BOREAS TGB-03 CH4 and CO2 Chamber Flux Data over NSA Upland Sites Summary The BOREAS TGB-03 team collected methane and carbon dioxide (CH4, CO2) chamber flux measurements at the NSA Fen site, OBS, YJP, and auxiliary sites along Gillam Road and the 1989 burn site. Gas samples were extracted from chambers and analyzed at the NSA lab facility approximately every 7 days during May to September 1994 and June to October 1996. 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-03 CH4 and CO2 Chamber Flux Data over NSA Upland Sites 1.2 Data Set Introduction Trace Gas biogeochemistry Team 3 (TGB-03) took chamber flux measurements at upland sites in the BOReal Ecosystem Atmosphere Study (BOREAS) Northern Study Area (NSA) from late May to early Sept 1994 and early June to late Oct 1996. 1.3 Objective/Purpose The purpose of these measurements was: 1) To examine the trace gas exchange between the atmosphere and the boreal upland soils. 2) To identify environmental controls on CH4 and CO2 flux 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. 1.4 Summary of Parameters In the 1994 sampling season, CH4 and CO2 chamber flux measurements were taken from 11 sites. These sites were designated as 1989 burn moss, 1989 burn spruce, palsa moss, palsa birch, Gillam aspen, Gillam pine, Gillam spruce, Young Jack Pine (YJP) wet, YJP dry, Old Black spruce (OBS) aspen, OBS spruce. In the 1996 sampling season, CH4 and CO2 chamber fluxes were measured at YJP wet, YJP dry, OBS aspen, OBS spruce, Old Jack Pine (OJP) moss, OJP aspen, and OJP pine (note OJP sites sampled by Patrick Crill in 1994). 1.5 Discussion In 1994, CH4 and CO2 chamber flux measurements were taken at the 11 sites within the NSA to determine the soil surface exchange rate of CH4 and CO2 at these locations. The locations represent both a hydraulic and disturbance gradient. The sampling collars were installed in the spring of 1994 by the McGill researchers (TGB-03), and measurements of CH4 and CO2 flux were made during and between the 1994 and 1996 Intensive Field Campaign (IFCs). 1.6 Related Data Sets Other data sets of interest are: BOREAS TGB-01 NSA CH4 and CO2 Chamber Flux Data BOREAS TGB-01 CH4 Concentration and Flux Data from NSA Tower Sites BOREAS TGB-01/TGB-03 CH4 Chamber Flux Data over the NSA Fen 2. Investigator(s) 2.1 Investigator(s) Name and Title Dr. Tim R. Moore Professor McGill University Kathleen Savage McGill University 2.2 Title of Investigation Environmental Controls on Methane Consumption and Carbon Dioxide Emissions in Upland Boreal Forest Soil 2.3 Contact Information Contact 1 Dr. Tim R. Moore Geography Department McGill University Montreal, Quebec Canada (514) 398-4961 (514) 398-743 (fax)7 moore@felix.geog.mcgill.ca Contact 2 Kathleen Savage Research Assistant Woods Hole Research Center Woods Hole, MA (508) 540-9900 ext. 142 (508) 540-2578 (fax) savage@whrc.org Contact 3 Sara K Conrad Raytheon STX Corporation NASA GSFC Greenbelt, MD (301)286-2624 (301)286-0239 (fax) Sara.Golightly@gsfc.nasa.gov 3. Theory of Measurements Chamber fluxes measure the changes in mixing ratio of trace gases (CH4 and CO2) in a closed headspace over a period of time. This headspace is isolated from the atmosphere; therefore, the exchange of material between the covered soil and the headspace can be quantified. 4. Equipment 4.1 Sensor/Instrument Description The CH4 and CO2 flux measurements were taken 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. CH4 and CO2 were quantified with a Shimadzu 14A Gas Chromatograph (GC) equipped with a flame ionization detector (FID) for CH4 and thermal conductivity Detector (TCD) for CO2. A HayeSepQ column was used, the GC temperature was set at 40 oC, and ultrapure (99.999%) N2 was used as the carrier gas flowing at 30 mL/min. The detectors were operated at 125 oC. 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 (UNH) and designed by Patrick Crill. 4.1.1 Collection Environment The chamber fluxes were collected under ambient environmental conditions. 4.1.2 Source/Platform Ground. 4.1.3 Source/Platform Mission Objectives The ground’s mission objective was to support the collars and chambers. 4.1.4 Key Variables The key variable measured during the sampling period was CH4 and CO2 flux. Soil temperature, moisture, and soil gas profile concentrations were also measured. 4.1.5 Principles of Operation The Shimadzu GC-14A is equipped with a FID and a TCD. The FID is used to detect CH4; the TCD is used to detect CO2. The FID uses 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). 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, MD 21046 (410) 381-1227 4.2 Calibration 4.2.1 Specifications Analyses were conducted with a Shimadzu GC with a FID (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 Canadian Atmospheric Environment Services (AES) certified primary standards acquired by the BOREAS project and a CO2/CH4 standard of Niwot Ridge air prepared by the National Oceanic 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 6,000 mV mL/mg. The FID's maximum sensitivity is 3 x 10-12 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 66 PVC collars were placed along the moisture and disturbance gradients in the NSA and sampled in 1994. CH4 and CO2 were 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 airtight seal. Air samples were obtained from each chamber by inserting a polypropylene syringe into the Tygon tubing equipped with a three-way stopcock and pumping the piston four or five 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 three-way stopcock. Four 10-mL samples were taken at 5-min intervals over a 20-minute period. Samples were returned to a laboratory in Thompson and analyzed for CH4 and CO2 within 4-6 hours of collection. 6. Observations 6.1 Data Notes None given. 6.2 Field Notes None given. 7. Data Description None given. 7.1 Spatial Characteristics 7.1.1 Spatial Coverage Burn Moss: BM: 55.906N, 98.947W Burn Spruce: BS: 55.906N, 98.949W Palsa Moss: PM: 55.902N, 98.418W Old Black Spruce, spruce stand: OBSS: 55.902N, 97.497W Gillam Road Spruce: GS: 55.904N, 97.706W Gillam Road Pine: GP: 55.901N, 97.709W Old Black Spruce, aspen stand: OBSA: 55.906N, 98.5W Gillam Road Aspen: GA: 53.901N, 97.712W Palsa Bog: PB: 55.902N, 98.419W Fen Tower site: FEN: 55.91481N, 98.42072W Old Black Spruce Tower site: OBS: 55.88007N, 98.48139W Old Jack Pine Tower site: OJP: 55.92842N, 98.62396W Young Jack Pine Tower site: YJP: 55.89575N, 98.28706W Young Jack Pine dry site: YJPD: 55.896N, 98.298W Young Jack Pine wet site: YJPW: 55.883N, 98.286W 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution These are point source data made from the enclosed areas. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage CH4 and CO2 flux, temperature, moisture, and profile concentration measurements were made from mid-May through mid-September 1994 and June through October 1996. 7.2.2 Temporal Coverage Map Not available. 7.2.3 Temporal Resolution CH4 and CO2 flux measurements were made once a week at each of the 66 collars throughout the season. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (tgb3cofd.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (tgb3cofd.def). 8. Data Organization 8.1 Data Granularity All of the TGB-03 CH4 and CO2 Chamber Flux Data over NSA Upland Sites are contained in one dataset. 8.2 Data Format(s) The data file contains numerical and character fields of varying length separated by commas. The character fields are enclosed with single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition file (tgb3cofd.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 and CO2 concentrations were calculated from the average of 10 peak areas of known CH4 and CO2 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 and CO2 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 = temperature in Kelvins 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 HP ChemStation reports from the GC. They were entered into spreadsheets, and the concentrations were calculated using the formulas in Section 9.1. The spreadsheets then automatically calculated 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 and 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 two of the samples as long as the correlation coefficient was still significant at p < 0.05. 9.2.2 Processing Changes None given. 9.3 Calculations Not applicable. 9.3.2 Calculated Variables Refer to Section 9.1.1. 9.4 Graphs and Plots None given. 10. Errors 10.1 Sources of Error Field sampling error could 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 allowing them to come open during transport will cause dilution from ambient air. (Errors such as these would have been written down in the lab/field books, and these data have been edited out.) The analytical precision of the GCs is: 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 GCs is: 0.2% for CH4. 10.2.4 Additional Quality Assessments None given. 10.2.5 Data Verification by Data Center Data were examined for general consistency and clarity. 11. Notes 11.1 Limitations of the Data The analytical precision of the GCs is: 0.2% for CH4. 11.2 Known Problems with the Data None given. 11.3 Usage Guidance None given. 11.4 Other Relevant Information None given. 12. Application of the Data Set The chamber flux data can be used in connection with the tower flux data to determine the CH4 and CO2 exchange between the atmosphere and the boreal soils. 13. Future Modifications and Plans None given. 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) Elizabeth.Nelson@gsfc.nasa.gov 15.2 Data Center Identification See Section 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-03 upland chamber flux data are available from the Earth Observing System Data and Information System (EOSDIS) 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 16. Output Products and Availability 16.1 Tape Products None. 16.2 Film Products None. 16.3 Other Products Comma-separated American Standard Code for Information Interchange (ASCII) files. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation None given. 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. 1988. Methane flux from Minnesota peatlands, Global Biogeochemical Cycles, 2, 371-384. Daubenmire, R.F. 1968. Plant communities: a textbook of plant synecology. Harper and Row, New York, N.Y. Moore, T.R. and N.T. Roulet. 1991. A comparison of dynamic and static chambers for methane emission measurements from subarctic fens. Atmosphere-Ocean, 29, 102-109. Roulet, N., S. Hardill and N. Comer. 1991. Continuous measurement of the depth of water table (inundation) in wetlands with fluctuating surfaces. Hydrological Processes, 5, 399-403. Roulet, N.T. 1991. Surface level and water table fluctuations in a subarctic fen. Arctic and Alpine Research, 23, 303-310. Sjors, H. 1950. On the relation between vegetation and electrolytes in Swedish mire waters. Oikos, 2, 241-258. Sellers, P.and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P.and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P.and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue. Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and earlyresults from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. 17.3 Archive/DBMS Usage Documentation None given. 18. Glossary of Terms None given. 19. List of Acronyms AES - Atmospheric Environment Services, Canada ASCII - American Standard code for Information Interchange BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System 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 HP - Hewlett Packard IFC - Intensive Field Campaign IRGA - Infrared Gas Analyzer GSFC - Goddard Space Flight Center NASA - National Aeronautics and Space Administration NOAA - National Oceanic and Atmospheric Administration NSA - Northern Study Area OBS - Old Black Spruce OJP - Old Jack Pine ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park SSA - Southern Study Area TCD - Thermal Conductivity Detector TGB-03 - Trace Gas Biogeochemistry Team 3 UNH - University of New Hampshire URL - Uniform Resource Locator YJP - Young Jack Pine 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 The TGB-03 upland flux data were collected by Kathleen Savage and Tim Moore (McGill University). Their efforts in making these data are available are greatly appreciated. 20.5 Document Curator 20.6 Document URL Keywords -------- CH4, CO2, methane, carbon dioxide, trace gas TGB03_CO2_CH4_UplndFlux.doc 06/11/98