a comparison of the characteristics of cirrus and anvils ... · jay mace, sally benson-troth, min...
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A Comparison of the Characteristics of Cirrus and Anvils Observed During CRYSTAL-FACE Derived from Ground-Based and Aircraft data: Selected
Case Studies
Jay Mace, Sally Benson-Troth, Min Deng, Kristin Laribee-Dowd (Univ. of Utah)Jim Mather, Roger Marchand, Jennifer Comstock and Tom Ackerman (PNNL)
Mike Poellot, Cindy Twohy (UND Citation)
Goal: Report on data, show multi platform synergy, compare results to tropical cirrus
Thunderstorm and Anvil system observed on 25 July at Western Ground Site
PARSL Cloud Overview
Anvil Cirrus were observed at least 11 out of 17 days data were collected during CRYSTAL FACE
PARSL Cloud Overview
Ongoing Science Application of the CRYSTAL FACE data set
• Characterizing and understanding the synoptic modulation of diurnally driven convection (Mather)
• Characterization of the radiative properties of tropopause cirrus and comparison to tropopause cirrus observed in the TWP (Comstock)
• Characterization of the microphysical properties of anvil cirrus and comparison to cirrus observed in the TWP (Mace, Comstock)
• Development and validation of advanced cloud property retrieval algorithms using millimeter wave Doppler radar (Marchand and Mace)
• A-Train and EOS validation investigations (Mace, Marchand)
• We are currently evaluating several thousand hours of cirrus data collected by mm radar, lidar and passive sensors at the TWP ARM sites.
• Using cloud property algorithms derived for mid latitude cirrus may lead to significant error and potentially erroneous conclusions.
•Goal: Use the Crystal FACE data to teach us how important thesedifferences may be
Monthly Cloud Occurrence Fraction
Nauru Island Manus Island
Example Cloud Property Retrieval Forward Model Equations:
n L( ) = N exp −λL[ ]Ze = IWC
azbzambm
Γ bz{ }Γ bm{ }
bm +1Dmass
bm− bz
m = amDbm
V = avDbv
V Dq
= avbm +1Dmass
−bv
1+bvbz
Γ bz + bz{ }
Γ bz{ }
?
Sensitivity of IWC retrieval to the exponent in the particle size power law:
Crystal FACE Case Study: July 16
1745 UTC
1845 UTC 1932 UTC
Crystal FACE Case Study: July 16
#/lit
er/m
icro
n
Size (microns)
16 July anvilam=0.0138 bm=2.724av=11011 bv=1.6484
Bullet Rosettes am=0.0031 bm=2.26av=2150 bv=1.225
Crystal FACE Case Study: July 16
PARSL DopplerVelocity
Citation DopplerVelocity
1845 UTC
1830 193019001845 1915Time (UTC)
dBZe
8101214
8101214
Vd
-40
-20
0
0.51.0
0.0
1830 193019001845 1915Time (UTC)
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Crystal FACE Case Study: July 16
Crystal FACE Case Study: July 16
Aircraft IWC
Z-V IWC
Aircraft Particle Size
Z-V Particle Size
Florida Convective Cirrus vs Tropical Cirrus: ????
What can we determine from our existing data?
Use GMS data to track upper tropospheric cloud features observed by radar at Nauru back to any convective event in the previous 12 hours.
Question 1: How much of the cirrus observed by the radar can be traced to a convective source in the previous 12 hours?
Question 2: How does the longevity of tropical cirrus compare to Florida cirrus?
Question 3: Can we correlate the history to variations in the microphysics?
Nauru Island,11/06/1999
Question 3: Can we correlate the history to variations in the microphysics?
Particle Sizemicrons
Log(iwc)
Time (hours)
Summary:
• Western Ground Site data has been submitted to Ground Site Archive (ftp://iop.archive.arm.gov)
• Overall data quality is excellent with some residual issues being dealt with
• Science objectives being pursued.
• Strongly emphasize the need for additional measurements in tropical cirrus.
PARSL Instrument and Data Status
No IssuesYes100%•Standard InstrumentationSurface MET
Some QCYes100%•Standard GPS Vaisalasoundings Balloon-borne
sounding system (BBSS)
No IssuesYes100%•NFOV downwelling radiance (9-11 µm)Infrared
Thermometer (IRT)
No IssuesYes100%•Digital Sky Images at 1s or longer temporal intervalsTotal Sky Imager
AlignmentYes60%•Direct normal, diffuse horizontal, and total horizontal solar irradiances at 415, 500, 615, 673, 870 and 940 nm
Multi-Filter Rotating ShadowbandRadiometer (MFRSR)
No IssuesYes100%•Up and downwellingBroadband, hemispheric diffuse and direct solar and IR flux
Broadband radiometers
CautionYes70%•Brightness Temperature at 23.8 and 31.4 GHzMicrowave
Radiometer
SensitivityYes25%•Backscatter to extinction ratio523 nm Lidar
SensitivityNo100%•Radar Reflectivity,•Doppler Velocity,•Doppler Spectra
35 GHz cloud Radar
Doppler MomentsYes100%•Radar Reflectivity,•Doppler Velocity,•Doppler Spectra
94 GHz Cloud Radar
IssuesData Archived?Operational Status
Measurement(s)Instrument