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Mountain-induced gravity waves (MGWs) are found when typhoons impinge on rugged terrains.Convectively forced gravity waves (CGWs) can also be excited by deep convection within typhoons.During 0300-0500 UTC 18 September 2001,Typhoon Nari moved slowly across Taiwan with nearly-constant intensity.Morlet wavelet analysis is performed on the simulation result of Yang et al.(2008) with the 2-kn horizontal grid size and 2-min data interval.Two dominant scales of GWs were found near Mt.Yushan.For the mountain-induced GW,it was relatively steady with the horizontal (vertical) wavelength of 90 (10) km.MGWs above Mt.Ynshan resulted in abundant cloud water over the windward slope and little cloud water on the lee side.CGWs were sometimes produced and superposed upon the MGWs.Their ground-relative periods was about 23 minutes and horizontal (vertical) wavelength was 23 (6) km.CGWs consequently undulated wind,cloud water and surface rainfall at smaller spatial and temporal scales,compared to the MGWs.