  Using meteor wind data from the Super Dual Auroral Radar Network (SuperDARN)
in the Northern Hemisphere, we (1) demonstrate that the migrating
(Sun-synchronous) tides can be separated from the nonmigrating components in
the mesosphere and lower thermosphere (MLT) region and (2) use this to
determine the response of the different components of the semidiurnal tide
(SDT) to sudden stratospheric warming (SSW) conditions. The radars span a
limited range of latitudes around 60$^{\circ}$ N and are located over nearly
180$^{\circ}$ of longitude. The migrating tide is extracted from the
nonmigrating components observed in the meridional wind recorded from meteor
ablation drift velocities around 95-km altitude, and a 20-year climatology of
the different components is presented. The well-documented late summer and
wintertime maxima in the semidiurnal winds are shown to be due primarily to the
migrating SDT, whereas during late autumn and spring the nonmigrating
components are at least as strong as the migrating SDT. The robust behavior of
the SDT components during SSWs is then examined by compositing 13 SSW events
associated with an elevated stratopause recorded between 1995 and 2013. The
migrating SDT is seen to reduce in amplitude immediately after SSW onset and
then return anomalously strongly around 10-17 days after the SSW onset. We
conclude that changes in the underlying wind direction play a role in
modulating the tidal amplitude during the evolution of SSWs and that the
enhancement in the midlatitude migrating SDT (previously reported in modeling
studies) is observed in the MLT at least up to 60$^{\circ}$ N.
