BOREAS TE-04 Branch Bag Data from Boreal Tree Species Summary The BOREAS TE-04 team collected continuous records of gas exchange under ambient conditions from intact boreal forest trees in the BOREAS NSA from 23-Jul-1996 until 14-Aug-1996. These measurements can be used to test models of photosynthesis, stomatal conductance, and leaf respiration, such as SiB2 (Sellers et al., 1996) or the leaf model (Collatz et al., 1991), and programs can be obtained from the investigators. Table of Contents 1 Data Set Overview 2 Investigators 3 Theory of Measurements 4 Equipment 5 Data Acquisition Methods 5 Observations 7 Data Description 8 Data Organization 9 Data Manipulations 10 Errors 11 Notes 12 Application of the Data Set 13 Future Modification 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 TE-04 Branch Bag Data from Boreal Tree Species 1.2 Data Set Introduction These data are summaries of steady-state gas exchange measurements conducted under field conditions from 23-Jul-1996 until 14-Aug-1996 in the BOReal Ecosystem-Atmosphere Study (BOREAS). 1.3 Objective/Purpose These studies were conducted to provide a basis for calibrating models of stomatal conductance, photosynthesis, and respiration used in simulating boreal ecosystem-atmosphere interactions. 1.4 Summary of Parameters The parameters provided in each data set are intended to provide a sufficient description of the micro-environment of the leaf to permit the observations to be used for model validation. A complete list of the parameters is given in Section 4.1.1. The key measurements are the rates of net CO2 exchange, the rate of evaporation of water from the leaf, the stomatal conductance to water vapor, and the intercellular CO2 concentration. 1.5 Discussion The branch bag (described in Section 4.1) was installed at the top of the canopy with an attached tree crown inside. The bag was connected to an MPH-1000 steady- state gas exchange system. A heat exchanger was used to eliminate the difference between bag air temperature and ambient temperature; thus, the conditions inside the bag were very close to those outside. The measurements were made in a short interval (about 5 min) and could be used to check the photosynthesis model and the stomatal model. Parameters from fitting leaf model to leaf gas exchange data have been used to simulate these data. The simulation is still ongoing. Tree species measured were black spruce (Picea mariana) at the Old Black Spruce (OBS) site in the NSA and jack pine (Pinus banksiana) at the Old Jack Pine (OJP) site and the Young Jack Pine (YJP) site in the NSA. 1.6 Related Data Sets BOREAS TE-02 Foliage Respiration Data BOREAS TE-04 Gas Exchange Data from Boreal Tree Species BOREAS TE-05 Leaf Gas Exchange Data BOREAS TE-05 Surface Meteorological and Radiation Data BOREAS TE-09 In Situ Diurnal Gas Exchange of NSA Boreal Forest Stands BOREAS TF-03 NSA-OBS Tower Flux, Meteorological, and Soil Temperature Data 2. Investigators 2.1 Investigators Name and Title Dr. Joseph A. Berry Dr. John Gamon Dr. Wei Fu Dr. Art Fredeen 2.2 Title of Investigation Measurement and Prediction of CO2 and H2O Exchange from Boreal Forest Tree Species 2.3 Contact Information Contact 1: Dr. Joseph A. Berry Department of Plant Biology Carnegie Institution of Washington Stanford, CA (415) 325-1521 ext 221 (415) 325-6857 (fax) joeberry@biosphere.stanford.edu Contact 2: Andrea Papagno Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-3134 (301) 286-0239 (fax) Andrea.Papagno@gsfc.nasa.gov 3. Theory of Measurements The measurements reported here were made by generally accepted procedures for laboratory gas exchange. Branches were enclosed in a branch bag that was set up to trace ambient environmental conditions. Net exchange of CO2 and H2O was determined by infrared gas analysis of the air flowing through the stirred cuvette. 4. Equipment 4.1 Sensor/Instrument Branch Bag (cylindrical openflow transparent bag, diameter 0.8 m, length 1 m) Gas Exchange System (Model MPH-1000; Campbell Scientific, Logan UT) Infrared Gas Analyzer (IRGA) (Model 6262; LICOR Inc., Lincoln, NB) Dew Point Mirror (Model Dew-10; General Eastern, Woburn, MA) 4.1.1 Collection Environment All experiments were conducted with intact attached crowns of trees (top 0.9 m) in the NSA of BOREAS. For specific weather conditions on experiment days, see meteorological data files. 4.1.2 Source/Platform Branch bags were suspended from the canopy access towers. Other equipment was on the same towers. 4.1.3 Source/Platform Mission Objectives The experiments were conducted to validate models of photosynthesis, stomatal regulation, and respiration at an intermediate level. 4.1.4 Key Variables P0 atmospheric pressure (Pa) rbw boundary layer resistance (m2 s/mol) ea ambient water vapor pressure (Pa) Ca ambient CO2 concentration (?mol/mol) Ta ambient temperature (?C) PFD flux density of PAR (?mol/m2s) SW short wave radiation (W/m2) LW long wave radiation (W/m2) Tl leaf temperature (?C) Cs CO2 concentration at leaf surface (?mol/mol) Hs relative humidity at leaf surface (%) Ci CO2 concentration in intercellular air spaces (?mol/mol) Pn net photosynthetic rate (?mol/m2s) Gsw stomatal conductance (mol/m2 s) E transpiration rate (mmol/m2 s) 4.1.5 Principles of Operation Temperature, CO2 concentration, and H2O vapor pressure were determined with appropriate sensors. Net CO2 and H2O exchange was determined by mass balance analysis of the air flowing through the cuvette. Gas exchange parameters, Ci, and Gsw were calculated. The hemisurface leaf area used in these measurements was 1.0 to 3.9 m2 on a given tree. The projected area of the crown was estimated by analysis photographs. 4.1.6 Sensor Instrument Measurement Geometry Leaves/needles were enclosed in a cuvette. All measurements are expressed on a leaf area basis; for the conifers, this is reported as the hemisurface area of the needles (half of the total surface area) as determined by fresh weight calibrated to volume displacement (J. Norman, personal communication). 4.1.7 Manufacturer of Sensor/Instrument Gas exchange system (Model MPH-1000; Campbell Scientific, Logan, UT) IRGA (Model 6262; LICOR Inc., Lincoln, NE) Dew Point Mirror (Model Dew-10; General Eastern, Woburn, MA) 4.2 Calibration CO2 concentration was referenced to standard CO2 tanks provided by BOREAS; H2O vapor was referenced to a dew point mirror instrument; air flow was calibrated by volume displacement; photosynthetically active radiation (PAR) flux was referenced to a LICOR quantum probe. 4.2.1 Specifications There are no published specifications for the complete system of instruments used in this study. 4.2.1.1 Tolerance All calibrations are better than +/- 1%. 4.2.2 Frequency of Calibration Calibration and instrument zeros were checked daily. Checks against the BOREAS gas standards was made every week or two. 4.2.3 Other Calibration Information No significant adjustments or drift of calibration occurred over the interval of these measurements. 5. Data Acquisition Methods In each branch bag experiment, only flow rate was controlled. A plastic bag buffered air flow and gave stable CO2 supply. A heat exchanger was used to eliminate the temperature differences between bag air and ambient air. Conditions in the branch bag tracked those of the ambient. The hemisurface leaf area used in these measurements was 1.0 to 3.9 m2 on a given tree. The projected area of the crown was estimated by analysis photographs. 6. Observations 6.1 Data Notes These experiments were conducted from 23-Jul-1996 until 14-Aug-1996, spending a few consecutive days at each site. The studies were conducted with the top 0.8- 0.9 m of a single crown at each site. We believe that these measurements are representative of the trees at the site, but it was not possible to obtain a statistically representative sample. Measurements conducted with a LICOR 6400 photosynthesis system on needles from an adjacent tree can be used to determine the photosynthetic capacities at these sites. 6.2 Field Notes None given. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage The NSA measurement sites and associated North American Datum of 1983 (NAD83) coordinates are: OBS, site id T3R8T, Lat/Long: 55.88007°N, 98.48139°W, Universal Transverse Mercator (UTM) Zone 14, N: 6,192,853.4, E: 532,444.5. OJP, site id T7Q8T, Lat/Long: 55.92842°N, 98.62396°W, UTM Zone 14, N: 6,198,176.3, E: 523,496.2. YJP, site id T8S9T, Lat/Long: 55.89575°N, 98.28706°W, UTM Zone 14, N: 6,194,706.9, E: 544,583.9. 7.1.3 Spatial Resolution These data are point measurements taken from trees near the given locations. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics These measurements were coupled with the ambient environment. There is direct correspondence between the temperature, light intensity, or other environmental conditions in the branch bag during these experiments and the ambient environmental conditions at the site of the measurements. However, air temperature in the bag could be 2-4 °C above ambient during midday. Data presented here were collected under the conditions in the bag. 7.2.1 Temporal Coverage Data were collected from 23-Jul-1996 until 14-Aug-1996. 7.2.2 Temporal Coverage Map Not available. 7.2.3 Temporal Resolution Data were collected every 5 minutes over each site for several consecutive days. 7.3 Data Characteristics 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (te04bbag.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (te04bbag.def). 8. Data Organization 8.1 Data Granularity All of the branch bag gas exchange measurements are in one file. 8.2 Data Format(s) The data files contain American Standard Code for Information Interchange (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 (te04bbag.def). 9. Data Manipulations 9.1 Formulae Calculations of gas exchange parameters were conducted essentially as described by Ball (1987). 9.1.1 Derivation Techniques and Algorithms used See Section 9.1. 9.2 Data Processing Sequence Data were logged by a laptop computer, and calculations were made concurrent with the measurements. All of the primary data are archived. 9.2.1 Processing Steps No averaging. 9.2.2 Processing Changes 9.3 Calculations The calculations are as described by Ball (1987). 9.4 Graphs and Plots Plots of these experiments are available as PostScript files by anonymous ftp to biosphere.stanford.edu. Some of these may be found in the directory /submissions/Boreas_data/PS_files or http://biosphere.stanford.edu. 10. Errors 10.1 Sources of Error Uncertainty in these experiments arises from instrument noise and systematic calibration errors, and because the leaf experiences somewhat different conditions (e.g.) high temperature and Vapor Pressure Deficit (VPD) than do leaves in natural environments. 10.2 Quality Assessment 10.2.1 Data Validation by Source The data sets are being checked against calibrated equipment. 10.2.2 Confidence Level/Accuracy Judgment These data have been carefully checked and are equal in quality to measurements conducted under laboratory conditions. 10.2.3 Measurement Error for Parameters Gsw, stomatal conductance, +/- 5 mmol/m2s A, net CO2 exchange, +/- 0.1 micromole/m2s Ci, intercellular CO2, +/- 5 micromole/mol 10.2.4 Additional Quality Assessments None. 10.2.5 Data Verification by Data Center Data were examined for general consistency and clarity. 11. Notes 11.1 Limitations of the Data Unknown. 11.2 Known Problems with the Data Light interception by the enclosed crown varied with the ratio of direct to diffuse radiation intercepted, and was calculated from measurements of the projected area and geometric model of light interception. 11.3 Usage Guidance Calibrated data sets and models for simulation or analysis of these data can be obtained from J. Berry. 11.4. Other Relevant Information None. 12. Application of the Data Set The data set has been simulated with a leaf version of the Land-Surface Parameterization Model (SiB2) combining some special treatments of radiation absorption. Preliminary estimates can be obtained from J. Berry. 13. Future Modification and Plans None. 14. Software 14.1 Software Description SiB2 is in FORTRAN and runs in a workstation environment. The Collatz et al. (1991), model is in C and can be run on PCs or workstations. 14.2 Software Access Copies of SiB2 or the Collatz et al. (1991) model can be obtained from J. Berry. 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 TE-04 branch bag 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 ProductsNone.16.2 Film Products None. 16.3 Other Products These data are available on the BOREAS CD-ROM series. 17. References 17.1 Platform/Sensor Instrument/Data Processing Documentation None given. 17.2 Journal Articles and Study Reports Ball, J.T. 1987. Calculations related to gas exchange. In: E. Zeiger, G.D. Farquhar and I.R. Cowan (Eds.), Stomatal Function, Stanford University Press, Stanford. 446-476. Collatz, G.J., J.T. Ball, C. Grivet, and J.A. Berry. (1991). Physiological and environmental regulation of stomatal conductance, photosynthesis and transpiration: a model that includes a laminar boundary layer. Agricultural and Forest Meteorology, 54, 107-36. 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., 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.J., D.R. Randall, G.J. Collatz, J.A. Berry, C.B. Field, D.A. Dazlich, and G.D. Collelo. 1996. A revised land-surface parameterization (SiB2) for GCMs. Part 1: Model formulation. Journal of Climate, 9, 676-705. Sellers, P.J., 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. Bull. Am. Meteorol. Soc. 76:1549-1577. 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), 28731-28769. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms SiB2 - Land-Surface Parameterization Model 19. List of Acronyms ASCII - American Standard Code for Information Interchange BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System CD-ROM - Compact Disk-Read-Only memory DAAC - Distributed Active Archive Center DOY - Julian Day of Year EOS - Earth Observing System EOSDIS - EOS Data and Information System GSFC - Goddard Space Flight Center HTML - HyperText Markup Language IFC - Intensive Field Campaign IRGA - Infrared Gas Analyzer MIX - Mixed Wood NAD83 - North American Datum of 1983 NASA - National Aeronautics and Space Administration NOAA - National Oceanic and Atmospheric Administration NSA - Northern Study Area ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park PAR - Photosynthetically Active Radiation OA - Old Aspen OBS - Old Black Spruce OJP - Old Jack Pine ORNL - Oak Ridge National Laboratory SSA - Southern Study Area TE - Terrestrial Ecology TF - Tower Flux URL - Uniform Resource Locator UTM - Universal Transverse Mercator VPD - Vapor Pressure Deficit YA - Young Aspen Site YJP - Young Jack Pine 20. Document Information 20.1 Document Revision Date Written: 23-Jun-1997 Last Updated: 09-Feb-1999 20.2 Document Review Date BORIS Review: 23-Dec-1998 Science Review: 20.3 Document ID 20.4 Citation Dr. Joseph A. Berry, Carnegie Institution of Washington, Stanford, CA, 94305 Dr. John Gamon, Department of Biology, CSU--LA, LA, CA 90032 Dr. Wei Fu, Carnegie Institution of Washington, Stanford, CA, 94305 Dr. Art Fredeen, Faculty of Natural Rescources and Environmental Studies, University of N.B.C., Prince George, B.C., Canada 20.5 Document Curator 20.6 Document URL Keywords Branch Bag Photosynthesis CO2 Concentration Gas Exchange Photosynthetically Active Radiation Flux Density Steady-State System Stomatal Conductance Transpiration TE04_Branch_Bag.doc 03/03/99