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Readme Contents Overview The Data Characteristics The Files Format Data Access & Contacts Points of Contact The Science Instrument Related Publications

Overview

Cloud Microphysical measurements for TEFLUN-A Project were made by the NCAR & SPEC scientists using NASA Learjet aircraft . For the TEFLUN-A experiment the measurements were made during the month of April and May 1998 over eastern region of Texas under the directions of Dr. Andy Heymsfield, the Principal Investigator for the TEFLUN-A cloud microphysics measurement.

The Data

Characteristics

The data is very preliminary, before using this data in your publication, please contact the Principal Investigator Dr. Andy Heymsfield(heyms1@ucar.edu).
The details of the flights and performance are given below in Tables 1 & 2 .

Table 1.   TEFLUN-A Cloud Physics Aircraft (Lear) Flights Summary

Date	Flight   Times   (UTC)	ER-2	TRMM	RADAR	LOCATION	COMMENTS
4/18/98	17:47-19:55	X	X	HGX, X-POL	Houston	Moderate rain, mostly stratiform, best coordination.
4/27/98	16:05-18:00	--	--	ADRAD	East of TAMU	Decaying stratiform.
4/28/98	02:10-04:00	--	X	ADRAD	East of TAMU	Convective, stratiform, lightning strike.
4/29/98	05:40-07:35	--	X	LCH	Louisiana coast	Decaying MCS moving onshore in Louisiana.
5/1/98	00:00-02:15	X	X	Several	South of Georgia	Active MCS, trailing stratiform, lightning strike.
5/6/98	18:28-20:11	X	X	Mobile	Alabama Coast	Edge of strong convective storm; aircraft not together.
5/6/98	21:35-22:47	--	X	Mobile	South of Alabama Coast	Return to stratiform part of same storm over Gulf.
5/8/98	23:51-01:11	--	X	FTW, ABI	West of FTW	Brief penetration of supercell anvil; electrified, aborted.

 

The Files

File Naming Convention

There are four groups of files in ascii format. The names of the files are of the form:
mmddhhmm.xxx,
where mmdd is the date in month, day format and hhmm is the start time of the flight in hours and minutes format , and xxx designates the sensor( 2dc or fsp) or data type(sum or trk).

Files Format

The file begins with header lines of information. The header lines contain information about processing algorithm prameters and units.

Files containing Data from 2D Cloud PROBE DIODE ARRAY (2D-C)



Header of the ....2dc Data Files:
-------------------------------

LAWSON, Paul
SPEC, Incorporated, Boulder, CO, USA, 80301
SPEC Lear
2DC, SEA system
TEFLUN-A 1998
1998 04 18  1998 04 27
Date
Time_System (UT)
TAS(m/s)_Average
StaticTemp(C)
ConcChannel1   (#/L) between  0.00 -   25.00 um, midpoint  12.50 um
ConcChannel2   (#/L) between 25.00 -   50.00 um, midpoint  37.50 um
ConcChannel3   (#/L) between 50.00 -   75.00 um, midpoint  62.50 um
ConcChannel4   (#/L) between 75.00 -  100.00 um, midpoint  87.50 um
ConcChannel5   (#/L) between 00.00 -  125.00 um, midpoint 112.50 um
ConcChannel6   (#/L) between 25.00 -  150.00 um, midpoint 137.50 um
ConcChannel7   (#/L) between 50.00 -  175.00 um, midpoint 162.50 um
ConcChannel8   (#/L) between 75.00 -  200.00 um, midpoint 187.50 um
ConcChannel9   (#/L) between 00.00 -  225.00 um, midpoint 212.50 um
ConcChannel10  (#/L) between 25.00 -  250.00 um, midpoint 237.50 um
ConcChannel11  (#/L) between 50.00 -  275.00 um, midpoint 262.50 um
ConcChannel12  (#/L) between 75.00 -  300.00 um, midpoint 287.50 um
ConcChannel13  (#/L) between 00.00 -  325.00 um, midpoint 312.50 um
ConcChannel14  (#/L) between 25.00 -  350.00 um, midpoint 337.50 um
ConcChannel15  (#/L) between 50.00 -  375.00 um, midpoint 362.50 um
ConcChannel16  (#/L) between 75.00 -  400.00 um, midpoint 387.50 um
ConcChannel17  (#/L) between 00.00 -  425.00 um, midpoint 412.50 um
ConcChannel18  (#/L) between 25.00 -  450.00 um, midpoint 437.50 um
ConcChannel19  (#/L) between 50.00 -  475.00 um, midpoint 462.50 um
ConcChannel20  (#/L) between 75.00 -  500.00 um, midpoint 487.50 um
ConcChannel21  (#/L) between 00.00 -  525.00 um, midpoint 512.50 um
ConcChannel22  (#/L) between 25.00 -  550.00 um, midpoint 537.50 um
ConcChannel23  (#/L) between 50.00 -  575.00 um, midpoint 562.50 um
ConcChannel24  (#/L) between 75.00 -  600.00 um, midpoint 587.50 um
ConcChannel25  (#/L) between 00.00 -  625.00 um, midpoint 612.50 um
ConcChannel26  (#/L) between 25.00 -  650.00 um, midpoint 637.50 um
ConcChannel27  (#/L) between 50.00 -  675.00 um, midpoint 662.50 um
ConcChannel28  (#/L) between 75.00 -  700.00 um, midpoint 687.50 um
ConcChannel29  (#/L) between 00.00 -  725.00 um, midpoint 712.50 um
ConcChannel30  (#/L) between 25.00 -  750.00 um, midpoint 737.50 um
ConcChannel31  (#/L) between 50.00 -  775.00 um, midpoint 762.50 um
ConcChannel32  (#/L) between 75.00 -  800.00 um, midpoint 787.50 um

First few data records of  ..2dc Data Files:
---------------------------------

  98-04-18  17:49:27     0.000000     16.89	0.000000     0.000 - - ----
  98-04-18  17:49:28     0.000000     16.83	0.000000     0.000 - - ----
  98-04-18  17:49:29     0.000000     16.80	0.000000     0.000 - - ----
  98-



Files containing Data from Forward Scattering Spectrometer Probe(FSSP)



Header of the ....fsp Data Files:
--------------------------------

LAWSON, Paul
SPEC, Incorporated, Boulder, CO, USA, 80301
SPEC Lear
FSSP, SEA system
TEFLUN-A 1998
1998 04 18  1998 04 27
Date
Time_System (UT)
TAS(m/s)_Average
StaticTemp(C)
ConcChannel1  (#/L) between  2.000 -  5.000 um, midpoint  3.500 um
ConcChannel2  (#/L) between  5.000 -  8.000 um, midpoint  6.500 um
ConcChannel3  (#/L) between  8.000 - 11.000 um, midpoint  9.500 um
ConcChannel4  (#/L) between 11.000 - 14.000 um, midpoint 12.500 um
ConcChannel5  (#/L) between 14.000 - 17.000 um, midpoint 15.500 um
ConcChannel6  (#/L) between 17.000 - 20.000 um, midpoint 18.500 um
ConcChannel7  (#/L) between 20.000 - 23.000 um, midpoint 21.500 um
ConcChannel8  (#/L) between 23.000 - 26.000 um, midpoint 24.500 um
ConcChannel9  (#/L) between 26.000 - 29.000 um, midpoint 27.500 um
ConcChannel10 (#/L) between 29.000 - 32.000 um, midpoint 30.500 um
ConcChannel11 (#/L) between 32.000 - 35.000 um, midpoint 33.500 um
ConcChannel12 (#/L) between 35.000 - 38.000 um, midpoint 36.500 um
ConcChannel13 (#/L) between 38.000 - 41.000 um, midpoint 39.500 um
ConcChannel14 (#/L) between 41.000 - 44.000 um, midpoint 42.500 um
ConcChannel15 (#/L) between 44.000 - 47.000 um, midpoint 45.500 um

 

First few data records of  ..fsp Data Files:
------------------------------------------


  98-04-18  17:49:27     0.000000        16.89    79.939209     0.000 - - -----
  98-04-18  17:49:28     0.000000        16.83     0.303951     0.000 - - -----
  98-04-18  17:49:29     0.000000        16.80     0.000000     0.000 - - -----
  98-04-18  17:49:30     0.000000        16.77     0.303951     0.303 - - -----  
  98-04-18  17:49:31     0.000000        16.74     0.607903     0.000 - - -----
  98-0



Files containing Summary Informations


Header of the ....sum Data Files:
------------------------------



LAWSON, Paul
SPEC, Incorporated, Boulder, CO, USA, 80301
SPEC Lear
Flight summary information, SEA system
TEFLUN-A 1998
1998 04 18  1998 04 27
Date
Time_System (UT)
GPS_Time (UT)
Longitude(deg)
Latitude(deg)
Altitude(km)
TAS(m/s)_Average
StaticTemp(C)
DewPoint(C)
King_LWC(g/m3)
FSSP_TotalConc(#/cc)
FSSP_SumLWC(g/m3)
2DC_MaximumSize(um)
2DC_ConcSum(#/l)
2DC_MeanDiameter(um)




First few data records of  ..sum Data Files:
---------------------------------
 
 
  98-04-18  17:49:27  17:49:41   -96.361488    30.590500     4.039721    - - ------
  98-04-18  17:49:28  17:49:42   -96.361488    30.590500     4.037687    - - ------
  98-04-18  17:49:29  17:49:43   -96.361328    30.590500     3.517106    - - ------
  98-04-18  17:49:30  17:49:44   -96.361488    30.590332     3.512531    - - ------
  98-04-18  17:49:31  17:49:46   -96.361488    30.590332     2.989943    - - ------
  98-04-18  17:49:32  17:49:47   -96.361488    30.590332     2.987909    - - ------
  98-04-18  17:49:33  17:49:48   -96.361488    30.590164     3.512531    - - ------
 





Files Containing Track Informations

Header of the ....trk Data Files:
-----------------------------



LAWSON, Paul
SPEC, Incorporated, Boulder, CO, USA, 80301
SPEC Lear
Flight track information, SEA system
TEFLUN-A 1998
1998 04 18  1998 04 27
Date
Time_System (UT)
Longitude(deg)

Latitude(deg)
Altitude(km)



First few data records of  ..trk Data Files:
------------------------------------------


  98-04-18  17:49:27   -96.361488    30.590500     4.039721
  98-04-18  17:49:28   -96.361488    30.590500     4.037687
  98-04-18  17:49:29   -96.361328    30.590500     3.517106
  98-04-18  17:49:30   -96.361488    30.590332     3.512531
  98-04-18  17:49:31   -96.361488    30.590332     2.989943
 

Data Access and Contacts

FTP Site

The TEFLUN aircraft data resides on DISC anonymous FTP. You may access the files from this document,

Microphysical Data from SPEC Learjet Aircraft

Browse Images

or directly via FTP at

ftp disc2.nascom.nasa.gov

login: anonymous

password: < your internet address >

cd data/TEFLUNA/aircraft/spec_learjet

Points of Contact

For Information about TEFLUN data at Goddard DISC, please contact

Hydrology Datat Support Team
Email: hydrology-disc@listserv.gsfc.nasa.gov

Technical Inquiries about this Data should be addressed to:

Microphysical Data Investigators:

Dr. Andy Heymsfield
National Center for Atmospheric Research
P.O.Box 3000
3450 Mitchell Lane
Boulder, CO 80307
phone:303-497-8943
fax: 303-497-8171
email: heyms1@ucar.edu

Dr. Greg McFarquhar
National Center for Atmospheric Research
P.O.Box 3000
3450 Mitchell Lane
Boulder, CO 80307
phone:303-497-8948
fax: 303-497-8171
email: mfarq@ucar.edu

Data Processing information:

Steve Aulenbach
National Center for Atmospheric Research
P.O.Box 3000
3450 Mitchell Lane
Boulder, CO 80307
phone:303-497-8969
fax: 303-497-8171
email: aulenbac@ucar.edu

Instruments & Measurement information:

Dr. Paul Lawson
SPEC Incorporated
Boulder,CO 80301
phone:303-449-1105
fax: 303-449-0132
email: lawson@specinc.com

The Science

Platform

Microphysics Aircraft

The NASA learjet aircraft with number of radiometric and imaging sensors (installed by SPEC incorporated) has been used for TEFLUN-A cloud microphysics atmospheric measurements. The learjet can achieve an operating ceiling of 30,000 feet (8 km) in a very short time.

Instruments

(information mostly based on SPEC incorporated Web page)

The basic instrumentation package installed on Learjet aircraft measures temperature, dew point temperature, pressure, wind and cloud microphysical characteristics along with aircraft position, attitude and performance parameters.

Particle Measuring Systems (PMS)

Cloud microphysical measurements are made with an array of Particle Measuring Systems (PMS) probes mounted on the wing-tip.

Characteristics:

• PMS 2D Optical Array 2D-C used for cloud Particles
• Forward Scattering Spectrometer Probe ( FSSP ) used for cloud droplet spectrum

These probes measure concentrations and sizes of particles from one micrometer to several millimeters in diameter.

Cloud Particle Imager (CPI):

CPI is used to make digital images of cloud particles.

Characteristics

• High-power laser pulsed at 25 hs freezes image of particle on CCD camera.
• Unique optics produce in-focus images.
• 1 million pixel CCD camera with 2.3 mm size resolution provides images of particles up to 2 mm in size.
• Up to 40 frames s^-1 with up to 100 particles per frame.
• Individual particle images are identified, sized, cropped and stored in real time.

Cloud Drop Spectrometer (CPS):

CPS is used to measure drop size distribution and liquid water content (LWC) from an ensemble of drops.

Characteristics

• LWC and drop size distribution computed in software from raw measurements of scattered light collected on 512 element linear CCD array.
• Measures spherical particles from 3 to 200 mm in diameter.
• 6 cm³ sample volume.
• Measurements from ground or airborne are independent of airspeed.
• Tested at Mt. Washington Observatory for two winters.

Related Publications

Blyth, A. M., and R. P. Lawson, 1991: Calculations of light scattered from water droplets using Mie theory. Interim Report to: Atmospheric Environment Service of Canada. Contract No. KM175-0-8061/01-TOY.

Cormack, R. H. and R. P. Lawson, 1992: Cloud Liquid Water Content and Droplet Distribution Measurements From Forward Scattered Light. SPEC Technical Report No. OLWC-9201-B.

Cormack, R. H. and Lawson, R. P., 1993a: A digital holographic technique for automatic analysis of particle fields. Appl. Opt., (In Progress)

Cormack, R. H. and Lawson, R. P., 1993b: Sizing of spherical particles using automated measurements of far-field diffraction from a field of drops. Appl. Opt., (In Progress)

Lawson, R. P., 1978: Turbulent rates of dispersion of ice particles in convective cloud, 1978: Preprints: AMS Conference on Cloud Physics and Atmospheric Electricity, Issaquah, WA. 355-362.

Lawson, R. P., 1979: A System for the Airborne Measurement of Vertical Air Velocity, J. Appl. Meteor., 18, 1363-1368.

Lawson, R. P., 1980: On the Airborne Measurement of Vertical Air Velocity, J. Appl. Meteor., 19, 1416-1419.

Lawson, R. P., and R. A. Stewart, 1983: An improved optical ice particle counter. Preprints: Fifth AMS Symp. on Meteor. Obs. and Instr., Toronto, 46-53.

Lawson, R. P., R. D. Horn and L. D. Nelson, 1987: Atmospheric extinction measurements using an open-cavity laser. Preprints: Sixth AMS Symp. on Meteor. Obs. and Instr., New Orleans, 100-103.

Lawson, R. P., and K. A. Weaver, 1989: Development and laboratory tests of a high-volume particle spectrometer for atmospheric research. SPEC, Incorporated. Final Report to the National Science Foundation under Contract No. ISI-8860047.

Lawson, R. P., and W. A. Cooper, 1990: Performance of some airborne thermometers in clouds. J. Atmos. Oceanic Technol., 7, 480-494.

Lawson, R. P., 1992: Comparison icing conditions using NOAA/LAPS analyses and aircraft observations during WISP. Presented at WISP data analysis workshop sponsored by NCAR, June 3, 1992, Boulder, Colorado.

Lawson, R. P., and A. R. Rodi, 1992: A new airborne thermometer for atmospheric and cloud physics research. Part I. Design and preliminary flight tests. J. Atmos. Oceanic Technol., 9, 556-574.

Lawson, R. P., R. H. Cormack and K. A. Weaver, 1993: A new airborne precipitation spectrometer for atmospheric research. Preprints: Eighth Symposium on Meteor. Obs. and Instr., AMS, Anaheim, 17-22 January. 30-35.

Lawson, R. P., R. E. Stewart, J. W. Strapp and G. A. Isaac, 1993a: Aircraft Observations of the Origin and Growth of Very Large Snowflakes. Geo. Res. Let. 20, 53-56.

Lawson, R. P., R. H. Cormack and K. A. Weaver, 1993b: A new airborne precipitation spectrometer for atmospheric research. Preprints: Eighth Symposium on Meteor. Obs., Anaheim, 17-22 January. 30-35.

Lawson, R. P., 1995: Digital holographic measurements of cloud particles. Reprint from: AMS Conference on Cloud Physics, January 15-20, 1995, Dallas, Texas.

Lawson, R. P. and R. H. Cormack, 1995: Theoretical design and preliminary tests of two new particle spectrometers for cloud microphysics research. Atmos. Res., 35, 315-348.

Lawson, R. P. and M. K. Politovich, 1996: Freezing drizzle encountered by a research aircraft over the Park Range in Colorado. Presented at FAA International Conference on Aircraft Inflight Icing, 6-8 May, Springfield, Virginia.

Lawson, R. P., L. J. Angus, A. J. Heymsfield, 1996a: Cloud particle measurements in thunderstorm anvils and possible weather threat to aviation. AIAA 96-0400. Presented to the 34th Aerospace Sciences Meeting and Exhibit, January 15-18, Reno, Nevada.

Lawson, R. P., L. J. Angus, T. Huang, K. A. Weaver, and A. M. Blyth, 1996b: New airborne measurements in adiabatic cores during very early coalescence development in Florida Cumuli. Presented at 12th Intl. Conference on Clouds and Precipitation, 19-23 August, Zurich, Switzerland.

Lawson, R. P., A. V. Korolev, T. Huang, L. J. Angus, K. A. Weaver, J. W. Strapp, G. A. Isaac, and S. G. Cober, 1996d: Improved airborne measurements of the drop size distribution in freezing drizzle. Presented at 12th Intl. Conference on Clouds and Precipitation, 19-23 August, Zurich, Switzerland.

SPEC, 1990: A High Volume Particle Spectrometer for Atmospheric Research, NSF Phase II Contract, ISI-8922336.

SPEC, 1992: An Airborne Particle Imaging Nephelometer For Measuring Optical Phase Function, NASA Phase II Contract, NAS1-19591.

SPEC, 1995: A new instrument for automatic measurement of cloud liquid content and droplet size for U.S. Department of Defense Cold Regions Research and Engineering Laboratory, DOD Contract, DACA 33-93-C-0006.

Weil, J. C., R. P. Lawson and A. R. Rodi, 1993: Relative dispersion of ice crystals in seeded cumuli. J. Appl. Meteorol., 32, 1055-1073.