INLETDYNAMICSINITIATIVEALGARVE(INDIA)
REPORTOFTHECONTRIBUTIONOFTHEINSTITUTEFORBIODIVERSITYANDECOSYSTEMDYNAMICS,UNIVERSITYOFAMSTERDAM
1AEOLIANSANDTRANSPORTEVENTSONTHEPENINSULADOANCAO
S.M.Arens,J.H.vanBoxel,R.M.K.HaringUniversityofAmsterdam
InstituteforBiodiversityandEcosystemDynamicsPhysicalGeography
NieuweAchtergracht166
1018WVAmsterdamTheNetherlands
Introduction
WithintheframeworkofalargeprojectoninletdynamicsinabarriersystemintheAlgarveregion(O'Connoretal.,1999,Williamsetal.1999)afieldstudywasperformedontheaeoliandynamicsofbeachanddunesonthebarrierridge.Sandtransportbywindwasstudiedatseveraltemporalandspatialscalestogetinsightintheeffectsofmeteorologicalandenvironmentalconditionsonaeoliantransport,themagnitudeofaeoliantransportandtheresultinginputofsedimentinthedunes.Duringanumberofevents,detailedmeasurementscouldbeperformedofmeteorologicalconditionsandthetransportonthebeachandoverthedunes.
Studyarea
Thestudyareaisdescribedindetailinthepaper"DUNEBUILDINGONTHEPENINSULADOANCAO".Thesiteissouth-westerlyexposed,andcharacterisedbyasteepandnarrowreflectivebeachborderedbylow,hummockydunesthatarepartlyvegetated.Duneheightrangesbetween1and5mabovethehightidemark.Especiallythehigherdunesare vegetated,andvegetationcoverrangesbetween5and25%,withclusteringofplants.Onbeachanddunes,thesandbedisusuallydryandloose,alsobecauseofdisturbancebytrespassers.Crusts,duetothestrongevaporationrates,arerarelyobserved.Onthebeach,thesandislocallyverycoarse(>1mm).Grain-sizeattheupperpartofthebeachandinthe dunesaverages350mm.
Methods
Detailedmeasurementsofsandtransportandmeteorologywereperformedovera3-monthperiod,from12-01-1999to28-03-1999.Omnidirectionalsandtraps(ArensandVanderLee,1995)wereplacedinanarrayonthebeachandthedune,tomeasuretransportgradients.
Saltiphones(SpaanandvandenAbeele,1991;Arens,1996)wereinstalledonthebeachandnearthedunefoottomeasureintensityoftransport.Erosionpinswereplacedinagridoverthedunestomeasureheightchangesasaresultofsandtransport.Theduneprofilewas
measuredwithatotalstation.Windspeedanddirectionatthesiteweremeasuredintwomasts,oneatthedunefootandtheotheronthecrest.Windspeedsweremeasuredat0.7,1.2,2.2and4.2mabovethesurface.Figure1showstheconfigurationofmasts,sandtrapsandsaltiphonesovertheduneprofile.Temperatureandrelativeairhumidityweremeasured inthecrestmastataheightof1.5mabovethesurface.Netradiationwasmeasurednearthedunefoot.Duetoinstrumentfailure,onlyremoterainfalldataareavailable,measuredbythePortugueseMeteorologicalOfficeatFaroairport,asdailytotals.Alsowindspeedsanddirectionwererecordedinavideomast(Morrisetal.,2000)attheislandofBarreta.Here,windspeedsweremeasuredataheightof10,13and20m,directionwasmeasuredat10m.Atthisheight,thewindprofilestillisadaptedtotheopenocean.Therefore,thesemeasurementsareusedtoestimatetheupstreamwindvelocity,whichisnotyetadaptedtothechangingsurface.Duringsomeeventswindprofilesweremeasuredonthebeach,withcupanemometersatheightsof0.25,0.50,1.0,2.0and4.0m.
Allelectronicinstrumentsweresampledevery5seconds.Datawereaveragedover10minutes,andaverage,maximum,minimumandstandarddeviationofeach10-minuteperiodwerestored.
Results
AeolianeventsintheAlgarveusuallylastforanumberofhoursduringthedaytime.Theyseemtobeassociatedtothedailyvariationinwindspeed.Occasionallywindsspeedsareveryhigh,butonlyforaveryshortduration.Windgustscanreachover20miswhiletheaverage10-minutewindspeedisintherangeof10-12mis.Especiallyduringstrongshowers,gustswithhighwindspeedsareobserved.Thesegustscanmoveaconsiderableamountofsand, butbecauseoftheirshortduration,theireffectondunebuildingisnegligible.
Table1.Aeolianevents,withwinddirection,maximumsaltationintensityandwindspeedstatistics.
winddirection / saltiphonebeach10minmax / saltiphonebeachmax10minave / saltiphonedunefoot10minmax / saltiphonedunefootmax10minave / U4.210minmax / U4.2
max10minave / Ut
21-1-99 / 184-228 / - / - / - / - / 20.2 / 12.9 / -
2-2-99 / 55-93 / - / - / - / - / 11.1 / 7.8 / -
6-2-99 / 249-289 / - / - / - / - / 10.5 / 8.7 / -
9-2-9914:05-15:50 / 265 / 2904 / 1680 / 2773 / 1578 / 13.9 / 11.1 / 6.5
9-2-9916:01-19:31 / 275 / 2781 / 1167 / 2458 / 1215 / 14.8 / 11.1 / 8.0
9-2-9919:41-21:10 / 270 / 3039 / 1140 / 2686 / 1244 / 15.0 / 12.1 / 8.5
24-2-9913:20-19:50 / 255-270 / - / - / 1959 / 185 / 20.7 / 12.2 / 7-
8.5
3-3-9913:10-14:50 / 248 / 1828 / 858 / 1786 / 732 / 15.2 / 12.3 / 7.8
3-3-9915:00-18:00 / 251-282 / 1655 / 678 / 1535 / 840 / 14.0 / 11.6 / 6.6
4-3-9911:00-19:10 / 261-328 / 82 / 1.2 / 135 / 7 / 12.7 / 8.5 / 6.7
10-3-9913:00-22:30 / 175-269 / - / - / - / 63 / 15.9 / 10.0 / 6.6
11-3-9910:10-14:20 / 184-278 / - / - / 3623 / 972 / 19.5 / 13.7 / 8.3
12-3-992:00-24:00 / 140-217 / - / - / 2519 / 181 / 19.1 / 13.7 / 9.2
13-3-990:00-22:00 / 88-189 / - / - / - / - / 21.4 / 10.4 / -
23-3-999:20-24:00 / 77-152 / 3646 / 2020 / 3167 / 1086 / 16.9 / 12.3 / 6.6
25-3-9913:10-16:20 / 249-268 / 1829 / 769 / 1607 / 678 / 12.6 / 10.4 / 8.3
25-3-9916:30-18:20 / 266-276 / 1893 / 524 / 1569 / 620 / 13.3 / 10.4 / 6.1
26-3-9912:10-19:10 / 287-321 / 2242 / 467 / 1221 / 411 / 12.3 / 9.0 / 6.4
27-3-991:00-3:00 / 286-313 / 748 / 22 / 998 / 98 / 11.1 / 9.1 / 8.6
27-3-993:10-9:10 / 263-314 / 2645 / 221 / 2038 / 363 / 14.0 / 10.8 / 8.6
27-3-999:20-18:00 / 264-325 / 2043 / 887 / 1770 / 691 / 13.2 / 10.5 / 7.1
27-3-9918:10-22:00 / 290-313 / 2022 / 858 / 1286 / 800 / 13.0 / 9.4 / 6.2
Table1givessomestatisticsforthemostimportantaeolianeventsduringthefieldwork.U4.210minmaxgivesthemaximumwindspeedmeasuredat4.2mheightatthedunecrestduringa10-minuteperiod.U4.2max10minavegivesthemaximum10-minuteaveragewindspeedduringtheevent.
Thethresholdwindspeedforsandtransportonthebeachvariesbetweenabout6.5and9.2 misfordayswhentransportcouldbemeasuredwiththesaltiphones.Thethresholdsareestimatedfromthescatterplotsofwindspeedversussaltiphonecounts.Foranumberofdaysthethresholdwasmuchhigher,duetorainfallorlimitedavailabilityoffinesand.Onlyduringstrongwindssandwasabletopassthedunefootandmoveinland.Itisestimatedthatthethresholdforlandwardtransportisabout9mis.Onlythenthesandcanbeliftedupand movedoverthevegetation.
Theerosivetimefractionisdefinedastheratioofallsampleintervalswithsaltationina10minuteperiod,dividedbythetotalnumberofintervalsina10minuteperiod(120)times100.Figure2showstherelationbetweentheerosivetimefractionandtheminimum,maximum andaverage10minutewindspeed.Thenumberof10-minuteperiodswithcontinuous saltationislimited.Evenwithverystrongwindstheerosivetimefractionisoftensmallerthan
100.Foraveragewindspeedstheplotshowsanalmostlinearincreasefrom0%at6misto100%at10mis,butthevariationislarge.
Description ofsomeevents in detail
Someeventsaredescribedhereindetailandillustratedbyplotsofsaltiphonecountsandsandtrapresults.InTable2thedurationofsandtraprunsfortheeventsaregiven,togetherwithsomemorestatistics.Forlongerrunsitisnecessarytoestimatethenumberofminutesthatsandcouldactuallyaccumulateinthetraps.Atwindspeedsbelowthreshold,nosandistransportedatall,awindspeedsjustabovethresholdsandistransportedonthebeachbutnottransferredtothedunes.Therefore,foreachrunthenumberofminutesisestimatedforwhicha10-minutemaximumwindspeedlargerthan10misisobserved.Forallrunsaveragewindspeed,averagemaximumwindspeedandaveragewindspeedforall10-minuteperiodswithwindspeedhigherthan6misarecalculated.
Table2.Durationandstatisticsforsandtrapruns.
date / time / run / numberofminutesforwhichUmax4.210 mis / averagewindspeed(4.2m)mis / averageofmaximumwindspeedsmis / averagewindspeedforallperiodswithU>6mis
9-2-99 / 14:06-14:27 / run1-B / 21 / 9.98 / 12.41 / 8.24
9-2-99 / 15:11-15:39 / run2-B / 28 / 9.94 / 12.08 / 8.18
9-2-99 / 13:00-15:40 / run2-D / 129 / 9.02 / 11.04 / 7.44
9-2-99 / 16:28-16:58 / run3-B / 30 / 9.67 / 11.59 / 7.88
9-2-99 / 15:55-17:40 / run3-D / 105 / 9.72 / 12.04 / 7.98
9-2-99 / 16:12-18:30 / run3-D6 / 138 / 9.52 / 11.81 / 7.83
24-2-99 / 13:15-0:00 / run1-D / 285 / 8.45 / 10.73 / 7.60
24-2-99 / 14:05-18:12 / run1-B,DT / 137 / 7.81 / 9.73 / 7.10
24-2-99 / 19:20-0:00 / run2-B,DT / 40 / 6.42 / 8.51 / 8.82
3-3-99 / 11:35:14:55 / run1-B,DT,D / 121 / 9.07 / 10.90 / 7.95
3-3-99 / 14:55-15:55 / run2-B,DT / 45 / 10.61 / 13.39 / 8.83
3-3-99 / 15:00-17:25 / run2-D2 / 145 / 10.12 / 12.50 / 8.47
3-3-99 / 15:00-0:00 / run2-D4,5 / 164 / 9.51 / 11.98 / 8.40
3-3-99 / 15:45-19:23 / run3-B,DT / 124 / 7.87 / 10.10 / 8.26
3-3-99 / 17:35-0:00 / run3-D / 14 / 6.40 / 8.49 / 7.28
3-3-99 / 19:23-0:00 / run4-B,DT / 0 / - / - / -
4-3-99 / 14:35-0:00 / run1-B,DT,D / 120 / 7.39 / 9.79 / 6.30
13-3-99 / 14:05-15:40 / run1-B / 85 / 9.15 / 12.16 / 6.53
13-3-99 / 14:10-16:00 / run1-DT / 110 / 8.97 / 11.99 / 6.51
13-3-99 / 14:15-19:10 / run1-D / 120 / 7.46 / 10.05 / 6.53
13-3-99 / 15:35-16:35 / run2-B / 30 / 7.79 / 10.60 / 6.33
13-3-99 / 16:10-22:00 / run2-DT / 60 / 6.51 / 9.13 / 0.00
13-3-99 / 19:10-22:10 / run2-D2 / 50 / 6.45 / 9.29 / 0.00
13-3-99 / 14:15-22:00 / run1/2-D4,5 / 170 / 7.01 / 9.71 / 6.53
23-3-99 / 16:10-17:20 / run4-B / 40 / 7.24 / 10.27 / 6.20
23-3-99 / 16:20-17:20 / run4-DT / 30 / 7.24 / 10.27 / 6.20
B=beach;DT=dunetoe;D=dune
21-1-99
Strongsaltationduringshowerswithstrongwinds.Verywet.
2-2-99
Transportneartheinlet.Ripplesonthesurface.Offshorewinds,onthebeachthewindvelocityisjustbelowthreshold.
6-2-99
Saltationnearthedunefoot,justabovethreshold,withobliqueonshorewinds.Grainsarenotdetectedbythesaltiphone,becausetransporttakesplacesinalayerveryclosetothesurface(<0.1m).
9-2-99
Transportintheafternoon,justafterashortandlightshower,withobliqueonshorewinds.Atthestart,saltationatthebeachismoreintensethanatthedunefoot(Figure3).Duringtheafternoon,thetransportgradientonthebeachchanges,becauseofadecreaseintransportonthelowbeach,duetoashortageinsupply.Probablythefinestgrainsareremoved,andthethresholdfortheremainingsandgrainsishigher.Thethresholdincreasesfrom6.5to8to8.5mis(at4.2mheight).Intheafternoon,transportdecays,withasuddenandshortincreaseintheevening.Therelationshipbetweenwindspeedandsaltiphonecountsisclear,andchangesduringtheday(Figure4).
ThechangeintransportgradientisclearlyvisiblefromFigure5.Forrun1thedifferencesbetweenthelowerbeachandupperbeacharesmall,forruns2and3thedifferencesbecomelarger.Figure6showsthetransportgradientsoverbeachanddune.Thedecreaseintransportlandwardfromthedunefootisextreme:almostallthesandaccumulatesinthefirstmeterswithvegetation.Duetothehighwindspeeds,somesandisdepositedfurtherlandward,buttheamountsareverysmall.Onthecrestthetransportislessthan1i100ofthetransportatthebeach.
24-2-99
Sandtransportintheafternoon(moderate)andevening(intense)(Figure7),partlywithsomerainandsomeverystrongobliqueonshorewindgusts(upto20.7mis).Saltationrespondstoanincreaseinwindspeed,notnecessarilytoahighwindspeed.Unfortunatelythesaltiphoneonthebeachisoutoforder.Intheeveningthethresholdincreasesconsiderablyfromabout7toabout8.5mis(Figure8).Duetotheshortdurationoftheintensetransportintheevening,depositionontheduneislimited.Figure9showsthesandtrapsresultswiththesedimentcurves.Irregularitiesinthecurvescouldberelatedtoblowoutofsand(forexamplesamplesBeach1andBeach3inRun1).Transportismainlyrestrictedtothebeachwithnegligibleinputinthedunes(Figure10).
3-3-99
Sandtransportintheafternoonwithobliqueonshorewinds.Againthetransportgradientonthebeachchangesduringtheday.Atthestarttransportatthelowerbeachishigherthanattheupperbeach,laterthisisreversed(Figure11).Thresholdwindspeeddecreasesduringthe day,butincreasesagainattheendoftheafternoon(Figure12).Transportoccursoverthedune,butagain,depositionatthebackoftheduneislimited.Mostofthesandaccumulatesbetweenthedunetoeanddunetrap#2(Figure13).Figure14showsasteepincreaseoftransportonthebeachandasteepdecreaseoftransportonthedune.
4-3-99
Verylimitedsaltation,withverylowintensityonthebeach,slightlyhighernearthedunefoot(Figure15).Scatteredrelationship,butmostofthecountsarerecordedforaveragewindspeedsof>4mis(Figure16).Themostintensetransportoccursduringparallelwinds,therestduringobliqueonshorewinds.Transporttotheduneislimited,mostofthedepositionoccursontheupperbeach,nearthedunefoot(Figure17and18).
10-3-99
Sandtransportincombinationwithheavyshowersandobliquetostraightonshorewinds.Duetotherainregistrationofthesaltiphonesisdisturbed.Becauseoftheraintransportislimited.
11-3-99
Sandtransportincombinationwithheavyshowersandobliquetostraightonshorewinds.Occasionallygustswithveryhighwindspeeds(19.5mis).Duetotherainregistrationofthesaltiphonesisdisturbed.OnlysomemeasurementsofthedunefootsaltiphonearereliableFigure19).Theseindicateahighthresholdof8.3mis(Figure20).Becauseoftheraintransportislimited.
12-3-99
Sandtransportincombinationwithheavyshowersandparalleltoobliqueonshorewinds.Occasionallygustswithveryhighwindspeeds(19.1mis).Duetotherainregistrationofthebeachsaltiphoneisdisturbed.Measurementsofthedunefootsaltiphoneindicateahighthresholdof9.2misandabadcorrelationbetweensaltiphonecountsandwindspeed(Figures21and22).
13-3-99
Sandtransportincombinationwithheavyshowersandparalleltoobliqueonshorewinds,attheendofthedaywithoffshorewinds.Occasionallygustswithveryhighwindspeeds(21.4mis).Duetotherainregistrationofthesaltiphonesisdisturbed.Sandtrapmeasurementsindicatelandwardtransport,andinitiallyaconsiderableamountofsandpassingthedunefoot
(Figures23and24).Again,mostofthesandisdepositedbetweenthedunefootanddunetrap#2.
23-3-99
Sandtransportinitiallywithoffshorewindsandintheafternoonwithparallelwinds.Therelationshipbetweensaltiphonecountsandwindspeedisdiffuse(Figure26).Thresholdwindspeedisabout6.4mis.Transportisrestrictedtothebeachanddunefoot.Saltationattheupperbeachishigherthannearthedunefoot(Figure25),butsandtrapmeasurements(Figures27and28)indicatethatduringpartofthedaytransportatthedunefootishigherthanonthebeach.
25-3-99
Sandtransportwithobliqueonshorewinds. Initiallytransportonthebeachishigher,laterintheafternoon,transportnearthedunefootishigher(Figure29).Goodcorrelationbetweensaltiphonecountsandwindspeed(Figure30).Scatterplotiscomparabletotheplotof3-3-1999,butthresholdislowerandcurveissteeper.Thresholdwindspeedis6.1mis.
26-3-99
Moderatesandtransportduringalmostparallelwinds,withstrongestintensityintheafternoon(Figure31).Vaguecorrelationbetweensaltiphonecountsandwindspeed(Figure32).Noclearthresholdwindspeed.Partofthedaysaltationishighernearthedunefoot,partofthedayitishigheronthebeach.
27-3-99
Daywithseveraltransportevents,withwindsvaryingfromobliqueonshoretoparallel.Intheearlymorningmoderatesaltationwithstrongwinds,intheafternoonandeveningstrongsaltationwithcomparablewindspeeds(Figure33).Thresholddecreasesduringtheday,from
8.6intheearlymorningto6.2misintheevening(Figure34).
Conclusionsanddiscussion
AeoliantransportintheAlgarveisavariableprocessasinmostcoastalsystems.Typicalaeolianeventsoccurduringthedaytimeandlastforanumberofhours.Duringanevent,windspeedsvarybetween6and13mis(10minuteaverages),andmaybeashighas21misduringshowerswithgusts.Mostofthetransportisrestrictedtothebeach,butduringstrongwinds,withwindspeedsabove9misthereistransferofsandfrombeachtodunes.However,thisislimited.Mostofthesandisdepositedatashortdistancelandwardofthedunetoe(lessthan 20m).
Thethresholdfortransportisnotconstantandisrelatedtosedimentavailabilityandmeteorologicalconditions.Ourmeasurementsindicateavariationinthresholdfrom6.5to9.2mis,butthiswillbeevenhigherduringrainevents.Measurementoftransportduringrainisvirtuallyimpossible,becausesaltiphonesandsandtrapsgetcloggedimmediately.During rain,occasionallytransportwasobserved,butduringveryheavyshowers,transportdeclines tozerobecauseoftoohighmoisturelevels.
Measurementsofseveraleventsindicatethatinitiallytransportonthebeachcanreachhighlevels,butaftersometimedeclines,whiletransportatthedunefootremainshigh.Ourinterpretationisthatatthestartoftheevent,finesandisavailableatthesurface.Aftersometime(hours)mostofthefinesandisremovedandacoarsergrainedsandremainsatthesurface.Apparently,coarserlagscandevelopatthistimescale.Afteradisturbanceofthe
surface,causedbywaveactionorbytrespassers,againfinesandisavailableandreadyfortransport.
Acknowledgements
ThisstudywasperformedaspartoftheMAST3INDIAresearchprojectfundedbytheEuropeanCommission,DirectorateGeneralforScience,ResearchandDevelopment,underContractMAS3-CT97-0106.
Wethankthefollowingpersonsfortheirhelpduringtheresearch:AxelBoom,RobertKuijper,GijsbertWind,EugeneSabajo,AnaMatias,HeleneHowa,YanBalouin,OscarFerreira,AnaVilaConcejo,MiguelA'CastroandSteveShayler.
References
Arens,S.M.Lee,G.vander,1995.Saltationsandtrapsforthemeasurementofaeoliantransportintotheforedunes.SoilTechnology,8:61-74.
Arens,S.M.,1996.Actualaeoliantransportratesonabeachinatemperatehumidclimate.
Geomorphology,17:3-18.
O'ConnorB.A.,WilliamsJ.J.,DiasJ.,CollinsM.,DavidsonM.,ArensB.,HowaH.,SarmentoA.,Seabra-SantosF.,AubreyD.,Salles,P.,SmithJ.,HeronM.,PiresH.,SilvaA.,BellP.PanS.(1999).Tidalinletmonitoringimodellingproject(InDIA).
ProceedingsOceanologyInternational,Singapore,12pp.
Spaan,W.P.Abeele,G.D.vanden,1991.Windborneparticlemeasurementswithacousticsensors.SoilTechnology,4:51-63.
inlet.CoastalSediments.
WilliamsJ.J.,ArensB.,AubreyD.,BellP.,BizzaroA.,CollinsM.,DavidsonM.,DiasJ.,FerreiraO.,HeronM.,HowaH.,HughesZ.,HuntleyD.,JonesM.T.,O'ConnorB.,PanS.,SarmentoA.,Seabra-SantosF.,ShaylerS.,SmithJ.,VoulgarisG.(1999). InletDynamicsInitiative:Algarve(InDIA). ProceedingsCoastalSediments'99,ASCE,LongIsland,NewYork,Usa,16pp.
Figures
Figure1.Duneprofilewitharrangementofinstruments.
Figure2.Erosivetimefractionversus10minuteminimum,averageandmaximumwindspeed.
Figure3.Developmentofsaltationduringtheeventof9-2-1999.
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windspeedAncaocrest,4.2mheight(mis)
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Figure4.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof9-2-1999.
Figure5.Sandtrapresultsforseveralrunsduringtheeventof9-2-1999.
Figure6.Transportgradientsforseveralrunsduringtheeventof9-2-1999.
Figure7.Developmentofsaltationduringtheeventof24-2-1999.
saltiphonedunefoot
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Figure8.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof24-2-1999.
Figure9.Sandtrapresultsforseveralrunsduringtheeventof24-2-1999.
Figure10.Transportgradientsforseveralrunsduringtheeventof24-2-1999.
Figure11.Developmentofsaltationduringtheeventof3-3-1999.
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Figure12.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof3-3-1999.
Figure13.Sandtrapresultsforseveralrunsduringtheeventof3-3-1999.
Figure14.Transportgradientsforseveralrunsduringtheeventof3-3-1999.
Figure15.Developmentofsaltationduringtheeventof4-3-1999.
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Figure16.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof4-3-1999.
Figure17.Sandtrapresults fortheeventof4-3-1999.
Figure18.Transportgradientsforseveralrunsduringtheeventof4-3-1999.
Figure19.Developmentofsaltationduringtheeventof11-3-1999.
saltiphonedunefoot
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Figure20.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof11-3-1999.
Figure21.Developmentofsaltationduringtheeventof12-3-1999.
saltiphonedunefoot
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Figure22.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof12-3-1999.
Date13-3-99,run1
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trappedweight(gram)
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Figure23.Sandtrapresultsforseveralrunsduringtheeventof13-3-1999.
Figure24.Transportgradientsforseveralrunsduringtheeventof13-3-1999.
Figure25.Developmentofsaltationduringtheeventof23-3-1999.
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Figure26.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof23-3-1999.
Figure27.Sandtrapresultsfortheeventof23-3-1999.
Figure28.Transportgradientsforseveralrunsduringtheeventof23-3-1999.
Figure29.Developmentofsaltationduringtheeventof25-3-1999.
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Figure30.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof25-3-1999.
Figure31.Developmentofsaltationduringtheeventof26-3-1999.
saltiphonebeach500
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Figure32.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof26-3-1999.
Figure33.Developmentofsaltationduringtheeventof27-3-1999.
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400 / 27-03-999:20
300 / 27-03-9918:10
200
100
0
0 / 2 / 4 / 6810 / 12
Figure34.Correlationbetweenwindspeedandsaltiphonecountsfortheeventof27-3-1999.