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].
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.
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]).
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.
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
2.2 Title of Investigation
Eddy Correlation Flux Measurements of CO2 and H2O for BOREAS (NSA-OBS).
2.3 Contact Information
fax: (617) 495-2768
(617) 495-9837 (fax)
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.
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
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
6395 Gunpark Dr
Boulder, CO 80301-3390
Campbell Scientific Instruments
P.O. Box 551
Logan, UT 84321
P.O. Box 4425
Lincoln, NE 68504-0425
6 Shattuck Rd
Andover, MA 01810-2495
4.2.1 SpecificationsReturn to top of document.
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.184.108.40.206 Tolerance
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
6.2 Field Notes
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
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.
7.1.5 Grid Description
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
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_DATE7.3.2 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-01Return to top of document.
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.
9.1.1 Derivation Techniques and Algorithms
9.2 Data Processing Sequence
9.2.1 Processing Steps
BORIS staff processed these data by:
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
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
9.4 Graphs and Plots
10.2 Quality Assessment
10.2.1 Data Validation by SourceReturn to top of document.
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
10.2.3 Measurement Error for Parameters
10.2.4 Additional Quality Assessments
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.
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
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.
14.2 Software Access
ORNL DAAC User Services
Oak Ridge National Laboratory
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.
16.2 Film Products
16.3 Other Products
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,
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17.3 Archive/DBMS Usage Documentation
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 OrganizationReturn to top of document.
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.
SENSIBLE HEAT FLUX
LATENT HEAT FLUX
CARBON DIOXIDE FLUX
CARBON DIOXIDE CONCENTRATION
PHOTOSYNTHETIC PHOTON FLUX DENSITY
PHOTOSYNTHETICALLY ACTIVE RADIATION