Ash cloud modelling using FALL3D - BSC.pdf
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Transcript of Ash cloud modelling using FALL3D - BSC.pdf
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Ash cloud modelling using FALL3D
A. Folch
Volcanic Ash Awareness Workshop, Catania, June 23-24, 2009
Barcelona Supercomputing Center(BSC), Barcelona, Spain
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Overview
Eulerianmodelbasedontheadvectiondiffusionsedimentationequation.
Multipurposemodel:
Computesthedeposit(ashfalloutforecast,elaborationofhazardmaps,etc).
Computesairborneconcentration(FL,integrated,etc.).
Canbeusedtoforecastortostudypastevents.
Admitsdifferentparameterizationsfor:
i)Verticalandhorizontaldiffusion(atmosphericturbulence).
ii)Terminalsettlingvelocities(severalsemiempiricalmodelsavailable).
iii)Sourceterm(e.g.buoyantplumetheory).
Multiscalemodel:runsatscalesfromsynoptic(1000skm)toverylocal(fewkm).
Followsanoff-lineapproach.However,NMMb(NCEP)on-linecouplinginprogress...
Multipleclassesorbins(fromtephratoveryineash;lithicsorjuvenilecomposition).
Testedfor:Ves.(44),MSH(80),Chichn(86),Spurr(92),Etna(98;01;02),Chaitn(08).
Soonoperationalat:BsAsVAAC,COPAIRE(Quito),IGN(Spain).
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Meteorological inputs
Global
Mesoscale
Local
Database
FALL3D
0.5o2.5o
220km
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Postprocessstrategy
1)Resultsatground:
Depositload.Depositthickness.
PM10,PM5,PM2.5.
2)Resultsonair:
Columnmass(load).
Concentrationatlightlevels.3DConcentration.
*Cuts.
*Verticalproiles.
3)Trackingatselectedpoints:
(e.g.anairport).
Ashaccumulationrates.
AirQuality.
FALL3D
NetCDF Tracking
Images
Animations
GoogleEarth
GRD GIS
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Numericalperformance
Serialandparallelversions.
Solvingalgorithm:
Finitedifferences.
Terrainfollowing.
Secondorderschemewithlimiters.
Parallelizationattwolevels(speedupacceptable125proc.,block256proc.):
i)Classes(bins).ii)Domain.
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VAACs:
Regionalashcloudtracking/forecast.Largedomains,lowresolutionmodelling.
Europe:Denselypopulatedareas(localeffectsalsoimportant!!).
Likelytohavesmallscaleevents.
e.g.Etna,Vesuvius,Aores,Tenerife
Teide
2kmheightplume.Considerthesmallestexplosiveevent24h
WRFwindsat2kmresolution(PBL,localeffects,etc.)
Whyamultiscalemodelisnecessary?
1x1
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Tenerife
airport
airport
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