BOREAS TGB-05 CO2, CH4, and CO Chamber Flux Data over the NSA Summary The BOREAS TGB-05 team collected a variety of trace gas concentration and flux measurements at several NSA sites. This data set contains carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) chamber flux measurements conducted in 1994 at upland forest sites that experienced stand-replacement fires. These measurements were acquired to understand the impact of fires on soil biogeochemistry and related changes in trace gas exchange in boreal forest soils. Relevant ancillary data, including data concerning the soil temperature, solar irradiance, and information from nearby unburned control sites, are included to provide a basis for modeling the regional impacts of fire and climate changes on trace gas biogeochemistry. 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-05 CO2, CH4, and CO Chamber Flux Data over the NSA 1.2 Data Set Introduction These measurements are required to understand the impact of fires on soil biogeochemistry and related changes in trace gas exchange in boreal forest soils. Relevant ancillary data, including data concerning the soil temperature and solar irradiance, are included to provide a basis for modeling the regional impacts of fire and climate changes on trace gas biogeochemistry. 1.3 Objective/Purpose The objective of this study is to examine the effects of fire on soil-atmosphere fluxes of trace carbon gases (CO2, CH4, CO) in upland black spruce and jack pine ecosystems located within the BOReal Ecosystem-Atmosphere Study (BOREAS) Northern Study Area (NSA) near Thompson, Manitoba. 1.4 Summary of Parameters This data set contains measurements of ambient carbon dioxide (CO2), methane CH4 and CO concentrations; CO2, CH4, and CO fluxes; ambient and soil temperatures; and solar irradiance. 1.5 Discussion The soil-atmosphere exchange of CO2 is an important component of the carbon budget of the boreal forest biome. Soil-atmosphere exchange of CH4 and CO in the boreal biome has major effects on the atmospheric content of these radiatively and chemically important trace gases. Closed chamber techniques with gas chromatography were used to determine the soil surface flux of CO2, CH4, and CO at five BOREAS auxiliary sites in the NSA that were exposed to intense stand-replacement fires during the 7-year period prior to 1994. Flux data were also obtained at nearby control sites. Relevant ancillary data were simultaneously obtained at the sites. The experiments were conducted from the beginning of June through the end of August 1995. The results from this study indicate that upland soils in burned boreal forests are generally net sources of both CO2 and CO, but net sinks of atmospheric CH4. Soil temperatures in these burned sites were generally higher than those observed in nearby unburned controls. Soil respiration includes both root respiration and decomposition of soil organic matter (SOM). Despite the loss of root respiration in the burn sites, soil respiration was nearly the same in the burn sites as in unburned controls. This indicates that enhancement of SOM decomposition by the warming of the soil offset the reduction in root respiration. In sites exposed to the most intense fires, however, where surface organic matter was considerably reduced and converted to charcoal by fire, soil respiration was significantly reduced compared to other sites that were investigated. CH4 sinks were generally greater in the well-drained jack pine stands than in black spruce stands. CO fluxes are affected by thermal and photochemical production at the soil surface and by microbial consumption deeper in the soil. Thus, CO fluxes in the open burn sites were positive during daylight, whereas the fluxes were negative in the unburned forest soils. 1.6 Related Data Sets BOREAS TGB-01 Soil CH4 and CO2 Profile Data over NSA Tower Sites BOREAS TGB-01 CH4 and CO2 Chamber Flux Data from NSA Tower Sites BOREAS TGB-01 CH4 Concentration and Flux Data from NSA Tower Sites BOREAS TGB-01 SF6 Chamber Flux Data over NSA Jack Pine Sites BOREAS TGB-03 CO2 and CH4 Chamber Flux Data over the NSA 2. Investigator(s) 2.1 Investigator(s) Name and Title Dr. Richard G. Zepp and Dr. Roger A. Burke U.S. EPA, Athens, GA 2.2 Title of Investigation Trace Gas Exchange in the Boreal Forest Biome: Effects of Fire and Beaver Activity 2.3 Contact Information Contact 1 --------- Dr. Richard G. Zepp U.S. Environmental Protection Agency Athens, GA (706) 355-8117 zepp.richard@epamail.epa.gov Contact 2 --------- Sara Golightley Raytheon STX Corporation NASA Goddard Space Flight Center Greenbelt, MD (301) 286-2624 Sara.Golightly@gsfc.nasa.gov 3. Theory of Measurements The CO2, CH4, and CO fluxes at the surface of the soil are important components of the carbon budget of the boreal forest. Stand-replacement fires may affect the soil-surface fluxes of these gases. Fire removes the canopy and part of the moss, lichen, and shrub cover, thus altering soil temperature, moisture, and nutrient composition. Models of trace gas biogeochemistry in the boreal forest, such as CENTURY, require field measurements of these fluxes in order to calibrate the models and test their predicted fluxes. In order to understand and quantify the carbon gas exchange in these systems, it is necessary to measure their exchange under a variety of conditions in unburned plots and burned plots of various postburn ages. In particular, CO exchange from the forest ecosystem floor is a poorly understood process that may exhibit a significant effect on the ambient CO levels. The forest floor may act as both a source and sink for CO. Sink activity is believed to be the result of consumption of CO by microbial activity, while production is primarily the result of thermal and photochemical decomposition of living and dead organic matter. The net exchange from the forest floor will therefore be determined by the relative source and sink strengths of these processes. Some parameters that are believed to be important in CO exchange are temperature, moisture content, soil nutrient levels, SOM content, and light intensity. 4. Equipment 4.1 Sensor/Instrument Description CH4 and CO2 were measured using a Karl Gas Chromatograph (GC) equipped with flame-ionization detector (FID) (for CH4) and thermal conductivity detector (TCD) (for CO2). CO was measured using a Trace Analytical (Menlo Park, CA) RGA- 3 GC. This instrument isolates CO, and reacts with HgO, producing Hg vapor. The Hg vapor is detected by atomic absorbance. Samples are injected through an injection loop (0.5 or 1mL). Aluminum chamber bases (0.215-m inner diameter [i.d.]) were used for isolating a section of the forest floor. The chambers were anchored with three or four spikes that were 0.20 m in length. The chambers were also equipped with a cylindrical skirt to prevent lateral diffusion of gases. Three skirt sizes were used depending on the ecosystem type: 5 cm, 10 cm, and 20 cm. The opening of the base had a trough filled with water to provide support and seal the chamber top. Light measurements were made with an International Light IL1700 radiometer using probes for various light regions (SED 623 for visible, SED 240 for ultraviolet [UV]-A, and SED 033 for UV-B). Soil temperature was measured with a portable temperature probe (Cole-Palmer thermistor thermometer L-08110-20). Soil water content was measured using a 1502B Time Domain Reflectometer (TDR) [Topp et al., 1980]. 4.1.1 Collection Environment Measurements were made at open sites that had experienced stand-replacement fires within the prior 7 years or at nearby shaded control forest sites that had not burned for at least 70 years. The soil temperatures and solar irradiance were typically much higher at the burned sites than at the control sites. Data were collected under a variety of ambient temperatures ranging from near 0 degrees C to near 28 degrees C. 4.1.2 Source/Platform All measurements were made on the ground 4.1.3 Source/Platform Mission Objectives The mission objective was to measure soil surface CO2, CH4, and CO fluxes and relevant ancillary data in fire scars and nearby controls. 4.1.4 Key Variables CO2, CH4, and CO flux; soil temperature; soil moisture content; and light intensity (total, UV-A, and UV-B). 4.1.5 Principles of Operation The chamber assays for CO, CO2, and CH4 followed the methods established by Hutchinson and Livingston [1993]. Analysis of CH4 [Crill, 1991] was conducted with 0.5% precision. 4.1.6 Sensor/Instrument Measurement Geometry Not applicable. 4.1.7 Manufacturer of Sensor/Instrument RGA-3 Chromatograph Trace Analytical 3517-A Edison Way Menlo Park, CA 94025 IL-1700 Radiometer International Light, Inc. 17 Graf Road Newburyport, MA 01950 Temperature Probe Cole-Palmer Instrument Company 7425 North Oak Park Avenue Niles, IL 60714 TDR Tektronix, Inc. Beaverton, OR 4.2 Calibration 4.2.1 Specifications Instruments were configured and maintained according to manufacturers' specifications noted in the instruction manuals and were calibrated routinely according to standards. 4.2.1.1 Tolerance The precision of fluxes, for the trace gas measurements, computed from three replicates, is expected to be 15% for CO2 and CH4, and 5-10% for CO. The precision is judged by the standard deviation of the three measurements. 4.2.2 Frequency of Calibration Calibration was performed immediately before measuring each day's samples. Correlation coefficients of 0.99 or better were achieved in all cases. A secondary standard of near atmospheric CO2, CH4, or CO concentration was injected periodically during analysis to ensure that no instrumental drift occurred. 4.2.3 Other Calibration Information CH4 and CO2 concentrations were calculated by comparing sample peak areas obtained with a Shimadzu CR501 dual channel integrator to those resulting from repeated analysis of two CH4 standards and two CO2 standards. The CH4 standards contained 0.90-ppm and 2.05-ppm CH4, and the CO2 standards contained 356.1-ppm and 397.4-ppm CO2. The standard gases were supplied by the BOREAS project and calibrated by the Atmospheric Environment Service (AES) of Canada. Based on 10 to 15 daily measurements of these standards, the precision of analysis (standard deviation divided by the mean value expressed in percentage) was 0.7 ± 0.3% for CH4 and 1.7 ± 0.4% for CO2. For CO calibration, a standard curve was generated each day by injecting calibrated volumes of a 9.5 ± 0.14-ppm CO primary standard (National Institute of Standards and Technology, Gaithersburg, MD). 5. Data Acquisition Methods A static chamber technique [such as that described by Whalen and Reeburgh, 1988] was used to estimate soil/atmosphere CH4 and CO2 exchange. The chamber consists of a permanently deployed circular aluminum collar, with a water seal and skirt, and an opaque lid. The collars were ~10, 25, or 30 cm deep in areas with significant moss, lichen, or burned vegetation cover, and ~5 cm deep in areas in which the vegetation had burned to the mineral layer. The lid is constructed of aluminum and is equipped with a septum for syringe sampling and a small hole to equalize pressure. The total enclosed area is 0.036 m2, and the enclosed volume is about 8.7 liters. CH4 and CO2 flux samples were collected at 5-minute intervals over the course of 20 minutes in 60-mL polypropylene syringes with siliconized polypropylene plungers and nylon three-way stopcocks. Syringes were stored in the dark at ambient temperature until analysis. Concentration determinations were made using a Carle AGC GC equipped with a TCD and a FID. Gas samples were introduced to the GC via a 10-port gas sampling valve plumbed for the simultaneous filling of two sample loops and then injection into two columns. Separation of CH4 and CO2 was accomplished with 1/8-inch outer diameter (o.d.) stainless steel Hayesep-D (3 m for the FID side and 2 m for the TCD side) analytical columns. Soil-atmosphere CO exchange was measured using transparent, static soil chambers. These chambers consisted of two parts: a semipermanent base installed into the ground and a removable glass cover that isolated the atmosphere immediately above the base. The aluminum chamber bases consisted of an open- ended, 0.215-m i.d. cylinder (the skirt). The bottom edge of the skirt was beveled to aid insertion into the soil. Skirt lengths were either 0.5 or 0.10 m, depending upon the thickness of the organic layer above the mineral soil. A concentric trough (~30 cm i.d. and 4 cm deep) was welded to the top of the chamber. This trough, when filled with water, provided an airtight seal with the top. Three or four 0.5-cm-o.d. x 10-cm-long aluminum spikes were attached symmetrically around the circumference of the skirt to provide a secure installation. The glass chamber tops were Kimax™ (Kimble, Vineland, NJ) borosilicate jars (25 cm deep, ~24 cm i.d., volume ~12 liters). These jars were transparent to visible (400-700 nm) and UV-A (315-400 nm) light, but filtered out a part of UV-B (280-315 nm) radiation. Two 1/4-inch holes were drilled in the side of each glass jar with a 90-degree radial displacement and ~15 cm vertical displacement between each hole. These holes were used as sampling and vent ports. The holes were plugged with small corks, and needles were inserted through the corks. The vent consisted of a 1inch-long, 22-gauge needle, and the sampling port consisted of a 4- to 6-inch-long, 18-gauge needle. Both needles were left open to the atmosphere during sampling, thereby preventing pressure differentials during experiments. Soil-atmosphere CO exchange was measured in the following manner. First, the trough of the chamber base was filled with enough water to ensure an airtight seal with the chamber top. Then, the top was quickly but gently placed in the trough and a gas sample of ~20 mL was removed from the chamber. Additional samples were collected (usually at 7-minute intervals) for a total of at least four samples. For each sample, the syringe was connected to the sampling needle and pumped three times to ensure a well-mixed chamber. Approximately 20 mL of sample was collected, and the syringe stopcock was closed. The back of the syringe barrel was sealed with a minimum amount of distilled water and stored in a plastic ziplock bag on ice until analysis. The all-glass syringes (Popper & Sons, New Hyde Park, NY) were fitted with gas-tight Teflon™ stopcocks (Alltech Associates, Deerfield, IL) and encased in black heat-shrink tubing to keep their contents dark. Sampling was conducted between the hours of 1000 and 1500 local time with the exception of two diurnal studies. Air and soil temperatures (at a depth of 10 cm for CO2 and CH4; 1.0 cm for CO) were measured with a thermocouple probe. Volumetric soil moisture content was measured with a TDR as described by Topp et al. [1984]. Total solar irradiance was measured during the CO flux measurements with the light probe placed close to the environmental chamber. 6. Observations 6.1 Data Notes None given. 6.2 Field Notes Date Location Activity July 19 Arrive Thompson July 20 Lab Set up laboratory July 21 Gillam Road: 94GR, CGR CH4, CO2, CO fluxes July 22 Gillam Road: 92GR, 87GR CH4, CO2, CO fluxes July 23 Leaf Rapids Road: 89JP, CJP CH4, CO2, CO fluxes July 24 Leaf Rapids Road: 89FR, CFR CH4, CO2, CO fluxes July 25 Gillam Road: 94GR CH4, CO2, CO fluxes; process studies July 26 Gillam Road: 94GR, 87GR CH4, CO2, CO fluxes July 27 Gillam Road: CGR, 92GR CH4, CO2, CO fluxes July 28 Gillam Road: CGR, 92GR CH4, CO2, CO fluxes; process studies July 29 Tower Beaver Pond CO flux from pond July 30 Off July 31 Off Aug 1 Gillam Road: 94GR, 92GR CH4, CO2, CO fluxes Aug 2 Gillam Road: CGR, 87GR CH4, CO2, CO fluxes Aug 3 Leaf Rapids Rd: 89JP, CJP CH4, CO2, CO fluxes Aug 4 Gillam Road: 92GR CH4, CO2, CO fluxes; diurnal Aug 5 Gillam Road: 92GR CH4, CO2, CO fluxes; diurnal continued Aug 6 Gillam Road: CGR, 87GR CH4, CO2, CO fluxes Aug 7 Gillam Road: 94GR, 92GR CH4, CO2, CO fluxes Aug 8 Lab Shut down equipment; ship soil samples Aug 14 Arrive Thompson Aug 15 Lab Set up lab Aug 16 Gillam Road: CGR, 94GR CH4, CO2, CO fluxes 94GR #6 dug up by animal;. re-install in another location about 10 ft toward Thompson Aug 17 Gillam Road: 92GR, 87GR CH4, CO2, CO fluxes Aug 18 Gillam Road: CGR CH4, CO2, CO fluxes; diurnal Aug 19 Gillam Road: CGR CH4, CO2, CO fluxes; diurnal continued Aug 20 Off Aug 21 Leaf Rapids Road: 89FR, CFR CH4, CO2, CO fluxes Aug 22 Leaf Rapids Road: 89JP, CJP CH4, CO2, CO fluxes Four chamber bases missing from 89 Jack Pine site - presumed stolen; remove remaining bases to prevent additional theft and remove some chambers from CJP site for placement in new control site on Gillam Road Aug 23 Gillam Road: CGR, 92GR CH4, CO2, CO fluxes Aug 24 Gillam Road: 87GR, 94GR CH4, CO2, CO fluxes Aug 25 Gillam Road: NGRC, CGR, 87GR CH4, CO2, CO fluxes; SF6 at 87GR Place three chamber bases in New Gillam Road Control (two medium skirt, one deep skirt) Aug 26 Gillam Road: CGR, 92GR, 87GR Simul. rain event at CGR, 92GR, 87GR, 94GR, NCGR 94GR; CH4, CO2, CO fluxes at NCGR Aug 27 Off Aug 28 Gillam Road: CGR, 92GR CH4, CO2, CO fluxes Aug 29 Gillam Road: 87GR, 94GR CH4, CO2, CO fluxes Aug 30 Gillam Road: 92GR, 94GR, 87GR SF6 diffusion studies Aug 31 Lab; Leaf Rapids Road: 89FR, CFR SF6 analysis; SF6 diffusion and CH4/CO2 at 89FR and CFR Sept 1 Gillam Road: 92GR, 94GR SF6 diffusion studies Sept 2 Lab Pack and ship equipment Sept 2 Leave Thompson 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage Measurements were performed on upland black spruce (Picea mariana) and jack pine (Pinus banksiana) forest sites in the vicinity of the BOREAS NSA, which is located near Thompson, Manitoba (55¤91' N, 98¤42' W). Four black spruce sites, three burned and one control, were selected about 100 km northeast of Thompson, Manitoba. The sites were located at 56¤09' N, 96¤44' W; 56¤08' N, 96¤42' W. All four black spruce sites, which were located within 5 km of each other, were exposed to very similar climatic conditions. The jack pine burn site was located in a large burn site (115,643 ha; summer 1989) on Hwy 391 near Leaf Rapids, Manitoba, 140 km west-northwest of Thompson, Manitoba. A jack pine stand located 133 km west-northwest of Thompson, unburned for at least 80 years, served as the control for the jack pine burn site. At each site, the environmental chambers were used to measure fluxes within an area that was approximately 10,000 m2. 7.1.2 Spatial Coverage Map A map showing site locations is included. 7.1.3 Spatial Resolution The environmental chambers used to measure soil fluxes of CO2, CO, and CH4 covered an area about 0.036 m2. Flux measurements for CO2, CO, and CH4 were at six locations within the site. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage The environmental chambers were used to measure soil surface fluxes between June and September 1994. Data were obtained during Intensive Field Campaign (IFC)- 1, IFC-2, August 1994, and the first week of IFC-3. 7.2.2 Temporal Coverage Map Not available. 7.2.3 Temporal Resolution Individual flux measurements generally were made over a period of 20 to 30 minutes. Flux experiments were routinely conducted between the hours of 10:00 and 1600. local time with selected diurnal studies during August 1994 conducted throughout the day and night. The flux and ancillary data at a given black spruce site were obtained with a sampling frequency of 2-3 days during the periods noted in Section 7.2.1. Data at the jack pine sites were obtained on a weekly basis. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (tgb5cflx.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (tgb5cflx.def). 8. Data Organization 8.1 Data Granularity All of the CO2, CH4 and CO Chamber Flux Data over the NSA 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 a single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition file (tgb5cflx.def). 9. Data Manipulations 9.1 Formulae 9.1.1 Derivation Techniques and Algorithms None. 9.2 Data Processing Sequence 9.2.1 Processing Steps Gas samples were collected from the environmental chambers at the field sites, transferred to the laboratory, and analyzed by gas chromatography. The fluxes were then calculated from measured concentrations of the gases vs. time. 9.2.2 Processing Changes None given. 9.3 Calculations 9.3.1 Special Corrections/Adjustments For each chamber experiment, the concentration of CO within the chamber was plotted as a function of time after sealing the chamber top over the base. These plots showed three different patterns: (1) linear changes with time, (2) first-order decay with time, and (3) initial linear increase followed by a diminished rate of increase, often yielding a steady state. Concentration vs. time plots were initially plotted to determine the curve shape, and the data analysis was determined based on curve shape. Data were analyzed by performing linear regression (slope = CO exchange rate), by performing log-linear regression (slope = first-order rate constant), or by determining the initial slope. 9.3.2 Calculated Variables Fluxes of CO2 and CH4 were calculated by linear regression of the measured concentrations of samples (typically five) collected during each chamber deployment. CO fluxes were calculated as described in Section 9.3.1. 9.4 Graphs and Plots Data were plotted using Lotus Freelance, Lotus 123, and Quattro Pro. 10. Errors 10.1 Sources of Error A few flux measurements were rejected because of various problems such as loss of one or more time points, contaminated or leaky syringes, GC problems, or disturbance of the site during sampling. These problems usually became apparent when either: (1) the initial concentration was not close to the ambient concentration, or (2) the correlation coefficient of the linear regression was not significant at the 90% confidence level (r2 = 0.810 for n = 4; r2 = 0.648 for n = 5). 10.2 Quality Assessment Based on the actual performance of the flux measurement system during this study, the minimum detectable flux of CH4 is estimated to be about 0.3 mg CH4-C m-2 d-1, and the minimum detectable flux of CO2 to be 0.1 g CO2-C m-2 d-1. 10.2.1 Data Validation by Source Calibrations and instrumentation ranges were checked, and data were checked for values that were not in expected ranges. 10.2.2 Confidence Level/Accuracy Judgment For all of the CO2 and CH4 data analyzed with regressions, data sets were rejected if the correlation coefficient of the linear regression was not significant at the 90% confidence level (r2 = 0.810 for n = 4; r2 = 0.648 for n = 5). For CO measurements that exhibited decreasing CO concentrations vs. time, the data sets were rejected if the correlation coefficient of the linear regression of log concentration vs. time was not significant at the 90% confidence level. 10.2.3 Measurement Error for Parameters Typically, replicate measurements of the same gas sample are within 10% RSD for CO2, CH4, and CO. 10.2.4 Additional Quality Assessments Multiple comparison procedures were performed with the software package SigmaStat (Jandel Scientific, San Rafael, CA) to test for statistically significant differences in gas fluxes and volumetric water content among sets of samples grouped by site or by date within a given site. Each data group was tested for normality (Kolmogorov-Smirnov test) and equal variance (Levene median test) with the SigmaStat package. For comparisons of data groups with normal distributions and equal variances, a One Way Analysis of Variance (ANOVA) was performed to test for differences in mean values of the different groups. If significant differences in the means were found, then a Student-Newman-Keuls (SNK) All Pairwise Multiple Comparisons Procedure was performed to identify specific differences between groups. For comparisons of data groups in which normality and/or equal variance conditions were not met, a Kruskal-Wallis ANOVA on ranks was performed. If the differences in the median values among these groups were found to be significant, then specific differences between groups were tested for by the DunnĚs Method of All Pairwise Multiple Comparisons. Mean ranks were calculated from the results of the ranking procedures associated with the nonparametric tests and are presented to indicate trends in the various parameters. Probability and significance levels were set to 0.05 in the SigmaStat package unless otherwise specified. Simple and multiple linear regression procedures were also performed with the SigmaStat package. Zar [1984] and Glanz and Slinker [1990] give details of the statistical tests performed. 10.2.5 Data Verification by Data Center Data were examined for general consistency and clarity. 11. Notes 11.1 Limitations of the Data There are no known limitations. However, the user should be aware that there are few other data sets available on soil trace gas fluxes in sites that have been recently burned. Therefore, there is no way at this point to judge the representativeness of this data set. 11.2 Known Problems with the Data None. 11.3 Usage Guidance None given. 11.4 Other Relevant Information The procedures and data obtained in this study are monitored by several mechanisms: a) Formal methods of comparisons. Several comparisons have been made under field and laboratory conditions that have substantiated that the instruments used in this study provide reliable measurements of trace gases. b) Informal comparisons among investigators. Comparisons of the data obtained in this study at unburned control sites with flux data obtained using environmental chambers or towers at other BOREAS NSA sites indicate that these fluxes are in the same range as those observed elsewhere in this region. This favorable comparison suggests that these results are representative of this region. c) Review in the scientific literature. These and other BOREAS results will be published in a timely fashion in a Special Issue of the Journal of Geophysical Research so that they will be available to the international scientific community. In these publications, the methods must be justified to peer referees. These justifications are based on other published methods and tests, which are described in previous papers. 12. Application of the Data Set None given. 13. Future Modifications and Plans None. 14. Software 14.1 Software Description These results are being used to improve the CENTURY soils model so that it can be used to evaluate carbon storage and trace gas fluxes in boreal forest soils. 14.2 Software Access The SigmaStat, Lotus, and other commercial software packages are available from their specific commercial developers. The CENTURY software will be available from Dr. Dennis Ojima and Dr. William Parton, NREL, Colorado State University, Ft. Collins, CO. The data also likely will be used to improve and test other models that simulate the biosphere- atmosphere exchange of trace gases. 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 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 These 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 Tabular American Standard Code for Information Interchange (ASCII) files. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation None. 17.2 Journal Articles and Study Reports Burke, R.A., R.G. Zepp, M.A. Tarr, W.L. Miller, and B.J. Stocks. 1998. Effect of fire on soil-atmosphere exchange of methane and carbon dioxide in a Canadian Boreal Forest. J.Geophys. Res. (accepted). Crill, P.M. 1991. Seasonal patterns of methane uptake and carbon dioxide release by a temperate woodland soil. Global Biogeochemical Cycles 5: 319-334. Glanz, S.A. and B.K. Slinker. 1990. Primer of Applied Regression and Analysis of Variance. McGraw-Hill, New York, 777 pp. Hutchinson, G.L., and G.P. Livingston. 1993. Use of chamber systems to measure trace gas fluxes, in Agricultural Ecosystem Effects on Trace Gases and Global Climate Change. ASA Special Publication No. 55. American Society of Agronomy, Madison, WI, pp. 63-78. 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. Versi on 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P.and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue (in press). Whalen, S.C., and W.S. Reeburgh. 1988. A methane flux time series for tundra environments. Global Biogeochem. Cycles, 2, 399-409. 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 early results from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. Topp, G.C., J.L. Davis, W.G. Bailey, and W.D. Zebchuk. 1984. The measurement of soil water content using a portable TDR hand probe. Can. J. Soil Sci., 313-321. Zar, J.H. Biostatistical Analysis, 2nd Ed. Prentice-Hall, Englewood Cliffs, NJ, 718 pp. Zepp, R.G., W.L. Miller, M.A. Tarr, R.A. Burke, and B.J. Stocks. 1998. Soil- atmosphere fluxes of carbon monoxide during early stages of post-fire succession in upland Canadian boreal forests. J. Geophys. Res. (accepted). 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None given. 19. List of Acronyms AES - Atmospheric Environment Services ANOVA - One Way Analysis of Variance ASCII - American Standard Code for Information Interchange BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System CGR - Certified by Group CPI - Checked by PI CPI-??? - CPI but questionable DAAC - Distributed Active Archive Center EOS - Earth Observing System EOSDIS - EOS Data and Information System FID - Flame Ionization Detector GC - Gas Chromatograph GMT - Greenwich Mean Time GSFC - Goddard Space Flight Center IFC - Intensive Field Campaign NASA - National Aeronautics and Space Administration URL - Uniform Resource Locator PANP - Prince Albert Natinoal Park PI - Principal Investigator PRE - Preliminary ORNL - Oak Ridge National Laboratory SNK - Student-Newman-Keuls SOM - Soil Organic Matter SSA - Southern Study Area TCD - Thermal conductivity Detector TDR - Time Domin Reflectometer TGB - Trace Gas Biogeochemistry UV - Ultraviolet 20. Document Information 20.1 Document Revision Date Written: 04-Jun-1997 Last updated: 20-Jul-1998 20.2 Document Review Date(s) BORIS Review: 06-Oct-1997 Science Review: 20.3 Document ID 20.4 Citation 20.5 Document Curator 20.6 Document URL Keywords Methane Carbon Dioxide Carbon Monoxide TGB05_C_Flux.doc Page 1 of 1 05/26/98