Measurement Information

Transcription

1 Measurement Information, M/S Skaugran page 1/6 Monitoring of Atmosphere-Ocean Carbon Dioxide Exchange by Ship of Opportunity conducted by Center for Global Environmental Research (CGER), National Institute for Environmental Studies (NIES) Measurement Information Principal Investigator Dr. Yukihiro Nojiri National Institute for Environmental Studies Address: 16-2, Onogawa, Tsukuba, Ibaraki, , JAPAN Tel: , Fax: Platform M/S Skaugran Length over all : m Gross tonnage : ton Operator: Seaboard International Shipping Co., Canada Locations for equipments' install Container lab on the deck of Skaugran Container lab is set to monitor for meteorological data and for canister sampling of atmospheric CO 2. Air intake for hourly measurement of atmospheric CO 2 locates here. 90m of Teflon line was installed to supply air for engine room CO 2 instruments. Atmospheric sampling canisters in the container laboratory CO 2, CH 4 and N 2 O concentrations are measured in CGER/NIES laboratory.

2 Measurement Information, M/S Skaugran page 2/6 pco 2 observation system in the engine room pco 2 observation system is set to draw discrete water samples and to make quasi-continuous measurements for temperature, salinity, pco 2 in surface seawater and in the atmosphere, chlorophyll fluorescence, and ph Overall System for discrete and continuous measurement Figure: Configuration of the overall system for discrete and continuous measurements. M indicates an automatic safety value, and H20 indicates the Hydrolab sensor package for temperature, salinity and ph Water Pump Water pump at the bottom of the ship Depth of seawater intake: 8-12 m (the bottom of the ship, changing with the load) Water Supply Line Branch pipe connected to fire line, length is 25m to pco 2 system. Diameter: 3.2 cm Water supply flow rate: 60-80L min-1 History of supply line Start - Dec 1996: steel line Dec Feb 1997: stainless steel line Feb End: (stainless steel line with thermally insulated)

3 Measurement Information, M/S Skaugran page 3/6 H20 Sensor Package H20 is the Hydrolab sensor package for temperature, salinity, and ph. Manufacturer: Hydrolab Type: model H20 Continuous Measurement System Using Tandem Type Equilibrator Figure: Configuration of AS2 using the tandem equilibrator. Major changes to this system are shown by the shaded boxes. A feedback bubbling gas system was installed before 10E cruise to match the bubbling gas concentration to the approximate water concentration. The feedback gas was generated from a mixture of 4% CO 2 -in-nitrogen and zero air. Before 12E, the standard gas humidifier was removed and a membrane dryer installed. Tandem Type Equilibrator Intercalibration test in, 1999 using indoor seawater pool The equilibrator on the left is a tandem design. Seawater flows continuously into the transparent cylindrical tube (main equilibrator body) near the top but below the water drain level. The flow of water draining out the equilibrator is maintained by monitoring the flow rate and adjusting inlet and outlet valves. The overflow water drains to a reservoir which is vented to the atmosphere. This reservoir is important to the design for 3 reasons; create a water seal which prevented contamination by room air maintain atmospheric pressure in the equilibrator minimized the loss of tandem gas from the system. The feedback gas, which is generated from a mixture of 4% CO 2 -in-nitrogen and zero air, is bubbled through a glass frit from below the midpoint of the equilibrator body, also continuously. As the water flows down through the equilibrator body, the tandem gas rise through 1.5 m of water and into the headspace above the water column. To minimize tandem gas losses through the bottom drain, the base of the equilibrator body has a larger diameter than the main body. Part of the tandem gas went to the analysis line; the other is vented to the atmosphere through the bypass line (see system map), ensuring atmospheric pressure in the equilibrator headspace. For the analysis path, gas is pumped to provide

4 Measurement Information, M/S Skaugran page 4/6 sufficient pressure through a dehumidifier and flowmeter, then into the analyzer. One of the unusual features of this system is the open split interface using differential pressure between the lines (instead of valves) to direct gas flows. There were no valves along the analysis gas flow line from the equilibrator to the pump. This system has been used aboard a domestic ferry route in Japan [Kimoto and Harashima, 1993; Harashima et al., 1997] NDIR and Other Equipments NDIR analyzer Manufacture: Fuji Electric Company, Ltd., Japan Type: ZAR Reference cell: closed, containing N2 gas Dehumidifier and Membrane Dryer Shower Type Equilibrator Sea water is supplied at a flow rate of 5-10 L min -1. Gas flow design is a stopped flow system with two circulation paths - one through the analysis cell which included gas dryers and filters, and another bypass path to pre-equilibrate the gas from the equilibrator headspace. During the hourly cycle, four standard gases pass through the analysis path for each 5 minutes and are measured for each 1 minute after the pump is turned off. Atmospheric air passes through the analysis path for 19 min followed by 1 minute of analysis, and then gas from the equilibrator headspace passes through for 15 minutes before 1 minute of analysis (totally 60 minutes cycle). During the period that the atmospheric measurements are made, gas from the equilibrator headspace circulates in the bypass loop as a pre-equilibration step before entering the analysis path. In June 1996 (before 12E) the equilibrator for this system was moved. It had been located behind the analytical system, and the water level and exhaust flow were difficult to monitor. The change to a stainless steel supply line in December 1996 (before 15W) helped to keep the equilibrator free of rust. These two changes made it easier to monitor the water level and to adjust the gas and water flows to ensure proper operation of the equilibrator. NDIR Manufacture: Fisher-Rosemount Type: Model 880A Reference cell: N 2 gas flow-through Feedback Gas Generator Feedback gas generator is used to bubble the sea water inside of equilibrator. 4% CO 2 -in-n 2 gas (750 ml min -1 ) is bubbled through a glass frit from below the midpoint of the equilibrator body, also continuously. Part of the bubbling gas (--500 ml min -1 ) goes to the analysis line; the other 250 ml min -1 is vented to the atmosphere through the bypass line, ensuring atmospheric pressure in the equilibrator headspace. For the analysis path, gas is pumped (to provide sufficient pressure) through a dehumidifier (2 o C cooler) and flowmeter, then into the analyzer. The bubbling gas is originally zero gas (air with zero CO2 concentration, generated by passing ambient air through a heatless air dryer (molecular sieve), and then a soda lime column. Gas Cylinders of Reference Gases Concentrations of calibration gases used: 250, 320, 390, 460 ppm Manufacturer: Nippon Sanso Corporation, Japan Date of certification: every three round trips, calibrated standard gases were supplied from NIES Traceability of certification: NIES 95 standard gas scale Expected accuracy of certification: within 0.12 ppm agreement with NOAA/CMDL scale, by 1996 round robin test of CO 2 standard gas cylinders [QA/SAC, 1998] Frequency of calibration: at least daily, twice daily after 10E

5 Measurement Information, M/S Skaugran page 5/6 Calibration of the pressure and temperature Sea surface temperature: XBT XBT operated by NOAA is used for 1E-17W (May 95-Apr 97) to calibrate sea surface temperature and to correct temperature warming-up effect on data. Manufacturer: Accuracy: ±0.15 C, Resolution: 0.01 C (-2.2 to 35.6 C) Drop times for comparison with data: 2-4 times per day Bottom Temperature Sensor Sensor is set in fire line to correct temperature warming-up effect to pco 2 data. Temperature recording is logged at every minute. Pt resistance thermometer is used from 18E- (Apr ). Manufacturer: Shinko Technos Co. Ltd. Uncertainty: ±0.05 C. Resolution: 0.02 C. Equilibrator temperature: Thermosalinograph Thermosalinograph is set to calibrate equilibrator temperature. Manufacturer: Sea-Bird Electronics, Inc. Recalibration: in spring 1997 (after, another Seabird is installed) Temperature drift between : C References 1. Bychkov, A., and T. Saino (1998): JGOFS NPTT meets to review plans for studies in North Pacific, U. S. JGOFS Newslett., 8, Boutin, J., and J. Etcheto (1997): Long-term variability of the air-sea CO 2 exchange coefficient: Consequences for the CO 2 fluxes in the equatorial Pacific Ocean, Global Biogeochem. Cycles, 11, Dickson, A. G. (1994): The plastic menagerie: CO 2 teams compare sea going systems, in U. S. JGOFS Newsletter, pp Harashima, A., R. Tsuda, Y. Tanaka, T. Kimoto, H. Tatsuta, and K. Furusawa (1997): Monitoring algal blooms and related biogeochemical changes with a flow-through system deployed on ferries in the adjacent seas of Japan, in Monitoring Algal Blooms: New Techniques for Detecting Large-Scale Environmental Change, edited by M. Kahru, and C. Brown, pp , Springer-Verlag. 5. Inoue, H., and Y. Sugimura (1992): Variations and distribution of CO 2 in and over the equatorial Pacific during the period from the 1986/88 El Nino to the 1988/89 La Nina event, Tellus, 44B, Kimoto, T., and A. Harashima (1993): High resolution time/space monitoring of the surface seawater CO2 partial pressure by ship-of-opportunity, in Fourth International Carbon Dioxide Conference Abstracts, pp , Carqueiranne, France. 7. Koertzinger, A., L. Mintrop, and J. C. Duinker (1999) The international intercomparison exercise of underway fco 2 systems during the R/V Meteor Cruise 36/1 in the North Atlantic ocean (Inst. Meereskunde, Kiel, Germany), Rep. NRDL/CDIAC, NDP Landrum, L. L., R. H. Gammon, R. A. Feely, P. P. Murphy, K. C. Kimberly, C. E. Cosca, and R. F. Weiss (1996): North Pacific Ocean CO 2 disequilibrium for spring through summer, , J. Geophys. Res., 101, Murphy, P. P., K. K. Kelly, R. A. Feely, and R. H. Gammon (1995): Carbon dioxide concentrations in surface water and the atmosphere during NOAA/PMEL cruises in the Pacific and Indian Oceans (Oak Ridge Natl. Lab., Oak Ridge, TN), Rep. NRNL/CDIAC-75, NDP Murphy, P. P., Y. Nojiri, Y. Fujinuma, C. S. Wong, J. Zeng, T. Kimoto, and H. Kimoto (1999): Measurements in the northern North Pacific from a commercial vessel: 1. Introduction and CO 2 methods, J. Geophys. Res. (submitted).

6 Measurement Information, M/S Skaugran page 6/6 11. Nojiri, Y. (1998): A new ocean time series station in the western subarctic Pacific, PICES Press, 6, Nojiri, Y., Y. Fujinuma, J. Zeng, and C. S. Wong (1999): Measurements in the northern North Pacific from a commercial vessel: 2. Seasonal and spatial characteristics of fco 2, , J. Geophys. Res. (submitted). 13. QA/SAC (Quality Assurance/Science Activity Centre) (1998): Activity report, WMO/GAW. 14. Stephens, M. P., G. Samuels, D. B. Olson, R. A. Fine, and T. Takahashi (1995): Sea-air flux of CO 2 in the North Pacific using shipboard and satellite data, J. Geophys. Res., 100, Takahashi, T., J. Olafsson, J. G. Goddard, D. W. Chipman, and S. C. Sutherland (1993): Seasonal variation of CO 2 and nutrients in the high-latitude surface oceans: A comparative study, Global Biogeochem. Cycles, 7, Takahashi, T., R. A. Feely, R. F. Weiss, R. H. Wanninkhof, D. W. Chipman, S. C. Sutherland, and T. T. Takahashi (1997): Global air-sea flux of CO 2 : An estimate based on measurements of sea-air pco 2 difference, Proc. Natl., Acad. Sci. USA., 94, Tans, P. P., I. Y. Fung, and T. Takahashi (1990): Observational constraints on the global atmospheric CO 2 budget, Science, 247, Wong, C. S., and Y.-H. Chan (1991): Temporal variations in the partial pressure and flux of CO 2 at ocean station P in the subarctic northeast Pacific Ocean., Tellus, 43B, Wong, C. S., Y.-H. Chan, J. S. Page, G. E. Smith and R. D. Bellegay (1993): Change in equatorial CO 2 flux and new production estimated from CO 2 and nutrient levels in Pacific surface waters during the 1986/87 El Nino, Tellus, 45B, Wong, C. S., Y.-H. Chan, J. S. Page, G. E. Smith, R. D. Bellegay, and K. Iseki (1995): Geographical, seasonal and interannual variations of air-sea CO 2 exchange in the subtropical Pacific surface waters during (I). Variabilities of oceanic fco 2, Tellus, 47B, Wong, C. S., Y.-H. Chan, and J. S. Page (1995): Geographical, seasonal and interannual variations of air-sea CO 2 exchange in the subtropical Pacific surface waters during (II). Air-sea CO 2 fluxes with skin-temperature adjustments, Tellus, 47B, (end of document)