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Flight altitude 20,000ft(~6km) Atsugi (N35°27′,E139°27′) Minamitorishima (N24°17′,E153°59′) Ryori Yonagunijima JMA aircraft observation using a cargo aircraft C-130H Yousuke Sawa 1 , K. Tsuboi 1 , H. Matsueda 1 , Y. Niwa 1 , M. Nakamura 2 , D. Kuboike 2 , K. Saito 2 , H. Oomori 2 , S. Iwatsubo 2 ,H. Nishi 2 , Y. Hanamiya 2 , K. Tsuji 2 , Y. Baba 2 , and T. Machida 3 1 Meteorological Research Institute, Tsukuba, Japan 2 Japan Meteorological Agency, Tokyo, Japan, 3 National Institute for Environmental Studies, Tsukuba, Japan contact:[email protected] 2. Air sampling onboard the aircraft 4. New measurement system for flask sampled air 5. Performances of the system (AP-6) 6. Observed time series of CO 2 , CH 4 and CO at 6 km The data is available from WMO/GAW the World Data Centre for Greenhouse Gases (WDCGG) http://gaw.kishou.go.jp/wdcgg/wdcgg.html 3. Test flight observation (2010.6-2010.12) Sample air was taken from an air-conditioning blowing nozzle upstream of the recirculation fan to avoid the contamination of cabin air. We prepared a 1.7-L titanium flask of which internal surface is coated by silicon. Air samples are pressurized into the flasks by a manual diaphragm pump to an absolute pressure of about 0.4 MPa. The storage tests for the flask samples during several days were repeated to ensure the stability of trace gases until analyses. We conducted test flights using the cargo aircraft to establish a flask sampling procedure on board the aircraft. Specially coordinated flights at a low altitude of 1000 ft over MNM were made in 2010. Mixing ratios for CO 2 , CH 4 and CO in the air samples were analyzed at MRI to compare with the ground-based measurements from the MNM monitoring system in JMA. It was confirmed that our aircraft sampling procedure was suitable for the precise measurements of trace gases. The JMA/MRI developed the automated measuring system for flask sampled air including recently advanced spectroscopic instruments. High-precision analyses were estimated by the experiments using standard gases and natural air samples. N 2 O (ICOS) CO (VURF) CH 4 (CRDS) Species Measurement techniques Analyzer CO2 Non Dispersive Infrared Absorption Spectrometry Licor Li7000 CH4(CO2, H2O) Wavelength-Scanned Cavity Ring Down Spectroscopy (WS-CRDS *1 ) Picarro G2301 CO Vacuum Ultraviolet Resonance Fluorescence (VURF *2 ) Aero-Laser AL5002 N2O(CO, H2O) Off-axis Integrated Cavity Output Spectroscopy (Off-axis ICOS *3 ) Losgatos DLT100 -0.027 CO2 (ppm) ΔNDIR-CRDS ±0.066 N=213 0.7 CH4 (ppb) ΔCRDS-GC/FID ±2.26 N=74 -0.15 N2O (ppb) ΔICOS-GC/ECD ±1.10 N=103 -0.12 CO (ppb) ΔICOS-VURF ±0.25 N=128 Fig. 1. Locations of the air samples collected from flights between Atsugi and Minamitorishima (a). JMA operates 3 GAW stations; Ryori, Yonagunijima, and Minamitorishima (b). (a) (b) Minamitorishima GAW global station. It is situated on a remote coral island in the western North Pacific, about 2000 km southeast of Tokyo. A cargo aircraft Fig. 2. A cargo aircraft and air sampling equipments. Air-conditioning blowing nozzle 1.7-L titanium flasks coated by silicon A manual diaphragm pump A tube with chemical desiccant (Mg(ClO 4 ) 2 ) Air sampling onboard the aircraft 382 386 390 394 398 402 MNM Station Aircraft (1000ft) CO 2 (2010) M J J A S O N D (ppm) 1760 1780 1800 1820 1840 1860 1880 1900 1920 MNM Station Aircraft (1000ft) CH 4 (2010) M J J A S O N D (ppb) 40 60 80 100 120 140 160 180 MNM Station Aircraft (1000ft) CO (2010) M J J A S O N D (ppb) CO 2 ：+0.08±0.28 (ppm) CH 4 ：+1.2±3.9 (ppb) CO：+2.4±4.5 (ppb) Fig. 3. Comparison of time series of CO 2 , CH 4 and CO between air samples at 1000 ft and ground based station at MNM. 4.57μm 1.6μm 150nm LI-COR LI-7000 LGR DLT-100 Fast N2O/CO Analyzer Picarro G1301 Analyzer Aero-Laser GmbH Fast CO Analyzer AL5002 Ti-Flask Stirling Cooler Standard Gases Flask measurement Unit Calibration Unit Flask Selection Unit Dehumidify Unit Analyzing Unit CO 2 (NDIR) Fig. 4. New measurement system at JMA. Fig. 5. Schematic diagram of the measurement system for flask sampled air at JMA. Table 1. Measurement techniques used for flask sampled air. Before introducing sample air to the instruments, line tubes are vacuumed. At the same time, back purge gases are introduced to the instruments with keeping the flow rates/pressures in the measurement cells to avoid the signal drift of the instruments. Fig. 6. Examples of the signal changes of ICOS. Flask sample is introduced to the instruments from at 2 min. after line tube vacuuming/back purging for the cells. Fig. 7. Examples of the signal changes during the 6 flask air sample measurements. Measurements are conducted in a sequence with 5 standard gases → 3 flasks → 5 standard gases → 3 flasks → 5 standard gases. Experiments using standard gases and natural air samples showed high repetitive accuracy, linear responses, consistency among the different measuring techniques for CO 2 , CH 4 , CO and N 2 O. It is also suggested relatively smaller isotopic influences for the measurements. 0.08 0.07 0.28 0.26 0.014 SD (SD:ppb) (SD:ppb) (SD:ppb) (SD:ppb) (SD:ppm) N=9 CO‐ICOS N2O‐ICOS CO‐VURF CH4‐CRDS CO2‐CRDS Table 2. Standard deviations of repeated measurements of standard gas. 0.58 ‐0.01 0.49 0.99 0.09 Δ (A)-(B) 101.04 314.00 101.19 1778.18 387.14 Assigned （B) 0.31 0.03 0.33 0.62 0.06 SD 101.62 313.99 101.68 1779.17 387.23 Average (A) (ppb) (ppb) (ppb) (ppb) (ppm) N=6 CO‐ICOS N2O‐ICOS CO‐VURF CH4‐CRDS CO2‐CRDS Table 3. Comparison of mixing ratios between results from air in the flask filled from a standard cylinder and their assigned values. 290 300 310 320 330 340 350 290 300 310 320 330 340 350 N 2 O-ICOS Output N 2 O (ppb) N 2 O-ICOS 0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 350 CO-ICOS Output CO (ppb) CO-ICOS -1.0 -0.5 0.0 0.5 1.0 290 300 310 320 330 340 350 Residual (ppb) N 2 O (ppb) N 2 O-ICOS -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 0 50 100 150 200 250 300 350 Residual (ppb) CO (ppb) CO-ICOS Fig. 8. Responses of ICOS for 5 standard gases and the residuals from a linear fitted line. Fig. 9. Histograms for differences in CO between measured by ICOS and VURF (a), and N 2 O between ICOS and GC/ECD (b). Table 4. Differences in mixing ratios of sampled air between two types of instruments. Table 5. Theoretical estimations for isotopic effects on the measurements by different isotopic compositions between natural air and standard gases By JMA test/routine aircraft observations, about 1 year time series of CO 2 , CH 4 and CO are obtained. Preliminary analysis suggested higher CO 2 mixing ratios at 6 km compared with those at about 10 km in CONTRAIL project *8 from winter to spring. The observed data will contribute the study for the distributions and transport of trace gases in the middle troposphere over the western North Pacific. Air intake Fig. 10. Observed time series of CO 2 , CH 4 and CO between Atsugi and Minamitorishima at 6 km height. Vertical bars denote the standard deviations of about 20 air samples in each month. Observed mixing ratios between 30 N and 25 N during the flights between Australia and Japan in the CONTRAIL project are shown in red colors. 350 370 390 410 430 450 0 30 60 90 120 150 180 210 240 270 CO 2 Signal NDIR-CO 2 CRDS-CO 2 1600 1700 1800 1900 2000 2100 0 30 60 90 120 150 180 210 240 270 CH 4 Signal CRDS-CH 4 Time (min) 0 50 100 150 200 250 300 350 0 30 60 90 120 150 180 210 240 270 CO Signal VURF-CO ICOS-CO 290 300 310 320 330 340 350 0 30 60 90 120 150 180 210 240 270 N 2 O Signal ICOS-N 2 O Time (min) 0 50 100 150 200 250 300 350 400 0 30 60 90 120 150 180 210 240 270 Pressure (kPa) Sample Pressure (PS-7) -0.002 -0.001 0.000 0.001 0.002 0.003 0.004 0.005 0.006 0 30 60 90 120 150 180 210 240 270 H 2 O (%) Time (min) H 2 O-CRDS Acknowledgements: We would like to many staff of the Japan Ministry of Defense, crew members and staff of Japan Air and Marine Self-Defense Force for supporting the aircraft observations. The system development is supported by Mr. Kitao, Uchiyama from KANSO Technos, and Kudo from JANS. Dr. Murayama, Tohjima, Ishijima, and Katsumata give the useful technical advices. References: *1 Crosson, E. R. (2008), Appl. Phys., B92, 403-408. *2 Gerbig, C. et al. (1999), J. Geophys. Res., 104(D1), 1699-1704. *3 Baer, D. S. et al. (2002), Appl. Phys. B, doi:10.1007/ s00340-002-0971-z *4 Chen, H. et al. (2010), Atmos. Meas. Tech., 3, 375-386. *5 Umezawa, T. (2009), D.Sc. thesis, Tohoku Univ., Sendai, Japan. *6 Coplen, T. B. et al. (2002), Pure Appl. Chem., 74(10), 1987-2017. *7 Ishijima, K. (2003), D.Sc. thesis, Tohoku Univ., Sendai, Japan. *8 Machida, T. et al. (2008), J. Atmos. Oceanic Technol., 25, 1744-1754. 0 10 20 30 40 50 -1.2 -0.8 -0.4 0 0.4 0.8 1.2 Number of data AV: 0.12 ppb SD : 0.25 ppb N=128 CO ICOS-VURF Difference of CO (ppb) 0 10 20 30 40 -5 -4 -3 -2 -1 0 1 2 3 4 5 Difference of N 2 O (ppb) AV: 0.15 ppb SD :1.10 ppb N=103 Number of data N 2 O ICOS-GC/ECD -100 0 100 200 300 400 30 40 50 60 70 80 Sample Pressure (kPa) Sample flow (cm 3 /min) Sample Pressure during Flask analysis 0 2 4 6 8 10 12 ICOS Flow (cm 3 /min) 305 310 315 320 325 330 80 100 120 140 160 180 0 2 4 6 8 10 12 ICOS N 2 O(ppb) ICOS CO(ppb) N 2 O CO Time (min) Switching sample line CRDS-CO2 *4 CRDS- CH4 *5 ICOS-CO *6 ICOS-N2O *7 (ppm) (ppb) (ppb) (ppb) ∆ -0.11～-0.15 0.05 ＜±0.1 ～-0.03 AIR δ13C-VPDB(‰) -8 -47 -27 δ15N-VPDB(‰) +7 δ18O-VSMOW(‰) +40～+42 +10 +45 δD-VSMOW(‰) -95 Standard Gas δ13C-VPDB(‰) -27～-37 -40 -22～-50 δ15N-VPDB(‰) -2 δ18O-VSMOW(‰) +12～+24 +10～+22 +26 δD-VSMOW(‰) -175 50 100 150 200 2010 2011 CO (6km) (ppb) (a) (b) 1. JMA aircraft observation for Green house gases Japan Meteorological Agency (JMA) has started an operational aircraft observation of greenhouse gases as a new atmospheric monitoring activity in 2011. A cargo aircraft C- 130H in Japan Ministry of Defense is used for the flask sampling observation during a regular flight between Atsugi and Minamitorishima (MNM) once a month. The air samples are collected during a cruising flight at about 6 km over the western North Pacific as well as a descending to MNM. After the flight, we measure 4 trace gas concentrations of carbon dioxide (CO 2 ), methane (CH 4 ), carbon monoxide (CO), and nitrous oxide (N 2 O). 382 386 390 394 398 2010 2011 CO 2 (6km) CONTRAIL-CME&ASE (10km, 30N-25N) (ppm) 1780 1810 1840 1870 1900 2010 2011 CH 4 (6km) CONTRAIL-ASE (10km, 30N-25N) (ppb)
