Modeling the lava heat flux during severe effusive volcanic eruption: An important impact on surface air quality

Abstract

The Reunion Island experienced its biggest eruption of Piton de la Fournaise Volcano during April 2007. Known as the eruption of the century, this event degassed more than 230 kt of SO 2 . Theses emissions led to important health issues, accompanied by environmental and infrastructure degradations. This modeling study uses the mesoscale chemical model MesoNH-C to simulate the transport of gaseous SO 2 between 2 and 7 April, with a focus on the influence of heat fluxes from lava. This study required the implementation of a reduced chemical scheme, a basic surface model, and an estimation of lava heat fluxes in the atmospheric model. The model was able to reproduce general trends of this eruption, in particular the crossing of trade wind inversion, the SO 2 surface concentration (with highest peak of SO 2 of 600 μg m −3 observed on 4 April for western Reunion locations), and the wet deposition associated to rainfall. A sensitivity study shows that without heat fluxes over the vent and the lava flow, simulated SO 2 surface concentration are up to 45 times higher than observed.

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

“…Several MESO‐NH simulations have been successfully performed over Reunion Island at different resolutions to study cyclone formation or pollutant transport [ Tulet and Villeneuve , ; Lesouëf et al ., , ; Jolivet et al ., ; Durand et al ., ; Sivia et al ., ; Vérèmes et al ., ]. The model was set up with four two‐way nested domains having horizontal grid spacing of 16, 8, 2, and 0.5 km and grid size of 200 × 200, 128 × 128, 128 × 128, and 192 × 160 points, respectively.…”

“…Several MESO-NH simulations have been successfully performed over Reunion Island at different resolutions to study cyclone formation or pollutant transport [Tulet and Villeneuve, 2011;Lesouëf et al, 2011Lesouëf et al, , 2013Jolivet et al, 2013;Durand et al, 2014;Sivia et al, 2015;Vérèmes et al, 2016] First, we will use the FLEXPART (FLEXible PARTicle dispersion model) Lagrangian particle dispersion model to assess air masses origin and transport pathways. We will focus on May 2015 to take advantage of the Maïdo ObservatoRy Gaz and Aerosols Ndacc Experiment (MORGANE) field campaign that started in May [Duflot et al, 2017].…”

Preliminary results from the FARCE 2015 campaign: multidisciplinary study of the forest–gas–aerosol–cloud system on the tropical island of La Réunion

“…Forests, gases (especially biogenic volatile organic compounds, BVOCs), aerosols (especially secondary organic aerosols, SOAs) and clouds are linked through deep, complex, and interdependent bio-physico-chemical mechanisms. Forests emit BVOCs whose oxidative products may undergo a phase transition and form SOA in the gas-phase chemistry (van Donkelaar et al, 2007;Carlton et al, 2009) or after dissolution and photo-oxidation in cloud water (Yao Liu et al, 2009;Chen et al, 2007;Hallquist et al, 2009;Ervens et al, 2011;Couvidat et al, 2013). Aside from modifying the Earth's radiative budget through their direct effects via scattering and absorption of radiation, aerosols also produce semi-indirect and indirect effects that modify the dynamics of the atmosphere and the cloud life cycle by adjusting their radiative and microphysical properties.…”

First results of the Piton de la Fournaise STRAP 2015 experiment: multidisciplinary tracking of a volcanic gas and aerosol plume

“…The small amount of silicate ash and primary aerosol in the plumes of Piton de la Fournaise make this volcano an ideal target to better understand the time and space evolution of volcanic gas. So this database will be useful to evaluate chemistry transport models (CTMs), especially in their ability to model the plume chemical composition and the impact of the local circulations on pollutant accumulation in densely populated areas (Durand et al, 2014). Then future studies will focus on the evolution of gas-particle formation in areas close to the vent with a significant presence of water and at a greater distance in a drier air mass.…”

“…Clouds develop daily on the summits and on the flanks of the island, with a well-established diurnal cycle (formation in the late morning, dissipation at the end of the afternoon or at the beginning of the night). Durand et al (2014) have shown that air quality during volcanic eruptions is strongly dependent on mesoscale atmospheric circulation on La Réunion Island.…”