Tammy Weckwerth and Jim Wilson
on November 14, 1997 at 17:19:37:
One cause for the periodicity and timing of thunderstorm initiation
along boundary layer convergence zones is waves that can be bserved
by an FMCW radar (wavelength <10 km) propagating atop the convective
Balaji and Clark (1988) simulated waves atop horizontal convective
rolls which then acted to influence convection initiation along
the rolls. Mahoney (1988) observed colliding boundaries and showed
an undulating behavior in convection that appeared to be attributed
to buoyancy oscillations with a wavelength of 2.5 km. Weckwerth
and Wakimoto (1992) found that waves with a 3-km wavelength atop
a cold-air outflow boundary organized convective cells generated
by the gust front. When the wave motions do not exhibit linear cloud
features and are therefore invisible in satellite imagery, then
it has been difficult to observe real-time wave characteristics.
The study of this hypothesis will use an FM-CW radar which has the
ability to observe such wave features.
Balaji, V., and T.L. Clark, 1988: Scale selection in locally forced
convective fields and the initiation of deep cumulus. J. Atmos.
Sci., 45, 3188-3211.
Mahoney, W.P., 1988: Gust front characteristics and the kinematics
associated with interacting thunderstorm outflows. Mon. Wea. Rev.,
Weckwerth, T.M., and R.M. Wakimoto, 1992: The initiation and organization
of convective cells atop a cold-air outflow boundary. Mon. Wea.
Rev., 120, 2169-2187.