BOREAS TF-04 SSA-YJP Tower Flux, Meteorological, and Canopy Condition Data
Summary
The BOREAS TF-04 team collected energy, carbon dioxide, and water vapor flux
data at the BOREAS SSA-YJP site during the growing season of 1994. In addition,
meteorological data were collected both above and within the canopy. 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-04 SSA-YJP Tower Flux, Meteorological, and Canopy Condition Data
1.2 Data Set Introduction
Measurements of CO2 and latent and sensible heat flux were made both above and
within the BOReal Ecosystem-Atmosphere Study (BOREAS) Southern Study Area (SSA)
Young Jack Pine (YJP) canopy during a growing season. Combined with soil gas
effluxes of CO2 and CH4, the data were used to determine daily and seasonal
patterns in carbon fluxes, evapotranspiration, and environmental controls
regulating the partitioning of available energy and net ecosystem productivity
(NEP). Comparisons were made between young and mature jack pine stands in
proximity to one another in terms of NEP and water use.
1.3 Objective/Purpose
The objectives of this study were to investigate carbon, water, and energy
fluxes in boreal forests through an integrated approach involving flux estimates
across the atmosphere-forest and soil-atmosphere boundaries. Eddy correlation
measurements of CO2, latent and sensible heat fluxes, and momentum were made
above the SSA-YJP stand. Concentration profiles of CH4, 12CO2, and 13CO2 were
determined within the canopy during one Intensive Field Campaign (IFC). Soil-
atmosphere flux studies employed soil depth vs. gas concentration measurements,
flux chambers, and diffusion modeling to determine source and movement of CH4,
12CO2, and 13CO2 in the air-soil-water continuum. The distribution and storage
of carbon species in the soil profile were also determined. Long-term carbon
accumulation was evaluated by 14C decay of soil carbon. Net, incoming, and
Photosynthetically Active Radiation (PAR); leaf photosynthesis; and certain soil
parameters (heat flux, thermal profile) were also measured at the site.
1.4 Summary of Parameters and Variables
Types of Data Collected:
Above-canopy fluxes: CO2, latent heat, sensible heat
Forest floor fluxes: CO2, sensible heat, latent heat
Radiation: Net, PAR, and shortwave
Profiles: CO2, air temperature, vapor pressure
Tree: Tree bole temperatures
Other Mean Variables:
Above-canopy: Wind direction and speed, air temperature, vapor pressure
Below-canopy: Wind speed, temperature, vapor pressure
1.5 Discussion
Flux data were collected from a 12-m tower in an 11- to 16-year old jack pine
stand. The trees were about 4 to 5 meters tall. Flux and meteorological data
were collected from mid-May through mid-September 1994.
1.6 Related Data Sets
BOREAS TF-04 CO2 and CH4 Chamber Flux Data from the SSA
BOREAS TF-05 SSA-OJP Tower Flux, Meteorological, and Soil Temperature Data
BOREAS TF-10 NSA-YJP Tower Flux, Meteorological, and Porometry Data
BOREAS TF-11 SSA Fen Tower Flux, Meteorological, and Soil Temperature Data
2. Investigator(s)
2.1 Investigator(s) Name and Title
Dr. Dean Anderson
United States Geological Survey
Dr. Rob Striegl
Hydrologist, USGS
Dr. Kimberly Wickland
Hydrologist, USGS
2.2 Title of Investigation
Exchange of Trace Gases, Water, and Energy in Disturbed and Undisturbed Boreal
Forests
2.3 Contact Information
Contact 1
Dr. Rob Striegl
Hydrologist, USGS
Denver, CO
rstriegl@usgs.gov
Contact 2
Dr. Kimberly P. Wickland
Hydrologist, USGS
Denver, CO
Contact 3
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
The sonic anemometer/thermometer is designed to measure wind velocity components
by transmitting and receiving sonic signals along fixed orthogonal directions.
The microcomputer electronics then processes this information and calculates the
wind speed in three axes. Since there are no moving parts to come into dynamic
equilibrium with the air flow, the sonic anemometer/thermometer responds rapidly
to wind velocity fluctuations. It responds linearly to wind velocity and is
free from contamination from pressure, temperature, and relative humidity. The
calibration of the sensor is established by its design parameters and therefore
can be used as an absolute instrument. The probe array is designed to minimize
flow distortion created by the supporting base and to permit a very wide
unobstructed coverage of the vertical component.
4. Equipment
4.1 Sensor/Instrument Description
4.1.1 Collection Environment
Measurements were collected from mid-May through mid-September 1994 in an 11- to
16-year-old jack pine stand. Over that time period, temperature conditions went
from slightly below freezing up to 29 �C.
4.1.2 Source/Platform
Instruments were mounted on a 12-m-tall Rohn tower.
4.1.3 Source/Platform Mission Objectives
The purpose of the tower was to suspend instruments to measure trace gas, energy
fluxes, and meteorological variables above a young jack pine stand.
4.1.4 Key Variables
Sensible and latent heat fluxes were measured both above and below the tree
canopies. CO2 flux and concentration were measured above the canopy.
Measurements of radiation included net radiation, PAR, and shortwave radiation.
Meteorological measurements included wind speed and direction, friction
velocity, air temperature, vapor pressure, air pressure, and rainfall. Under
the canopy, data on air temperature, vapor pressure, and wind speed were
collected. Bole temperature and leaf wetness data were collected. Within the
canopy, air temperature, vapor pressure, and air pressure were measured.
4.1.5 Principles of Operation
Heat, water, and CO2 fluxes were measured using eddy correlation techniques.
Meteorological measurements were collected using standard instruments and
methods.
4.1.6 Sensor/Instrument Measurement Geometry
The placement of instruments on the tower was at the following heights above the
ground:
? Solar Radiation, LI-COR LI200S, at 12.9 m.
? PAR sensor, LI-COR LI190SZ, at 12.9 m.
? Air temperature and vapor pressure, Campbell Scientific, Inc., HMP35C, at
1.1, 9.1, and 12.2 m. Used an unaspirated, white plastic 12-plate Gill
radiation shield, Campbell Scientific, Inc., model 41002.
? Wind speed and direction, R.M. Young 03001-5, at 1.1, 10.0, and 11.0 m.
? Net Radiation at 9.1 m
? Sonic anemometer, both Applied Technologies, Inc. (ATI), and Campbell, at 1.1
and 9.1 m.
? LI-COR CO2 sensor at 9.1 m.
? National Center for Atmospheric Research (NCAR)/Atmospheric Technology
Division (ATD) CO2 sensor at 1.1 m.
Bole temperatures were measured in two trees. In each tree, thermocouples were
inserted into the north, east, south, and west sides of the bole, to
approximately one half the radius of the trunk, at four heights. The first tree
was 4.6 m tall; about average for the canopy. For that tree, the four heights
were 0.58 m, 1.73 m, 2.79 m, and 3.68 m; the corresponding trunk diameters at
those heights were 5.7 cm, 5.1 cm, 3.8 cm, and 2.9 cm. The second tree was about
3.6 m tall. The four heights were 0.46 m, 1.35 m, 2.24 m, and 2.74 m; the
corresponding diameters were 3.3 cm, 2.9 cm, 2.2 cm, and 1.1 cm.
Within-canopy air temperature and vapor pressure were measured with the Campbell
Scientific, Inc., HMP35C, at 1.2 m above ground level. An unaspirated, white
plastic 12-plate Gill radiation shield (Campbell Scientific, Inc. model 41002)
was also used. Within-canopy atmospheric pressure was measured using the Setra
270, at 1.7 m
Leaf wetness sensors (Campbell Scientific, Inc., 237) were placed at heights of
1.6 m and 1.4 m. The first leaf wetness sensor was deployed in a small opening
in the trees, sloping about 40� to the northeast. The second sensor was placed
about 10 cm from a tree trunk, sloping about 40� to the west.
Rainfall was measured using a tipping bucket rain gauge (Weathertronics 6010) in
a clearing approximately 10 m in diameter at 0.6 m height. The 45�-angle cone
above the rain gauge may have been slightly encroached upon by treetops as the
average tree height was about 4.6 m.
4.1.7 Manufacturer of Sensor/Instrument
Sonic anemometer:
Applied Technologies, Inc.
1120 Delaware Ave.
Longmont, C) 80501
(303) 684-8722
(303) 684-8773 (fax)
sales@apptech.com
Sonic anemometer, CO2 sensor:
NCAR/ATD
P.O. Box 3000, 1850 Table Mesa Drive
Boulder, CO 80307 USA
(303) 497-8833,
(303) 497-8770 (fax)
atd_info@atd.ucar.edu
Sonic anemometer, temperature/humidity sensor HMP35C, Campbell 21X data logger,
Gill radiation shield model 41002, leaf wetness sensor model 237, AM416
multiplexer, AM-ENCT insulating enclosure, CO2 sensor:
Campbell Scientific, Inc.
815 West 1800 North
Logan, UT 84321-1784
(435) 753-2342
(435) 750-9540 (fax)
info@campbellsci.com
LI-COR LI200S, LI190SZN, CO2 sensor:
LI-COR Environmental Division
4421 Superior Street
Lincoln, NE 68504
(800) 447-3576
(402) 467-3576
(402) 467-2819 (fax)
Wind direction and speed 03001-5:
R.M. Young Company
2801 Aero Park Drive
Traverse City, MI 49686
(616) 946-3980
(616) 946-4772 (fax)
met.sales@youngusa.com
Rain Gauge Weathertronics 6010:
WeatherMeasure Weathertronics
Qualimetrics, Inc.
1165 National Drive
Sacramento, CA 95834
(916) 928-1000
(916) 928-1165 (fax)
4.2 Calibration
None.
4.2.1 Specifications
Two problems remain, to one degree or another, with all existing sonic
anemometers: distortion of the measured flow field by the anemometer array
itself and reliable detection of the transmitted sound pulses by the anemometer
electronics over a wide range of environmental conditions.
4.2.1.1 Tolerance
None.
4.2.2 Frequency of Calibration
None.
4.2.3 Other Calibration Information
None.
5. Data Acquisition Methods
The tower meteorological data were collected using a Campbell 21X data logger.
All sensors except the rain gauge were located on the flux tower. Sensors were
scanned every 5 s, and half-hour averages were recorded. Vapor pressure was
calculated as the product of saturated vapor pressure at air temperature and
relative humidity (100% = 1). Saturated vapor pressure was calculated using the
Lowe (1977) equation. The tipping bucket rain gauge (one tip = 0.25 mm of rain)
was deployed in a clearing approximately 10 m in diameter. The 45� cone above
the rain gauge may have been slightly encroached upon by treetops.
The canopy meteorological data were collected using a Campbell 21X data logger.
Sensors were scanned every 60 s, and half-hour averages were recorded. Vapor
pressure was calculated as described above. The reported air pressure was
atmospheric (i.e., not corrected to sea level) rather than barometric pressure.
Air pressure was recorded to the nearest mb until day of year 215 at 2000
Greenwich Mean Time (GMT), and to the nearest hundredth of a mb thereafter. The
leaf wetness sensors were artificial leaf electrical resistance types, with
interlacing gold plated copper fingers. Water droplets that bridge between
fingers lower the resistance. These sensors were not painted or coated. The
manufacturer suggests that the transition from "wet" to "dry" for an uncoated
sensor occurs between 50 and 200 kohms. The first leaf wetness sensor was
deployed in a small opening in the trees, sloping about 40� to the northeast.
The second leaf wetness sensor was deployed about 10 cm from a tree trunk,
sloping about 40� to the west.
Tree bole temperatures were collected using a Campbell 21X data logger. Copper-
constantan thermocouples were glued into tree boles to make all of these
temperature measurements. A Campbell AM416 multiplexer was used to route the
thermocouples to the logger. An extra thermocouple reference junction was glued
to the AM416 surface, and the AM416 was enclosed in a Campbell AM-ENCT
insulating enclosure to minimize temperature gradients in the AM416. Sensors
were scanned every 5 s during the last minute of each half-hour, and averages
of the 13 readings were recorded.
Two trees were chosen to instrument. The first was 4.6 m tall about average for
the canopy. Thermocouples were inserted into the north, east, south, and west
sides, to approximately one half the radius of the trunk, at four heights. The
four heights were 0.58 m, 1.73 m, 2.79 m, and 3.68 m; the corresponding trunk
diameters at those heights were 5.7 cm, 5.1 cm, 3.8 cm, and 2.9 cm. The second
tree was about 3.6 m tall. The four heights were 0.46 m, 1.35 m, 2.24 m, and
2.74 m; the corresponding diameters were 3.3 cm, 2.9 cm, 2.2 cm, and 1.1 cm. In
the reported data set, the 16 temperatures from each tree were averaged together
for each half-hour, and the mean temperature was reported.
6. Observations
6.1 Data Notes
Measurements began during IFC-1 and ended a day after IFC-3. Equipment operated
almost continuously. Notable was the lack of CO2 data following a lightning
strike and a malfunction of the CO2 sensor 16-Jun to 20-Jun and 10-Jul to 19-
Jul-1994. CO2 profile instruments were not operational until IFC-2. Forest
floor sensible and latent heat flux record had numerous lapses due to equipment
problems. Considering all measurements, IFC-3 had the most complete record.
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-YJP site. North American Datum of
1983 (NAD83) coordinates for the site are latitude 53.87581� N, longitude
104.64529� W, and elevation of 533.54 m.
7.1.2 Spatial Coverage Map
Not applicable.
7.1.3 Spatial Resolution
Data collected from flux towers are often thought of as point data. However,
particularly in terms of the eddy flux data, they actually represent an
integrated upwind source region. The size of the region being sampled is
related to factors such as the height of the tower, the roughness of the canopy,
and the wind speed. An estimate of the upwind distance for the YJP site is 20
to 400 m upwind.
7.1.4 Projection
Not applicable.
7.1.5 Grid Description
Not applicable.
7.2 Temporal Characteristics
7.2.1 Temporal Coverage
Meteorological data were collected from 02- to 06-Sep-1993, and during 1994 from
15-May to 20-Sep. Within-canopy meteorological data were collected continuously
during 1994 from 3-June to 20-September, except for a gap from 04- to 07-Aug.
Tree bole temperature data were collected continuously from 10-Jun to 20-Sep-
1994, except for a gap from 14-Jun to 21-Jun. Flux data were collected from 26-
May to 20-September, 1994. There were gaps in CO2 data following a lightning
strike and a malfunction of the CO2 sensor 16-Jun to 20-Jun and 10-Jul to 19-
Jul-1994. CO2 profile instruments were not operational until IFC-2. The forest
floor sensible and latent heat flux record had numerous lapses due to equipment
problems.
7.2.2 Temporal Coverage Map
None.
7.2.3 Temporal Resolution
Meteorological and radiation sensors were scanned every 5 s, and half-hour
averages were recorded. Within-canopy meteorology data sensors were scanned
every 60 s, and half-hour averages were recorded. Tree bole temperature sensors
were scanned every 5 s during the last minute of each half-hour, and averages of
the 13 readings were recorded.
7.3 Data Characteristics
Data characteristics are defined in the companion data definition file
(tf04flux.def)
7.4 Sample Data Record
Sample data format shown in the companion data definition file (tf04flux.def).
8. Data Organization
8.1 Data Granularity
All of the SSA-YJP Tower Flux, Meteorological, and Canopy Condition Data are
contained in one dataset.
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 (tf04flux.def).
9. Data Manipulations
9.1 Formulae
9.1.1 Derivation Techniques and Algorithms
Vapor pressure was calculated as product of saturated vapor pressure at air
temperature and relative humidity. Saturated vapor pressure was calculated
using the Lowe (1977) equation.
Tree bole temperatures were scanned every 5 s during the last minute of each
half-hour, and averages of the 13 readings were recorded. Thermocouples were
inserted into the boles of two trees on the north, east, south, and west sides,
to approximately one half the radius of the trunk, at four heights. In the
reported data set the 16 temperatures from each tree were averaged together for
each half-hour, and the mean temperature was reported.
9.2 Data Processing Sequence
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
Air pressure was recorded to the nearest mb until day of year 215 at 2000 GMT,
and to the nearest hundredth of a mb thereafter.
9.3.2 Calculated Variables
See Section 9.1.1.
9.4 Graphs and Plots
None.
10. Errors
10.1 Sources of Error
None given.
10.2 Quality Assessment
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
These data were collected during the growing season; thus, there was little data
collected under cold conditions.
11.2 Known Problems with the Data
The tipping bucket rain gauge was deployed in clearing about 10 m in diameter.
The 45� cone above the rain gauge may have been slightly encroached upon by
treetops.
There is a gap in the CO2 data following a lightning strike and a malfunction of
the CO2 sensor 16-Jun to 20-Jun and 10-Jul to 19-Jul-1994. CO2 profile
instruments were not operational until IFC-2. The forest floor sensible and
latent heat flux record had numerous lapses due to equipment problems.
11.3 Usage Guidance
None given.
11.4 Other Relevant Information
None.
12. Application of the Data Set
These data are useful for the study of water, energy, and carbon exchange in a
young jack pine forest.
13. Future Modifications and Plans
None.
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
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.
17.2 Journal Articles and Study Reports
Lowe, P.R. 1977. An approximating polynomial for the computation of saturation
vapor pressure. Journal of Applied Meteorology, 16(1): 100-103.
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):28,731-28,769.
17.3 Archive/DBMS Usage Documentation
None.
18. Glossary of Terms
None.
19. List of Acronyms
ASCII - American Standard Code for Information Interchange
ATD - Atmospheric Technology Division
ATI - Applied Technologies, Inc.
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
GMT - Greenwich Mean Time
GSFC - Goddard Space Flight Center
HTML - Hyper-text Markup Language
IFC - Intensive Field Campaign
NAD83 - North American Datum of 1983
NASA - National Aeronautics and Space Administration
NCAR - National Center for Atmospheric Research
NEP - Net Ecosystem Productivity
NSA - Northern Study Area
ORNL - Oak Ridge National Laboratory
PANP - Prince Albert National Park
PAR - Photosynthetically Active Radiation
SSA - Southern Study Area
TF - Tower Flux
URL - Uniform Resource Locator
USGS - United States Geological Survey
YJP - Young Jack Pine
20. Document Information
20.1 Document Revision Date
Written: 22-April-1999
Revised: 25-May-1999
20.2 Document Review Date(s)
BORIS Review: 04-May-1999
Science Review:
20.3 Document ID
20.4 Citation
When using these data, please include the following acknowledgment:
Data were collected and processed by Dean Anderson, Rob Striegl, and Kimberly
Wickland of the United States Geological Survey.
If using data from the BOREAS CD-ROMs please also reference the data as:
Anderson, D., R. Striegl, and K. Wickland, "Exchange of Trace Gases, Water, and
Energy in Disturbed and Undisturbed Boreal Forests." 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
AIR TEMPERATURE
CARBON DIOXIDE CONCENTRATION
CARBON DIOXIDE FLUX
JACK PINE
LATENT HEAT FLUX
METEOROLOGY
NET RADIATION
PAR
PHOTOSYNTHETIC PHOTON FLUX DENSITY
PHOTOSYNTHETICALLY ACTIVE RADIATION
PPFD
RAINFALL
SENSIBLE HEAT FLUX
TOWER FLUX
VAPOR PRESSURE
WIND SPEED
TF04_Flux_Met.doc
06/09/99