Transcript Document

CuPIDO: Cumulus Photogrammetric,
In Situ, and radar Doppler Observations
The UWKA/WCR Role
WCR Group
•Rick Damiani, Bart Geerts, and Larry Oolman, UWyo
•Joe Zehnder, ASU
CuPIDO Preparation meeting. Boulder, CO. April 12, 2006
Contents
UWKA/WCR
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Objectives
Resources
Expected data analysis
Strategy and Logistics
CuPIDO meeting, Boulder, CO
April, 2006
Objective I.
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Cu radar echo and kinematic structure
Cloud microphysical & thermodynamic structure
Entrainment patterns
Cloud evolution
synergy: photogrammetry + sounding systems
Objective II.
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Environmental changes during Cu convection
 Cu deepening and orographic mesoscale circulations
• synergy: photogrammetry+sounding systems+PAM-III network
CuPIDO meeting, Boulder, CO
April, 2006
Conceptual Model of Cu Growth Dynamics
(objective I.)
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Plume
Pulsating Clouds?
Thermals or plumes?
Time/spatial scale
Rate of rise
Bubble
(Blyth, 1988)
(Schmidt, 1941) (Scorer, 1957)
CuPIDO meeting, Boulder, CO
April, 2006
Conceptual Model of Cu Growth Dynamics
(objective I.)
• Major vorticity structures.
Vortex-Rings
• Role on entrainment
• Role of shear?
• Cloud base thermodynamics
• Undiluted parcels?
• In-cloud and environmental
thermodynamics
• Orographic locking and effects
CuPIDO meeting, Boulder, CO
April, 2006
How do we Reach the goals?
• UWKA platform + in situ probes:
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Standard Meteo variables
Cloud Particle Spectrometers (FSSP,1DC,2DC)
LICOR (H2O, CO2)
Radiation Sensors (visible, IR)
Forward looking camera
• WCR
• Flight Strategies
CuPIDO meeting, Boulder, CO
April, 2006
WCR specs.
Frequency
94.92 GHz ( =3.16 mm)
Nominal Peak Power
1.6 kW (1% duty cycle)
Nominal Pulse Length
•100, 250, 500 ns
Pulse Repetit. Frequency (PRF)
1-20 kHz
Receivers
-dynamic range
-bandwidth
2
>70 dB
10, 5, 2 MHz
Antennas
- aperture
- beamwidth
- gain
- polarization (linear)
4; 5 fixed beam positions
0.30, 0.30, 0.38, 0.46 m
0.8, 0.8, 0.6, 0.5º
45, 46, 48, 50 dB
one dual (H,V), three single
Doppler Velocity
- pulse-pair processor
- FFT spectrum
± 15.8 m/s @ 20 kHz PRF
32 or 64 spectral lines
Volume Resolution
(250ns, 0.3m antenna)
37(range) x 12 x 15 m @ 1km
37(range) x 36 x 39 m @ 3km
Minimum Detectable Signal
(250 ns, 500 averaged pulses,
0.3 m antenna, @1 km)
-30 dBZ
(1 std. dev. above mean noise)
CuPIDO meeting, Boulder, CO
April, 2006
WCR cloud scanning modes
Up/Down profiling mode
beam 2
Vertical Plane Dual-Doppler
beam 1
Horizontal Beam Dual-Doppler
CuPIDO meeting, Boulder, CO
April, 2006
WCR: Profiling Configurations
• Single-Doppler modes:
• Side/down mode is achieved using beam 1 from both HBDD and VPDD
configurations
• Profiling Mode (Up/Down) is achieved by redirecting the HBDD beam 1 upward
via mirror plate
CuPIDO meeting, Boulder, CO
April, 2006
Data Analysis
• Process WCR data
• Combine in situ and remote sensing
• Integrate with ISSF data and
profilers/soundings
CuPIDO meeting, Boulder, CO
April, 2006
Up/Down Profile Mode
Density
temperature (Tr)
and liquid water
content (lwc100)
gust-probe
vertical velocity
& 1-s gust
vectors
• Cloud base thermodynamics
(initial stages of cloud
formation)
• Thermal base convergence
and entrainment
WCR
retrieved
vertical
velocity &
reflectivity
CuPIDO meeting, Boulder, CO
20030719, 19:45UTC
April, 2006
Up/Down Profile Mode
Ice (iwcc) and
liquid water
content (lwc100)
gust-probe
vertical velocity
& 1-s gust
vectors
• Convergence and LWC
drop indicate ambient air
entrainment driven by
WCR
the circulation.
retrieved
vertical
velocity &
reflectivity
CuPIDO meeting, Boulder, CO
20030713, 20:58UTC
Flight level
April, 2006
VPDD
dBZ
20030826, 18:23UTC
8m/s
• Two counter-rotating vortices are visible in the
ascending cloud-top.
(Damiani et al., 2005, JAS)
CuPIDO meeting, Boulder, CO
April, 2006
Conceptual Model of Cu Growth Dynamics
Potential Entrainment Sites:
primary and secondary circulations
drive intrusions of ‘dry’ air
CuPIDO meeting, Boulder, CO
April, 2006
VPDD
20030718, 20:43UTC
• Ambient air intrusion at the base of the thermal
• Hydrometeor recycling
CuPIDO meeting, Boulder, CO
April, 2006
Conceptual Model of Cu Growth Dynamics
asymmetric vorticity structures in stronger
winds (and shear): tilted vortex rings
CuPIDO meeting, Boulder, CO
April, 2006
VPDD
20030717, 21:42UTC
• Ambient shear effects
• Tilted vortex rings?
CuPIDO meeting, Boulder, CO
April, 2006
Conceptual Model of Cu Growth Dynamics
horizontal cross-sections
CuPIDO meeting, Boulder, CO
April, 2006
HBDD
20030717, 20:50UTC
• Vertical vorticity and entrainment patterns
• Divergence (thermal top?)
CuPIDO meeting, Boulder, CO
April, 2006
Conclusions
• Flight planning strategy will be based on:
Sought kinematic patterns, vortical structures
Entrainment mechanisms (intrusions)
Soundings’ availability
Thermodynamics and microphysics at different altitudes
Multi-scanning capabilities of the WCR
Lagrangian investigation of rising turrets (evolution)
Horizontal plane kinematics and entrainment
Cloud evolution
CuPIDO meeting, Boulder, CO
April, 2006
Flight Plan
60 Flight hrs: 15 IOPs
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Forecast: convection onset time
Forecast: LCL, LFC, NBL, Cloud-top
Wind direction/ Shear Direction/ Vertical Profile
in the layer of observations
Take-off before cu-convection (7am-1pm LT)
1. Circle (20 min~30-40km f): GPS-routed loop
2. Cloud base transects: UD, SD, SS
3. Climb and Scan mid levels: UD, SS, DD
(possibly DPDD)
4. Over the top: DD, SS
5. Post-Cu investigation
CuPIDO meeting, Boulder, CO
April, 2006
CBL Air-stream Assessment
Sub-Cloud Layer Characterization
 f~20-40km~ 20
min
 FL: 1000’ AGL,
LCL, detrainment
level ~18kft MSL
(also objective II.)
Pusch Ridge
Dt~10 min
FL: LCL-1000’
Wilderness
• Synergy: Ground Stations + Soundings
CuPIDO meeting, Boulder, CO
April, 2006
cumuli modifying
the environment
(objective II.)
• difference between
upstream and downstream
environment
• also: fixed-level Cu
mapping and HBDD
CuPIDO meeting, Boulder, CO
April, 2006
Cu penetration patterns: summary
CuPIDO meeting, Boulder, CO
April, 2006
Pre-Cu-Convection Assessment
• Document: CBL air-stream channeled by
the complex terrain, feeding the cloud
development.
• If the WCR signal is marginal in the clear
CBL, the in situ thermodynamic and
kinematic information will be important in
describing first cumulus development.
• Synergy: PAM stations/ Tower/ GAOS-Soundings
CuPIDO meeting, Boulder, CO
April, 2006
Cu Initial Phases: Cloud Base Investigation
• Transects at cloud base: LCL+1000’
climb
View A
SS
UD
1000’
climb
climb
• Tot time:~ 6-10min depending on
development (if turret grows
climb to next phase)
SD
SD
UD
climb
300’
SS
CuPIDO meeting, Boulder, CO
shear/
mean wind
A
April, 2006
Cu Initial Phases: Cloud Base Investigation
• Document: changes in echo, vertical
velocity structure, as well as in buoyancy,
water loading, and entrainment
characteristics.
• The UWKA will also document changes in
the environment as the cumulus detrains
and eventually collapses, leaving behind a
mixture of CBL and ambient air.
• Synergy: cameras/LCLforecast/GAOS-Sounding
CuPIDO meeting, Boulder, CO
April, 2006
Cu Mid-Stages: Kinematics & Entrainment
wind/shear
• Alternate passes: SS/DD,DPDD
• Along or Across-wind direction
DD
SS
• Tot time:~ 10-20min depending
on development (if turret
grows climb to next phase)
CuPIDO meeting, Boulder, CO
April, 2006
Cu Mid-Stages: Kinematics and
Microphysics
• Document:
– towers’ growth
– entrainment at mid
levels;
– pulsating nature;
– structure of thermals;
– vertical vorticity;
– Adiabatic cores?
– Droplet spectrum
evolution
– Recirculation of drizzle
or ice particles
– Secondary ice
multiplication processes
• Synergy: cameras/wind
profilers
CuPIDO meeting, Boulder, CO
April, 2006
Environmental Changes at mid-stages
• Closed patterns at fixed MSL altitude, long (~40km)
legs directed along the wind
wind/shear
• When: strong prevailing wind and multiple cloud (cluster)
• Tot time:~ 20-30min each
CuPIDO meeting, Boulder, CO
April, 2006
Cu Advanced Stages: Cloud Top
DD
wind/shear
• Alternate passes: DD,DPDD/SS
• Along or Across-wind direction
• Let the top outclimb the ACSS
CuPIDO meeting, Boulder, CO
SS
April, 2006
Cu Advanced-Stages: cloud-top mechanics
• Document:
– Vorticity structures and entrainment near
cloud outer boundaries
• Synergy: cameras/wind profilers
•The UWKA/WCR will sample Cu evolution at various
levels in the cloud, until over-development starts
CuPIDO meeting, Boulder, CO
April, 2006
Cu Post-Stages
• UWKA will investigate detrainment stages by
circling around the mountain range and possibly
descending to low levels to repeat
circumnavigation, in order to sample both the
convective outflow and the generation of new
inflow. This pattern will also keep the UWKA at
distance from electric activity which is focused over
the mountain peaks.
• The sequence then can be repeated, with cloud
transects as soon as the new inflow engenders
cumulus development.
• Synergy: cameras/PAMs/Forecast
CuPIDO meeting, Boulder, CO
April, 2006
flight operations
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operations base: Tucson Int’l
60 research flt hours, ~15 IOPs
normal time window: 7 am – 1 pm MST (UTC-7)
tentative take-off time decided after the 3 pm daily
weather briefing
• update on T/O decision after 6 am weather update
(using the 5 am (12 Z) Tucson sounding)
CuPIDO meeting, Boulder, CO
April, 2006