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BOREAS FOLLOW-ON FLX-01 NSA-OBS TOWER FLUX, METEOROLOGICAL, AND SOIL TEMP. DATA
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Summary

The BOREAS Follow-On FLX-01 team collected tower flux, surface meteorological, and soil temperature data at the BOREAS NSA-OBS site continuously from March 1994 through December 1998. Data from March 1994 through October 1996 are included in the BOREAS TF-03 effort while data from the end of October 1996 through December 1998 are included in the BOREAS Follow-On FLX-01 effort. The BOREAS follow-On data are available in tabular ASCII files.

The FLX-01 (BOREAS legacy TF-3) team efforts at the NSA-OBS site are ongoing. Updates and data beyond 1998 may be available at the group's Web site: http://atmos.seas.harvard.edu/lab/data/boreasdata.html [Internet Link].

Data Citation

Cite this data set as follows (citation revised on October 30, 2002):

Wofsy, S. C., and A. Dunn. 2001. BOREAS Follow-On FLX-01 NSA-OBS Tower Flux, Meteorological, and Soil Temp[erature] Data. Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A.

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 Follow-On FLX-01 NSA-OBS Tower Flux, Meteorological, and Soil Temp. Data

1.2 Data Set Introduction
      Continuous eddy-correlation flux measurements of sensible heat, latent heat, CO2, and momentum fluxes were made at the BOReal Ecosystem-Atmosphere Study (BOREAS) Northern Study Area (NSA) Old Black Spruce (OBS) site from March 1994 through December 1998. Data from March 1994 through October 1996 are included in the BOREAS TF-03 effort while data from the end of October 1996 through December 1998 are included in the BOREAS Follow-on FLX-01 effort. The measurements at NSA-OBS are ongoing and regular updates are made on the group's web site, where other useful data are also available (http://atmos.seas.harvard.edu/lab/data/boreasdata.html [Internet Link]).

1.3 Objective/Purpose
      The principal objective of this study was to determine directly the net ecosystem exchange of CO2 and the surface energy budget over diurnal, seasonal, and annual time scales, and to couple these observations with a comprehensive characterization of the physical environment (Photosynthetically Active Radiation (PAR), soil temperature, etc.). In addition, CO2 and water vapor concentration were measured. This suite of long-term measurements should provide information to assess the effect of seasons and seasonal changes on the carbon balance of the forest. Determination of the boundary layer CO2 concentration anomaly can also be determined, and thus the effect of the forest on the boundary layer CO2 concentration can be studied.

1.4 Summary of Parameters
      Latent heat flux, sensible heat flux, carbon dioxide flux, momentum flux, CO2 profile, water vapor profile, air temperature profile, net radiation, incident Photosynthetic Photon Flux Density (PPFD), reflected PPFD, below-canopy PPFD, wind speed and direction, soil temperature, precipitation amount.

1.5 Discussion
      The principal objective was to directly determine the net ecosystem exchange of CO2, and the surface energy budget over diurnal, seasonal and annual time scales, coupling these observations with a comprehensive characterization of the physical environment (PAR, soil temperature, etc.). A low-power automated array was installed to measure eddy fluxes of CO2, sensible heat, latent heat, and momentum; column CO2 content, air temperature and moisture, soil temperature, incident and intercepted PAR, and net radiation. Among other things, these long-term measurements should allow assessment of the importance of winter respiration and assimilation during transitional periods to the annual carbon balance of the boreal forest.

1.6 Related Data Sets
BOREAS Follow-on FLX-01 NSA-OBS Derived Data - NEE, GEE, and Respiration

Tower flux measurements made at other sites:
BOREAS TF-09 NSA OJP Tower Flux, Meteorological, and Soil Temperature Data
BOREAS TF-09 SSA OBS Tower Flux, Meteorological, and Soil Temperature Data
BOREAS TF-10 NSA Fen and YJP Flux, Meteorological, and Soil Temperature Data

Other measurements made at the NSA-OBS site:
BOREAS TGB-01 NSA CH4 and CO2 Chamber Flux Data
BOREAS TE-06 Forest Biophysical Measurements
BOREAS TE-09 NSA Photosynthetic Response Data

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2. Investigator(s)

2.1 Investigator(s) Name and Title
      Steven C. Wofsy, Abbot Lawrence Rotch Professor of Atmospheric and Environmental Science

2.2 Title of Investigation
      Eddy Correlation Flux Measurements of CO2 and H2O for BOREAS (NSA-OBS).

2.3 Contact Information

Contact 1:
Allison Dunn
Harvard University
Cambridge, MA
(617) 496-6246
ald@io.harvard.edu
fax: (617) 495-2768

Contact 2:
Steven Wofsy
Harvard University
Cambridge, MA
(617) 495-4566
(617) 495-9837 (fax)
scw@io.harvard.edu

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3. Theory of Measurements

Most investigations of forest CO2 exchange have relied on models to extrapolate short-term gas-exchange measurements made with small chambers. This approach has contributed greatly to understanding, but uncertainties are inevitable when small-scale observations are aggregated to whole ecosystems, and short-term data to annual balances. An alternative approach, used here, was to use the eddy covariance technique over a complete growing season to directly measure the net exchange of CO2 between the atmosphere and a patch of forest several hectares in size.

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4. Equipment

4.1 Sensor/Instrument Description
4.1.1 Collection Environment
      The measurements were made at a remote (50 km from the nearest town and 5 km from the nearest road), old (100-120 years) black spruce site. The coverage was relatively homogeneous, and the trees were approximately 10 m tall. The ground cover was primarily feather moss mixed with some lower-level areas of sphagnum bog. The data were collected continuously over several years; therefore the full range of boreal weather conditions was experienced including temperature ranges between 30° and -40° C.

4.1.2 Source/Platform
      The instruments were supported on a 31 m tall Rohn 25 G triangular cross section communications tower.

Summary of Eddy Correlation System used by Harvard:

Sensor/Instrument Manufacturer/Specifications
Vertical and horizontal velocity sensor 3 axis ATI sonic with Kaimel probe
Temperature sensor ATI virtual temperature
Moisture sensor LiCor 6262 Infrared Gas Analyzer (IRGA)
CO2 sensor LiCor 6262 IRGA
Vertical wind speed ATI sonic anemometer
Horizontal wind speed ATI sonic anemometer
Horizontal wind speed Met One spinning cup
Wind direction ATI sonic anemometer
Temperature Met One thermistor
CO2 LiCor 6262
H2O LiCor 6262
Inlet Filter Gelman Zeflour 3 µm pores, 4 x 50 mm diameter
Tubing 0.64" ID high-density polyethylene 50 meters long (replaced May 1996 with PFA Teflon)
Pumps KNF Neuberger K022 ANA pumps
Data logger Campbell Scientific CR10
Pressure and flow controllers MKS Instruments

4.1.3 Source/Platform Mission Objectives
      The tower was erected to support instruments above the forest canopy to collect flux data at NSA-OBS.

4.1.4 Key Variables
      Eddy-correlation measurements of latent heat flux, sensible heat flux, CO2 flux, and momentum flux, net radiation. Profiles of CO2, water vapor, and air temperature. Incident, reflected, and below-canopy PPFD. Wind speed and direction, soil temperature, precipitation.

4.1.5 Principles of Operation

Sonic Anemometer:
      Three-dimensional orthogonal wind velocities (u, v, and w) and virtual temperature (Tv) were measured with a sonic anemometer (Applied Technology, Boulder, CO). The path length between transducers was 0.15 m. The sensor software corrected for transducer shadowing effects (see Kaimal et al., 1990). Virtual temperature heat flux was converted to sensible heat flux using algorithms described by Kaimal and Gaynor (1991) and Schotanus et al. (1983).

Infrared Absorption Spectrometer:
      Water vapor and CO2 concentrations were measured with an open-path infrared absorption spectrometer.

4.1.6 Sensor/Instrument Measurement Geometry
      The sonic anemometer was located at a height of 29 m on a 31 m triangular- cross-section radio tower (Rohn 25 G). The tubing inlet for the air sample was located 0.5 m below the sonic anemometer. The LiCor sensors were placed in a climate-controlled hut 20 m northeast of the tower. The air was drawn down the tower at 18 standard liters per minute. The air was passed through a thermostated block to stabilize the temperature and drawn through the LiCor at 4 standard liters per minute. Pressure was controlled in the cell of the LiCor at 53 kPa.
      Air temperature profiles were measured at 27.0 m, 8.2 m, and 1.15 m above ground level. Relative humidity was measured at 27.0 m. The sonic anemometer was mounted at 29 m and measured wind direction and velocity. Under-canopy PPFD sensor arrays were placed at ground level. Soil temperature probes were placed at depths of 1 cm, 5 cm, 10 cm, 20 cm, 50 cm, and 100 cm. Soil heat flux plates were at depths of 1 cm, 5 cm, and 10 cm.

4.1.7 Manufacturer of Sensor/Instrument
ATI
Applied Technologies
6395 Gunpark Dr
Boulder, CO 80301-3390

Campbell Scientific Instruments
P.O. Box 551
Logan, UT 84321

LiCor
P.O. Box 4425
Lincoln, NE 68504-0425

MKS Instruments
6 Shattuck Rd
Andover, MA 01810-2495


4.2 Calibration

4.2.1 Specifications
      Sonic anemometer: Supplied by the manufacturer. Instrument zeros and maintenance performed at least twice per year.
      CO2 sensor: Calibrated every 3 hours by standard addition of 4% CO2 at 40 and 80 standard milliliters per minute for 2 minutes 15-m below the sample inlet on tower. Zero datum for the LiCor IRGA was achieved by passing sample air through a column of soda lime for 2 minutes.
      H2O sensor: Calibration was checked by comparison with a Vaisala probe on the tower. Zero information was recorded every 3 hours by passing sample air through a column of magnesium perchlorate for 2 minutes.
      CO2 concentration calibration: Used an independent LiCor 6262 IGA and two span gases (~340 ppm and ~420 ppm). These gas samples are traceable to the 1993 Scripps-World Meteorological Organization (WMO) standard. Calibrations were performed every 3 hours by passing each of the gases through the LiCor IGA at 1.25 standard liters per minute for 2 minutes. Zero information was achieved by the same method as that used for the eddy CO2-sensor.
4.2.1.1 Tolerance
      Not known.


4.2.2 Frequency of Calibration
      Sonic anemometer: Instrument zeros and maintenance performed at least twice per year.
      CO2 sensor: Calibrated every 3 hours by standard addition of 4% CO2 at 40 and 80 standard milliliters per minute for 2 minutes 15-m below the sample inlet on tower.
      H2O sensor: Zero information is recorded every 3 hours by passing sample air through a column of magnesium perchlorate for 2 minutes.
      CO2 concentration calibration: Calibrations are done every 3 hours by passing each of the gas samples through the LiCor at 1.25 standard liters per minute for 2 minutes.

4.2.3 Other Calibration Information
      Not known.

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5. Data Acquisition Methods

Data for flux measurements were continuously recorded at 4 Hz while other parameters were recorded at 0.5 Hz. The data were stored on a PC and collected once a week. The delay time between the wind speed and concentration measurement was calculated at 5.5 seconds. The time constant for response time of the instrument to a change in the mixing ratio of the air sample was determined to be 0.6 seconds for CO2 and 1.25 seconds for H2O. The difference in time was due to adsorption of H2O to the tubing. The response-time corrections typically were 5 to 10% during the day and 15 to 25% at night. An averaging time of 30 minutes was used and a linear least-squares regression was used to detrend the flux data.

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6. Observations

6.1 Data Notes
      Data are available from 1994-1998. The measurements are ongoing and regular updates are made on the group's FTP server. The FTP server can be found at ftp://ftp.as.harvard.edu/pub/nigec/Boreas_OBS/ [Internet Link] and data can be directly downloaded.
      Note that the times in the derived data set do not match the measured data (Tower Flux, Meteorological, Soil Temperature Data) exactly in 1998. This is due to a problem with the time-matching program that caused some of
the records to repeat the times in the 1998 processing. The derived data set was created before this problem was corrected and the derived data have not been reprocessed yet, although the measured data have. An update to the derived data will be placed on the Harvard web site sometime in the summer or fall of 2001.

6.2 Field Notes
      None given.

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7. Data Description

7.1 Spatial Characteristics
7.1.1 Spatial Coverage
      All data were collected at the BOREAS NSA-OBS site. The North American Datum 1983 (NAD83) location for this site is latitude 55.88007° N, longitude 98.48139° W, and at an elevation of 259 m.

7.1.2 Spatial Coverage Map
      Not applicable.

7.1.3 Spatial Resolution
      The data represent point source measurements taken at the given location. The location and size of the footprint from which the measurements were made varied with ambient meteorological conditions.

7.1.4 Projection
      Not applicable.

7.1.5 Grid Description
      Not applicable.


7.2 Temporal Characteristics

7.2.1 Temporal Coverage
      Measurements are available from March 1994 through December 1998. Data from March 1994 through October 1996 are included in the BOREAS TF-03 effort while data from the end of October 1996 through December 1998 are included in the BOREAS Follow-on FLX-01 effort.

7.2.2 Temporal Coverage Map
      All data were collected at the NSA-OBS site.

7.2.3 Temporal Resolution
      Data for flux measurements were continuously recorded at 4 Hz while other parameters were recorded at 0.5 Hz. The delay time between the wind speed and concentration measurement was calculated at 5.5 seconds. The time constant for response of the instrument to a change in the mixing ratio of the air sample was determined to be 0.6 seconds for CO2 and 1.25 seconds for H2O. The difference in time was due to adsorption of H2O to the tubing. The response-time corrections typically were 5 to 10% during the day and 15 to 25% at night. An averaging time of 30 minutes was used and a linear least-squares regression was used to detrend the flux data.


7.3 Data Characteristics

7.3.1 Parameter/Variable
     The parameters contained in the data files are:
         Column Name
------------------------------
SITE_NAME
DATE_OBS
TIME_OBS
SENSIBLE_HEAT_FLUX_ABV_CNPY
LATENT_HEAT_FLUX_ABV_CNPY
NET_RAD_ABV_CNPY
CO2_FLUX_ABV_CNPY
CO2_CONC_ABV_CNPY
CO2_STORAGE
PPFD_ABV_CNPY
PPFD_BELOW_CNPY
WIND_DIR_ABV_CNPY
WIND_SPEED_ABV_CNPY
FRICTION_VELOC_ABV_CNPY
AIR_TEMP_ABV_CNPY
AIR_TEMP_10M
AIR_TEMP_2M
SOIL_T_5CM_SM_BS_SPHAG
SOIL_T_10CM_SM_BS_SPHAG
SOIL_T_20CM_SM_BS_SPHAG
SOIL_T_50CM_SM_BS_SPHAG
SOIL_T_100CM_SM_BS_SPHAG
SOIL_T_5CM_TALL_BS_FEATHER
SOIL_T_10CM_TALL_BS_FEATHER
SOIL_T_20CM_TALL_BS_FEATHER
SOIL_T_50CM_TALL_BS_FEATHER
SOIL_T_100CM_TALL_BS_FEATHER
VAPOR_PRESS_ABV_CNPY
RAINFALL
MONIN_OBUKHOV_LENGTH
CRTFCN_CODE
REVISION_DATE

7.3.2 Variable Description/Definition
     The descriptions of the parameters contained in the data files are:
         Column Name                             Description
------------------------------ --------------------------------------
SITE_NAME                      The identifier assigned to the site by BOREAS, in
                               the format SSS-TTT-CCCCC, where SSS identifies
                               the portion of the study area: NSA, SSA, REG,
                               TRN, and TTT identifies the cover type for the
                               site, 999 if unknown, and CCCCC is the identifier
                               for site, exactly what it means will vary with
                               site type.
DATE_OBS                       The date on which the data were collected.
TIME_OBS                       The Greenwich Mean Time (GMT) representing the
                               midpoint of the half-hour period when the data
                               were collected.
SENSIBLE_HEAT_FLUX_ABV_CNPY    The sensible heat flux measured above the canopy.
LATENT_HEAT_FLUX_ABV_CNPY      The latent heat flux measured above the canopy.
NET_RAD_ABV_CNPY               The net radiation measured above the canopy.
CO2_FLUX_ABV_CNPY              The carbon dioxide flux measured above the canopy
CO2_CONC_ABV_CNPY              The carbon dioxide concentration measured above
                               the canopy.
CO2_STORAGE                    The storage term of carbon dioxide below 30m.
PPFD_ABV_CNPY                  The incident photosynthetic photon flux density
                               measured above the canopy.
PPFD_BELOW_CNPY                The median value from 8 ground-level incident 
                               photosynthetic photon flux density measurements
                               under the canopy.
WIND_DIR_ABV_CNPY              The wind direction measured above the canopy from
                               magnetic north.
WIND_SPEED_ABV_CNPY            The wind speed measured above the canopy.
FRICTION_VELOC_ABV_CNPY        The friction velocity above the canopy.
AIR_TEMP_ABV_CNPY              The air temperature measured at 30 meters above
                               the ground (above the canopy).
AIR_TEMP_10M                   The air temperature measured at 10 meters above
                               the ground.
AIR_TEMP_2M                    The air temperature at 2 meters above the ground
SOIL_T_5CM_SM_BS_SPHAG         The soil temperature recorded at 5 cm depth at a
                               plot of stunted black spruce on sphagnum.
SOIL_T_10CM_SM_BS_SPHAG        The soil temperature recorded at 10 cm depth at a
                               plot of stunted black spruce on sphagnum.
SOIL_T_20CM_SM_BS_SPHAG        The soil temperature recorded at 20 cm depth at a
                               plot of stunted black spruce on sphagnum.
SOIL_T_50CM_SM_BS_SPHAG        The soil temperature recorded at 50 cm depth at a
                               plot of stunted black spruce on sphagnum.
SOIL_T_100CM_SM_BS_SPHAG       The soil temperature recorded at 1 m depth at a
                               plot of stunted black spruce on sphagnum.
SOIL_T_5CM_TALL_BS_FEATHER     The soil temperature recorded at 5 cm depth at a
                               plot of upland tall black spruce on feather moss.
SOIL_T_10CM_TALL_BS_FEATHER    The soil temperature recorded at 10 cm depth at a
                               plot of upland tall black spruce on feather moss.
SOIL_T_20CM_TALL_BS_FEATHER    The soil temperature recorded at 20 cm depth at a
                               plot of upland tall black spruce on feather moss.
SOIL_T_50CM_TALL_BS_FEATHER    The soil temperature recorded at 50 cm depth at a
                               plot of upland tall black spruce on feather moss.
SOIL_T_100CM_TALL_BS_FEATHER   The soil temperature recorded at 1 m depth at a
                               plot of upland tall black spruce on feather moss.
VAPOR_PRESS_ABV_CNPY           The vapor pressure measured above the canopy.
RAINFALL                       The amount of rainfall measured above the canopy
                               over the 30 minute period.
MONIN_OBUKHOV_LENGTH           The Monin-Obukhov length.
CRTFCN_CODE                    The BOREAS certification level of the data.
                               Examples are CPI (Checked by PI), CGR (Certified
                               by Group), PRE (Preliminary), and CPI-??? (CPI
                               but questionable).
REVISION_DATE                  The most recent date when the information in the
                               referenced data base table record was revised.

7.3.3 Unit of Measurement
     The measurement units for the parameters contained in the data files are:
         Column Name                                Units
------------------------------ ------------------------------------------------
SITE_NAME                      [none]
DATE_OBS                       [DD-MON-YY]
TIME_OBS                       [HHMM GMT]
SENSIBLE_HEAT_FLUX_ABV_CNPY    [Watts][meter^-2]
LATENT_HEAT_FLUX_ABV_CNPY      [Watts][meter^-2]
NET_RAD_ABV_CNPY               [Watts][meter^-2]
CO2_FLUX_ABV_CNPY              [micromoles][meter^-2][second^-1]
CO2_CONC_ABV_CNPY              [parts per million]
CO2_STORAGE                    [micromoles][meter^-2][second^-1]
PPFD_ABV_CNPY                  [micromoles][meter^-2][second^-1]
PPFD_BELOW_CNPY                [micromoles][meter^-2][second^-1]
WIND_DIR_ABV_CNPY              [degrees from magnetic North]
WIND_SPEED_ABV_CNPY            [meters][second^-1]
FRICTION_VELOC_ABV_CNPY        [meters][second^-1]
AIR_TEMP_ABV_CNPY              [degrees Celsius]
AIR_TEMP_10M                   [degrees Celsius]
AIR_TEMP_2M                    [degrees Celsius]
SOIL_T_5CM_SM_BS_SPHAG         [degrees Celsius]
SOIL_T_10CM_SM_BS_SPHAG        [degrees Celsius]
SOIL_T_20CM_SM_BS_SPHAG        [degrees Celsius]
SOIL_T_50CM_SM_BS_SPHAG        [degrees Celsius]
SOIL_T_100CM_SM_BS_SPHAG       [degrees Celsius]
SOIL_T_5CM_TALL_BS_FEATHER     [degrees Celsius]
SOIL_T_10CM_TALL_BS_FEATHER    [degrees Celsius]
SOIL_T_20CM_TALL_BS_FEATHER    [degrees Celsius]
SOIL_T_50CM_TALL_BS_FEATHER    [degrees Celsius]
SOIL_T_100CM_TALL_BS_FEATHER   [degrees Celsius]
VAPOR_PRESS_ABV_CNPY           [kiloPascals]
RAINFALL                       [millimeters]
MONIN_OBUKHOV_LENGTH           [meters]
CRTFCN_CODE                    [none]
REVISION_DATE                  [DD-MON-YY]

7.3.4 Data Source
     The source of the parameter values contained in the data files are:
         Column Name                             Data Source
------------------------------ ------------------------------------------------
SITE_NAME                      [Assigned by BORIS]
DATE_OBS                       [Investigator]
TIME_OBS                       [Investigator]
SENSIBLE_HEAT_FLUX_ABV_CNPY    [ATI sonic anemometer]
LATENT_HEAT_FLUX_ABV_CNPY      [Infrared Gas Analyzer]
NET_RAD_ABV_CNPY               [Net radiometer]
CO2_FLUX_ABV_CNPY              [Infrared Gas Analyzer]
CO2_CONC_ABV_CNPY              [Infrared Gas Analyzer]
CO2_STORAGE                    [Infrared Gas Analyzer]
PPFD_ABV_CNPY                  [Quantum sensor]
PPFD_BELOW_CNPY                [Quantum sensor]
WIND_DIR_ABV_CNPY              [ATI sonic anemometer]
WIND_SPEED_ABV_CNPY            [Met One spinning cup]
FRICTION_VELOC_ABV_CNPY        [ATI sonic anemometer]
AIR_TEMP_ABV_CNPY              [thermocouple]
AIR_TEMP_10M                   [thermocouple]
AIR_TEMP_2M                    [thermocouple]
SOIL_T_5CM_SM_BS_SPHAG         [thermocouple]
SOIL_T_10CM_SM_BS_SPHAG        [thermocouple]
SOIL_T_20CM_SM_BS_SPHAG        [thermocouple]
SOIL_T_50CM_SM_BS_SPHAG        [thermocouple]
SOIL_T_100CM_SM_BS_SPHAG       [thermocouple]
SOIL_T_5CM_TALL_BS_FEATHER     [thermocouple]
SOIL_T_10CM_TALL_BS_FEATHER    [thermocouple]
SOIL_T_20CM_TALL_BS_FEATHER    [thermocouple]
SOIL_T_50CM_TALL_BS_FEATHER    [thermocouple]
SOIL_T_100CM_TALL_BS_FEATHER   [thermocouple]
VAPOR_PRESS_ABV_CNPY           [thermocouple]
RAINFALL                       [tipping bucket rain gauge]
MONIN_OBUKHOV_LENGTH           [ATI sonic anemometer]
CRTFCN_CODE                    [Assigned by BORIS]
REVISION_DATE                  [Assigned by BORIS]

7.3.5 Data Range
     The following table gives information about the parameter values found in the data files.
                     Minimum        Maximum        Missng  Unrel  Below   Data
                     Data           Data           Data    Data   Detect  Not
Column Name          Value          Value          Value   Value  Limit   Cllctd
--------------------------------------------------------------------------------
SITE_NAME            NSA-OBS-FLXTR  NSA-OBS-FLXTR  None    None   None    None
DATE_OBS             31-OCT-96      31-DEC-98      None    None   None    None
TIME_OBS             0              2330           None    None   None    None
SENSIBLE_HEAT_FLUX_  -146.026       745.292        -999    None   None    None
ABV_CNPY
LATENT_HEAT_FLUX_ABV -139.295       484.545        -999    None   None    None
_CNPY
NET_RAD_ABV_CNPY     -87.29         849.105        -999    None   None    None
CO2_FLUX_ABV_CNPY    -18.7334       45.1075        -999    None   None    None
CO2_CONC_ABV_CNPY    337.243        466.21         -999    None   None    None
CO2_STORAGE          -23.85         17.05          -999    None   None    None
PPFD_ABV_CNPY        -41.486        2124.802       -999    None   None    None
PPFD_BELOW_CNPY       -4.639        329.028        -999    None   None    None
WIND_DIR_ABV_CNPY     0             360            -999    None   None    None
WIND_SPEED_ABV_CNPY  .04            14.64          -999    None   None    None
FRICTION_VELOC_ABV_  .01            2.024          -999    None   None    None
CNPY
AIR_TEMP_ABV_CNPY    -52.879        31.563         -999    None   None    None
AIR_TEMP_10M         -62.039        32.791         -999    None   None    None
AIR_TEMP_2M          -62.787        33.03          -999    None   None    None
SOIL_T_5CM_SM_BS_     -7.53         26.938         -999    None   None    None
SPHAG
SOIL_T_10CM_SM_BS_    -2.147        19.626         -999    None   None    None
SPHAG
SOIL_T_20CM_SM_BS_    -1.503        14.925         -999    None   None    None
SPHAG
SOIL_T_50CM_SM_BS_    -0.778         8.779         -999    None   None    None
SPHAG
SOIL_T_100CM_SM_BS_   -0.263         5.905         -999    None   None    None
SPHAG
SOIL_T_5CM_TALL_     -19.509        28.658         -999    None   None    None
BS_FEATHER
SOIL_T_10CM_TALL_    -20.55         28.258         -999    None   None    None
BS_FEATHER
SOIL_T_20CM_TALL_    -13.219        23.817         -999    None   None    None
BS_FEATHER
SOIL_T_50CM_TALL_     -4.09          0.247         -999    None   None    None
BS_FEATHER
SOIL_T_100CM_TALL_     -.868         3.539         -999    None   None    None
BS_FEATHER
VAPOR_PRESS_ABV_CNPY .0401          2.2684         -999    None   None    None
RAINFALL             0              10.5           -999    None   None    None
MONIN_OBUKHOV_LENGTH -195787.7    200982.1         -999    None   None    None
CRTFCN_CODE          CPI            CPI            None    None   None    None
REVISION_DATE        25-OCT-99      5-MAR-01       None    None   None    None
--------------------------------------------------------------------------------
Minimum Data Value -- The minimum value found in the column.
Maximum Data Value -- The maximum value found in the column.
Missng Data Value  -- The value that indicates missing data. This is used to
                      indicate that an attempt was made to determine the
                      parameter value, but the attempt was unsuccessful.
Unrel Data Value   -- The value that indicates unreliable data.  This is used
                      to indicate an attempt was made to determine the
                      parameter value, but the value was deemed to be
                      unreliable by the analysis personnel.
Below Detect Limit -- The value that indicates parameter values below the
                      instruments detection limits.  This is used to
                      indicate that an attempt was made to determine the
                      parameter value, but the analysis personnel determined
                      that the parameter value was below the detection
                      limit of the instrumentation.
Data Not Cllctd    -- This value indicates that no attempt was made to
                      determine the parameter value.  This usually
                      indicates that BORIS combined several similar but
                      not identical data sets into the same data base table
                      but this particular science team did not
                      measure that parameter.

Blank -- Indicates that blank spaces are used to denote that type of value.
N/A   -- Indicates that the value is not applicable to the respective column.
None  -- Indicates that no values of that sort were found in the column.
--------------------------------------------------------------------------------


7.4 Sample Data Record
     The following are wrapped versions of data record from a sample data file:

SITE_NAME,DATE_OBS,TIME_OBS,SENSIBLE_HEAT_FLUX_ABV_CNPY,LATENT_HEAT_FLUX_ABV_CNPY,
NET_RAD_ABV_CNPY,CO2_FLUX_ABV_CNPY,CO2_CONC_ABV_CNPY,CO2_STORAGE,PPFD_ABV_CNPY,
PPFD_BELOW_CNPY,WIND_DIR_ABV_CNPY,WIND_SPEED_ABV_CNPY,FRICTION_VELOC_ABV_CNPY,
AIR_TEMP_ABV_CNPY,AIR_TEMP_10M,AIR_TEMP_2M,SOIL_TEMP_5CM_SM_BS_SPHAG,
SOIL_TEMP_10CM_SM_BS_SPHAG,SOIL_TEMP_20CM_SM_BS_SPHAG,SOIL_TEMP_50CM_SM_BS_SPHAG,
SOIL_TEMP_100CM_SM_BS_SPHAG,SOIL_TEMP_5CM_TALL_BS_FEATHER,
SOIL_TEMP_10CM_TALL_BS_FEATHER,SOIL_TEMP_20CM_TALL_BS_FEATHER,
SOIL_TEMP_50CM_TALL_BS_FEATHER,SOIL_TEMP_100CM_TALL_BS_FEATHER,
VAPOR_PRESS_ABV_CNPY,RAINFALL,MONIN_OBUKHOV_LENGTH,CRTFCN_CODE,REVISION_DATE
'NSA-OBS-FLXTR',1-Jul-98,0,48.5163,67.2044,111.959,-0.4847,359.556,0.01,
348.328,47.289,359,2.67,0.5668,25.638,26.275,25.863,16.51,12.47,7.059,3.08,
0.991,18.674,15.774,-999,-999,-0.374,0.8339,0,-340.9753,'CPI',5-Mar-01
'NSA-OBS-FLXTR',1-Jul-98,30,67.4628,67.1134,167.033,-0.7433,359.377,-0.13,
484.137,46.869,3,2.29,0.6111,25.34,25.825,25.414,16.436,12.395,7.098,3.08,
0.991,18.564,15.7,-999,-999,-0.374,0.8739,0,-307.9844,'CPI',5-Mar-01
'NSA-OBS-FLXTR',1-Jul-98,100,-999,36.1456,21.628,0.0683,359.318,0.13,
171.816,23.0145,355,6.16,0.5493,25.005,25.116,24.707,16.142,12.357,7.138,
3.08,0.991,18.381,15.516,-999,-999,-0.374,0.85,0,-6314.8093,'CPI',5-Mar-01
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8. Data Organization

8.1 Data Granularity
      All of the FLX-01 NSA-OBS tower flux, meteorological, and soil temperature data were organized to yearly data files and compressed.

8.2 Data Format
      The data files contains numerical and character fields of varying length separated by commas. The character fields are enclosed within single apostrophe marks. There are no spaces between the fields.

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9. Data Manipulations

9.1 Formulae
      None.
9.1.1 Derivation Techniques and Algorithms
      None.


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.
Updates to the 1997 soil temperature columns were made in early March 2001, and all of the 1998 data were updated at this time as well. These updates were made to correct for an electrical problem that had caused problems in the soil temperature measurements and to fix some problems in the processing procedure that had resulted in some of the lines in the 1998 files to be repeated. Due to the timing of this update, the above-mentioned steps were not performed on the updated data.

9.2.2 Processing Changes
      None.


9.3 Calculations

9.3.1 Special Corrections/Adjustments
      The sonic anemometer developed occasional problems with spiking, caused either by precipitation or by malfunctioning transducers. Processing code was adapted to determine the number of spikes in each interval and to recalculate the turbulent fluxes after filtering out spikes.

9.3.2 Calculated Variables
      None.


9.4 Graphs and Plots
      None.

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10. Errors

10.1 Sources of Error
      Errors in flux measurements may be associated with wind from behind the tower, calm conditions, and the damping of high-frequency fluctuations. The sonic anemometer developed occasional problems with spiking, caused either by precipitation or by malfunctioning transducers.

10.2 Quality Assessment

10.2.1 Data Validation by Source
      Raw flux data were examined for errors associated with wind from behind the tower, calm conditions, and the damping of high-frequency fluctuations, and for intervals with malfunctioning instruments. These periods were excluded or the errors were corrected.

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
      Due to the timing of the most recent update to these data, quality checking was performed by the PI only.

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11. Notes

11.1 Limitations of the Data
      None given.

11.2 Known Problems with the Data
      CO2 fluxes may be underestimated when the friction velocity is less than 0.2 m/sec. The closed-path IRGA and long sampling tube resulted in an underestimation of water vapor and CO2 flux because of the damping of high-frequency fluctuations.

11.3 Usage Guidance
      None given.

11.4 Other Relevant Information
      Data are available from 1994-1998. The measurements are ongoing and regular updates are made on the group's FTP server. The FTP server can be found at ftp://ftp.as.harvard.edu/pub/nigec/Boreas_OBS/ [Internet Link] and data can be directly downloaded.

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12. Application of the Data Set

This suite of long-term measurements should provide information to assess the effect of seasons and seasonal changes on the carbon balance of the forest. Determination of the boundary layer CO2 concentration anomaly can also be determined, and thus the effect of the forest on the boundary layer CO2 concentration can be studied.

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13. Future Modifications and Plans

The measurements are ongoing and regular updates are made on the group's FTP server. The FTP server can be found at ftp://ftp.as.harvard.edu/pub/nigec/Boreas_OBS/ [Internet Link] and data can be directly downloaded.

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14. Software

14.1 Software Description
      None given.

14.2 Software Access
      None given.

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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.daac.ornl.gov/ [Internet Link] or users may place requests for data by telephone or by electronic mail.

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.

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16. Output Products and Availability

16.1 Tape Products
      None.

16.2 Film Products
      None.

16.3 Other Products
      None.

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17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation
LI-COR 1991. LI-6262 CO2/H2O analyzer operating and service manual. Publ. 9003-59, Linclon,NE.
 

17.2 Journal Articles and Study Reports
Goulden, M.L., S.C. Wofsy, J.W. Harden, S.E. Trumbore, P.M. Crill, S.T. Gower, T. Fries, B.C. Daube, S.-M. Fan, D.J. Sutton, A. Bazzaz, and J.W. Munger. Sensitivity of boreal forest carbon balance to soil thaw, Science, 279, 214-217, 1998.

Goulden, M.L., B.C. Daube, S.M. Fan, D.J. Sutton, A. Bazzaz, J.W. Munger, and S.C. Wofsy. 1997. Physiological responses of a black spruce forest to weather, Journal of Geophysical Research 102 (D24):28987,28996.

Kaimal, J.C. and J.E. Gaynor. 1991. Another look at sonic thermometry. Boundary Layer Meteorology. 56:401-410.

Kaimal, J.C., J.E. Gaynor, H.A. Zimmerman, and G.A. Zimmerman. 1990. Minimizing flow distortion errors in a sonic anemometer. Boundary Layer Meteorology. 53:103-115.

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. Boundary-Layer Meteorology. 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., 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., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 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. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96).

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):28731-28770.
 

17.3 Archive/DBMS Usage Documentation
      None.

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18. Glossary of Terms

None.

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19. List of Acronyms

    ASCII   - American Standard Code for Information Interchange
    BOREAS  - BOReal Ecosystem-Atmosphere Study
    BORIS   - BOREAS Information System
    DAAC    - Distributed Active Archive Center
    EOS     - Earth Observing System
    EOSDIS  - EOS Data and Information System
    GMT     - Greenwich Mean Time
    GSFC    - Goddard Space Flight Center
    IRGA    - Infrared Gas Analyzer
    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
    PPFD    - Photosynthetic Photon Flux Density
    SSA     - Southern Study Area
    URL     - Uniform Resource Locator
    WMO     - World Meteorological Organization
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20. Document Information

20.1 Document Revision Date

Written: 07-Jul-1995
Revised: 27-Apr-2001 (citation revised on 30-Oct-2002)

20.2 Document Review Date(s)

BORIS Review: 19-May-1998
Science Review: 13-Dec-1999

20.3 Document ID

flx01_tfx

20.4 Citation

Cite this data set as follows (citation revised on October 30, 2002):

Wofsy, S. C., and A. Dunn. 2001. BOREAS Follow-On FLX-01 NSA-OBS Tower Flux, Meteorological, and Soil Temp[erature] Data. Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A.

20.5 Document Curator:

webmaster@daac.ornl.gov

20.6 Document URL:

http://daac.ornl.gov/BOREAS/FollowOn/guides/flx01_flux_met_temp_doc.html

Keywords
BLACK SPRUCE
TOWER FLUX
METEOROLOGY
SENSIBLE HEAT FLUX
LATENT HEAT FLUX
CARBON DIOXIDE FLUX
CARBON DIOXIDE CONCENTRATION
PHOTOSYNTHETIC PHOTON FLUX DENSITY
PHOTOSYNTHETICALLY ACTIVE RADIATION
PPFD
PAR
NET RADIATION
AIR TEMPERATURE
SOIL TEMPERATURE
VAPOR PRESSURE
WIND SPEED
RAINFALL

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