简介:Longwavesgeneratedbyamovingatmosphericpressuredistribution,associatedwithastorm,incoastalregionareinvestigatednumerically.Forsimplicitythemovingatmosphericpressureisassumedtobemovingonlyinthealongshoredirectionandthebeachslopeisassumedtobeaconstantintheon-offshoredirection.Bysolvingthelinearshallowwaterequationsweobtainnumericalsolutionsforawiderangeofphysicalparameters,includingstormsize(2a),stormspeed(U),andbeachslope(α).Basedonthenumericalresults,itisdeterminedthatedgewavepacketsaregeneratedifthestormspeedisequaltoorgreaterthanthecriticalvelocity,Ucr,whichisdefinedasthephasespeedofthefundamentaledgewavemodewhosewavelengthisscaledbythewidthofthestormsize.ThelengthandthelocationofthepositivelymovingedgewavepacketisroughlyUt/2≤y≤Ut,whereyisinthealongshoredirectionandtisthetime.Oncetheedgewavepacketisgenerated,thewavelengthisthesameasthatofthefundamentaledgewavemodecorrespondingtothestormspeedandisindependentofthestormsize,whichcan,however,affectthewaveamplitude.Whenthestormspeedislessthanthecriticalvelocity,theprimarysurfacesignatureisadepressiondirectlycorrelatedtotheatmosphericpressuredistribution.