Transcript Jorgensen NOAA P-3 Presentation

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NOAA P-3 Status for BAMEX
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148 flight hours approved
20 May - 6 July
Chief Scientists:
– Jorgensen: 20 May - 6 July, except 27-30 May & 22-24 June (maybe)
– Ziegler: 20 May - 3 June
– Smull: 2 June - 24 June
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Doppler Scientists:
– Jorgensen: 20 May - 6 July, except 27-30 May & 22-24 June (maybe)
– Ziegler: 20 May - 3 June
– Smull: 2 June - 24 June
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Cloud Physics Scientists:
– Greg McFarquhar
– Robert Rauber
– Brian Jewett
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Key P-3 Objectives
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NOAA P-3:
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Airborne Doppler radar mapping of 3-D flows
Cloud Physics observations from ~5°C to ~-15°C
Multiple snapshots of rear inflow system structure
Coordinated legs with NRL P-3 where possible (quad Doppler)
Straight-line flight tracks in bow-echo “rear” at 18,000 ft (~-15°C)
NRL P-3:
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Airborne Doppler (ELDORA) radar mapping of convective line
Multiple snapshots
Coordinated legs with NOAA P-3 where possible (quad-Doppler)
Flight level as low as practical
Straight-line flight tracks best
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Aircraft Hazards
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NOAA P-3:
– Lightning strikes near 0°C!
– Wind shear at base of anvil near top of rear inflow
– Aircraft charging in ice
– Icing in strong stratiform regions
NRL P-3:
– Strong convection near leading edge - avoid in spite of
no LF radar!
– Tracks within ~5 na mi. of leading edge
– Tornadic activity usually from the apex of the bow
northward and in “tail end charlie” supercells.
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Dropsonde Jet
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– Avoiding leading line convective cells
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Airborne Doppler Scanning
~1.4 km
ELDORA ~400 m
Pseudo-dual-Doppler Analysis: w
from vertical divergence integration
with w=0 @ echo top
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Optimal range for Doppler Analysis
To minimize vertical velocity contamination on radial winds need
to keep scanning angles < 45°
R should be > h-RA
h
R
Example:
h~10 na mi. (50kft)
RA ~ 5 na mi. (25kft)
R ~ 5 na mi.
45¡
45¡
RA
H ~ 10 na mi. (50kft)
RA ~ 1 na mi. (5kft)
R ~ 9 na mi.
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Squall Line Example - “Quad-Doppler”
Example from TOGA COARE [Jorgensen et al. 1997]
NOAA P-3
NOAA P-3
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NOAA P-3 Flight Strategies
• Basic Doppler survey
module (twin legs) at 18,000
feet to facilitate switching to
microphysics modules.
• Complete survey in 45 min
or less
• Microphysics modules by
NOAA P-3 will be attempted
in suitable regions
• Attempt at least 2 legs ~70
km system relative
separation (~38 na. mi).
Doppler coverage overlap of
~10 km
• Where possible coordinate
legs with NRL P-3
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System Relative Tracks
Sys Rel (u=0)
u=20 knts
u=40 knts
u=60 knts
38 nm
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Line Speed
Cross leg
(knots)
length (n mi.)
0
38
10
35.8
20
34.3
30
32.7
40
31.2
50
29.6
60
28.0
 (°)
0.0
2.4
4.8
7.2
9.6
12.0
14.4
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Microphysical Modules (NOAA P-3)
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~22 - 45 min flight pattern modules in welldeveloped stratiform rain regions
• Lagrangian spirals
• Descent rate ~ 1 m/s above 0°C, ~ 5
m/s below
• Standard rate turn (~22° bank angle)
• Wind is allowed to advect aircraft
• Descend from ~-10°C (~6 km)
through the melting level (~4 km) to
as low as practical
• Requires ~22-45 minutes depending
on vertical extent
• Perform several times
• As an alternative, could fly
Doppler legs at different
altitudes
• Either line parallel or line
perpendicular oriented flight
legs could be flown
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NOAA P-3 mphysics options
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Possible Flight Module Sequence
~50 na mi
42 min
33 min
45 min
For 6 hour on-station time ~ 3 sequences of above
~2 hrs
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Flight Direction Strategies
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Each aircraft has a Chief Scientist
Ops Director and Nowcaster at Ops Center
Must have reliable sat com for information exchange
between these groups
– Email messages
– ftp of gif images
– Voice (if necessary)
Ops Center to provide general guidance as to region to
investigate, including suggesting end points of flight legs
Chief Scientists will fix flight legs to optimize best tracks
for objectives
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NOAA P-3 – Ops Center Comms
Global-Star, 9600 baud
PPP link,:ftp, e-mail
B
• Observation reports
• Radar images
A
• Flight track guidance
• Hourly nowcast & short-term
forecasts
• Satellite & radar images
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Go/No Go Flight Decision
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Proposal:
– While at or above flight optimum flight
utilization curve flight decisions will be
relatively conservative (i.e., aircraft launch will
be predicated on observing mesoscale
organization and behavior)
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% used
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20 May
Project Days
6 July