Comparisons to Observations Yumin Moon and David S Nolan 2014 Rainband Classification Data amp Methodology Principal Rainband Secondary Rainband Distant Rainband Inner Rainband Four types of rainbands primary secondary distant and inner ID: 552033
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Spiral Rainbands in a Numerical Simulation of Hurricane Bill (2009). Part I: Structures and
Comparisons
to Observations
Yumin
Moon and David S. Nolan 2014
Rainband Classification
Data & Methodology
Principal Rainband
Secondary Rainband
Distant Rainband
Inner Rainband
Four types of rainbands: primary, secondary, distant, and inner
Simulation of Hurricane Bill 2009 was done using the WRF 3.2.1
over a 3 day
period of max
intensity from
1200 UTC 18 August to 1200 UTC 21 August
Graphs are radius-height cross sectional averages for each rainband
1.Radial tilt outwards
2. Overturning secondary circulation
3. Enhanced tangential velocity on radial outward side
4. Higher theta-e in updraft
Updraft
Downdraft
Radial inflow from outward side z=2-4km that descends to surface
or
Indirect overturning circulation on inward side called inner-edge downdraft (IED)
Stratiform
1. Found on downwind sector of band
2. Radial tilt outwards with bright band at 5 km
Updraft
1.Radial tilt outwards
2. More mature convection with higher vertical extent found on downwind side
3. Overturning circulation on radial outward side
Downdraft
Left side displays descending midlevel radial flow and right side is indirect overturning circulation on inward side
1.Radial tilt inwards
2. Updraft on radial outward side
3. Strong horizontal convergence at base of updraft and divergence above
4. Structure similar to squall lines
1. Shallow convection below 5 km
2. Reflectivity above 7km is condensates from eyewall convection
3. Hypothesized to
form close
to the eyewall and
propagate outwards
-Primary and secondary are very similar
except with primary being more stationary-Distant has convection similar to squall lines -Inner, not shown in the diagram, are found in closer proximity to the eyewall than the secondary
Houze(2010)