Convection in the Genesis Phase of Ophelia 2005 WenChau LeeMichael Bell Robert Houze

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Convection in the Genesis Phase of Ophelia
(2005) Wen-Chau Lee Michael Bell Robert
HouzeNCAR/EOLUniversity of WashingtonAMS
28th Conf. on Hurricanes Tropical
MeteorologyOrlando, Florida - 29 April 2007
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Existing Ideas on Upscale Effects of Clouds in TC
Genesis

• Hendricks et al. (2004)
• Convective

Bister and Emanuel (1997) Stratiform
Richie et al. (2003) Multiple stratiform
Other??
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Ophelias history
6 Sep RAINEX flight
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6 Sep RAINEX flight
200 km
12 hours later
24 hours later
Satellite IR
Coastal radar
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200 km
Satellite IR
Coastal radar
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2 km
2108
2123
ELDORA reflectivity
2136
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dBZ, wind
dBZ, wind
2108 UTC
1.6 km
6 km
dBZ, wind
?, perturbation wind
14 km
6.0 km
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dBZ, wind
dBZ, wind
2123 UTC
1.6 km
6 km
dBZ, wind
?, perturbation wind
14 km
6.0 km
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dBZ, wind
dBZ, wind
2136 UTC
1.6 km
6 km
dBZ, wind
?, perturbation wind
14 km
6.0 km
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Pressure and Buoyancy Retrieval
8 km2108 UTC
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(No Transcript)
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Structure in the Stratiform Region
Reflectivity Wind
Vorticity perturbation wind
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Circulation
Average vorticity profile
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Summary

• Deep convective updaft of an MCS is important in
  genesis stage of Ophelia
• Convective updraft generates positive PV at low
  and midlevels
• Convective updraft is deep (16 km), wide (20
  km), and strong (up to 30 m/s)
• T and p both contribute to updraft
• Downdrafts dont play an obvious role
• These observations dont exactly fit the previous
  notions of convection related to genesis

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Thank You
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CFAD of Mass Transport and Vertical Velocity in
Ophelia
Stratiform Region
Convective Region
Mass transport in the convective domain. Left
column shows mass transport normalized to the
peak positive value for the three convective
analysis legs. Black lines indicate upward
transport, dashed dark gray line denotes downward
transport, and light gray dash-dot line is net
transport. Right column shows contour frequency
by altitude (CFAD) diagrams with mass weighted
vertical velocity in 106kg s-1 contours, with
30x106kg s-1 contour highlighted. Data is binned
in 1 m s-1vertical velocity increments.
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Radar Loop from KMLB
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Can synthesize the 3-D wind fields by flying by a
phenomenon.
Nyquist Velocity up to 100 m/s
300 m
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3-D Variational Formulation (Gamache 1997)