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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are needed to see this picture.

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