BOREAS TGB-01/TGB-03 CH4 Chamber flux data over the NSA Fen Summary: The BOREAS TGB-03 team collected methane (CH4) chamber flux measurements at the NSA fen site during May-September 1994 and June-October 1996. Gas samples were extracted approximately every 7 days from chambers and analyzed at the NSA lab facility. The data are provided 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 TGB-01/BOREAS TGB-03 CH4 Chamber flux data over the NSA Fen 1.2 Data Set Introduction Trace Gas Biogeochemistry Teams 1 and 3 (TGB-01 and TGB-03) collected chamber flux measurements at the BOReal Ecosystem Atmosphere Study (BOREAS) Northern Study Area (NSA) Fen site from May to September 1994 and April to late October 1996. 1.3 Objective/Purpose The purpose of these measurements was: 1) To examine the trace gas exchange between the atmosphere and the boreal wetland soils. 2) To quantify CH4 emissions from the range of peatland soils in the Nelson House area, as represented by a suite of peatlands in the Tower Fen complex. 3) To identify environmental controls on CH4 emission and the spatial and temporal variability associated with those controls, in order to improve the process models that describe exchanges of trace gases between the boreal ecosystem and the atmosphere. 4) To examine the change in CH4 flux associated with the evolution of palsas and peat plateaus into collapse, through thermal degradation of permafrost. 5) To identify the role of plant associations, as integrators of the environmental controls, in determining CH4 flux in order to provide a framework for extrapolating single point CH4 measurements from the chamber to the landscape scale. 1.4 Summary of Parameters In the 1994 sampling season, CH4 chamber flux measurements were taken from six sites. These sites were designated as collapse bog (CB), collapse fen (CF), tower fen (TF), remote bog (RB), remote fen (RF), and zoltai fen (ZF). In the 1996 sampling season, CH4 chamber fluxes were measured at four subsites in the NSA fen. These sites were designated as collapse bog (CB), collapse fen (CF), tower fen (TF) and Zoltai fen (ZF). A spur (1, 2, 3, or 4) further designates each collar location along the boardwalk at each subsite. The collar location is also designated by the microtopography, or dominant ground cover, of the collar location: palsa, hummock, hollow, lawn, open water at the edge of the collapse scars, brown moss, sphagnum, lichen. 1.5 Discussion In 1994, CH4 chamber flux measurements were taken at six subsites within the NSA Tower Fen site to determine the soil surface exchange rate of CH4 at these locations. The locations represent the range of plant communities, water chemistry, and peatland types found in northern peatlands, including bog, rich fen, poor fen and collapse scar (pH ranges from 3.8 to 7.2). The sampling collars were installed in the spring of 1994 by the McGill researchers (TGB-03), and measurements of CH4 flux were made during and between the IFC’s of the 1994 field campaign. In 1996, Chamber CH4 flux measurements were taken at four subsites within the fen complex in the NSA to determine the soil surface exchange rates of CH4 at these locations. A subset of the collars installed by the McGill researchers (TGB-03) was measured again from June until the end of October 1996. In addition, the UNH researchers (TGB-01) installed fifteen collars in the fall of 1995; nine additional collars were installed by the UNH researchers in the spring of 1996. CH4 flux measurements began in early April 1996 and continued until the end of October 1996. Two different types of data are presented: 1) CH4 flux measurements using the University of New Hampshire (UNH) collars 2) CH4 flux measurements using the McGill University collars. 1.6 Related Data Sets Other data sets of interest are: BOREAS TGB-01 CO2 and CH4 Chamber Flux data over the NSA BOREAS TGB-01 CH4 Tower Flux data over the NSA BOREAS TGB-03 CH4 and CO2 Chamber Flux Data over NSA Upland Sites BOREAS TGB-03 NEE data over the NSA Fen BOREAS TGB-03 Water Table and Peat Temperature data over the NSA Fen BOREAS TGB-01 1996 plant species data for the UNH NEE and CH4 collars 2. Investigator(s) 2.1 Investigator(s) Name and Title Dr. Jill L. Bubier Research Associate University of New Hampshire Dr. Patrick M. Crill Research Associate Professor University of New Hampshire Dr. Tim R. Moore Professor McGill University 2.2 Title of Investigation Magnitude and Control of Trace Gas Exchange in Boreal Ecosystems 2.3 Contact Information Contact 1 Dr. Jill L. Bubier Institute for the Study of Earth, Oceans, and Space Complex Systems Research Center University of New Hampshire Durham, NH Phone: (603) 862-4208 Fax: (603)862-0188 e-mail: jill.bubier@unh.edu Contact 2 Dr. Patrick M. Crill Institute for the Study of Earth, Oceans, and Space Complex Systems Research Center University of New Hampshire Durham, NH Phone: (603) 862-3519 Fax: (603)862-0188 e-mail: patrick.crill@unh.edu Contact 3 Ruth K. Varner Research Scientist Institute for the Study of Earth, Oceans, and Space Complex Systems Research Center University of New Hampshire Durham, NH Phone: (603) 862-2939 Fax: (603)862-0188 e-mail: ruth.kerwin@unh.edu Contact 4 Dr. Tim R. Moore Geography Department McGill University Montreal, Quebec Canada Phone: (514) 398-4961 Fax: (514) 398-7437 e-mail: moore@felix.geog.mcgill.ca 3. Theory of Measurements Chamber fluxes measure the changes in mixing ratio of trace gases (CH4) in a closed headspace over a period of time. This headspace is isolated from the atmosphere; therefore we can quantify the exchange of material between the covered soil and the headspace. 4. Equipment: 4.1 Sensor/Instrument Description The CH4 flux measurements were measured with PVC collars (26 cm in diameter) and chambers made from polycarbonate bottles (26 cm in diameter; 40 cm tall; area of exposure 0.053 m2; Moore and Roulet, 1991). Bottles were covered with aluminum foil to reduce heating. The neck of each bottle was sealed with a rubber stopper that contained a glass tube with a rubber septum with a 1 m length of Tygon tubing attached to the top to minimize disturbance. Syringes were made of polypropylene syringes. CH4 was quantified with a Shimadzu 14A Gas Chromatograph (GC) or a Shimadzu Mini2GC with a flame ionization detector (FID) operated at 125oC after separation on a HayeSepQ column at 40oC using ultrapure (99.999%) N2 as a carrier gas flowing at 30 mL/min. Analog signals (0-1 V) from the detectors were digitized at 10 Hz with a Hewlett Packard (HP) 35000D A/D board and quantified and logged using HP ChemStation software. Chamber fluxes were accomplished with aluminum chambers manufactured at the University of New Hampshire and designed by Patrick Crill. 4.1.1 Collection Environment The chamber fluxes were collected under all ambient environmental conditions. The GC analysis was completed at the Heritage North Museum Lab in Thompson, Manitoba. 4.1.2 Source/Platform CH4 flux collars were inserted into the peat approximately 4-6 inches. Chambers were set in a groove in the collars. 4.1.3 Source/Platform Mission Objectives The ground supported the collars which supported the chambers. 4.1.4 Key Variables The key variable measured during the sampling period was CH4 flux. NEE was measured at the same time along with temperature and water table position. Percent cover of vascular plant species and bryophyte species was also recorded for each collar. 4.1.5 Principles of Operation The Shimadzu GC-14A is equipped with a FID and a thermal conductivity detector (TCD). The FID is used to detect CH4 while the TCD is used to detect CO2. The FID employs a hydrogen flame in an air atmosphere to burn components as they exit the column. In the flame, carbon-carbon bonds are fragmented so that various organic ions and free electrons exist. Application of a voltage across a collector electrode over the flame causes an ion current to flow that is amplified and then measured as the output signal. The TCD detects CO2 by passing a sample in a helium carrier gas past metallic filaments with current flowing through them. The sample components with lower thermal conductivity than the helium carrier gas raise the filament temperature when they pass through. The signal output from the TCD is a measurement of the change in filament resistance caused by the temperature rise. The signal output from both the FID and TCD is for a data processor, integrator, recorder, or computer. (Instruction Manual: GC-14A; Shimadzu Corporation, Kyoto, Japan) The GC-MINI2 was equipped with a FID and operated in the same manner as the GC- 14A FID. 4.1.6 Sensor/Instrument Measurement Geometry Not applicable. 4.1.7 Manufacturer of Sensor/Instrument The investigator manufactured collar and chambers. Manufacturer of GC-14A FID/TCD and GC-MINI2 Shimadzu Scientific Instruments, Inc. 7102 Riverwood Drive Columbia, Maryland 21046 Phone: (401) 381-1227 4.2 Calibration 4.2.1 Specifications Analyses were conducted with a Shimadzu gas chromatograph with a flame ionization detector (FID-GC) using a Porapak Q column. Nitrogen was used as the carrier gas and CH4 standards of 2.349 ppmv were used to calibrate. Precision of the analysis (standard deviation as percent of the mean of 10-15 daily repetitions of the standard) was less than 1% of the standards. Fluxes between 0.1 and -0.1 mg/m2/d-1 were not detectable. Signal peaks from the detectors were quantified with working standards calibrated against AES (Canadian Atmospheric Environment Services) certified primary standards acquired by the BOREAS project and a CO2/ CH4 standard of Niwot Ridge air prepared by National Oceans and Atmospheric Administration (NOAA) Climate Monitoring and Diagnostics Laboratory (CMDL). Uncertainty in the standards' analyses on a given day ranged from 0.1 to 0.2%. 4.2.1.1 Tolerance The sensitivity of the TCD is approximately 6000 mV mL/mg. The FID's maximum sensitivity is 3 x10-12 g/s for diphenyl. 4.2.2 Frequency of Calibration The instrument is calibrated on a daily basis. Standards are run generally before and after samples on a given day of analysis. 4.2.3 Other Calibration Information None Given. 5. Data Acquisition Methods A total of 124 PVC collars were placed along the moisture, chemistry, plant community, and permafrost gradients in the peatland complex, and were sampled in 1994. At four of the sites (bog collapse scar (BC), fen collapse scar (FC), tower fen (TF), and Zoltai fen (ZF), boardwalks were installed spanning the environmental gradients to minimize disturbance. CH4 was sampled at each of the collars once a week from early May through mid-September 1994 using a static chamber technique (Crill et al., 1988). Water was added to the groove in each collar before inserting the chamber in order to make an air-tight seal. Air samples were obtained from each chamber by inserting a polypropylene syringe into the Tygon tubing equipped with a 3-way stopcock, pumping the piston 4-5 times to mix air in the chamber before a 60 mL sample was drawn. A 10 mL sample was taken from the 60 mL syringe using the 3-way stopcock. Five 10 mL samples were taken at 4 min intervals over a 20 minute period. Samples were returned to a laboratory in Thompson and analyzed for CH4 within 4- 6 hours of collection. After analysis, the syringes were disassembled and allowed to equilibrate with ambient air. Syringe barrels and plungers were reassembled immediately before sampling. The 1996 chamber fluxes are determined by analysis of concentrations of methane (CH4) in a time series of grab samples of headspace over the ground surface enclosed by a clear chamber covered in an opaque shroud to prevent light from entering the chamber. For the TGB-01 collars, the NEE chambers were used. The chambers were 0.3660 m2 in area and were either 0.905 m or 0.045 m in height. For the TGB-03 collars, chambers were made of polycarbonate bottles (0.026 m in diameter; 0.040 m tall; area of exposure 0.053 m2) and were covered with aluminum foil to reduce heating. The neck was sealed with a rubber stopper that contained a glass tube with a rubber septum. Tygon tubing (1 m in length), equipped with a 3-way stopcock, was attached to the top of each chamber to allow sampling at a distance that would minimize disturbance. TGB-03 collars were made of PVC tubing. The rim of the collars were routed with a groove that was filled with water when the chambers were put in place in order to create an air tight seal. TGB-01 collars were made of aluminum and were also designed with a trough for creating an air tight seal. For both types of chambers and collars, the chamber was placed on the trough of a collar imbedded in the ground. Water was added to the trough of the collar to create an airtight seal. Five 60 mL samples were removed from the headspace with polypropylene syringes and polycarbonate/nylon stopcocks at 4 minute intervals for 20 minutes or at 2 minute intervals for 10 minutes (5 samples per chamber). Samples were returned to the Heritage North Museum lab in Thompson, Manitoba and analyzed for CO2 and CH4, using gas chromatography within 12 hours after collection. 6. Observations 6.1 Data Notes None Given 6.2 Field Notes None Given. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage 1994 TGB-03 Collars: The area of exposure for each collar and chamber was 0.053 m2. The 100 collars were placed so as to cover the environmental gradients in the tower fen complex, an area approximately 6 km2. GPS coordinates for the major sampling locations are: Site NLat SDev WLon SDev Elevation SDev CB 55o55’4.931” 2.75 98o25’5.294” 1.18 217.20 3.86 CF 55o54’59.959” 5.60 98o25’6.109” 1.90 218.40 7.62 ZF 55o55’5.477” 2.07 98o25’26.396” 1.29 217.10 3.11 1996 TGB-01 Collars: The collars were located as follows: Collapse bog (CB). Collars were located in a small, circular collapse scar (75 m diameter) almost completely surrounded by permafrost peat plateau, behind the generator shed. Three spurs were located perpendicular to the boardwalk. Spur 1 was adjacent to the moat, or open water lagg area; spur 2 was in a hummock- hollow area; and spur 3 was in the center of the collapse scar. In addition to the collars in the collapse scar, this subsite had two collars on the palsa (frozen peat plateau) adjacent to the collapse scar. Collar designations were as follows: CB1moat = collapse bog, spur 1, moat CB2hk = collapse bog, spur 2, hummock CB2hw = collapse bog, spur 2, hollow CB3hk = collapse bog, spur 3, hummock CBpalmoss = collapse bog, palsa, moss Cbpallich = collapse bog, palsa, lichen Collapse fen (CF) collars were located in a small, linear collapse feature that was east of and accessed from the main trail to the tower hut. Four spurs were located perpendicular to the main boardwalk. Spur 1 was located adjacent to the moat; spur 2 was in a uniform lawn of Sphagnum riparium; spur 3 was in a small treed ridge; and spur 4 was on the far edge of the collapse scar where the influence of groundwater was apparent. Collar designations were as follows: CF1moat = collapse fen, spur 1, moat CF2lwn = collapse fen, spur 2, lawn CF3hka = collapse fen, spur 3, hummock (a) CF3hkb = collapse fen, spur 3, hummock (b) CF4b_moss = collapse fen, spur 4, brown moss CF4sph = collapse fen, spur 4, sphagnum Tower Fen (TF) collars were located along the boardwalk to the micrometeorological tower in the NSA fen. Four spurs were located perpendicular to the main boardwalk. Spur 1 was just beyond the moat at the beginning of the boardwalk in a treed area of tamarack (Larix laricina). Spur 2 was in a tall shrub zone (Betula glandulosa). Spur 3 was in a low shrub zone just before the hut. Spur 4 was just beyond the hut in a mixed low shrub/sedge zone. Collar designations were as follows: TF1hk = tower fen, spur 1, hummock TF2hk = tower fen, spur 2, hummock TF2hw = tower fen, spur 2, hollow TF3hk = tower fen, spur 3, hummock TF3hw = tower fen, spur 3, hollow TF4hw = tower fen, spur 4, hollow Zoltai Fen (ZF) collars were located in a sedge-dominated (Carex spp.) fen area of the peatland complex, north of the fen tower, and accessed from Rt. 391. Three spurs were located perpendicular to the main boardwalk. Spur 1 was on a treed ridge; spur 2 was in a shrub-dominated hummock-hollow area; spur 3 was in a wet, sedge-dominated area near the edge of a palsa. Collar designations were as follows: ZF1hk = zoltai fen, spur 1, hummock ZF2hk = zoltai fen, spur 2, hummock ZF2hw = zoltai fen, spur 2, hollow ZF3b_moss = zoltai fen, spur 3, brown moss ZF3hw = zoltai fen, spur 3, hollow (Sphagnum) ZF3hk = zoltai fen, spur 3, hummock (Sphagnum) 1996 TGB-03 Collars: For chamber CH4 flux data from the McGill collars, the collars were the same as those sampled by TGB-03 in 1994. Major locations and spurs are the same as for the UNH collars described above. Microtopography for the McGill collars is designated as: Hummock Hollow Lawn (uniform area with little microtopography) Carpet (uniform area with water table closer to the peat surface than in lawn areas, peat is often a floating mat) Pool (water table above peat surface; submerged bryophytes, and Carex spp. or other emergent vascular plants present in collars) Moat (open water area or lagg at edge of peatland). Collapse fen location and spurs are the same as for the UNH collars described above. McGill collars are as follows: FC4p16 = collapse fen, spur 4, pool, collar 16 FC4p17 = collapse fen, spur 4, pool, collar 17 FC4p16new = collapse fen, spur 4, pool, collar 16 relocated to new position on 22-August-96 because vegetation was dying within the collar FC4p17new = collapse fen, spur 4, pool, collar 17 relocated to new position on 22-August-96 because vegetation was dying within the collar FC4p19 = collapse fen, spur 4, pool, collar 19 FC4p20 = collapse fen, spur 4, pool, collar 20 FCm3f = collapse fen, moat spur 1, collar 3 floating FCm2f = collapse fen, moat spur 1, collar 2 floating FCm1f = collapse fen, moat spur 1, collar 1 floating Tower fen location and spurs are the same as for the UNH collars described above. McGill collars are as follows: TF4c16 = tower fen, spur 4, carpet, collar 16 TF4n17 = tower fen, spur 4, lawn, collar 17 TF4c18 = tower fen, spur 4, carpet, collar 18 TF4n19 = tower fen, spur 4, lawn, collar 19 TF4c20 = tower fen, spur 4 lawn, collar 20 TF3w11 = tower fen, spur 3, hollow, collar 11 TF3k12 = tower fen, spur 3, hummock, collar 12 TF3w14 = tower fen, spur 3, hollow, collar 14 TF3w15 = tower fen, spur 3, hollow, collar 15 TFm1f = tower fen, moat, collar 1 floating TFm2f = tower fen, moat, collar 2 floating TFm3f = tower fen, moat, collar 3 floating Zoltai fen location and spurs are the same as the UNH collars above. McGill collars are as follows: ZF3k11 = zoltai fen, spur 3, hummock, collar 11 ZF3new = zoltai fen, spur 3, new collar ZF3p15 = zoltai fen, spur 3, pool, collar 15 ZFmike = zoltai fen, new spur used by Mike Waddington in 1994 (Carex rostrata, C. aquatilis lawn) ZF2w8 = zoltai fen, spur 2, hollow, collar 8 7.1.2 Spatial Coverage Map None Given. 7.1.3 Spatial Resolution The 24 UNH collars spanned the full range of hydrologic, plant community and water chemistry gradients found in the larger peatland complex in order to capture the spatial variability in CH4 fluxes. The 26 1996 McGill collars were placed along the same gradients with an emphasis on the wet end of the moisture gradient in order to resample the 1994 sites that exhibited the highest CH4 fluxes. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage CH4 flux, water table, and peat temperature measurements were made from mid-May through mid-September 1994. The chamber CH4 flux measurements for 15 of the UNH collars were made from 15- April-96 to 23-October-96. The chamber CH4 flux measurements for the other 9 UNH collars were made 15-June-96 to 23-October-96. Chamber CH4 flux measurements for the McGill collars were made from 3-June-96 to 22-October-96. 7.2.2 Temporal Coverage Map Not applicable. 7.2.3 Temporal Resolution CH4 flux measurements were made once at week at each of the 124 collars throughout the 1994 season. The chamber CH4 flux measurements for 15 of the UNH collars were made approximately every 7 days from 15-April-96 to 23-October-96. The chamber CH4 flux measurements for the other 9 UNH collars were made approximately every 7 days from approximately 15-June-96 to 23-October-96. Chamber CH4 flux measurements for the McGill collars were made approximately every 7 days from 3- June-96 to 22-October-96. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (tgbfenfx.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (tgbfenfx.def). 8. Data Organization 8.1 Data Granularity All of the CH4 Chamber flux data over the NSA Fen data are contained on one dataset. 8.2 Data Format(s) The CD-ROM files contain numerical and character fields of varying length separated by commas. The character fields are enclosed with single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition file (tgbfenfx.def). 9. Data Manipulations 9.1 Formulae 9.1.1 Derivation Techniques and Algorithms Rf = Cstd / Astd Cs = Rf * As Rf = Response factor Astd = average of 10 Standard peak areas Cstd = Concentration of the standard Cs = Concentration of the sample As = peak area of sample CH4 concentrations were calculated from the average of 10 peak areas of known CH4 standards. The response factor was calculated as the concentration of the known standard divided by the average of 10 standard peak areas. The peak area of the unknown sample was multiplied by the response factor. The flux calculations were made by fitting a regression curve to the time series of CH4 concentrations. The flux rate of a gas is calculated using the following equation : Flux(mg/m2/d)=ppmv/min*(P/R*g/mol of the gas)*(1/T)*Vc/Ac *(1000mg/g*1440min/d) where: P = pressure in atmospheres R = 8.2054 x 10-5 m3atm mol-1K-1 gases: CH4 = 16 g/mol T = degrees K of the chamber Vc = chamber volume in m3 Ac = chamber area in m2 Vc=((E/100 x 0.047 x 1000) + Vt Vc = volume of the chamber Vt = volume of the top narrow part of chamber = 1.4 E = height of cylindrical part of chamber in cm 9.2 Data Processing Sequence 9.2.1 Processing Steps The peak areas were taken directly from the HPChemstation reports from the GC. They were entered into spreadsheets and the concentrations were calculated by the formulas in Section 9.1. The spreadsheets then automatically calculate the flux using the formulas in Section 9.1. The flux equation included the slope of the regression line of the five samples; the height and volume of the chamber; air temperature (see above). Fluxes were calculated by linear regression of the concentration change in the five samples. If one sample deviated from the line, the flux was recalculated without the outlier. The correlation coefficient of the regression had to be significant to the 95% confidence limit for n=4 or 5 (r2 = 0. 95 or 0.87); otherwise the sample was rejected. Sites with ebullition were kept in the data set even if a large increase was observed between 2 of the samples as long as the correlation coefficient was still significant at p < 0.05. 9.2.2 Processing Changes Not applicable. 9.3 Calculations At sites where oxidation of CH4 occurs, the flux needed to start at or near ambient levels of CH4 and be drawn down below ambient. The correlation coefficient also had to show significant correlation. If these criteria were not met then the flux was determined to be below our minimal detectable flux and was regarded as a 0 flux rate. If there was an efflux of CH4 measured at any of these sites then the data were eliminated. For sites where CH4 were known to have a positive flux (from the soil into the atmosphere) the regressions of the time series were expected to have an r2 of greater than 0.85 for n=5. If this was not the case with 5 data points, then one or at most two points might be dropped to get a better fit. The r2 would have to be greater than 0.92 for n=4, and 0.96 for n=3 (90% confidence interval). If the fit was not good enough (r2 less than required for 90% confidence interval), the data were eliminated. If -888 is present in the data set, it represents a measurement was taken but discarded for some reason. If -999 is present then no data was taken. 9.3.1 Special Corrections/Adjustments Not applicable. 9.3.2 Calculated Variables Not applicable. 9.4 Graphs and Plots None given. 10. Errors 10.1 Sources of Error One source of error was disturbance while sampling the chamber. If the peat or the chamber was disturbed a large pulse of CH4 was emitted. These samples were eliminated from the data set and the number -9666 was recorded to note the error. If no data was taken at that collar on a particular date, -999 was recorded to denote missing data. Field sampling error could also account for some error in the concentration of the syringe samples: 1.) Not flushing the sampling line from the chamber before sampling could cause dilution of the sample with air from the last sampling time. 2.) Not completely closing the syringes or having them come open during transport will cause dilution from ambient air. 3.) Placing the chamber down with much force can change the pressure inside the chamber to other than ambient and can effect the mechanisms and processes producing/taking up CH4. (Errors such as this would have been written down in the lab/field books and that data have been edited out) The analytical precision of the GC's are: 0.2% for CH4. 10.2 Quality Assessment 10.2.1 Data Validation by Source Each flux measurement has been verified by checking the calculations in the spreadsheets and assessing the slope and intercept for the linear regression. 10.2.2 Confidence Level/Accuracy Judgment None Given. 10.2.3 Measurement Error for Parameters The analytical precision of the GC's are: 0.2% for CH4. 10.2.4 Additional Quality Assessments None Given. 10.2.5 Data Verification by Data Center Data was examined for general consistency and clarity. 11. Notes 11.1 Limitations of the Data The analytical precision of the GC's are: 0.2% for CH4. 11.2 Known Problems with the Data None Given. 11.3 Usage Guidance The manuscript by Bubier et al. (1995) contains predictive relationships developed from data described in this document. 11.4 Other Relevant Information Not applicable. 12. Application of the Data Set The chamber flux data can be used in connection with the tower flux data to determine the CH4 exchange between the atmosphere and the boreal soils. The plant community and water table and temperature data can be used in comparison with the flux data to determine controls on the fluxes for a certain biome. The chamber CH4 flux data can also be compared with chamber NEE data to examine the relationship between net ecosystem productivity and CH4 flux. 13. Future Modifications and Plans This data is in its draft format. 14. Software 14.1 Software Description None given. 14.2 Software Access None given. 15. Data Access 15.1 Contact Information Ms. Beth Nelson BOREAS Data Manager NASA GSFC Greenbelt, MD (301) 286-4005 (301) 286-0239 (fax) beth@ltpmail.gsfc.nasa.gov 15.2 Data Center Identification See 15.1. 15.3 Procedures for Obtaining Data Users may place requests by telephone, electronic mail, or FAX. 15.4 Data Center Status/Plans The TGB-01/TGB-03 fen flux data are available from the EOSDIS ORNL DAAC (Earth Observing System Data and Information System) (Oak Ridge National Laboratory) (Distributed Active Archive Center). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory (865) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 16. Output Products and Availability 16.1 Tape Products None. 16.2 Film products None. 16.3 Other Products Comma separated ASCII files. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation Not applicable. 17.2 Journal Articles and Study Reports Bubier, J.L., T.R. Moore, L. Bellisario, N.T. Comer and P.M. Crill. 1995. Ecological controls on methane emissions from a northern peatland complex in the zone of discontinuous permafrost, Manitoba, Canada. Global Biogeochemical Cycles 9: 455-470. Crill, P. M., K. B. Bartlett, R. C. Harriss, E. Gorham, E. S. Verry, D. I. Sebacher, L. Madzer and W. Sanner, Methane flux from Minnesota peatlands, Global Biogeochemical Cycles, 2, 371-384, 1988. Daubenmire, R. F., Plant communities: a textbook of plant synecology, Harper and Row, New York, N.Y., 1968. Moore, T. R. and N. T. Roulet, A comparison of dynamic and static chambers for methane emission measurements from subarctic fens, Atmosphere-Ocean, 29, 102- 109, 1991. Roulet, N., S. Hardill and N. Comer, Continuous measurement of the depth of water table (inundation) in wetlands with fluctuating surfaces, Hydrological Processes, 5, 399-403, 1991. Roulet, N. T., Surface level and water table fluctuations in a subarctic fen, Arctic and Alpine Research, 23, 303-310, 1991. Sjors, H., On the relation between vegetation and electrolytes in Swedish mire waters, Oikos, 2, 241-258, 1950. Sellers, P., F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P., F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P., F. Hall, K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). Sellers, P., F. Hall, 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 earlyresults from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. Sellers, P., F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue (in press). 17.3 Archive/DBMS Usage Documentation 18. Glossary of Terms 19. List of Acronyms AES - Atmospheric Environment Services, Canada BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System BP - Beaver Pond site, NSA CB - collapse bog subsite, NSA fen complex CF - collapse fen subsite, NSA fen complex CMDL - Climate Monitoring and Diagnostics Laboratory DAAC - Distributed Active Archive Center ECD - Electron Capture Detector EOS - Earth Observing System EOSDIS - EOS Data and Information System FID - Flame Ionization Detector GC - Gas Chromatograph IRGA - Infrared Gas Analyzer GSFC - Goddard Space Flight Center LI-6200 - LI-COR portable photosynthesis system NASA - National Aeronautics and Space Administration NEE - net ecosystem exchange of carbon dioxide NSA - Northern Study Area OBS - Old Black Spruce site, NSA OJP - Old Jack Pine, NSA ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park SSA - Southern Study Area TF - tower fen subsite, NSA fen complex TCD - Thermal Conductivity Detector URL - Uniform Resource Locator YJP - Young Jack Pine site, NSA ZF - Zoltai fen subsite, NSA fen complex 20. Document Information 20.1 Document Revision Date Written: Last Updated: 05-Jun-98 20.2 Document Review Date(s) BORIS Review: 10-Mar-98 Science Review: 20.3 Document 20.4 Citation None given. 20.5 Document Curator 20.6 Document URL Key Words: CH4 methane permafrost predictive model Canada peatland bog fen collapse scar palsa peat plateau carbon trace gas TGB01_TGB03_CH4_FenFlux.doc 06/11/98