Global and Direct UV Irradiance Variation in the Nahuel Huapi National Park (Patagonia, Argentina) After the Eruption of Puyehue-Cordon Caulle (Chile).

1. DIAZ, S. B., PALADINI, A. A., BRAILE, H. G., DIEGUEZ, M.C., DEFERRARI, G. A., VERNET, M. & VRSALOVIC, J.

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Waltham, MA; Año: 2014 vol. 112 p. 47 - 56

1364-6826

On June 4th, 2011,the Puyehue-CordonCaulle volcaniccomplex (40135025″S 72107002″W,Chile) started eruption, sending ash 45,000 feet into the atmosphere. After the initial period,the eruption continuedfor several months,with less intensity.ChangesinglobalirradianceintheUV-BandUV-A,anddirectirradiance andAODintheUV-A,asconsequenceoftheeruption,werestudied.Globalirradiancehasbeen permanentlymeasuredattheLaboratoryofPhotobiology(LPh)(41.13S,71.42W,804msl)since1998.Inaddition,intheframeofaprojecttostudyaltitudeeffectondirectandglobalirradiance, fieldcampaigns wereperformedduringSeptember17thto23rd,2010andSeptember14thto18th,2011,inthe regionoftheNahuelHuapiNationalPark,near100kmfromtheeruption.Inthoseperiods,simultaneous measurementsofdirectandglobalirradianceandaerosolopticaldepth(AOD)werecarried outatthreesites:LaboratoryofPhotobiology(LPh),MtOtto(41.15S,71.38W,1386msl)andMt Catedral(41.17S,71.48W,1930msl).Theanalysisofaerosolsin2011,threetofourmonthaftertheeruption started,showedthepresenceoflargerparticlesandmorevariabilitythanin2010,atallsites.Global irradiance,atLPh,alsoexhibitedlargervariability,comparedto1999,whennoeruptionoranyother eventthatcouldhaveproducedmajorchangesinaerosolsoccurred.Themeandecrease,asconsequenceofthevolcanoactivity,atLPh,wasaround20%,at305nmandclosedto10%,at320nm.At 380nm,thedecreasewasverysmallandnotstatisticallysignificant, althoughinparticulardays,withlarge aerosolload,asignificant decreasewasobserved.Directirradiance,intheUV-A,showedlargerdecrease thanglobalirradiance.Theeffectoftheeruptionwasmorepronouncedatthelowaltitudesite.