Pertaining to atmospheric phenomena having horizontal scales ranging from a few to several hundred kilometers, including thunderstorms, sordil lines, fronts, precipitation bands in tropical and extrat
ropical cyclones, and topographically generated weather systems such as mountain waves and sea and land breezes. From a dynamical perspective, this term pertains to processes with timescales ranging from the inverse of the Brunt?V?is?l? frequency to a pendulum day, encompassing deep moist convection and the full spectrum of inertio-gravity waves but stopping short of synoptic-scale phenomena, which have Rossby numbers less than 1.
A regular pattern of convective cells that can develop in an atmospheric boundary layer heated from below or radiatively cooled from cloud top. This phenomenon is readily observed in satellite imagery
during cold air outbreaks when continental air passes over the relatively warm coastal ocean. Cloud lines, marking horizontal roll vortices, form initially in the developing marine atmospheric boundary layer. These lines evolve into open cells, which are defined by clouds in the upward motion along the edges of honeycomb- shaped cells, with less cloudy subsiding air in their centers. The convective structure further evolves into closed cells, which have cloudy centers and cloud-free edges.
A subset of mesoscale convective systems (MCS) that exhibit a large, circular (as observed by satellite), long-lived, cold cloud shield. Alternatively, a dynamical definition of an MCC requires that
the system have a Rossby number of order 1 and exhibit a horizontal scale comparable to the Rossby radius of deformation. In midlatitude MCS environments, the Rossby radius of deformation is about 300 km.
A cloud system that occurs in connection with an ensemble of thunderstorms and produces a contiguous precipitation area on the order of 100 km or more in horizontal scale in at least one direction. An
MCS exhibits deep, moist convective overturning contiguous with or embedded within a mesoscale vertical circulation that is at least partially driven by the convective overturning.
A disturbance where the atmospheric feature has a Rossby number of order 1 and exhibits a horizontal scale comparable to the Rossby radius of deformation. For such systems, both ageostrophic advection
and rotational influences are important.
In oceanography, densely packed, irregularly oval- shaped high and low pressure centers roughly 400 km (240 miles) in diameter in which current intensities are typically tenfold greater than the local
means.
The region of the Earth’s atmosphere between the upper limit of the stratosphere (approximately 30 km altitude) and the lower limit of the thermosphere (approximately 80 km altitude).
The mesosphere refers to the mantle in the region between the asthenosphere and the outer core. The upper boundary is defined as the sharp increase in seismic wave velocities and density at a depth of
660 km. [Wikipedia]
The layer of the atmosphere located between the stratosphere and the ionosphere, where temperature drops rapidly with increasing height. It extends between 17 to 80 kilometers above the Earth's surfac
e.