BOREAS Calibration Gas Standards Summary: In order to improve the comparability of trace gas measurements made by various science teams, the BOReal Ecosystem-Atmosphere Study (BOREAS) obtained several cylinders of carbon dioxide (CO2) and methane (CH4) that were used as calibration standards. The cylinders were stored in the field laboratories established in Paddockwood, Saskatchewan (Southern Study Area) (SSA) and in Thompson, Manitoba (Northern Study Area) (NSA) from May 1994 until November 1996. Personnel from the Atmospheric Environment Service (AES) of Environment Canada performed a calibration of the gas cylinders overnight on April 26 - April 28, 1994. The calibration of each cylinder was performed only once due to time constraints. The calibration system that was used consisted of a Hewlett Packard 5890 gas chromatograph with a Hewlett Packard 5790 catalyst unit that allows the analysis of CO2 as well as CH4. The system contained a ten-foot stainless steel column with Poropak Q packing and a 3-mL sample loop volume. The 0.5, 0.9, and 2-ppm CH4 cylinders were calibrated using the standard AES-012, a mixture of CO2 and CH4 in dry air. The AES-012 CH4 content was determined using a gas chromatograph using a primary CH4-in-air standard of 0.913 +/- 0.010 ppmv (National Institute for Standards and Technology (NIST) Standard Reference Material 1658a) having a mixing ratio of 1.8774 ppm. For the 9-ppm CH4 cylinders, a primary CH4-in-air standard (CAL-8297) of 9.79 +/- 0.08 ppmv (NIST SRM 1659a)was used. The calibration consisted of a three-injection cycle that was repeated every half hour, as follows: 1. AES Standard (AES-012 or CAL-8297) 2. First uncalibrated cylinder 3. Second uncalibrated cylinder The peak height count of the standard’s CH4 peak was used to calculate a system response factor (concentration per height count), which was then used to determine the CH4 mixing ratios of the gas cylinders. This was also used to evaluate the mixing ratio of the AES standard in the next injection sequence, giving an indication of the system’s response stability from half-hour to half- hour. The CH4 calibration system was only tested for linearity within 0.9 ppm to 2 ppm. The 9-ppm standard was run using the 0.9-ppm standard, but standards were unavailable for the range in-between. At the time of the calibration, AES reported that literature found the Flame Ionization Detector (FID) to be quite linear for CH4. AES could not be certain of the precision or reproducibility outside of the 300 to 390-ppmv range for CO2. The concentrations of CO2 may drift, and this drift may vary from cylinder to cylinder. Brass cylinder regulators CGA 590, model UPE were used with the cylinders. At the end of November 1996, PRAXAIR (the original provider) collected the gas cylinders. Results from the calibration are given in the following table and were taken when the system was most stable. Concentration (ppm) Gas Cylinder Number Objective Average Measured Standard Deviation Number of Samples Study Area CH4 15761 0.5 0.5078 0.0009 7 NSA CH4 15779 0.5 0.5079 0.0004 7 SSA CH4 15641 0.8 0.8988 0.0016 7 NSA CH4 15746 0.8 0.9006 0.0022 7 SSA CH4 15755 2 2.0455 0.0005 9 NSA CH4 15758 2 2.0515 0.0015 9 SSA CH4 15777 9 9.1145 0.0017 10 NSA CH4 15752 9 9.1302 0.0029 10 SSA CO2 15743 300 301# Unknown Unknown NSA CO2 15635 300 301# Unknown Unknown SSA CO2 78301 300 299.661 0.018 Unknown NSA CO2 15628 300 299.164 0.0168 Unknown SSA CO2 15741 355 357# Unknown Unknown NSA CO2 15796 355 356.170 0.0091 Unknown SSA CO2 15653 355 356.104 0.0228 Unknown NSA CO2 15753 355 354# Unknown Unknown SSA CO2 15763* 400 397.353 0.03 Unknown NSA CO2 15652 400 399# Unknown Unknown SSA CO2 15760 400 398.089 0.0315 Unknown SSA CO2 Unknown* 400 Unknown Unknown Unknown NSA CO2 15771 700 705# Unknown Unknown NSA CO2 15791 700 697# Unknown Unknown SSA CO2 15626 2000 2008# Unknown Unknown NSA CO2 15744 2000 2007# Unknown Unknown SSA * These two cylinders were reported as not arriving to the NSA laboratory as of 19 May 1994. They possibly showed up later at the NSA lab. # These concentration values were recorded by the science team from labels on the gas cylinders at the NSA and SSA labs. BOREAS or AES personnel performed no formal calibration of the cylinders. Contact Information: Jeffrey A. Newcomer Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-7858 (301) 286-0239 (fax) Jeffrey.Newcomer@gsfc.nasa.gov Jaime Nickeson Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-3373 (301) 286-0239 (fax) Jaime.Nickeson@gsfc.nasa.gov Data Access Contact for Data Center/Data Access Information: These BOREAS data are available from the Earth Observing System Data and Information System (EOS-DIS) 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 Procedures for Obtaining Data: BOREAS data may be obtained through the ORNL DAAC World Wide Web site at http://www-eosdis.ornl.gov/ or users may place requests for data by telephone, electronic mail, or fax. Output Products and Availability: Requested data can be provided electronically on the ORNL DAAC's anonymous FTP site or on various media including, CD-ROMs, 8-MM tapes, or diskettes. The complete set of BOREAS data CD-ROMs, entitled "Collected Data of the Boreal Ecosystem-Atmosphere Study", edited by Newcomer, J., et al., NASA, 1999, are also available. Document Information Written: 28-June-1999 Revised: 28-July-1999 BORIS Review: 30-June-1999 Calib_Gas_Std.doc 08/21/99