Extratropical Cyclones: Their Mesoscale Structure, ...
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SNOW
SOUTH
NORTH
t
NORTH
SHOW
PRECIPITATION BAND
(BRIGHT BAND)
RAIN
SOUTH
~
Figure 6.3: The "production" of an apparent precipitation band by the downwards tilting of the
radar bright band within storm producing rain and snow at the surface. Adapted from Stewart
and King (1990).
when they move over open ocean which in the case of the north Atlantic, can be quite cold.
Satellite-borne lightning detection systems will allow for a much better quantitative assessment
of such an evolution.
The overall cloud fields are produced by broad slantwise ascent within "conveyor belts" that
redistribute heat, momentum and moisture over great distances (see for example Carlson, 1980;
Browning and Monk, 1982; Saarikivi and Puhakka, 1990), as shown in Figure 6.1. These
"conveyor belts" are synoptic scale in origin but mesoscale ascent may significantly influence
their character. Such mesoscale motions certainly alter the local properties of the layered
clouds and precipitation through modification of the profiles of moisture and temperature.
The measurement of the pattern of mesoscale vertical motion is particularly important to
quantitative studies of these processes.