@article{fdi:010068351,
  title = {{D}istribution of sulfur aerosol precursors in the {SPCZ} released by continuous volcanic degassing at {A}mbrym, {V}anuatu},
  author = {{L}efevre, {J}{\'e}r{\^o}me and {M}enk{\`e}s, {C}hristophe and {B}ani, {P}hilipson and {M}archesiello, {P}atrick and {C}urci, {G}. and {G}rell, {G}. {A}. and {F}rouin, {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {M}elanesian {V}olcanic {A}rc ({MVA}) emits about 12 k{T} d(-1) of sulfur dioxide ({SO}2) to the atmosphere from continuous passive (non-explosive) volcanic degassing, which contributes 20% of the global {SO}2 emission from volcanoes. {H}ere we assess, from up-to-date and long-term observations, the {SO}2 emission of the {A}mbrym volcano, one of the dominant volcanoes in the {MVA}, and we investigate its role as sulfate precursor on the regional distribution of aerosols, using both satellite observations and model results at 1 x 1 spatial resolution from {WRF}-{C}hem/{GOCART}. {W}ithout considering aerosol forcing on clouds, our model parameterizations for convection, vertical mixing and cloud properties provide a reliable chemical weather representation, making possible a cross-examination of model solution and observations. {T}his preliminary work enables the identification of biases and limitations affecting both the model (missing sources) and satellite sensors and algorithms (for aerosol detection and classification) and leads to the implementation of improved transport and aerosol processes in the modeling system. {O}n the one hand, the model confirms a 50% underestimation of {SO}2 emissions due to satellite swath sampling of the {O}zone {M}onitoring {I}nstrument ({OMI}), consistent with field studies. {T}he {OMI} irregular sampling also produces a level of noise that impairs its monitoring capacity during short-term volcanic events. {O}n the other hand, the model reveals a large sensitivity on aerosol composition and {A}erosol {O}ptical {D}epth ({AOD}) due to choices of both the source function in {WRF}-{C}hem and size parameters for sea-salt in {FI}ex{AOD}, the post-processor used to compute offline the simulated {AOD}. {W}e then proceed to diagnosing the role of {SO}2 volcanic emission in the regional aerosol composition. {T}he model shows that both dynamics and cloud properties associated with the {S}outh {P}acific {C}onvergence {Z}one ({SPCZ}) have a large influence on the oxidation of {SO}2 and on the transport pathways of volcanic species across the {S}outh {P}acific atmosphere. {F}or example, in the tropical cloudy air, the sulfate production in the aqueous phase is very efficient, resulting in the formation of a large cloud of highly scattering sulfate aerosols advected horizontally to {E}astern {I}ndonesia, in agreement with the {AOD} feature captured by {MODIS}/{A}qua, but missed in {CALIOP}/{CALIPSO} (lidar) products. {M}odel sensitivity experiments indicate that aerosol re-suspension due to evaporating droplets is a significant pathway for the supply of volcanic sulfur species in the remote marine boundary layer. {B}y strongly modulating the irreversible loss due to wet scavenging, this aerosol process has a similar influence on the sulfur burden as natural emission from volcanoes or biogenic sources like dimethyl sulfate ({DMS}). {T}he results emphasize the importance of {MVA} passive degassing and {SPCZ} dynamics on the aerosol background, and raise questions about potential impacts on the local climate and marine ecosystems.},
  keywords = {{R}egional aerosol climatology ; {SPCZ} dynamics ; {SO}2 dispersal ; {A}erosol modeling ; {R}emote sensing ; {V}olcanic plume impacts ; {VANUATU} ; {PACIFIQUE} {SUD}},
  booktitle = {{U}nderstanding volcanoes in the {V}anuatu arc},
  journal = {{J}ournal of {V}olcanology and {G}eothermal {R}esearch},
  volume = {322},
  numero = {{N}o {S}p{\'e}cial},
  pages = {76--104},
  ISSN = {0377-0273},
  year = {2016},
  DOI = {10.1016/j.jvolgeores.2015.07.018},
  URL = {https://www.documentation.ird.fr/hor/fdi:010068351},
}