BOREAS AFM-03 NCAR Electra 1994 Aircraft Sounding Data

Summary

The BOREAS AFM-03 team used the NCAR Electra aircraft to make sounding 
measurements to study the planetary boundary layer using in situ and remote-
sensing measurements.  Measurements were made of wind speed and direction, air 
pressure and temperature, potential temperature, dewpoint, mixing ratio of H2O, 
CO2 concentration, and ozone concentration.  Twenty-five research missions were 
flown over the NSA, SSA, and the transect during BOREAS IFCs 1, 2, and 3 during 
1994. All missions had from 4 to 10 soundings through the top of the planetary 
boundary layer. This sounding data set contains all of the in situ vertical 
profiles through the boundary layer top that were made (with the exception of 
"porpoise" maneuvers).  Data were recorded in 1-second time intervals. These 
data are stored in tabular ASCII files.

Table of Contents

   *  1 Data Set Overview
   *  2 Investigator(s)
   *  3 Theory of Measurements
   *  4 Equipment
   *  5 Data Acquisition Methods
   *  6 Observations
   *  7 Data Description
   *  8 Data Organization
   *  9 Data Manipulations
   *  10 Errors
   *  11 Notes
   *  12 Application of the Data Set
   *  13 Future Modifications and Plans
   *  14 Software
   *  15 Data Access
   *  16 Output Products and Availability
   *  17 References
   *  18 Glossary of Terms
   *  19 List of Acronyms
   *  20 Document Information

1. Data Set Overview

1.1 Data Set Identification

BOREAS AFM-03 NCAR Electra 1994 Aircraft Sounding Data

1.2 Data Set Introduction

The BOReal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology 
(AFM)-03 team used the National Center for Atmospheric Research (NCAR) Electra 
aircraft to make sounding measurements to study the planetary boundary layer 
using in situ and remote-sensing measurements.  Measurements were made of wind 
speed and direction, air pressure and temperature, potential temperature, 
dewpoint, mixing ratio of  H2O, CO2 concentration, and ozone concentration.  
Twenty-five research missions were flown over the Northern Study Area (NSA), 
Southern Study Area (SSA), and the transect during BOREAS Intensive Field 
Campaigns (IFCs) 1, 2, and 3 during 1994. All missions had from 4 to 10 
soundings through the top of the planetary boundary layer. This sounding data 
set contains all of the in situ vertical profiles through the boundary layer top 
that were made (with the exception of "porpoise" maneuvers).  Data were recorded 
in 1-second time intervals.  These data are stored in tabular American Standard 
Code for Information Interchange (ASCII) files.

1.3 Objective/Purpose

The Electra aircraft was used both to measure surface fluxes and to study the 
planetary boundary layer using in situ and remote-sensing measurements.
This sounding data set contains all of the in situ vertical profiles through
the boundary layer top that were made (with the exception of "porpoise"
maneuvers).

1.4 Summary of Parameters

The AFM-03 soundings data include time, date, location, wind speed and 
direction, air pressure and temperature, potential temperature, dewpoint, mixing 
ratio of  H2O, CO2 concentration, and ozone concentration.

1.5 Discussion

A total of 25 research missions were flown, distributed fairly evenly throughout 
IFCs 1, 2, and 3.  Flights were always along the regional transect, following 
the waypoints between Saskatoon and Churchill, except for some deviations north 
of the NSA.  See Section 7.1 for location of the waypoints.  Some missions 
concentrated exclusively on the SSA (waypoints A-H).  Other missions (at least 
one each IFC) went to/from Churchill, Manitoba (YYQ).  All missions had from 4 
to 10 soundings through the top of the planetary boundary layer.  Takeoff and 
landing vertical profiles (at Saskatoon (YXE) or Churchill (YYQ)) are included 
when they penetrated the top of the boundary layer.  Most soundings were 
transitions between legs flown at 100 meters above ground level (AGL) to measure 
fluxes close to the surface and legs flown above the boundary layer  (sometimes 
as high as 3,150 meters AGL) to measure continuous water vapor profiles remotely 
using a downward-looking water vapor DIAL instrument.  These soundings were 
flown as circles near the waypoint so that both the low and high legs would 
begin/end at the same location.  There are several flights, such as R05, where a 
very long (in this case 1,000 km) flight at 100 meters was broken up by an "up-
and-down" sounding.  All flights had other changes of altitude within the 
boundary layer that have not been included in this data set.

1.6 Related Data Sets

BOREAS AFM-01 NOAA/ATDD Long-EZ 1994 Aircraft Flux Data over the SSA
BOREAS AFM-02 Wyoming King Air 1994 Aircraft Flux and Moving Window Data
BOREAS AFM-03 NCAR Electra 1994 Aircraft Flux Data
BOREAS AFM-03 NCAR Electra 1994 Aircraft Moving Window Data
BOREAS AFM-04 NRC Twin Otter Aircraft Flux Data
BOREAS AFM-04 NRC Twin Otter Aircraft Sounding Data
BOREAS AFM-05 Level-1 Upper Air Network Data
BOREAS AFM-05 Level-2 Upper Air Network Standard Pressure Level Data

2. Investigator(s)

2.1 Investigator(s) Name and Title

Donald H. Lenschow
National Center for Atmospheric Research/MMM
Boulder, CO 
(303) 497-8903
(303) 497-8181 (fax)

2.2 Title of Investigation

Airborne Investigation of BiosphereAtmosphere Interactions Over the Boreal 
Forest

2.3 Contact Information

Contact 1
----------
Donald H. Lenschow
NCAR/MMM
Boulder, CO 
(303) 497-8903
(303) 497-8181 (fax)
lenschow@ncar.ucar.edu

Contact 2
----------
Steven P. Oncley
NCAR/ATD/SSSF
Boulder, CO  
(303) 497-8757
(303) 497-8770  (fax)
oncley@ucar.edu

Contact 3
----------
Jeffrey A. Newcomer
Raytheon ITSS
NASA GSFC
Greenbelt, MD 
(301) 286-7858
(301) 286-0239 (fax)

3. Theory of Measurements

This section summarizes the capabilities of the Electra as used in BOREAS.  For 
a complete description, see the Project Summary Documentation for BOREAS 
distributed by the Research Aviation Facility (RAF) and associated RAF 
Bulletins. Winds were determined by combining measurements of the air motion 
relative to the aircraft by pressure sensors connected to five holes on the 
radome of the Electra, with aircraft motion measured by a Honeywell laser 
inertial reference system (IRS).  Corrections to the IRS data were made using 
measurements by a Global Positioning System (GPS) satellite receiver.  See NCAR 
RAF Bulletin No. 23 for a complete description of this system and the data 
processing used.  In situ measurements of temperature, humidity, atmospheric 
pressure, aerosol and cloud droplet size distributions were made by sensors 
mounted to the wing and fuselage of the aircraft (RAF Bulletin Nos. 22 and 24).  
In situ measurements of chemical constituents were made by drawing outside air 
into closed-path sensors within the aircraft cabin.  These sensors included a 
LI-COR LI-6262 for water vapor and carbon dioxide and two NCAR gas-phase 
chemiluminescent sensors for ozone. 

4. Equipment

4.1 Sensor/Instrument Description

None given.

4.1.1 Collection Environment

Most data were acquired by an onboard computer that handled serial digital data, 
analog data (after anti-alias filtering), and event counters.  (The DIAL system 
and disjunct sampler each had independent data systems.)  Data were written to 
8-mm digital tape in flight and were later processed using the Nimbus program to 
calibrate, digitally filter (when necessary), and synchronize the final time 
series.  The time series data sets are available in NetCDF format at two data 
rates: 1) all channels output at 1 sample/second, and 2) all turbulence channels 
output at 25 samples/second.

4.1.2 Source/Platform

All instruments were mounted on a Lockheed Electra, which is a pressurized, low-
wing, turbo-propeller airplane, designed as a medium-range airliner. It is 
powered by four Allison 501-D13 constant-speed, axial-flow, turbine engines that 
drive four-bladed, full-feathering, reversible-pitch, turbo-propellers. Flight 
is approved in known icing conditions; however, external instrumentation 
installations may restrict operations in icing conditions. 

4.1.3 Source/Platform Mission Objectives

See Section 1.3.

4.1.4 Key Variables

See Sections 1.4 and 7.3.

4.1.5 Principles of Operation

See Section 4 and associated documents.

4.1.6 Sensor/Instrument Measurement Geometry

Most turbulence sensors are mounted on or near the aircraft radome on the 
fuselage.  The air-chemistry instruments had sampling inlets protruding from 
window locations along the fuselage.  Particle size sensors were mounted from 
pylons on the wings.

4.1.7 Manufacturer of Sensor/Instrument

None given. 

4.2 Calibration 

Most of the sensors were calibrated following normal NCAR/RAF procedures.  See 
the Project Documentation Summary for BOREAS (in particular, the Data Quality 
Report), available from Paul Spyers-Duran, for a complete description of the 
data used for these calibrations and a list of unique problems.  Some general 
conclusions:

Wind finding was good once a 10- to 15-degree bias in wind direction was 
removed.

Aircraft position and velocity measured by the IRS were adjusted to match 
positions from the GPS receiver.

The Lyman-alpha hygrometer failed during flights 3, 9, and 12, and during 
periods of flights 17 and 20.  For these flights, the LI-COR measurement of 
humidity was used.

The bottom dewpoint hygrometer performed worse than a "top" one, so the top 
sensor was used for all flights.

The LI-COR carbon dioxide channel was calibrated using a series of measurements 
with calibration gases during preflight testing and in-flight.  An empirical fit 
using pressure and temperature was used, since the manufacturer calibration 
equation performed poorly.

4.2.1 Specifications

Specifications for standard Electra sensors are given in RAF Bulletin No. 4.

4.2.1.1 Tolerance

None given.

4.2.2 Frequency of Calibration

See the Project Documentation Summary for BOREAS (in particular, the Data 
Quality Report), available from Paul Spyers-Duran.  Many sensors are checked 
before every flight.

4.2.3 Other Calibration Information

None given.  

5. Data Acquisition Methods

Most data were acquired by an onboard computer that handled serial digital data, 
analog data (after anti-alias filtering), and event counters.  (The DIAL system 
and disjunct sampler each had independent data systems.) Data were written to 8- 
mm digital tape in flight and were later processed using the Nimbus program to 
calibrate, digitally filter (when necessary), and synchronize the final time 
series.  The time series data sets are available in NetCDF format at two data 
rates: 1) all channels output at 1 sample/second, and 2) all turbulence channels 
output at 25 samples/second.  

6. Observations

6.1 Data Notes

None given.

6.2 Field Notes

Each investigator on the aircraft kept his/her own set of (usually handwritten) 
notes.  These have not yet been assembled into a complete document.

7. Data Description

7.1 Spatial Characteristics

These data were taken at 1-second intervals during aircraft vertical spiral 
maneuvers and during takeoff and landings.  At a nominal airspeed of 100 m/s and 
climb rate of 10 m/s, this corresponds to measurements every 100 m horizontally 
and 10 m vertically.  A total of 25 research missions were flown, distributed 
fairly evenly throughout IFCs 1, 2, and 3.  

Flights were always along the regional transect, following the waypoints between   
Saskatoon and Churchill, except for some  deviations north of the NSA.
This track was approximately a line from Saskatoon, Saskatchewan (52? N, 107? W) 
to a point north of Churchill (61? N, 95? W).

The North American Datum of 1983 (NAD83) are:
 
Waypoint	Latitude	Longitude
A		53? 32 N    106? 34 W
H		54?  7 N    104? 13.5 W
K		54? 41.7 N  103? 47.5 W 
L		54? 57.3 N  101? 58 W
M		55? 54.8 N  99? 7.5 W
O		55? 53.2 N  98? 00 W
P		60? 30 N    98? 00 W
Q		60? 30 N    95? 30 W
R		59? 00 N    95? 30 W
CH		58? 44.5 N  94? 04 W

Some missions concentrated exclusively on the SSA (waypoints A-H). Waypoints 
between A and H:

Waypoint	Latitude	Longitudes
a		53? 34.7 N  106? 23.8 W
b		53? 42.8 N  105? 52 W
c		53? 55 N    105? 04 W
d		53? 59 N    104? 47.2 W	

Other missions (at least one each IFC) went to/from Churchill, Manitoba (YYQ).  
All missions had from 4 to 10 soundings through the top of the planetary 
boundary layer.  Takeoff and landing vertical profiles (at Saskatoon (YXE) or 
Churchill (YYQ)) are included when they penetrated the top of the boundary 
layer. 

7.1.1 Spatial Coverage

All soundings are nominally taken at one point horizontally, though these 
usually are in the form of tight (6-km diameter) circles flown near one of
the waypoints listed above.  In a few cases (such as takeoffs and landings) the 
sounding was taken as an "enroute" climb or descent.  The altitude range 
typically is 100 meters AGL to about 300 m above the inversion height for these 
soundings.  Obviously, the takeoff and landing soundings go to 0 meters AGL.  In 
some cases, the bottom of the soundings are higher.

7.1.2 Spatial Coverage Map

None given.

7.1.3 Spatial Resolution

Individual position measurements should be accurate to 100 m horizontally, and 1 
m vertically.

7.1.4 Projection

None given.

7.1.5 Grid Description

None given.

7.2 Temporal Characteristics

The Electra flew 25 missions during the 1994 IFCs (25-May-1994 to 16-Sep-1994): 
8 in IFC-1, 8 in IFC-2, and 9 in IFC-3.

7.2.1 Temporal Coverage

Each flight was about 7 hours in duration and was usually between 11:00 a.m. and 
4:00 p.m. local time (all daylight hours).

7.2.2 Temporal Coverage Map

Measurements were made from 25-May-1994 to 16-Sep-1994.

7.2.3 Temporal Resolution

Measurements were made at intervals of 1 second. Missions were flown five to 
seven times per month.

7.3 Data Characteristics

Data characteristics are defined in the companion data definition file 
(afm3as94.def).

7.4 Sample Data Record

Sample data format shown in the companion data definition file (afm3as94.def).

8. Data Organization

8.1 Data Granularity

All of the AFM-03 NCAR Electra 1994 Aircraft sounding Data are contained in one 
data set.

8.2 Data Format(s)

The data files contain numerical and character fields of varying length 
separated by commas.  The character fields are enclosed with single apostrophe 
marks.  There are no spaces between the fields. Sample data records are shown in 
the companion data definition file (afm3as94.def).

9. Data Manipulations

9.1 Formulae

Values are reported at one sample per second.  Since all channels on the 
aircraft are sampled faster than this rate, these values are "boxcar" averages 
over all of the samples acquired during each second.

9.1.1 Derivation Techniques and Algorithms

None.

9.2 Data Processing Sequence

9.2.1 Processing Steps

1.  AFM-03 processed data and sent them to the BOREAS Information System 
(BORIS).
2.  BORIS staff received the data, made necessary conversions to standard units, 
and loaded the data into the database.
3.  BORIS staff documented the data set and compiled basic statistics about the 
data.

9.2.2 Processing Changes

None.

9.3 Calculations

None.

9.3.1 Special Corrections/Adjustments

Most values reported here are copied directly from the standard RAF low-rate 
data file.  The only exception is radar altitude, which was derived from two 
independent sensors.  A single radar altitude was synthesized from the low-range 
altimeter (HGM) for altitudes less than 780 m, and from the high-range altimeter 
(HGME) above 780 m.  This synthesized altitude had occasional spikes.  These 
spikes were detected by testing if the difference between the pressure altitude 
and sum of radar altitude plus height of the ground was greater than 50 m.  The 
ground height was set to the difference between pressure altitude and radar 
altitude at the first point in the sounding.  Spikes were replaced by pressure 
altitude minus the ground height.

9.3.2 Calculated Variables

Most values reported here are copied directly from the standard RAF low-rate 
data file.  The only exception is radar altitude, which was derived from two 
independent sensors.  A single radar altitude was synthesized from the low-range 
altimeter (HGM) for altitudes less than 780 m, and from the high-range altimeter 
(HGME) above 780 m.  See Section 9.3.1 for information about corrections to this 
parameter.

9.4 Graphs and Plots

None.

10. Errors

10.1 Sources of Error

There were several instrument malfunctions during this program.  See the Data 
Quality section of the Project Documentation Summary.

Calibration gas was connected to the LI-COR CO2/H2O sensor during some flight 
legs.  Most of these periods were near the beginning or end of a flight leg and 
have been removed by selection of leg start and stop times, but a few cases have 
been included.

The LI-COR CO2 calibration is still somewhat uncertain, though it is the best we 
can do at this time.

The Lyman-alpha hygrometer has spikes caused by rain that have not yet been 
removed from the data.

The radar altimeter has spikes from an unknown source.  These have not been 
removed, but should not contaminate the mean altitude much. (They should be 
detectable by comparing the altitude standard deviation from the radar altimeter 
and pressure altitude.)

The dew-point hygrometer sometimes cannot keep up with large changes in 
temperature (as occur during ascents and descents), so humidity profiles (not 
included in the leg-average data) should be used with caution.

10.2 Quality Assessment

Spot checks of data quality were done in the field, in calibration by NCAR/RAF, 
and in post-processing.  These checks mostly relied on the experience of the 
person checking to determine if values were suspicious.  Time series, profiles, 
and spectra have been used.  According to the AFM03 team, this process is 
ongoing and the quality of these products is still unknown.

10.2.1 Data Validation by Source

10.2.2 Confidence Level/Accuracy Judgment

None given.

10.2.3 Measurement Error for Parameters

None given.

10.2.4 Additional Quality Assessments

None given.

10.2.5 Data Verification by Data Center

BOREAS personnel verified that the delivered data agreed with the information 
provided by the AFM-03 team.

11. Notes

11.1 Limitations of the Data

None given.

11.2 Known Problems with the Data

See the Data Quality Report (Appendix A.4) for a complete list of data quality 
issues.  In particular, pay attention to the sections describing the following 
sensors:

The Electra carried two dewpoint hygrometers, a Lyman-alpha hygrometer, and a 
LI-COR closed-path infrared absorption hygrometer.  The dewpoint reported here 
came from the dewpoint hygrometer, which was determined to behave the best (by 
inspection).  Even so, there are periods where this signal has large 
oscillations due to the inability of the hygrometer to cycle fast enough to 
follow the large changes in humidity often found in soundings.  This behavior 
can be checked qualitatively by looking at the mean water vapor density, which 
was derived from either the Lyman-alpha or LI-COR sensor.  However, both of 
these sensors have their own problems: the Lyman-alpha can read high after cloud 
penetration or rain, and the LI-COR had a pressure dependence that obviously 
changed with height. Also, calibrations of the LI-COR often were performed 
during soundings.

Mean carbon dioxide (from the LI-COR) and ozone values should not be trusted due 
to instrument and calibration problems.

Wind calculations on the Electra depend on accurate measurements of aircraft 
acceleration, which is large during the turns typical of these soundings.  
Therefore, the wind speed and direction reported here could be in error, though 
it is difficult assign a magnitude for this error.

11.3 Usage Guidance

The Lyman-alpha hygrometer can read high after cloud penetration or rain, and 
the LI-COR closed-path infrared absorption hygrometer had a pressure dependence 
that changed with height.

11.4 Other Relevant Information

None given.

12. Application of the Data Set

These data could be used to verify the quality of the AFM-03 flux and moving 
window data.

13. Future Modifications and Plans

None given.

14. Software

14.1 Software Description

None given.

14.2 Software Access

None given.

15.   Data Access

15.1  Contact for Data Center/Data Access Information

These BOREAS data are available from the Earth Observing System Data and 
Information System (EOS-DIS) Oak Ridge National Laboratory (ORNL) Distributed 
Active Archive Center (DAAC). The BOREAS contact at ORNL is:

ORNL DAAC User Services
Oak Ridge National Laboratory
(865) 241-3952
ornldaac@ornl.gov
ornl@eos.nasa.gov

15.2  Procedures for Obtaining Data

BOREAS data may be obtained through the ORNL DAAC World Wide Web site at 
http://www-eosdis.ornl.gov/ or users may place requests for data by 
telephone, electronic mail, or fax.

15.3  Output Products and Availability

Requested data can be provided electronically on the ORNL DAAC's anonymous FTP 
site or on various media including, CD-ROMs, 8-MM tapes, or diskettes.

The complete set of BOREAS data CD-ROMs, entitled "Collected Data of the Boreal 
Ecosystem-Atmosphere Study", edited by Newcomer, J., et al., NASA, 1999, are 
also available.

16. Output Products and Availability

16.1 Tape Products

All time series as recorded by the investigators are saved on the NCAR Mass-
Store System in NetCDF format and are available from the investigators upon 
request.  Contact Steven Oncley or Don Lenschow.

16.2 Film Products

Videotapes with imagery from forward-, side (left)-, and downward-looking 
cameras are also available from the investigators.  The forward-looking is black 
and white, and the others are color.  The quality is medium, since the tapes 
were recorded in "extended play" mode to create one tape for each (6-7 hour) 
flight.  All videotapes have a time stamp in the image.  Contact Steven Oncley 
for details.

16.3 Other Products

These data are available on the BOREAS CD-ROM series.

17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

Airborne Humidity Measurements. 1987. NCAR Research Aviation Facility Bull. No. 
22, Boulder, CO.

Baumgardner, D. 1989. Airborne measurements for cloud microphysics. NCAR 
Research Aviation Facility Bull. No. 24, Boulder, CO.

Flight Planning: The NCAR Electra. 1993. NCAR Research Aviation Facility Bull. 
No. 7, Boulder, CO.

Glover, V. and L. Bannehr. 1993. Radiation measurements from NCAR aircraft. NCAR 
Research Aviation Facility Bull. No. 25, Boulder, CO.

Lenschow, D.H. and P. Spyers-Duran. 1989. Measurement Techniques: Air motion 
sensing. NCAR Research Aviation Facility Bull. No. 23, Boulder, CO.

17.2 Journal Articles and Study Reports

Davis, K.J. et al. 1996. 22nd Conference on Agricultural and Forest Meteorology, 
Atlanta, GA, Jan. 28-Feb. 2, American Meteorological Society.
  
Lenschow, D.H., Q. Wang, S.P. Oncley, K.J. Davis, and J. Mann. 1996.
Lake-induced modification of the boundary layer over the boreal forest.
22nd Conference on Agricultural and Forest Meteorology, Atlanta, GA, Jan. 28-
Feb. 2, American Meteorological Society.

Mann, J., K.J. Davis, D.H. Lenschow, S.P. Oncley, C. Kiemle, G. Ehret, A. Giez, 
and H.G. Schreiber. 1995. Airborne observations of the boundary layer top, and 
associated gravity waves and boundary layer structure.  Ninth Symp. on Met. Obs. 
and Instrum., Amer. Met. Soc., Boston, MA.

Oncley, S.P., D.H. Lenschow, K.J. Davis, T. Campos, and J. Mann. 1996.
Regional-scale surface flux observations across the boreal forest during
BOREAS.  22nd Conference on Agricultural and Forest Meteorology,
Atlanta, GA, Jan. 28-Feb. 2, American Meteorological Society.

Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment 
Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). 

Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment 
Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). 

Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere 
Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). 

Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere 
Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). 

Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. 
Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. 
Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and 
early results from the 1994 field year. Bulletin of the American Meteorological 
Society. 76(9):1549-1577.

Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry, M.  
Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J. Cihlar, J. 
Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D. Halliwell, D. Williams, B.  
Goodison, D.E. Wickland, and F.E. Guertin. 1997. BOREAS in 1997: Experiment 
Overview, Scientific Results and Future Directions. Journal of Geophysical 
Research 102 (D24): 28,731-28,770.

17.3 Archive/DBMS Usage Documentation

None.

18. Glossary of Terms

None.

19. List of Acronyms

      AFM      - Airborne Fluxes and Meteorology
      AGL      - Above Ground Level
      ASCII    - American Standard Code for Information Interchange
      ATD      - Atmospheric Technology Division of NCAR
	BL	   - atmospheric Boundary Layer
	BOREAS   - BOReal Ecosystem-Atmosphere Study
	BORIS    - BOREAS Information System
      CD-ROM   - Compact Disk-Read-Only Memory
	DAAC	   - Distributed Active Archive Center
	EOS	   - Earth Observing System
	EOSDIS   - EOS Data and Information System
      GPS      - Global Positioning System
	GSFC	   - Goddard Space Flight Center
      HTML     - HyperText Markup Language
      IFC      - Intensive Field Campaign
      INS      - Inertial Navigation System
      IRS      - Inertial Reference System
      MMM      - Mesoscale and Microscale Research Division, NCAR
      NAD83    - North American Datum of 1983
	NASA	   - National Aeronautics and Space Administration
	NCAR	   - National Center for Atmospheric Research
      NDVI     - Normalized Difference Vegetation Index
	NRC	   - National Research Council, Canada
      NSA      - Northern Study Area
      OA       - Old Aspen
	ORNL	   - Oak Ridge National Laboratory
      PANP     - Prince Albert National Park
      PPFD     - Photosynthetic Photon Flux Density
      RAF      - Research Aviation Facility, NCAR
      SSA      - Southern Study Area
      SSSF     - Sounding and Surface System Facility, NCAR
      TF       - Tower Flux
	URL	   - Uniform Resource Locator
      UTC      - Universal Time Code

20. Document Information

20.1 Document Revision Date

Written: 	29-Sep-1995
Last Updated: 20-Jul-1999 

20.2 Document Review Date(s)

      BORIS Review: 30-Jun-1999
     	Science Review:
 

20.3 Document ID 

20.4 Citation 

These data were provided by the National Center for Atmospheric Research, which 
is sponsored by the National Science Foundation.

20.5 Document Curator 

20.6 Document URL

Atmospheric Pressure
Wind direction
Wind speed
Temperature
Dewpoint temperature
Mixing ratio
Carbon dioxide concentration
Ozone concentration

AFM03_Soundings.doc
08/21/99