Basedonacurrentfogdetectiontheory,amultibandthresholdmethodforMODISdatawasputforwardtodetectdaytimefogintheSouthChinaSea.ItusedBands1,2,18,20and31ofMODISdatatoseparatefogfromthecloudandtheseasurface.Thedigitaldetectionindexeswereasfollows.IfRB1<20%,RB2<20%andRB1>RB2,thepixelwasidentifiedtobetheseasurface.IfRB1>55%,RB2>55%andTB31<273K,thepixelwasidentifiedtobeamiddle-andhigh-levelcloud.IfIFC>20,thepixelwasclassifiedtobeseafog.ThemethodwasverifiedwithseafogdataobservedfromthecoastalregionofGuangdongduringJanuary-April2011.Outofthe13samplesofsatellitedetection,ninewereconsistentwiththesurfaceobservations,threewereidentifiedtobelow-levelthecloudaccordingtothesatellitedetectionbutfogaccordingtothesurfaceobservations,andonlyonesamplewasidentifiedtobetheoceansurfacebythesatellitedetectionbutfogbythesurfaceobservations.BecausetheMODISdatacannotpenetratethecloudorfog,themodelwasdesignedforasinglefieldofviewwhichhadonlyonelayerofcloudorfog.Itcanaccuratelydistinguishfogwhichisnotcoveredbythecloud,butitidentifiesfogascloudiftheformeriscoveredbyacloud.Generallyspeaking,themodeliseffectiveandfeasible.
