything ? Ozone depletion Etna 2012 Smallest O3 mixing ratio measured 40 ppb Surl, et al., 2014 Models predict complete ozone depletion in plume [ Von Glasow ] Nyiragongo and Etna Nyirag ongo Nyiragongo 2004/2007) 3 Etna 9 May 2005 Etna 2004 Etna -4 2 -- Nyiragongo 10 2 BrO/SO 1 0 0 20 40 60 time [min] Bobrowski et al., 2015 Variation in initial plume composition lead to significant difference in BrO formation in an ageing plume, shown in measurements and model Simultaneous Br/S and BrO/SO2 data: 60 Masaya 50 Nyiragongo Measurements Stromboli Mt Etna 40 Gorely 30 20 BrO fraction[%] BrO Simultaneous measurements of Br/S 10 and BrO/SO2 ratios at 5 different volcanoes 0 0.0 2.0 4.0 6.0 8.0 10.0 molar Br/S 10-4 Model Recent Model studies of T. Roberts et al., 2014 CCVG - Chile Further Gases: Etna 5th August 2004 – OClO detection 4,0 2,0 ] 2 ] 2 3,0 1,5 molecules/cm 14 2,0 1,0 molecules/cm 10 [ 18 , [10 , 2 OClO , 1,0 0,5 SO BrO SCD SCD 0,0 0,0 -1,0 -0,5 0 20 40 60 80 100 120 viewing angle Bobrowski et al., 2007 Chlorine chemistry OClO formation in the plume of Mt Etna Gliss et al., 2014 General et al., 2014 scanning Airplane measurements DOAS Chlorine Chemistry Formation of OClO: BrO + ClO OClO + Br, k = 610-12cm3 molecule-1 s-1 other products OClO Destruction: OClO + h ClO + O Assuming a photo-stationary state: Sept. 11, 2012, 11:30 UTC d OClO BrO ClO k OClO J 0 11 Gliss et al., 2014 dt OClO J1 S OClO J1 ClO BrO k S BrO k 1 1 From ClO we can calculate also the amount of Cl atoms -> Reduction of CH4 lifetime 2 orders of magnitude – however even assuming only 1 pbb O3 would lead to a CH4 lifetime of the order of half a day (CH4 mean lifetime in the atmosphere 10 years) Summary • Reactive halogens (e.g. BrO, OClO) abundant in volcanic plumes • Measured mixing ratios can be roughly explained by known chemistry, however in detail model and measurements are in disagreement • Influence on tropospheric chemistry poorly studied • How much of emitted bromine is transformed into BrO • Is the transformation factor constant ? (how to measure total bromine?) • Sensitivity to environmental and volcanic factors ? • What about iodine? • … Merci ! Danke – Grazie - Gracias - Aksanti – Thanks Questions??? Mercury in volcanic plumes Major emitted species GEM (Hg0) – chemical inert, low water solubility Bagnato,et al., 2011 Adapted from Pacyna et al., 2006 An advantage of ratios: radiative transfer can be a smaller issue => The ratio of two gases is less influenced by radiative transfer than the absolute column density Lübcke, 2014 Preliminary results – Copahue, Argentina 5,0 R2=0.54 BrO/SO - 1.6x106 4,0 2 2 3,0 2,0 molecules/cm 13 1,0 BrO 10 BrO 0,0 0,0 2,0 4,0 6,0 8,0 10,0 12,0 14,0 SO 1018 molecules/cm2 2 Global volcanic gas studies: NOVAC – the great opportunity BrO NOVAC BrO Harestua Vulcano Eijafjallajökull, Stromboli Hekla Mount Etna Bárdarbunga Popocatépetl INSTRUMENT, NETWORKING, GLOBAL STUDIES Colima Santa Ana COORDINATOR: Chalmers U.