BOREAS TF-07 SSA-OBS Tower Flux and Meteorological Data

Summary

The BOREAS TF-07 team collected meteorological data as well as energy, carbon 
dioxide, water vapor, methane, and nitrous oxide flux data at the BOREAS SSA-OBS 
site.  The data were collected from May 24 to September 19, 1994. The data are 
available 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 TF-07 SSA-OBS Tower Flux and Meteorological Data

1.2 Data Set Introduction

Tower-based flux of heat, momentum, H2O, CO2, CH4, and N2O measured by eddy-
correlation and/or aerodynamic gradient techniques, over the BOReal Ecosystem-
Atmosphere Study (BOREAS) Southern Study Area (SSA) Old Black Spruce (OBS) stand, 
from day of year 144 to 155, 200 to 209, 251 to 261, in 1994.

1.3 Objective/Purpose

The purpose of this study is to determine the contribution of the boreal 
ecosystem to the greenhouse gas composition of the atmosphere and how this 
ecosystem responds to environmental conditions.
 
Specific objectives are the following: i) scaling-up of mass and energy surface 
fluxes from the local scale to the regional scale (spatial representativeness of 
tower-based measurements), ii) quantification of the effects of ambient 
conditions and biological processes on gas exchanges in order to carry out a 
carbon budget of a black spruce stand, iii) determination of differences by 
conditional analysis of aircraft and tower data, and iv) intercomparison between 
tower-based fluxes.

1.4 Summary of Parameters

Latent heat flux; sensible heat flux; water vapor flux; fluxes and concentrations 
of carbon dioxide, methane, and nitrous oxide; momentum flux; net radiation; 
incident solar radiation; mean and standard deviation of wind speed and 
direction; friction velocity; mean U and V components of wind speed; standard 
deviation of the U, V, and W components of the wind speed; mean and standard 
deviation of specific humidity, vapor pressure, and air temperature.

1.5 Discussion

Tower Flux (TF)-07 surface fluxes were measured by micrometeorological techniques 
at the BOREAS SSA-OBS tower.  

Momentum, CO2, and sensible and latent heat fluxes were measured using the eddy-
correlation technique (EC), while methane and nitrous oxide fluxes were measured 
using either EC or the aerodynamic-gradient techniques (AG).  Several measurement 
periods of isoprene fluxes by the relaxed eddy-accumulation technique (REA) were 
carried out in collaboration with Dr. Hal Westberg, Trace Gas Biogeochemistry 
(TGB)-10.

The measurements were made at 20 m above the ground (about 12 m above the 
displacement plane).  Wind velocities and temperature were measured with a sonic 
anemometer-thermometer (Kaijo-Denki DAT-310).  Sensible heat flux was corrected 
for water vapor transfer (Schotanus et al., 1983).  The sonic anemometer and the 
intake tubes of the closed-path analyzers were located on a boom 1.65 m long 
parallel to the soil surface.  By rotating and/or moving the boom to one of the 
two ends of the south side of the tower, the sensors were oriented in the 
prevalent wind direction.  CO2 and H2O concentrations were measured in fast-
response absolute mode with an infrared gas analyzer (IRGA; LI-COR 6262) equipped 
with a 4-m-long sampling tube.  The flow in the inlet was turbulent, and the 
signals were time adjusted to maximize the correlation with the vertical wind 
velocity.  The CO2 fluxes were corrected for density fluctuations associated with 
water vapor (Webb et al., 1980) and for sensitivity of the IRGA to water vapor, 
as determined in our laboratory (Pattey et al., 1992).  A detailed description of 
the data acquisition system can be found in Pattey et al., 1995.  Methane and 
nitrous oxide gradients between 16 and 24 m above the ground were measured with 
tunable diode lasers (Campbell  Scientific, TGA).  The eddy diffusivity 
coefficient, K, was calculated based on the measurements from a sonic anemometer.  
Isoprene fluxes were measured using REA (Pattey et al., 1993).  Isoprene 
concentration analyses were carried out by Dr. Westberg's team (TGB-10).  All the 
fluxes were calculated on a 30-minute basis.  Measurements were carried out 
during the three Intensive Field Campaigns (IFCs) in 1994 between calendar days 
144-155 (May-June), 200-209 (July), and 251-261 (September).

1.6 Related Data Sets

BOREAS TF-09 SSA-OBS Tower Flux, Meteorological, and Soil Temperature Data
BOREAS TF-05 SSA-OJP Tower Flux, Meteorological, and Soil Temperature Data
BOREAS TF-03 NSA-OBS Tower Flux, Meteorological, and Soil Temperature Data
BOREAS TF-04 SSA-YJP Tower Flux, Meteorological, and Soil Temperature Data
BOREAS TF-11 SSA-Fen Tower Flux, Meteorological, and Soil Temperature Data

2. Investigator(s)

2.1 Investigator(s) Name and Title

Dr. Raymond L. Desjardins
Project Leader, Air Quality Group,
 
Dr. Elizabeth Pattey
Research Scientist, Air Quality Group

2.2 Title of Investigation

Areal Estimates of Mass and Energy from a Boreal Forest Biome

2.3 Contact Information

Contact 1    
---------
Dr. Elizabeth Pattey
Centre for Land and Biological Research Resources
Agriculture and Agri-Food Canada
Ottawa, ONT. 
CANADA
(613) 759-1523
(613) 996-0646 (fax)
PATTEYE@GW.AGR.CA

Contact 2
---------
K. Fred Huemmrich
University of Maryland
NASA GSFC
Greenbelt, MD 
(301) 286-4862
(301) 286-0239 (fax)
Karl.Huemmrich@gsfc.nasa.gov

3. Theory of Measurements

Ec provides the most direct measurement of the flux of a gas at the land-
atmosphere interface.  It provides measurements of gas exchange without 
disturbing the environment under study and integrates the flux over a mosaic of 
different sources and sinks.  The instantaneous transfer across a horizontal 
plane per unit area and per unit time is given by F = WS, where W is the vertical 
velocity, and S is the mixing ratio of the gas of interest.  Because turbulent 
transfer is intermittent, it must be averaged over a certain time or distance to 
obtain a representative sample.  The mean flux of a gas over a horizontally 
homogeneous surface under steady-state conditions is given by F = <W'S'>, where 
W' and S' are the fluctuations from their mean.  Reasonably stationary 
conditions, little horizontal advection and no chemical reaction involving the 
gas of interest within the air column below the measuring system are required for 
accurate flux measurements.  These effects need to be taken into account to 
minimize flux divergence with height, which can lead to significant errors of 
surface flux estimates from aircraft-based systems (Desjardins et al., 1992).

4. Equipment

4.1 Sensor/Instrument Description

A three-axis sonic wind anemometer/thermometer from Kaijo Denki Co. (Japan) was 
used for measuring the fluctuations of the three wind components (U, V, W) and 
the temperature (T).  The sonic is equipped with 90-degree probes and has a 20-cm 
open-path.  The sonic outputs the following signals: U and V at 90, the 
horizontal wind speed (U1= SQRT(U2+V2)), and theta the wind angle relative to the 
sonic position, in addition to W and T.

An IRGA from LI-COR Inc., model 6262, was used for measuring water vapor and CO2 
fluctuations, equipped with a pressure transducer between the outlet of the 
sample cell and the pump.

A tunable-diode laser (TDL) from Campbell Scientific equipped with the laser, 
sample and reference detector was used for measuring CH4 fluctuations and N2O 
fluctuations. 

A pyranometer from LI-COR Inc., model LI-200s was used to measure incoming solar 
radiation. 

4.1.1 Collection Environment

Measurements were collected in intervals from late May through mid-September 
1994.  Over the data collection periods, the low temperatures experienced did not 
drop below freezing and the high temperatures were not over 27 C.

4.1.2 Source/Platform

Above-canopy measurements were made from a 23-meter double scaffold walk-up 
tower.

4.1.3 Source/Platform Mission Objectives

The objectives were to measure energy and momentum fluxes and fluxes of CO2, CH4, 
and N2O from a boreal black spruce stand and to obtain diurnal patterns of 
regional fluxes by combining aircraft- and tower-based flux measurements.
 
4.1.4 Key Variables

Sensible heat flux, latent heat flux, momentum flux, trace gas fluxes of CO2, 
CH4, and N2O.

4.1.5 Principles of Operation

Three-axis sonic wind anemometer/thermometer from Kaijo Denki:

The ultrasonic anemometer thermometer measurement is based on the characteristics 
of sound waves in the atmosphere.  Sound waves are propagated in air linearly at 
an essentially constant speed of approximately 340 m/s.  Ultrasonic propagating 
speed in moving air, however, is slightly variable, traveling faster in a tail 
wind and slower in a head wind.  The wind speed is deducted from the duration 
taken by ultrasonic pulses to travel between two ultrasonic pulse transducer 
elements facing each other at a fixed distance.  Two ultrasonic pulse signals are 
alternatively emitted in opposite directions.  The sound velocity in air 
fluctuates with temperature, as well as with humidity and atmospheric pressure.  
Air temperature fluctuations can be measured assuming longer pressure and 
humidity fluctuating cycles.  In fact, humidity fluctuations should be taken into 
account to correct sensible heat flux as proposed by Schotanus et al. (1983).

IRGA from LI-COR:
Heteroatomic molecules are known to absorb infrared radiation at specific 
wavelengths; each gas has a specific absorption spectra.  Radiation absorption at 
a given wavelength follows the Beer-Lambert Law, i.e., is a function of the path 
length of the measuring cell, the extinction coefficient at the specified 
wavelength, and the molar concentration of the heteroatomic molecule in air. The 
wavelength for CO2 absorption shows sensitivity to water vapor that is attenuated 
by using filters.  As the temperature of the cell is measured, the signals can be 
corrected for density fluctuations due to temperature.  To be read in fast-
response mode, signals should be linearized and pressure within the measuring 
cell included in the linearization equation.

TDL from Campbell Scientific:
The trace gas analyzer system (TGAS, Campbell Scientific) measures absolute 
concentrations of trace gas species by infrared absorption techniques using a TDL 
source.  The TGAS is a fast-response closed-path analyzer, in which absorption of 
a specific infrared laser line by trace gas molecules (i.e. either methane or 
nitrous oxide) is detected.  The emission lines are selected to minimize the 
error caused by absorption from interfering species.  The laser intensity 
absorption follows the Beer-Lambert law of attenuation and is a function of the 
absorption cross-section, the path-length, and the concentration of methane or 
nitrous oxide molecules.  In the TGAS, the laser beam absorption is measured 
simultaneously in a 155-cm long sample cell and in a 5-cm-long reference cell 
filled with either 3.05% certified methane or 0.2668% certified nitrous oxide in 
nitrogen maintained at about 8 kPa.  The number of molecules in the sample cell 
is equal to the known number of molecules in the reference cell multiplied by the 
ratio of path-lengths between the reference and sample cell and multiplied by the 
ratio of the wavelength integrated absorbance between the sample and the 
reference cell.  Both cells are maintained at low pressure to limit pressure 
broadening of methane or nitrous oxide absorption line.  The operating 
temperature of the TGAS diode laser is in the range of 90 K, which is maintained 
with liquid nitrogen.  Most TDLs are very sensitive to vibration.

Pyranometer from LI-COR:
The pyranometer is constituted of thermopiles.  It is used to measure incoming 
solar radiation.

4.1.6 Sensor/Instrument Measurement Geometry

The sonic anemometer and the intake tubes of the closed-path analyzers were 
located on a boom 1.65 m long, parallel to the soil surface.  The boom was 
mounted on a rotating table to orient the sensors in the prevalent wind 
direction, and on a sliding carriage to access both ends of the south side of the 
tower.  The infrared CO2 and H2O analyzer (IRGA; LI-COR 6262) was located on the 
18.7-m-high platform close to the south side of the tower.  It was equipped with 
a 4-m sampling tube.  The TDLs were located on the ground.  The methane analyzer 
was located between the tower and the hut and had a 34.5-m-long sampling tube, 
while the N2O analyzer was hooked to the ceiling of the hut and had a 61.5-m-long 
sampling tube.  The conditional sampling system was located on the same platform 
as the IRGA.  Methane and nitrous oxide gradients were measured between 16 and 24 
m above the ground.

4.1.7 Manufacturer of Sensor/Instrument

Sonic Anemometer:
Kaijo Denki Co.
GENEQ, Inc.
7978 EST, rue Jarry
Montreal, QUE., H1J 1H5
 
H2O CO2 IRGA and Pyranometer:
LICOR, Inc.
P.O. Box 4425
Lincoln, NE 68504
 
TDL:
Campbell Scientific
P.O. Box 551,
Logan, UT 84321
 
Fine-Wire Thermocouple:
Campbell Scientific
P.O. Box 551,
Logan, UT 84321.
 
Net Radiometer:
Middleton Instruments, Inc.
P.O. Box 442
South Melbourne,
Victoria, 3205,
Australia
 
Data Logging System:
Campbell Scientific
P.O. Box 551,
Logan, UT 84321

4.2 Calibration

4.2.1 Specifications

The manufacturer calibration of the LI-6262 to establish the linearization 
functions was done in July 1993.  The field calibration of the LI-6262 was done 
by removing the offsets on the CO2 and H2O signals by passing nitrogen through 
the reference and sample cells, and by adjusting the gain on CO2 channel by 
passing known CO2 concentration in dry air and by passing known water vapor 
concentration in air to adjust the H2O channel.  The CO2 standard was cross-
referenced with BOREAS standards.  

During IFC-1 and -2, a 10 liter bag was filled with ambient air and connected via 
a dewpoint hygrometer to the sample cell of the LI-6262.  During IFC-3, the LI-
610 dewpoint generator was used to produce air at known water vapor 
concentration.

The sonic anemometer was factory calibrated, except for the temperature, for 
which a linear correction function was established after IFC-3 in Ottawa against 
another sonic anemometer.  The other signals were well calibrated.

Calibration of the TDLs: the reference cell has a known methane or nitrous oxide 
certified concentration flowing through it, and the signal is compensated for 
pressure variation, although the pressure is maintained at a steady value.

4.2.1.1 Tolerance

None given. 

4.2.2 Frequency of Calibration

None given. 

4.2.3 Other Calibration Information

None given. 

5. Data Acquisition Methods

The signals of the instruments were collected at 20 Hz through a Labmaster board 
(Scientific Solutions) (analog to digital (A/D) converter) and preprocessed in 
real time on a microcomputer.  The vertical wind speed was high-pass filtered at 
0.001 Hz by a digital filter. Sums, sums of square, and sum of cross-product were 
accumulated over 15 seconds and saved on a binary format without being converted 
into the proper units, so that they could be processed again if the calibration 
factor needed to be changed.  Nonlinearized signals, like those of the LI-COR 
6262, were linearized in real time before being summed.
 
The tower had the capability to rotate to be aligned in the mean horizontal wind 
direction.
 
The data acquisition and control system was able to control a fast-response valve 
to perform conditional sampling based on the vertical wind velocity signal.  
Nonmethane hydrocarbon was collected in canisters for several periods following 
REA (Businger and Oncley, 1990; Pattey et al., 1993).
 
Subcanopy signals were collected via a CR-21X (Campbell Scientific) data logger.

6. Observations

6.1 Data Notes

None.

6.2 Field Notes

None.

7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

All data were collected at the BOREAS SSA-OBS site.  North American Datum of 1983 
(NAD83) coordinates for the site are latitude 53.98717 N, longitude 105.11779 
W, and elevation of 628.94 m.

7.1.2 Spatial Coverage Map

Not applicable.

7.1.3 Spatial Resolution

The fluxes measured at 12 m above the displacement height integrate surface 
contribution, which can be described by footprint functions.  The surface 
contributing to the flux mainly depends on the horizontal wind velocity, the wind 
direction, surface roughness, the atmospheric stability, and the height of 
measurements.  The spatial coverage can be evaluated by using footprint 
algorithms (Schuepp et al., 1990; Horst and Weil, 1992).  Flux measurements, for 
which the wind was blowing over a sector including the hut, the ecology tower, 
and/or the access path, were discarded.  

7.1.4 Projection

Not applicable.

7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

Surface flux data were collected during IFC-1 (24 May to 8 June), IFC-2 (19 July 
to 1 August), and IFC-3 (5 to 19 September), 1994.

7.2.2 Temporal Coverage Map

Not available.

7.2.3 Temporal Resolution

The reported data values are 30 minute averages with the reported time 
corresponding to the start of the sampling period.

7.3 Data Characteristics

Data characteristics are defined in the companion data definition file 
(tf07flux.def).

7.4 Sample Data Record

Sample data format shown in the companion data definition file (tf07flux.def).

8. Data Organization

8.1 Data Granularity

All of the SSA-OBS Tower Flux and Meteorological Data are contained in one data 
set.

8.2 Data Format

The data file contains 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 (tf07flux.def).

9. Data Manipulations

9.1 Formulae

See Section 9.1.1.

9.1.1 Derivation Techniques and Algorithms

Momentum flux (FU; N m-2):
      FU= rhoa <W'U1'>
where:
W: vertical wind velocity (m s-1)
U1: horizontal wind speed (m s-1)
<  >: average over the averaging period
': fluctuation
rhoa: air density (g m-3)
 
Sensible heat flux (FT; W m-2)
      FT = rhoa Cp <W'T'>
where:
Cp: air specific heat at constant pressure
T: air temperature (C)
FT is corrected for humidity and velocity fluctuations (Schotanus et al, 1983)
 
Latent heat flux (FQ; W m-2):
      FQ = L rhoa MV/MA <W'NQ'> 10-3
where:
L: coefficient of vaporization (J g-1 K-1)
MV: molecular mass of water vapor (18 g mol-2)
MA: molecular mass of dry air (29 g mol-1)
NQ: molar fraction (mmol H2O mol-2 dry air)
 
Flux of trace gases (FS; g m-2 s-1):
      FS = rhoa MS/MA <W'NS'> + rhoS DF
where:
NS: molar fraction of the species (mol S mol-2 dry air)
MS: molecular mass of the species (g mol-1)
rhoS: density of the species (g m-3)
DF= density fluctuation correction (Webb et al., 1980)
 
Expected sensitivity of trace gases to density fluctuation correction can be 
found in Pattey et al (1992).
 
For CO2 flux measured by the LI-COR 6262, only density fluctuations due to water 
vapor fluctuations are involved in the correction.

9.2 Data Processing Sequence

The following steps were used to process the data:

1)  Collection of 15-s blocks.  
2)  Sum over the averaging period.  
3)  Scaling  and conversion of binary data to channel units.
4)  Mean, standard deviation, and flux calculation.

9.2.1 Processing Steps

BORIS staff processed these data by:

1) Reviewing the initial data files and loading them online for BOREAS team 
access.
2) Designing relational data base tables to inventory and store the data.
3) Loading the data into the relational data base tables.
4) Working with the team to document the data set.
5) Extracting the data into logical files.

9.2.2 Processing Changes

None.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

None.

9.3.2 Calculated Variables

Sensible heat flux, latent heat flux, momentum flux, trace gas fluxes of CO2, 
CH4, and N2O.

9.4 Graphs and Plots

None.

10. Errors

10.1 Sources of Error

None given.

10.2 Quality Assessment

The data were not verified against wind direction and rejection sector.

10.2.1 Data Validation by Source

None given.

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

Data were examined to check for spikes, values that are four standard deviations 
from the mean, long periods of constant values, and missing data.

11. Notes

11.1 Limitations of the Data

Data were collected only during the IFCs in 1994.

11.2 Known Problems with the Data

Missing data with TDL-TGAS are associated with vibration problems, analysis of 
REA samples, and, for IFC-1, pump troubleshooting.

11.3 Usage Guidance

None given.

11.4 Other Relevant Information

None given.

12. Application of the Data Set

These data are useful for the study of water, energy, carbon, and nitrogen 
exchange in a mature black spruce forest.

13. Future Modifications and Plans

None.

14. Software

14.1 Software Description

None given.

14.2 Software Access

None.

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

None.

16.2 Film Products

None.

16.3 Other Products

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

17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

None given.

17.2 Journal Articles and Study Reports

Businger, J.A. 1986. Evaluation of the accuracy with which dry deposition can be 
measured with current micrometeorological techniques. J. Clim. and Appl.Meteorol. 
25:1100-1124.
 
Businger, J.A. and S.P. Oncley. 1990. Flux measurement with conditional sampling. 
J. Atmos. Ocean. Tech., 7: 349-352.
 
Chahuneau, F., R.L. Desjardins, E.J. Brach, and R. Verdon. 1989. A 
micrometeorological facility for eddy flux measurements of CO2 and H2O. J.Clim. 
Appl. Meteorol. 25: 1100-1124.
 
Desjardins, R.L., P. Rochette, J.I. MacPherson, and E. Pattey. 1992. Measurements 
of greenhouse gas fluxes using aircraft- and tower-based techniques. In 
"Agricultural Ecosystem Effects on Trace Gases and Global Climate Change" ASA 
special publication #55: 45-62.

Desjardins, R.L., J.I. MacPherson, L. Mahrt, P. Schuepp, E. Pattey, H. Neumann, 
D. Baldocchi, S. Wofsy, D. Fitzjarrald, H. McCaughey, and D.W. Joiner. 1997. 
Scaling up flux measurements for the boreal forest using aircraft-tower 
combination, Journal of Geophysical Research, 102(D24):29,125-29,134.
 
Horst, T.W. and J.C. Weil. 1992. Footprint estimation for scalar flux 
measurements in the atmospheric surface layer.  Boundary-Layer Meteorol., 59: 
279-296.

Pattey, E., R.L. Desjardins, F. Boudreau, and P. Rochette. 1992. Impact of 
density fluctuations on flux measurements of trace gases: implications for the 
relaxed eddy accumulation technique. Boundary-Layer Meteorol., 59: 195-203.
 
Pattey, E., R.L. Desjardins, and P. Rochette. 1993. Accuracy of the relaxed eddy-
accumulation technique, evaluated using CO2 flux measurements. Boundary-Layer 
Meteorol., 66: 341-355.

Pattey, E., R.L. Desjardins , and G. St-Amour. 1997. Mass and energy exchanges 
over a black spruce forest during key periods of BOREAS 1994. Journal of 
Geophysical Research, 102(D24):28,967-28,976. 
 
Pattey, E., W.G. Royds, R.L. Desjardins, D.J. Buckley and P. Rochette. 1995. 
Software description of a data acquisition and control system for measuring trace 
gas and energy fluxes by eddy-accumulation and correlation techniques. Computers 
and Electronics in Agriculture (submitted for publication).

Scheupp, P.H., M.Y. Leclerc, J.I. Macpherson, and R.L. Desjardins. 1990. 
Footprint prediction of scalar fluxes from analytical solutions of the diffusion 
equation. Bound. Layer Meteorol., 50:355-373. 

Schotanus, P., F.T.M. Nieuwstadt, and H.A.R. de Bruin. 1983. Temperature 
measurement with a sonic anemometer and its application to heat and moisture 
fluxes. Bound. Layer Meteorol., 26:81-93.
 
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.

Webb, E.K., G.I. Pearman, and R. Leuning. 1980. Correction of flux measurements 
density effects due to heat and water vapour transfer. Quart. J. R. Met. Soc. 
106:85-100.

17.3 Archive/DBMS Usage Documentation

None.

18. Glossary of Terms

None.

19. List of Acronyms

    A/D     - Analog to Digital
    AG      - Aerodynamic Gradient
    ASCII   - American Standard Code for Information Interchange
    BOREAS  - BOReal Ecosystem-Atmosphere Study
    BORIS   - BOREAS Information System
    CD-ROM  - Compact Disk-Read Only Memory
    DAAC    - Distributed Active Archive Center
    EC      - Eddy Covariance
    EOS     - Earth Observing System
    EOSDIS  - EOS Data and Information System
    GMT     - Greenwich Mean Time
    GSFC    - Goddard Space Flight Center
    HTML    - HyperText Markup Language
    IFC     - Intensive Field Campaign
    IRGA    - Infrared Gas Analyzer
    NAD83   - North American Datum of 1983
    NASA    - National Aeronautics and Space Administration
    NSA     - Northern Study Area
    OBS     - Old Black Spruce
    ORNL    - Oak Ridge National Laboratory
    PANP    - Prince Albert National Park
    PAR     - Photosynthetically Active Radiation
    PC      - Personal Computer
    PPFD    - Photosynthetic Photon Flux Density
    REA     - Relaxed Eddy Accumulation
    REBS    - Radiation Energy Balance Systems
    SSA     - Southern Study Area
    TDL     - Tunable-Diode Laser
    TF      - Tower Flux
    TGA     - Trace Gas Analyzer
    TGB     - Trace Gas Biogeochemistry
    TGAS    - Trace Gas Analyzer System
    URL     - Uniform Resource Locator
    WAB     - Wind Aligned Blob
    WMO     - World Meteorological Organization

20. Document Information

20.1 Document Revision Date

     Written: 04-Oct-1995
     Revised: 25-May-1999

20.2 Document Review Date(s)

     BORIS Review: 08-Apr-1999
     Science Review: 

20.3 Document ID

20.4 Citation

When using these data, please include the following acknowledgment:
These data were provided by Drs. E. Pattey and R.L. Desjardins.  This work was 
supported by Agriculture and Agri-Food Canada.

If using data from the BOREAS CD-ROMs please also reference the data as:
Dr. Raymond L. Desjardins and Dr. Elizabeth Pattey, "Areal Estimates of Mass and 
Energy from a Boreal Forest Biome." in Collected Data of The Boreal Ecosystem-
Atmosphere Study. Eds. J. Newcomer, D. Landis, S. Conrad, S. Curd, K. Huemmrich, 
D. Knapp, A. Morrell, J. Nickeson, A. Papagno, D. Rinker, R. Strub, T. Twine, F. 
Hall, and P. Sellers.  CD-ROM. NASA, 1999.

To cite the BOREAS CD-ROM set as a published volume, use:
J. Newcomer, D. Landis, S. Conrad, S. Curd, K. Huemmrich, D. Knapp, A. Morrell, 
J. Nickeson, A. Papagno, D. Rinker, R. Strub, T. Twine, F. Hall, and P. Sellers, 
eds. Collected Data of The Boreal Ecosystem-Atmosphere Study.  CD-ROM. NASA, 
1999.

20.5 Document Curator

20.6 Document URL

Keywords:

BLACK SPRUCE
TOWER FLUX
METEOROLOGY
SENSIBLE HEAT FLUX
LATENT HEAT FLUX
CARBON DIOXIDE FLUX
CARBON DIOXIDE CONCENTRATION
METHANE FLUX
METHANE CONCENTRATION
NITROUS OXIDE FLUX
NITROUS OXIDE CONCENTRATION
WATER VAPOR FLUX
MOMENTUM FLUX
SOLAR RADIATION
NET RADIATION
AIR TEMPERATURE
VAPOR PRESSURE
HUMIDITY
WIND SPEED

TF07_Flux_Met.doc
06/09/99