Carbon and hydrogen isotopic ratios of atmospheric methane in the upper troposphere over the Western Pacific

Abstract. We present the mixing ratio, δ13C and δD of atmospheric CH4 using commercial aircraft in the upper troposphere (UT) over the Western Pacific for the period December 2005–September 2010. The observed results were compared with those obtained using commercial container ships in the lower troposphere (LT) over the same region. In the Northern Hemisphere (NH), the UT CH4 mixing ratio shows high values in the boreal summer–autumn, when the LT CH4 mixing ratio reaches a seasonal minimum. From tagged tracer experiments made using an atmospheric chemistry transport model, we found that such high CH4 values are due to rapid transport of air masses influenced by CH4 sources in South Asia and East Asia. The observed isotopic ratio data imply that these areas have CH4 sources with relatively low δ13C and δD signatures such as biogenic sources. Latitudinal distributions of the annual average UT and LT CH4 mixing ratio intersect each other in the tropics; the mixing ratio value is lower in the UT than in the LT in the NH and the situation is reversed in the Southern Hemisphere (SH), due mainly to the NH air intrusion into the SH through the UT. Such intersection of the latitudinal distributions is observable in δD but not in δ13C, implying an additional contribution from reaction of CH4 with active chlorine in the marine boundary layer. δ13C and δD show low values in the NH and high values in the SH both in the UT and in the LT. We also observed an increase in the CH4 mixing ratio and decreases in δ13C and δ

[1]  R. Prinn,et al.  The value of high‐frequency, high‐precision methane isotopologue measurements for source and sink estimation , 2012 .

[2]  Hidekazu Matsueda,et al.  Aircraft observation of the seasonal variation in the transport of CO2 in the upper atmosphere , 2012 .

[3]  Yongwon Kim,et al.  Carbon and hydrogen stable isotopic ratios of methane emitted from wetlands and wildfires in Alaska: Aircraft observations and bonfire experiments , 2011 .

[4]  Shamil Maksyutov,et al.  Interannual variability and trends in atmospheric methane over the western Pacific from 1994 to 2010 , 2011 .

[5]  Shamil Maksyutov,et al.  TransCom model simulations of CH4 and related species: linking transport, surface flux and chemical loss with CH4 variability in the troposphere and lower stratosphere , 2011 .

[6]  E. Dlugokencky,et al.  Global atmospheric methane: budget, changes and dangers , 2011, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[7]  Peter Bergamaschi,et al.  Global column-averaged methane mixing ratios from 2003 to 2009 as derived from SCIAMACHY: Trends and variability , 2011 .

[8]  T. Röckmann,et al.  Continuous-flow isotope ratio mass spectrometry method for carbon and hydrogen isotope measurements on atmospheric methane , 2010 .

[9]  Philippe Ciais,et al.  Source attribution of the changes in atmospheric methane for 2006–2008 , 2010 .

[10]  Tatsuya Yokota,et al.  Retrieval algorithm for CO 2 and CH 4 column abundances from short-wavelength infrared spectral observations by the Greenhouse gases observing satellite , 2010 .

[11]  P. Krummel,et al.  Stratospheric influence on the seasonal cycle of nitrous oxide in the troposphere as deduced from aircraft observations and model simulations , 2010 .

[12]  P. V. Velthoven,et al.  Characterization of non-methane hydrocarbons in Asian summer monsoon outflow observed by the CARIBIC aircraft , 2010 .

[13]  W. Landman.  Climate change 2007: the physical science basis , 2010 .

[14]  F. Slemr,et al.  Greenhouse gas relationships in the Indian summer monsoon plume measured by the CARIBIC passenger aircraft , 2010 .

[15]  J. Schmitt,et al.  A gas chromatography/pyrolysis/isotope ratio mass spectrometry system for high-precision deltaD measurements of atmospheric methane extracted from ice cores. , 2010, Rapid communications in mass spectrometry : RCM.

[16]  D. Davydov,et al.  Continuous measurements of methane from a tower network over Siberia , 2010 .

[17]  J. F. Meirink,et al.  Inverse Modeling of Global and Regional CH4 Emissions Using SCIAMACHY Satellite Retrievals , 2009 .

[18]  P. Krummel,et al.  Trace gases and CO2 isotope records from Cabo de Rama, India , 2009 .

[19]  P. M. Lang,et al.  Observational constraints on recent increases in the atmospheric CH4 burden , 2009 .

[20]  Tae-Young Goo,et al.  Growth Rate, Seasonal, Synoptic, Diurnal Variations and Budget of Methane in the Lower Atmosphere , 2009 .

[21]  T. Umezawa,et al.  A High-precision Measurement System for Carbon and Hydrogen Isotopic Ratios of Atmospheric Methane and Its Application to Air Samples Collected in the Western Pacific Region , 2009 .

[22]  Mijeong Park,et al.  Transport pathways of carbon monoxide in the Asian summer monsoon diagnosed from Model of Ozone and Related Tracers (MOZART) , 2009 .

[23]  K. Sudo,et al.  Temporal and spatial variations of carbon monoxide over the western part of the Pacific Ocean , 2009 .

[24]  K. Ishijima,et al.  Variations of atmospheric nitrous oxide concentration in the northern and western Pacific , 2009 .

[25]  Y. Sawa,et al.  Seasonal variations of CO2 near the tropopause observed by commercial aircraft , 2008 .

[26]  Derek M. Cunnold,et al.  Renewed growth of atmospheric methane , 2008 .

[27]  Toshinobu Machida,et al.  Worldwide Measurements of Atmospheric CO2 and Other Trace Gas Species Using Commercial Airlines , 2008 .

[28]  Toshiki Iwasaki,et al.  Global-scale transport of carbon dioxide in the troposphere , 2008 .

[29]  Christopher D. Barnet,et al.  Methane plume over south Asia during the monsoon season: satellite observation and model simulation , 2008 .

[30]  R. Betts,et al.  Changes in Atmospheric Constituents and in Radiative Forcing. Chapter 2 , 2007 .

[31]  Paul J. Crutzen,et al.  Civil Aircraft for the regular investigation of the atmosphere based on an instrumented container: The new CARIBIC system , 2007 .

[32]  N. Livesey,et al.  Connecting surface emissions, convective uplifting, and long‐range transport of carbon monoxide in the upper troposphere: New observations from the Aura Microwave Limb Sounder , 2007 .

[33]  H. Schaefer,et al.  Constraining past global tropospheric methane budgets with carbon and hydrogen isotope ratios in ice , 2007, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[34]  S. Kobayashi,et al.  The JRA-25 Reanalysis , 2007 .

[35]  E. Dlugokencky,et al.  Airborne measurements indicate large methane emissions from the eastern Amazon basin , 2007 .

[36]  D. Lowe,et al.  Methane carbon isotope effects caused by atomic chlorine in the marine boundary layer: Global model results compared with Southern Hemisphere measurements , 2007 .

[37]  Andrew L. Rice,et al.  Stable isotope ratios in atmospheric CH4: Implications for seasonal sources and sinks , 2007 .

[38]  Peter Bergamaschi,et al.  Satellite chartography of atmospheric methane from SCIAMACHY on board ENVISAT: 2. Evaluation based on inverse model simulations , 2007 .

[39]  J. B. Miller,et al.  Contribution of anthropogenic and natural sources to atmospheric methane variability , 2006, Nature.

[40]  S. Sudo,et al.  Hydrogen and carbon isotopic measurements of methane from agricultural combustion: Implications for isotopic signatures of global biomass burning sources , 2006 .

[41]  Ilse Aben,et al.  Atmospheric constraints on global emissions of methane from plants , 2006 .

[42]  R. Prinn,et al.  Estimation of atmospheric methane emissions between 1996 and 2001 using a three-dimensional global chemical transport model , 2006 .

[43]  S. Aoki,et al.  Temporal variations of the carbon isotopic ratio of atmospheric methane observed at Ny Ålesund, Svalbard from 1996 to 2004 , 2006 .

[44]  G. Brailsford,et al.  Interannual variation of 13C in tropospheric methane: Implications for a possible atomic chlorine sink in the marine boundary layer , 2005 .

[45]  P. M. Lang,et al.  Ten years of atmospheric methane observations at a high elevation site in Western China , 2004 .

[46]  David G. Streets,et al.  Constraints on Asian and European sources of methane from CH4‐C2H6‐CO correlations in Asian outflow , 2004 .

[47]  P. Patra,et al.  Trends in methane and sulfur hexafluoride at a tropical coastal site, Thumba (8.6°N, 77.°E), in India , 2004 .

[48]  Rolando R. Garcia,et al.  Seasonal variation of methane, water vapor, and nitrogen oxides near the tropopause: Satellite observations and model simulations , 2004 .

[49]  Michael Q. Wang,et al.  An inventory of gaseous and primary aerosol emissions in Asia in the year 2000 , 2003 .

[50]  P. M. Lang,et al.  Atmospheric methane levels off: Temporary pause or a new steady‐state? , 2003 .

[51]  Toshimasa Ohara,et al.  A country-specific, high-resolution emission inventory for methane from livestock in Asia in 2000 , 2003 .

[52]  E. Atlas,et al.  Carbon and hydrogen isotopic compositions of stratospheric methane: 1. High‐precision observations from the NASA ER‐2 aircraft , 2003 .

[53]  T. Röckmann,et al.  The isotopic composition of methane in the stratosphere , 2003 .

[54]  Jed O. Kaplan,et al.  The application and interpretation of Keeling plots in terrestrial carbon cycle research , 2003 .

[55]  H. Akimoto,et al.  Development of region‐specific emission factors and estimation of methane emission from rice fields in the East, Southeast and South Asian countries , 2003 .

[56]  K. Sudo,et al.  CHASER: A global chemical model of the troposphere 1. Model description , 2002 .

[57]  R. Weiss,et al.  In situ measurements of atmospheric methane at GAGE/AGAGE sites during 1985–2000 and resulting source inferences , 2002 .

[58]  E. Dlugokencky,et al.  Development of analytical methods and measurements of 13C/12C in atmospheric CH4 from the NOAA Climate Monitoring and Diagnostics Laboratory Global Air Sampling Network , 2002 .

[59]  Shamil Maksyutov,et al.  Analysis and presentation of in situ atmospheric methane measurements from Cape Ochi‐ishi and Hateruma Island , 2002 .

[60]  Hidekazu Matsueda,et al.  Aircraft observation of carbon dioxide at 8–13 km altitude over the western Pacific from 1993 to 1999 , 2002 .

[61]  C. Brühl,et al.  Carbon 13 and D kinetic isotope effects in the reactions of CH4 with O(1 D) and OH: New laboratory measurements and their implications for the isotopic composition of stratospheric methane , 2001 .

[62]  S. Tyler,et al.  High-Precision Continuous-Flow Measurement of δ13C and δD of Atmospheric CH4 , 2001 .

[63]  A. Arneth,et al.  Vertical profiles, boundary layer budgets, and regional flux estimates for CO2 and its 13C/12C ratio and for water vapor above a forest/bog mosaic in central Siberia , 2001 .

[64]  M. Manning,et al.  Modeling the variation of δ13C in atmospheric methane: Phase ellipses and the kinetic isotope effect , 2001 .

[65]  W. Brand,et al.  Referencing strategies and techniques in stable isotope ratio analysis. , 2001, Rapid communications in mass spectrometry : RCM.

[66]  K. Higuchi,et al.  Latitudinal distribution of atmospheric CO2 sources and sinks inferred by δ13C measurements from 1985 to 1991 , 2000 .

[67]  R. Cicerone,et al.  Experimentally determined kinetic isotope effects in the reaction of CH4 with Cl: Implications for atmospheric CH4 , 2000 .

[68]  Michael B. McElroy,et al.  Three-dimensional climatological distribution of tropospheric OH: Update and evaluation , 2000 .

[69]  M. Manning,et al.  Aircraft observations of δ13C of atmospheric methane over the Pacific in August 1991 and 1993: Evidence of an enrichment in 13CH4 in the southern hemisphere , 2000 .

[70]  E. Dlugokencky,et al.  Stable carbon isotopic composition of atmospheric methane: A comparison of surface level and free tropospheric air , 1999 .

[71]  M. Takigawa,et al.  Simulation of ozone and other chemical species using a Center for Climate System Research/National Institute for Environmental Studies atmospheric GCM with coupled stratospheric chemistry , 1999 .

[72]  E. Dlugokencky,et al.  The isotopic composition of atmospheric methane , 1999 .

[73]  R. Francey,et al.  High Precision Long-Term Monitoring of Radiatively Active and Related Trace Gases at Surface Sites and from Aircraft in the Southern Hemisphere Atmosphere , 1999 .

[74]  H. Matsueda,et al.  Carbon monoxide in the upper troposphere over the western Pacific between 1993 and 1996 , 1998 .

[75]  D. Etheridge,et al.  Atmospheric methane between 1000 A.D. and present: Evidence of anthropogenic emissions and climatic variability , 1998 .

[76]  P. Crutzen,et al.  Isotope analysis based source identification for atmospheric CH4 and CO sampled across Russia using the Trans-Siberian railroad , 1998 .

[77]  T. Machida,et al.  Vertical profile of the carbon isotopic ratio of stratospheric methane over Japan , 1997 .

[78]  M. Ishizawa,et al.  TWO CURVE FITTING METHODS APPLIED TO CO2 FLASK DATA , 1997 .

[79]  S. Aoki,et al.  Temporal and spatial variations of the carbon isotopic ratio of atmospheric carbon dioxide in the western Pacific region , 1997 .

[80]  P. Bergamaschi,et al.  D/H kinetic isotope effect in the reaction CH4+Cl , 1996 .

[81]  T. Machida,et al.  Aircraft measurements of the stable carbon isotopic ratio of atmospheric methane over Siberia , 1996 .

[82]  H. Matsueda,et al.  Measurements of atmospheric CO2 and CH4 using a commercial airliner from 1993 to 1994 , 1996 .

[83]  P. Bergamaschi,et al.  Carbon kinetic isotope effect in the reaction of CH4 with Cl atoms , 1995 .

[84]  Edward J. Dlugokencky,et al.  The growth rate and distribution of atmospheric methane , 1994 .

[85]  C. Gautier,et al.  A Satellite-derived Climatology of the ITCZ , 1993 .

[86]  S. Morimoto,et al.  Time and space variations of the carbon isotopic ratio of tropospheric carbon dioxide over Japan , 1993 .

[87]  Toshinobu Machida,et al.  Differences of the atmospheric CH4 concentration between the Arctic and Antarctic regions in pre‐industrial/pre‐agricultural era , 1993 .

[88]  S. Murayama,et al.  Measurements of atmospheric methane at the Japanese Antarctic Station, Syowa , 1992 .

[89]  S. Murayama,et al.  Longitudinally different variations of lower tropospheric carbon dioxide concentrations over the North Pacific Ocean , 1992 .

[90]  J. Lerner,et al.  Three‐dimensional model synthesis of the global methane cycle , 1991 .

[91]  Takakiyo Nakazawa,et al.  Temporal and spatial variations of upper tropospheric and lower stratospheric carbon dioxide , 1991 .

[92]  Inez Y. Fung,et al.  Carbon isotopic composition of atmospheric CH4: Fossil and biomass burning source strengths , 1991 .

[93]  A. J. Crawford,et al.  The global distribution of methane in the troposphere , 1987 .

[94]  Inez Y. Fung,et al.  Methane emission from natural wetlands: Global distribution, area, and environmental characteristics of sources , 1987 .

[95]  R. Cicerone,et al.  Carbon kinetic isotope effect in the reaction of CH4 with HO , 1987 .

[96]  T. Nakazawa,et al.  Seasonal and meridional variations of atmospheric carbon dioxide in the lower troposphere of the northern and southern hemispheres , 1987 .

[97]  T. Nakazawa,et al.  Time and space variations of tropospheric carbon dioxide over Japan , 1987 .

[98]  D. Blake,et al.  World-wide increase in tropospheric methane, 1978–1983 , 1986 .

[99]  T. Nakazawa,et al.  Concentration of atmospheric carbon dioxide over Japan , 1983 .

[100]  Martin Schoell,et al.  The hydrogen and carbon isotopic composition of methane from natural gases of various origins , 1980 .

[101]  梅澤 拓.  A study of global methane cycle based on measurements of its carbon and hydrogen isotopes in the atmosphere , 2009 .

[102]  Y. Sawa,et al.  Evaluation of atmospheric CO2 measurements from new flask air sampling of JAL airliner observations , 2008 .

[103]  Peter Bergamaschi,et al.  SATELLITE CHARTOGRAPHY OF ATMOSPHERIC METHANE FROM SCIAMACHY ONBOARD ENVISAT , 2007 .

[104]  T. Saeki,et al.  Concentration variations of tropospheric nitrous oxide over Japan , 2001 .

[105]  E. Ferguson.  In Situ Measurements , 1982 .