BOREAS TGB-09 Above-canopy NMHC at SSA-OBS, SSA-OJP and SSA-OA Sites Summary THE BOREAS TGB-09 team collected data in order to inventory and quantify the anthropogenic and biogenic NMHC’s over the BOREAS study areas. This data set contains concentration and mixing ratio values for several NMHC’s collected at the BOREAS SSA from 27-MAY-1994 to 15-SEP-1994. 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-09 Above-Canopy NMHC at SSA-OBS, SSA-OJP, and SSA-OA Sites 1.2 Data Set Introduction BOReal Ecosystem-Atmosphere Study (BOREAS) Trace Gas Biogeochemistry Team 9 (TGB- 09) measured non-methane hydrocarbon (NMHC) data at the Southern Study Area (SSA)-Old Black Spruce (OBS), Old Jack Pine (OJP), and Old Aspen (OA) sites. 1.3 Objective/Purpose The mission objective was twofold: 1) to provide a quantitative inventory of NMHCs, both anthropogenic and biogenic, at the SSA-OBS, SSA-OJP and SSA-OA tower flux sites; and 2) to provide ambient concentration data for biogenic hydrocarbons suitable for calculating the flux of biogenic hydrocarbons at the tower flux sites using the gradient method. 1.4 Summary of Parameters Concentrations in the parts per trillion by volume (pptv) - parts per billion by volume (ppbv) range are reported for a variety of biogenic and anthropogenic NMHCs. Local sources and transport from distant sources contribute to the NMHCs inventory in the boreal forest region. A quantitative inventory of ambient hydrocarbon concentrations can aid in identification of sources important to the boreal atmosphere. In particular, gradient measurements allow biogenic emissions from the forest itself to be quantified. 1.5 Discussion Each sample was analyzed on two separate Gas Chromatograph (GC) Flame Ionization Detector (FID) systems. In one, the column and temperature program were chosen to optimize quantitation of C2-C6 hydrocarbons. In the other, the column and temperature program were chosen to optimize quantitation of C5-C10 hydrocarbons. Samples collected at the SSA sites were transported to the laboratory in Toronto for analysis. The time between collection and analysis varied greatly over the course of the study. The earliest samples were analyzed within 1 month of collection, whereas some of the latest samples were not analyzed until 6 months after collection. Extensive experience with such samples has demonstrated that these samples are stable over such long periods of time. 1.6 Related Data Sets BOREAS TGB-10 Oxidant Concentration Data over the SSA BOREAS TGB-10 Oxidant Flux Data over the SSA 2. Investigator(s) 2.1 Investigator(s) Name and Title Professor Hiromi Niki (deceased April 1995) 2.2 Title of Investigation Ambient Measurements of Non-Methane Hydrocarbons 2.3 Contact Information Contact 1 --------- Byron Kieser Centre for Atmospheric Chemistry 006A Steacie Science Library York University North York, ON Canada (416) 736-5410 (416) 736-5411 (fax) bnkieser@helios.sci.yorku.ca Contact 2 --------- 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 Estimates of the hydrocarbon flux above the canopy by the gradient method require measurement of the hydrocarbon concentration gradient. To accomplish this, simultaneous samples were collected at two heights above the canopy and analyzed for a range of hydrocarbons. The flux of any particular hydrocarbon (HC) can then be determined by the following relationship. FLUX(HC) = k(z) ? ([HC]" - [HC]') / (z" - z') where ([HC]" - [HC]') is the difference in [HC] between the two heights z" and z'. The eddy diffusivity coefficient k(z) should be obtained from other researchers performing simultaneous measurements at the same sites. Measurements of the hydrocarbon concentrations are made by collecting whole air samples over a 30-minute period in evacuated, electropolished stainless steel canisters that are then transported to the laboratory for analysis. Before being shipped to Saskatchewan for sample collection, the canisters were heated to 80° C and evacuated to 10-6 Torr for 2 hours. 4. Equipment 4.1 Sensor/Instrument Description a. The sample collection system filled two sample canisters simultaneously over 30 minutes. The system consists of: (i) Two electropolished stainless steel sample canisters (Biospherics Research Corp., Oregon, U.S.A.), 3- or 6- liter volume, evacuated, sealed by a Nupro metal bellows valve, and having a Swagelock connection on the inlet. (ii) Two mass flow controllers, Tylan FC-260V, 0 - 500 sccm. (iii) 12V DC 1.5 A KNF Neuberger metal bellows pump UN05 ATI. (iv) Stainless steel tubing and fittings between components. b. The sample analysis system for identification and quantification of hydrocarbons. The system consisted of: (i) Hewlett Packard (HP) 5890II GC-FID with DB-1 100 m x 0.25 mm ID x 0.5 micrometer film column, electronically programmable pressure control inlet, and HP PC-ChemStation v. 1.01 software, primarily for C5-C10 hydrocarbons. (ii) HP 5890II GC-FID with Al2O3/KCl PLOT 50 m x 0.32 mm ID column and HP PC- ChemStation v. 1.01 software, primarily for C2-C6 hydrocarbons. (iii) HP 5890 GC with SPB-5 30 m x 0.25 mm ID x 0.25 micrometer film column, HP 5970 MSD, HP 5970 GC-MS Workstation v. 3.2 software, and in-house constructed cryogenic sample prefocusing system. (iv) Cryogenic sample preconcentration system, one per GC system, constructed in- house. (v) Modified Tekran Cryotherm-100 cryogenic sample prefocusing system, one per GC-FID system. Tekran cryofocusers were modified by replacing all internal nickel tubing with stainless steel tubing. The prefocusing system for the GC-MSD was constructed in-house. 4.1.1 Collection Environment Samples were collected at each of the SSA-OBS and SSA-OJP sites during Intensive Field Campaign (IFC)-1, IFC-2, and IFC-3. Samples were collected at the SSA-OA site during IFC-2 and IFC-3. Samples were collected regardless of the prevailing weather conditions. 4.1.2 Source/Platform a. A portable sampling system mounted on a backpack frame and placed at the base of the tower. Sampling was through Teflon lines mounted on the tower. Full sample canisters were shipped to the laboratory for analysis. b. Benchtop systems in the laboratory at York University as described above. 4.1.3 Source/Platform Mission Objectives The objective of the tower was to provide a place to mount instrumentation for measurements. The objective of the backpack was to allow transport of equipment to measurement sites. The lab benchtop provided an area to use to analyze the samples. 4.1.4 Key Variables Concentration of individual NMHCs in air. Compounds that are measured (not all are included in this data set): ethylene, acetylene, ethane, propene, propane, propyne, isobutane, iso-butene, 1,3-butadiene, n-butane, t-2- butene, 2,2-dimethylpropane, 1-butyne, c-2-butene, 2-methylbutane, 1- pentene, 2-methyl-1-butene, n-pentane, isoprene, t-2-pentene, c-2-pentene, 2-methyl-2-butene, 2,2-dimethyl-butane, 4-methyl-1-pentene, 3-methyl-1- pentene, cyclopentane, 2,3-dimethyl-butane, c-4-methyl-2-pentene, 2- methylpentane, t-4-meth-2-pentene, 3-methylpentane, 2-ethyl-1-butene, 1- hexene, n-hexane, t-2-hexene, c-3-methyl-2-pentene, c-2-hexene, t-3-methyl- 2-pentene, 2,2-dimethylpentane, methylcyclopentane, 2,4-dimethylpentane, 2,2,3-trimethylbutane, benzene, cyclohexane, 2-methylhexane, 2,3- dimethylpentane, 3-methylhexane, 1-heptene, 2,4,4-trimeth-pentan, t-3- heptene, heptane, t-2/c-3-heptene, c-2-heptene, methylcyclohexane, 2,2- dimethylhexane, 2,5-dimethylhexane, 2,4-dimethylhexane, 2,3,4-trimethylpenta, toluene, 2-methylheptane, 4-methylheptane, 3-methylheptane, c-1,3- dimethylcycloh, t-1,4-dimethylcycloh, 2,2,5-trimethylhexane, 1-octene, n- octane, t-2-octene, t-1,3-dimethylcycloh, c-2-octene, c-1,2-dimethylcycloh, ethylbenzene, m-xylene, p-xylene, styrene, o-xylene, 1-nonene, n-nonane, iso-propylbenzene, benzaldehyde, alpha-pinene, 3,6-dimethyloctane, n- propylbenzene, camphene, 3-ethyltoluene, 4-ethyltoluene, 1,3,5- trimethylbenze, sabinene, 2-ethyltoluene, b-pinene, myrcene, 1,2,4- trimethylbenze, t-butylbenzene, n-decane, 2-carene, iso-butylbenzene, sec- butylbenzene, 3-carene, a-terpinene, 1,2,3-trimethylbenze, p-cymene, limonene, indan, 1,3-diethylbenzene, 1,4-diethylbenzene, n-butylbenzene, g- terpinene, 1,2-dieth-benz, undecane Other compounds may be identified at a later date. Contact the investigators for further information. 4.1.5 Principles of Operation a. Sample collection system Whole air samples were simultaneously collected at constant flow rates for 30 minutes (typically) into stainless steel canisters, from two heights on a flux tower during IFC-1, IFC-2, and IFC-3 at each of the SSA-OBS, SSA-OJP, and SSA-OA sites. Air was pumped from the sampling site on the tower through a Teflon line into a sample canister. The mass flow controller held the pumping rate constant as the can filled to a final pressure of about 20 pounds per square inch (psi). Two pumping systems (mounted on the same backpack) with inlets at different points on the tower were used in order to fill two cans simultaneously with air from different heights above the canopy. b. Sample analysis The collected samples were transported to the laboratory for analysis using GC techniques. Permissible injection volumes for capillary GC are below 1 cc (gas). Typical concentrations for the hydrocarbon species being measured are in the range of 10 pptv to 10 ppbv, which, for isoprene as example, gives an analyte range of 0.06 to 60 fg/cc. The constraint on injection volume for capillary GC combined with the low concentrations of analyte requires that the samples be preconcentrated prior to GC analysis. Sample preconcentration is accomplished by passing a known volume of the air sample through a trap filled with fine glass beads cooled to -180° C. Volatile hydrocarbons are retained on the beads. The bulk air constituents (nitrogen and oxygen) are collected in an evacuated reference volume. From the final pressure of the reference volume, the total volume of air that passed through the preconcentration system may be calculated. This volume is used to calculate the mixing ratio of each compound in the original air sample after GC analysis. The sample trapped cryogenically on the glass beads is thermally desorbed into a stream of ultrapure helium and retrapped on the surface of a fine stainless steel capillary cooled to -180° C. This second cryogenic trapping stage "focuses" the sample into a small linear section of tubing. Electrical resistance ballistically heats the cold stainless steel capillary, and the cryofocused sample quickly desorbs into the helium stream and is transferred to the chromatographic column. The volatile components of the sample are carried through the GC column by the mobile phase, the ultrapure helium. Capillary GC columns are typically a long (10-100m) section of fused silica capillary (0.18-0.53 mm inner diameter, I.D.). The inside surface of the column has a thin (0.05-5 m) coating of a stationary phase designed to interact with the components of a mixture passing through the column. For any individual hydrocarbon, the amount of time taken to traverse the length of the column (retention time) is determined by the component's affinity for the stationary phase, which, in turn, is a function of the chemical nature of the component. This differential affinity of various species for the stationary phase makes it possible for the GC column to separate a complex mixture as it travels through the column. Controlled variation of column temperature over the course of the analysis (temperature program) also affects the separation of the compounds, the retention time for each compound, and the total analysis time for the sample. Compounds are identified by their characteristic retention times. Compounds eluting from the end of the column are detected using an FID, in which the column effluent is introduced into a hydrogen-air diffusion flame. An electrical charge applied a potential across the flame collects species formed through radical reactions in the flame and the current is amplified by a sensitive electrometer. The FID displays a linear response to carbon atoms over a large dynamic range. The FID is very sensitive to hydrocarbons, but is insensitive to water or carbon dioxide. In addition to the FID detector, some of the samples are analyzed using a mass selective detector (MSD). The MSD produces mass spectra of the species eluted from the column. The MSD is less sensitive than the FID, but provides a more certain identification of the species eluted by relying not only on the retention time, but also on the mass spectrum of the effluent. The column separates components, they are introduced to a high-energy stream of electrons, and a fraction of the molecules are converted to ions. The ions are electrically accelerated into a quadrupole mass filter and passed to an electron multiplier. The electron multiplier counts the number of ions that strike it. By scanning a range of mass-charge ratios, the MSD can construct a mass spectrum for each compound exiting the column. The pattern and abundance of ions produced are characteristic of the chemical structure of a compound, and thus may be used to identify species eluting from the column. The MSD results are used to qualitatively identify unknown compounds, while the FID results provide quantitative data. Unlike the FID, the MSD is sensitive to water and carbon dioxide. Water and carbon dioxide are present in ambient air in amounts several orders of magnitude larger than any of theNMHCs. Although small amounts will not affect FID operation, typical ambient concentrations do pose chromatographic problems and problems with the MSD operation. Water and carbon dioxide have a detrimental effect on the chromatographic separation of hydrocarbons. Because of its polar nature, water interferes with the interaction between the hydrocarbons and the stationary phase of the column. Water can also clog the glass bead trap, cryo- focuser, or column during the analysis, and may extinguish the FID flame. In the MSD, high water and carbon dioxide signals increase the background signals for other ions such that the detection limit is raised to an unsuitable level. In order to avoid these problems, water and carbon dioxide are removed from the air samples prior to preconcentration. A cold trap (-20 to -60° C) removes water in sufficient amounts to allow chromatographic analysis to proceed without any clogging or FID quenching. A potassium carbonate trap at 80° C removes carbon dioxide. These traps were tested extensively to ensure that the concentrations of the hydrocarbons of interest are not affected. 4.1.6 Sensor/Instrument Measurement Geometry The Teflon sampling tubes are mounted on the main tower at each site. The height of the inlet above the ground, in meters, is given for each sample. Both inlets are above the mean canopy height. 4.1.7 Manufacturer of Sensor/Instrument a. The sampling system was assembled by the investigators. All tubing was chromatographic-grade stainless steel. (i) Stainless steel canisters were manufactured by: Biospherics Research Corp. 1121 N.W. Donelson Street Hillsboro, OR 97124 (503) 690-1077 (ii) Mass flow controllers were manufactured by: Tylan Corporation Torrance, CA 90501 (iii) The metal bellows pump was manufactured by: KNF Neuberger, Inc. Princeton, NJ (609) 799-4350 b. Analysis system (i,ii,iii) GC and GC-MSD was manufactured by: Hewlett-Packard (Canada) 5150 Spectrum Way H80 Mississauga, ON L4W 5G1 (905) 206-4725 (iv) The cryogenic sample preconcentration system was assembled by the investigators. (v) The cryogenic sample prefocusing system for the GC-FIDs was manufactured by: Tekran, Inc. Toronto, ON The cryogenic sample prefocusing system for the GC-MSD was assembled by the investigators 4.2 Calibration a. Sampling system The sampling system flow rate was calibrated using a soap bubble flow meter. b. Hydrocarbon analysis GC-FID systems were calibrated with standard mixtures from Environment Canada, National Center for Atmospheric Research (NCAR), Scott Specialty Gases, as well as standard mixtures prepared in the laboratory (Dr. Daniel Wang, Environment Canada, 351 St. Joseph Blvd., Hull, PQ K1A 0H3; Dr. Eric Apel, NCAR, 1850 Table Mesa Drive, Boulder, CO 80303; Scott Specialty Gases, 6141 Easton Road, Plumsteadville, PA 18949-0310), and checked with secondary standards mixed in the laboratory. Calibration of the GC systems was accomplished using prepared gas mixtures in air of known concentration to determine the characteristic retention time and FID response for each compound in the mixture. Measured FID responses were checked against the expected response based on the number of carbon atoms in each compound, since the FID response is linear over a large range, and is essentially mass responsive to carbon atoms. 4.2.1 Specifications 4.2.1.1 Tolerance a. Sampling system: Constant flow rate of 500 ±50 sccm air at STP. b. Hydrocarbon analysis: Detection limits and precision: NMHC analysis detection limit: 5 pptv NMHC Precision: +/-5pptv for [HC] < 0.1ppbv +/-5% for 0.1ppbv < [HC] < 1.0ppbv +/-1% for [HC] > 1.0ppbv NMHC GC-MSD analysis detection limit: 0.1-0.5 ppbv (depending on compound) Precision: not used for quantitative analysis 4.2.2 Frequency of Calibration a. Sample collection system calibration was checked weekly. b. NMHC analysis system was checked weekly for all components reported using standards from NCAR and/or Environment Canada and/or laboratory- prepared mixtures. 4.2.3 Other Calibration Information For NMHC analysis, the two samples in each pair were run consecutively on the same day by the same operator on the same GC. Before the project began, each operator demonstrated that he could achieve the precision quoted in Section 4.2.1.1 for multiple runs of the same sample. Each day, one sample was repeated by another operator on the same GC to test reproducibility between operators. The concentration of isoprene obtained from the two GCs was compared for each sample. Several samples from each IFC were analyzed more than once to monitor the system performance, as well as track any sample stability problems. 5. Data Acquisition Methods The two outlets of the pumping system were connected to evacuated stainless steel canisters. The inlets of the pumping system were connected to Teflon lines mounted on a tower so that air could be sampled simultaneously from two heights above the forest canopy. The flow rate for the mass flow controllers was set such that each can would fill to a pressure of about 20 psi during 30 minutes of sampling. The cans were sealed by shutting the valve, and the full cans were then shipped to the laboratory for analysis. Approximately 500 - 700 mL (at standard temperature and pressure) of sample was used for GC-FID analysis. The sample handling procedure is described in more detail in Section 4. 6. Observations 6.1 Data Notes None given. 6.2 Field Notes SSA-OBS: The mean canopy height was 9 m. Sampling inlets were placed at 12.4 m and 23.3 m above ground level. A path about 50 m wide was made from the road to the tower. Data taken when the wind was from the direction of the road may be suspect because of the removal of trees to create the path. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage Samples were collected only from the tower at each site. Each sample may be considered as an ambient sample whose spatial coverage could be determined by back-trajectory analysis for the 30-minute sampling period. The North American Datum 1983 (NAD83) coordinates of the measurement sites are: SSA-OBS: 53.98717N, 105.11779W SSA-OJP: 53.91634N, 104.69203W SSA-OA: 53.62889N, 106.19779W 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution The resolution, for gradient calculations, is no better than the footprint of forest considered in flux measurements. As ambient measurements, the spatial resolution is subject to the meteorological conditions at the time the measurements were made. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage Samples were collected at the three SSA tower flux sites during the IFCs from 27- May to 15-Sep-1994. 7.2.2 Temporal Coverage Map Note: Sample refers to a pair of upper- and lower-level samples. SSA-OJP 27-May-1994, 4 samples SSA-OJP 07-Jun to 12-Jun-1994, 33 samples SSA-OJP 27-Jul to 02-Aug-1994, 30 samples SSA-OJP 09-Sep to 11-Sep-1994, 8 samples SSA-OJP 15-Sep-1994, 4 samples SSA-OBS 31-May to 05-Jun-1994, 25 samples SSA-OBS 20-Jul to 24-Jul-1994, 32 samples SSA-OBS 01-Sep to 07-Sep-1994, 32 samples SSA-OA 04-Aug to 08-Aug-1994, 20 samples SSA-OA 12-Sep to 14-Sep-1994, 21 samples 7.2.3 Temporal Resolution On the dates listed in Section 7.2.2., samples were typically collected at 1-hour intervals, usually from late morning to evening. On several occasions, samples were collected over a 24-hour period, when there was no precipitation. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (tgb9nmhc.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (tgb9nmhc.def). 8. Data Organization 8.1 Data Granularity All of the Above-canopy NMHC at SSA-OBS, SSA-OJP and SSA-OA Sites are contained in one dataset. 8.2 Data Format(s) The data 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 (tgb9nmhc.def). 9. Data Manipulations 9.1 Formulae [Sample] = ((sample pk area) x (Response Factor) / (sample vol)) Where: [Sample] is the mixing ratio of the NMHC of interest in the sample. (sample pk area) is the area in area counts of the chromatogram peak that corresponds to NMHC of interest in the sample. Reponse Factor is the FID response in area counts per ppbv of the NMHC of interest per cc of sample. (sample vol) is the volume of sample analyzed in cc. 9.1.1 Derivation Techniques and Algorithms Calculations were performed by HP-ChemStation software. 9.2 Data Processing Sequence 9.2.1 Processing Steps 1. HP-ChemStation integrates each peak in chromatogram. 2. Operator verifies that software chose reasonable baseline and limits for peaks and manually sets baseline and limits if necessary. 3. Peaks are identified by comparison to retention times found using standard mixtures. 4. Operator transfers area count data to spreadsheet program for concentration calculations. 9.2.2 Processing Changes None. 9.3 Calculations Peak areas were converted to concentrations (mixing ratios) by formula in Section 9.1. 9.3.1 Special Corrections/Adjustments Data Below Detection Limit: When the NMHC of interest is not detected by the GC- FID system, it is assigned a concentration of 0.002 ppbv, which is approximately the average between the detection limit of 0.005 ppbv and 0.000 ppbv. Conversion to Greenwich Mean Time (GMT): Time at start of sampling was originally noted in local Saskatchewan time. This was converted to GMT by adding 6 hours. 9.3.2 Calculated Variables None. 9.4 Graphs and Plots None. 10. Errors 10.1 Sources of Error The user is advised to check meteorological data carefully before using these data to calculate fluxes by the gradient method and to know the limitations of this method. Because compound identification is based on retention time, it is possible to misidentify a compound that is present in a real sample but not present in the calibration standard. The temperature programs have been adjusted to achieve good separation for the compounds in the calibration standards, but additional species present in real samples may co-elute. This is unlikely to cause problems for the C2-C6 data, because the calibration standard for light hydrocarbons is comprehensive, but there may be interferences in the C5-C10 data. 10.2 Quality Assessment Laboratory analysis of the air samples was conducted, and the samples were examined for outliers. When an outlier was spotted, the original chromatogram was checked for correct integration and quantification. 10.2.1 Data Validation by Source Time series plots for each hydrocarbon and hydrocarbon distribution plots were analyzed. Samples were collected in evacuated stainless steel canisters and shipped to the laboratory in Toronto, ON, for analysis by GC-FID. Concentrations in the pptv-ppbv range are reported for a variety of biogenic and anthropogenic NMCs. The measurements are sufficiently precise for use in calculating fluxes by the gradient method. They are also valuable as a record of the ambient trace gas concentrations present in the region. 10.2.2 Confidence Level/Accuracy Judgment The investigators are quite confident in the C2-C10 data. Compound identification is made primarily by retention time only. This may lead to improper identifications, particularly for the larger hydrocarbons, such as C10. Users are cautioned that although the identifications are likely correct, they are not guaranteed. 10.2.3 Measurement Error for Parameters Absolute concentrations are considered accurate within 20%, limited primarily by the uncertainty in the concentrations in the calibration standards. Uncertainty in gradients calculated from these concentrations is determined by the precision of the analysis, which is quoted in section 5.2.1.1. 10.2.4 Additional Quality Assessments As data from other investigators become available, these results will be compared with theirs and the data and documentation updated as necessary. 10.2.5 Data Verification by Data Center Data were examined for general consistency and clarity. 11. Notes 11.1 Limitations of the Data None given. 11.2 Known Problems with the Data Three samples in this data set contain unusually high levels of anthropogenic hydrocarbons: 12.4m 02-Jun-94 13:25 12.4m 02-Jun-94 14:35 23.3m 04-Jun-94 12:00. This is not a problem with the GC analysis; values from the two GC-FID systems for C6 hydrocarbons agree well. The high concentrations of light hydrocarbons such as ethane and propane indicate that contamination of the canisters is not a factor; these species are removed very effectively by the cleaning procedure. In fact, 23.3m 04-Jun-94 12:00 was collected in a new canister purchased for this project. The investigators suggest referring to other measurements of trace gas concentrations at these times to determine whether a significant, transient, local anthropogenic source existed. 11.3 Usage Guidance Not all species identified are included in this data set. Researchers interested in specific compounds should contact the investigators directly for further information about the data. 11.4 Other Relevant Information None given. 12. Application of the Data Set These data are intended for use in the study of atmosphere-biosphere interactions, and the atmospheric chemistry of biogenic and anthropogenic hydrocarbons. The data have been used in conjunction with other data collected at the sites by other researchers for the calculation of biogenic hydrocarbon emissions from the various sites. 13. Future Modifications and Plans None given. 14. Software 14.1 Software Description HP 5970 GC-MS Workstation v. 3.2 software HP PC-ChemStation v. 1.01 software 14.2 Software Access Not applicable. 15.1 Contact Information Ms. Beth Nelson 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-09 NMHC data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Activ 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-delimited American Standard Code for Information Interchange (ASCII) text files. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation Sample analysis is performed by standard chromatographic techniques. No knowledge specific to the GC-FIDs used is required in order to assess or interpret the data. Any analytical instrumentation text should give the user sufficient information about GC-FID. 17.2 Journal Articles and Study Reports A comprehensive review of sample analysis and data analysis in the laboratory may be found in the Ph.D. dissertation of Byron Kieser and the Ph.D. dissertation of Bertram Thomas Jobson: Kieser, B. 1997. Measurements of Biogenic Hydrocarbon Emissions from the Boreal Forest. Department of Chemistry, York University. Jobson, B.T. 1994. Seasonal Trends of Non methane Hydrocarbons at a Remote Boreal and High Arctic Site in Canada Department of Chemistry York University. 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 (OPSDOC 94). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPSDOC 96). Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 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 FID - Flame Ionization Detector GC - Gas Chromatograph(y) GMT - Greenwich Mean Time GSFC - Goddard Space Flight Center HP - Hewlett Packard IFC - Intensive Field Campaign MSD - Mass Selective Detector NASA - National Aeronautics and Space Administration NMHC - Non-Methane Hydrocarbons NSA - Northern Study Area OA - Old Aspen OBS - Old Black Spruce OJP - Old Jack Pine ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park ppbv - Parts Per Billion by Volume pptv - Parts Per Trillion by Volume psi - Pounds Per Square Inch SSA - Southern Study Area TGB-09 - Trace Gas Biogeochemistry Team 9 URL - Uniform Resource Locator 20. Document Information 20.1 Document Revision Date Written: 22-Nov-1994 Last updated: 02-Jul-1998 20.2 Document Review Date(s) BORIS Review: 02-Jul-1998 Science Review: 20.3 Document ID 20.4 Citation 20.5 Document Curator 20.6 Document URL Keywords Nonmethane hydrocarbons Carbon flux TGB09_NMHC_DATA.doc 07/07/98