ThemeasurementsbyusingADCP(500KH)andCTDweremadeduringAugust2000inthesouth(37°55'N,120°25'E)oftheBohaiSea,wherethewaterdepthwasabout16.5m.Thedataofhorizontalvelocitywithsamplingintervalof2minin7layerswereobtained.Thepowerspectrumanalysisofthesedataindicatesthatthereareveryenergeticinfragravitywaveswithaperiodofabout6min.Thecoherencespectrumanalysisandtheanalysisoftemporalvariationofshearshowthattheseinfragravitywavesaremainlythefreewavemodel(propertiesofedgewaves),inthemeantimetheypossesssomecharacteristicsofinternalwaves,whicharelikelyduetothedistinctivemarineenvironmentinthisarea.Itisspeculatedonthattheinstabilityprocesses(chieflyshearinstability)ofshearedstratifiedtidalflowowingtotheeffectofsea-floorslopeinthecoastalareamightbethemainmechanismgeneratingtheseinfragravitywaves.
