BOREAS TF-04 CO2 and CH4 Chamber Flux Data from the SSA Summary: The BOREAS TF-04 team measured fluxes of carbon dioxide (CO2) and methane (CH4) across the soil-air interface in four ages of jack pine forest at the Southern Study Area of the Boreal Ecosystem Atmosphere Study (BOREAS) during August 1993 to March 1995. Gross and net flux of CO2 and flux of CH4 between soil and air are presented for 24 chamber sites in mature jack pine forest, 20-year old, 4- year old, and clear cut areas. 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 TF-04 CO2 and CH4 Chamber Flux Data from the SSA 1.2 Data Set Introduction Data presented in this document were collected at the Old Jack Pine and Young Jack Pine tower flux sites and nearby clear cut areas at the SSA. The BOREAS TF- 04 team measured fluxes of carbon dioxide (CO2) and methane (CH4) across the soil-air interface in four ages of jack pine forest at the Southern Study Area of the BOReal Ecosystem Atmosphere Study (BOREAS) during August 1993 to March 1995. Gross and net flux of CO2 and flux of CH4 between soil and air are presented for 24 chamber sites in mature jack pine forest, 20-year old and 4 year old stands and a clear cut area. The data are stored in tabular ASCII files. 1.3 Objective/Purpose This study presents data relevant to understanding the transfer and storage of carbon among soil, the unsaturated zone, ground cover vegetation, and understory air in jack pine forest at the SSA. The data were collected continuously from May through September 1994 and during March 1995. 1.4 Summary of Parameters The primary focus is on the net fluxes of CO2 and CH4 measured. 1.5 Discussion Jack pine woodlands are an important component of the boreal forest, covering more that 2x1012 m2 of predominantly well-drained uplands in northern North America. As part of BOREAS, our study objectives were (1) to compare soil respiration at an undisturbed 65- to 90-year-old mature jack pine-lichen woodland with soil respiration at a formerly continuous portion of the stand that was clear-cut harvested during the previous winter, and (2) to identify and quantify the sources of CO2 and CH4 production within the soil profile. 1.6 Related Data Sets 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 NSA SF6 Chamber Flux Data BOREAS TGB-01/TGB-03 CH4 Chamber Flux Data over the NSA Fen BOREAS TGB-03 Plant Species Composition Data over the NSA Fen BOREAS TGB-01/TGB-03 NEE Data over the NSA Fen BOREAS TGB-03 CH4 and CO2 Chamber Flux Data over NSA Upland Sites BOREAS TF-04 CO2 and CH4 Soil Profile Data from the SSA 2. Investigator(s) 2.1 Investigator(s) Name and Title Dr. Rob Striegl Hydrologist, United States Geological Survey Dr. Kimberly Wickland United States Geological Survey 2.2 Title of Investigation Automated Measurements of CO2 Exchange at the Moss Surface of a Black Spruce Forest. 2.3 Contact Information Contact 1 Dr. Rob Striegl Hydrologist, United States Geological Survey Denver, CO rstriegl@usgs.gov Contact 2 Dr. Kimberly P. Wickland Hydrologist, United States Geological Survey Denver, CO Contact 3 Sara Conrad Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-2624 (301) 286-0239 (fax) Sara.Conrad@gsfc.nasa.gov 3. Theory of Measurements Atmospheric chemistry measurements and modeling studies identify a global imbalance between known CO2 production and uptake, with a potentially large terrestrial carbon sink possible in boreal forests. Northern woodlands are also perceived to be very sensitive to climate change. The predicted warming and drying of the boreal region could profoundly affect regional carbon sources and sinks. Carbon cycling of the boreal forest has consequently been a central theme of much recent field research. With the intent of eventually extrapolating land-based carbon, energy, and water flux measurements to the entire boreal forest biome, the Boreal Ecosystem-Atmosphere Study (BOREAS) subdivided northern and southern section of Canadian boreal forest into aspen, jack pine, and bog-fen landscapes for intensive study. Studies within these vegetation types focused on a variety of factors that influence carbon cycling, including forest stand age and land surface disturbances (Seller et al., 1995). Soil respiration, the second largest flux in the global carbon cycle, includes all CO2 produced by roots, soil organisms, and oxidation that is emitted across the soil-air interface. Although globally important, soil respiration is not well characterized spatially or seasonally for most ecosystems. We derived response curves of measured soil CO2 emission versus soil temperature for the measurement transects and applied them to soil temperatures that were continuously recorded at the BOREAS OJP flux tower, located approximately 0.2 k, northwest of the OJP transect. This allowed for simulation of continuous soil CO2 emissions for May Ò September 1994. The simulation results, when considered with the winter tree removal, the deep well-sorted sandy soil, and the lack of complexity of the plant and soil communities, permitted separation of surface- soil, deep-soil, and tree-root respiration at the OJP stand. The OJP fluxes quantify the amount of CO2 that is transported across the forest floor and is available for photosynthetic uptake by ground cover and understory plants and tress or for emission to the atmosphere. Because the groundcover was destroyed and all trees were removed by clear-cutting, the ÎCCÌ site fluxes represent net CO2 emission to the atmosphere during the period between forest harvest and re- establishment of plant cover. 4. Equipment 4.1 Sensor/Instrument Description 4.1.1 Collection Environment Data were collected under all environmental conditions. 4.1.2 Source/Platform Ground. 4.1.3 Source/Platform Mission Objectives Support investigators and chambers. 4.1.4 Key Variables CO2 and CH4 flux. 4.1.5 Principles of Operation Carbon dioxide and CH4 fluxes were measured by the static chamber techniques, which involves measuring the accumulation or loss of gas concentration within chambers placed on the soil surface versus time. The chambers, which are cylindrical with an open bottom and a closed top, are constructed from 0.30 m inside diameter polyvinylchloride (PVC) irrigation pipe. To prevent gas leakage to or from the chambers during measurement, that were affixed by a gasket to a collar, constructed from the same pipe material, that was inserted permanently into the soil to a depth of 0.10 m. When deployed, the collars and chambers had a combined height of 0.28 to 0.30 m. The chambers have a coiled 1.6-mm inside diameter aluminum tube installed through the sidewall near the top to equalize inside and outside pressure and are fitted with various gas ports for air circulation and sample collection. Gross soil CO2 flux is the total amount of CO2 that passes across the soil-groundcover/air interface in the absence of photosynthesis. Chambers for measurement of gross CO2 flux and ch4 flux have opaque PVC tops that create a dark chamber environment. Net soil CO2 flux is gross flux minus CO2 uptake by groundcover photosynthesis. Chambers for measurement of net CO2 flux have clear polycarbonate tops that are optically transparent across the window of photsynthetically active radiation, allowing plant photosynthesis to occur. Air is recirculated inside the chambers at a rate of 0.25 chamber volume per minute to ensure mixing. Gross and net CO2 flux were measured by continuously monitoring the CO2 concentration in air circulating in a chamber placed on the soil surface. CO2 concentrations were recorded at 20-second intervals for 8 minutes using a LI-COR 6200 IRGA. Soil CH4 flux was measured by GC analysis of a time series of six syringe samples of air collected from the center of volume of the chamber. Deployment times ranged from 24 to 40 minutes, depending on the anticipated flux rate. Rate of gas emission of consumption were determined by the equation: J=dC/dt x h where J is the rate of gas flux across the soil surface (mol/m2/s) C is the gas concentration in the chamber at ambient temperature and pressure (mol/m3), t is time, h is chamber height (m), and dC/dt is the slope of the best fit of the time series of concentration in the chamber as time approaches zero. 4.1.6 Sensor/Instrument Measurement Geometry Not applicable. 4.1.7 Manufacturer of Sensor/Instrument The chambers, which are cylindrical with an open bottom and a closed top, are constructed from 0.30 m inside diameter polyvinylchloride (PVC) irrigation pipe. To prevent gas leakage to or from the chambers during measurement, that were affixed by a gasket to a collar, constructed from the same pipe material, that was inserted permanently into the soil to a depth of 0.10 m. When deployed, the collars and chambers had a combined height of 0.28 to 0.30 m. The chambers have a coiled 1.6-mm inside diameter aluminum tube installed through the sidewall near the top to equalize inside and outside pressure and are fitted with various gas ports for air circulation and sample collection. Infrared gas analyzer (IRGA) IRGA, Model 6262 LI-COR, Inc Lincoln, NE 4.2 Calibration 4.2.1.1 Tolerance None given. 4.2.2 Frequency of Calibration Traceable gas calibration standards for all CO2 and CH4 analyses were provided by the BOREAS project. 4.2.3 Other Calibration Information None given. 5. Data Acquisition Methods Soil respiration was measured using closed chambers that attached to chamber collars permanently installed in the soil. Three pairs of the 0.38 m diameter chamber collars were inserted 0.10 m into the soil at each site along a 60-m transect, having 30 m between pairs of collars and 1 m between collars within pairs. Traceable gas calibration standards for all CO2 and CH4 analyses were provided by BOREAS operations. Carbon dioxide concentrations were measured using non- dispersive infrared gas analyzers (IRGAS) calibrated to span the expected concentration range. Three different IRGAs were used for measuring CO2 concentration at the jack pine soil gas transects. Accumulation of CO2 in soil gas flux chambers was measured using LI-COR model 6200. In situ soil CO2 concentrations exceed the range of the LI-COR 6200, so two PP System model EGM IRGAs were used, one having a range up to 5000 parts per million (ppm) CO2 and the second having a range up to 10,000 ppm CO2. Methane concentrations were measured using a Chrompack model 438A gas chromatograph (GC) having a 2 meter 80-100 mesh Porapak-N column and a flame ionization detector. Carrier gas was nitrogen and the oven temperature was maintained at 38C. Methane concentrations were calculated from standards curves established from a series of CH4 Standards run between every 8 to 10 samples. Concentrations smaller than 0.49 ppm were calculated by linear extrapolation of integrator response between a 0.49 ppm CH4 standard and a nitrogen blank. The measurements were made by sealing a 0.30-m tall opaque polyvinyl chloride chamber cover over a chamber collar and continuously circulating air from the chamber at top center, through a LI-COR 6200 CO2 analyzer, and back into the chamber through a perforated air-dispersion ring on the inside of the chamber base. Chamber CO2 concentrations were measured at 1-s intervals and mean concentrations were recorded at 15-s intervals for 8 minutes. Insertion of the chamber collars into the soil, circulation of chamber air through the gas analyzer, the relatively large chamber diameter, and the relatively short chamber deployment times were all intended to minimize chamber effects known to influence soil gas flux measurements. CO2 emission rates were calculated using: J = dC/dt x h where J is the rate of CO2 flux across the soil surface (mol/(m2 s)) C is the CO2 concentration in the chamber at ambient temperature and pressure (mol/m3), t is time, h is chamber height (m), and dC/dt is the slope of the best fit of the time series of CO2 concentration in the chamber as time approaches zero. 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 The North American Datum of 1983 (NAD83) coordinates at the sites are: OJP: 53.91634° N, 104.69203° W YJP: 53.87581° N, 104.64529° W CC: 53.9090° N, 104.6595° W RC: 53.9091° N, 104.6671° W 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution These are point measurements made at the given locations. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage The data set covers the period from 26-MAY-94 to 21-MAR-95 7.2.2 Temporal Coverage Map Not available. 7.2.3 Temporal Resolution Gross and net CO2 flux were measured by continuously monitoring the CO2 concentration in air circulating in a chamber placed on the soil surface. CO2 concentrations were recorded at 20-second intervals for 8 minutes using a LI-COR 6200 IRGA. Soil CH4 flux was measured by GC analysis of a time series of six syringe samples of air collected from the center of volume of the chamber. Deployment times ranged from 24 to 40 minutes, depending on the anticipated flux rate. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (tf4ssafx.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (tf4ssafx.def). 8. Data Organization 8.1 Data Granularity CH4, gross CO2 and net CO2 data are in separate files. 8.2 Data Format(s) The data files contain ASCII 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 (tf4ssafx.def). 9. Data Manipulations 9.1 Formulae 9.1.1 Derivation Techniques and Algorithms None given. 9.2 Data Processing Sequence 9.2.1 Processing Steps None given 9.2.2 Processing Changes None given. 9.3 Calculations 9.3.1 Special Corrections/Adjustments None given. 9.3.2 Calculated Variables CO2 emission rates were calculated using J = dC/dt x h where J is the rate of CO2 flux across the soil surface (mol/(m2 s)) C is the CO2 concentration in the chamber at ambient temperature and pressure (mol/m3), t is time, h is chamber height (m), and dC/dt is the slope of the best fit of the time series of CO2 concentration in the chamber as time approaches zero. 9.4 Graphs and Plots None given. 10. Errors 10.1 Sources of Error None given. 10.2 Quality Assessment 10.2.1 Data Validation by Source None given. 10.2.2 Confidence Level/Accuracy Judgment None given. 10.2.3 Measurement Error for Parameters None given. 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 None given. 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 None given. 13. Future Modifications and Plans None given. 14. Software 14.1 Software Description None given. 14.2 Software Access Not applicable. 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 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 Comma-delimited ASCII text files. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation None given. 17.2 Journal Articles and Study Reports Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry, M. Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J. Cihlar, J. Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D. Halliwell, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin. 1997. BOREAS in 1997: Experiment Overview, Scientific Results and Future Directions. Journal of Geophysical Research 102 (D24): 28,731-28,770. Striegl, R.G., and Wickland, K.P., 1998, effects of a clear-cut harvest on soil respiration in a jack-pine lichen woodland, Can. Jour. Forest Research 28:534- 539. Wickland, K.P., and Striegl, R.G., 1997, Measurements of soil carbon dioxide and methane concentrations and fluxes, and soil properties at four ages of jack pine forest in the Southern Study Area of the Boreal Ecosystem Atmosphere Study, Saskatchewan, Canada, 1993-1995. U.S. Geological Survey Open-File Report. 97-49. 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 GSFC - Goddard Space Flight Center IRGA - Infrared Gas Analyzer NAD83 - North American Datum of 1983 NASA - National Aeronautics and Space Administration NSA - Northern Study Area OBS - Old Black Spruce ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Pike PPFD - Photosynthetically Active Photon Flux Density SSA - Southern Study Area TF - Tower Flux TGB - Trace Gas Biochemistry URL - Uniform Resource Locator SSA - Southern Study Area 20. Document Information 20.1 Document Revision Date Written: 01-Dec-1998 Last Updated: 09-Dec-1998 20.2 Document Review Date(s) BORIS Review: 03-Dec-1998 Science Review: 20.3 Document ID 20.4 Citation Wickland, K.P., and Striegl, R.G., 1997, Measurements of soil carbon dioxide and methane concentrations and fluxes, and soil properties at four ages of jack pine forest in the Southern Study Area of the Boreal Ecosystem Atmosphere Study, Saskatchewan, Canada, 1993-1995. U.S. Geological Survey Open-File Report. 97-49. Striegl, R.G., and Wickland, K.P., 1998, effects of a clear-cut harvest on soil respiration in a jack-pine lichen woodland, Can. Jour. Forest Research 28:534- 539. 20.5 Document Curator 20.6 Document URL Keywords: Carbon Dioxide flux Methane flux Methane consumption TF04_Chamberflux.doc 01/13/99