Long-term observations of the quasi two-day wave by Hawaii MF radar

摘要: [1] A mesospheric horizontal wind data set measured during 1991–2006 by the medium frequency (MF) radar at Kauai, Hawaii (22°N, 160°W) is analyzed to examine long-term variability of quasi two-day wave (QTDW). The QTDW over amplified twice a year, with January and July events most likely being representation zonal numbers 3 4 modes, respectively. amplitudes monthly mean in both meridional winds component are nearly phase solar cycle but maxima leading 1 or 2 years. However, more antiphase cycle. Enhanced oscillations evident components 1998, which related strong El Nino event winter 1997/1998. enhanced gravity activity increased barotropic/baroclinic/inertial instability strengthened stratosphere summer easterly jet might provide additional forcing amplify QTDW. Moreover, migrating diurnal tide warm Nino-Southern Oscillation could also contribute abnormally increasing refractive index thus growth rate Additional enhancement short period ~43 h observed major sudden stratospheric warming 2006.