Conceptual Model of:
Wave
Cloud Structure in Satellite Image
Typical cloud configurations
• Cloud bulge at rearward edge of frontal cloud band
• Bright in all three channels• Sometimes rearward edge
of cloud bulge translucent in VIS
• Rather smooth texture• Often in WV black stripe
indication an eddy
wave
Development of cloud bulge to cloud spiral and further to occlusion spiral
wavestage
initialoccl.stage
Meteorological Physical Background
Basic ideas:Development of cloud bulge and spiral through effect of vorticity
Conveyor Belt Theory:Lower layers
• Warm conveyor belt – rising in area of wave
• Upper relative stream– at the rear of the cloud band
and wave bulge
• Saddle point in upper relative stream– immediately south,
southweast of wave bulge– rising to the N,– sinking to the S
w.c.b
u.r.s
Conveyor Belt Theory:Upper layers
• Warm conveyor belt – rising
– more to the leading edge of
the cloud band
• Upper relative stream– partly superimposed on wave
bulge
– responsible for cloud dissolution
– distinct feature in WV: black stripe overrunning frontal cloud w.c.b
u.r.s
frontal cloud
wavecloud
Selection of relevantisentropic surface:
w.c.b
u.r.s
saddlepoint
Key Parameters: Relevant numerical parameters and their
typical distribution
Surface low and temperature advection• Surface minimum low:
– in the area of the cloud bulge
• Zeroline of TA– crosses cloud bulge:
• Juxtaposition of WA - CA maxima– WA maximum within
cloud bulge
– CA maximum immediately behind in cold air
WA
CA
Surfaceminimum:
L
LWA
CA
Upper level height and vorticity advection
• Upper level trough– behind cloud
feature
• PVA maximum– partly
superimposed on cloud bulge
– partly behind
PVAmax
LPVA
Important features:
• WA maximum:– within cloud bulge of
wave
• PVA maximum– superimposed on cloud
bulge
– partly behind, in CA
WA maximum: W
W
PVA maximum: P
P
Typical weather events
• Increasing widespread precipitation
• Possibly thunderstorms in the area of the PVA
• Most intensive precipitation to be found in the area of the emerging low cloud
• Increasing surface winds; ev. Stormy winds
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