Atmospheric Chemistry and Physics
www.atmos-chem-phys.net
1680-7316
1680-7324
6
11
2006
10.5194/acp-6-3535-2006
http://www.atmos-chem-phys.net/6/3535/2006/
http://www.atmos-chem-phys.net/6/3535/2006/acp-6-3535-2006.html
http://www.atmos-chem-phys.net/6/3535/2006/acp-6-3535-2006.pdf
3535
3556
2006-08-30
Probing stratospheric transport and chemistry with new balloon and aircraft observations of the meridional and vertical N<sub>2</sub>O isotope distribution
J. Kaiser
J.Kaiser@uea.ac.uk
A. Engel
R. Borchers
T. Röckmann
Atmospheric Physics Division, Max Planck Institute for Nuclear Physics, Heidelberg, Germany
Institute for Atmosphere and Environment, J. W. Goethe University, Frankfurt, Germany
Planets and Comets Department, Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
now at: School of Environmental Sciences, University of East Anglia, Norwich, UK
now at: Institute for Marine and Atmospheric Research Utrecht, Utrecht University, The Netherlands
A comprehensive set of stratospheric balloon and aircraft samples was analyzed
for the position-dependent isotopic composition of nitrous oxide (N<sub>2</sub>O).
Results for a total of 220 samples from between 1987 and 2003 are presented,
nearly tripling the number of mass-spectrometric N<sub>2</sub>O isotope measurements
in the stratosphere published to date. Cryogenic balloon samples were obtained
at polar (Kiruna/Sweden, 68° N), mid-latitude (southern France,
44° N) and tropical sites (Hyderabad/India, 18° N). Aircraft
samples were collected with a newly-developed whole air sampler on board of the
high-altitude aircraft M55 Geophysica during the EUPLEX 2003 campaign. For
mixing ratios above 200 nmol mol<sup>−1</sup>, relative isotope enrichments
(δ values) and mixing ratios display a compact relationship,
which is nearly independent of latitude and season and which can be explained
equally well by Rayleigh fractionation or mixing. However, for mixing ratios
below 200 nmol mol<sup>−1</sup> this compact relationship gives way to meridional,
seasonal and interannual variations. A comparison to a previously published
mid-latitude balloon profile even shows large zonal variations, justifying the
use of three-dimensional (3-D) models for further data interpretation.
<P>
In general, the magnitude of the apparent fractionation constants (i.e.,
apparent isotope effects) increases continuously with altitude and decreases
from the equator to the North Pole. Only the latter observation can be
understood qualitatively by the interplay between the time-scales of N<sub>2</sub>O
photochemistry and transport in a Rayleigh fractionation framework. Deviations
from Rayleigh fractionation behavior also occur where polar vortex air mixes
with nearly N<sub>2</sub>O-free upper stratospheric/mesospheric air (e.g., during the
boreal winters of 2003 and possibly 1992). Aircraft observations in the polar
vortex at mixing ratios below 200 nmol mol<sup>−1</sup> deviate from isotope
variations expected for both Rayleigh fractionation and two-end-member mixing, but
could be explained by continuous weak mixing between intravortex and extravortex
air (Plumb et al., 2000). However, it appears that none of the simple approaches
described here can capture all features of the stratospheric N<sub>2</sub>O isotope
distribution, again justifying the use of 3-D models. Finally, correlations
between <sup>18</sup>O/<sup>16</sup>O and average <sup>15</sup>N/<sup>14</sup>N isotope ratios or
between the position-dependent <sup>15</sup>N/<sup>14</sup>N isotope ratios show that
photo-oxidation makes a large contribution to the total N<sub>2</sub>O sink in the
lower stratosphere (possibly up to 100% for N<sub>2</sub>O mixing ratios above
300 nmol mol<sup>−1</sup>). Towards higher altitudes, the temperature dependence of
these isotope correlations becomes visible in the stratospheric observations.
Bender, M. L.: The $\delta ^18$O of dissolved O<sub>2</sub> in seawater: A unique tracer of circulation and respiration in the deep sea, J. Geophys. Res., 95, 22 243–22 252, 1990.
Bernard, S., Röckmann, T., Kaiser, J., Barnola, J.-M., Fischer, H., Blunier, T., and Chappellaz, J.: Constraints on N<sub>2</sub>O budget changes since pre-industrial time from new firn air and ice core isotope measurements, Atmos. Chem. Phys., 6, 493–503, 2006.
Boering, K. R., Wofsy, S. C., Daube, B. C., Schneider, H. R., Loewenstein, M., Podolske, J. R., and Conway, T. J.: Stratospheric mean ages and transport rates from observations of carbon dioxide and nitrous oxide, Science, 274, 1340–1343, 1996.
Brenninkmeijer, C. A. M. and Röckmann, T.: Mass spectrometry of the intramolecular nitrogen isotope distribution of environmental nitrous oxide using fragment-ion analysis, Rapid Commun. Mass Spectrom., 13, 2028–2033, 1999.
Brenninkmeijer, C. A. M., Janssen, C., Kaiser, J., Röckmann, T., Rhee, T. S., and Assonov, S. S.: Isotope effects in the chemistry of atmospheric trace compounds, Chem. Rev., 103, 5125–5162, 2003.
Curtius, J., Weigel, R., Všssing, H.-J., Wernli, H., Werner, A., Volk, C.-M., Konopka, P., Krebsbach, M., Schiller, C., Roiger, A., Schlager, H., Dreiling, V., and Borrmann, S.: Observations of meteoric material and implications for aerosol nucleation in the winter Arctic lower stratosphere derived from in situ particle measurements, Atmos. Chem. Phys., 5, 3053–3069, 2006.
Engel, A., Strunk, M., Müller, M., Haase, H.-P., Poss, C., Levin, I., and Schmidt, U.: Temporal development of total chlorine in the high-latitude stratosphere based on reference distributions of mean age derived from CO<sub>2</sub> and SF$_6$, J. Geophys. Res., 107, 1–11, 2002.
Engel, A., Möbius, T., Haase, H.-P., Bönisch, H., Wetter, T., Schmidt, U., Levin, I., Reddmann, T., Oelhaf, H., Grunow, K., Huret, N., and Pirre, M.: Observation of mesospheric air inside the arctic stratospheric polar vortex in early 2003, Atmos. Chem. Phys., 6, 267–282, 2006.
Esler, M. B., Griffith, D. W. T., Wilson, S. R., and Steele, L. P.: Precision trace gas analysis by FT-IR spectroscopy. 1. Simultaneous analysis of CO<sub>2</sub>, CH<sub>4</sub>, N<sub>2</sub>O, and CO in air, Anal. Chem., 72, 206–215, 2000.
Griffith, D. W. T., Toon, G. C., Sen, B., Blavier, J.-F., and Toth, R. A.: Vertical profiles of nitrous oxide isotopomer fractionation measured in the stratosphere, Geophys. Res. Lett., 27, 2485–2488, 2000.
Johnston, J. C., Cliff, S. S., and Thiemens, M. H.: Measurement of multioxygen isotopic ($\delta ^18$O and $\delta ^17$O) fractionation factors in the stratospheric sink reactions of nitrous oxide, J. Geophys. Res., 100, 16 801–16 804, 1995.
Kaiser, J.: Stable isotope investigations of atmospheric nitrous oxide (http://archimed.uni-mainz.de/pub/2003/0004/), Ph.D. thesis, Johannes Gutenberg-Universität, Mainz, 2002.
Kaiser, J., Brenninkmeijer, C. A. M., and Röckmann, T.: Intramolecular $^15$N and $^18$O fractionation in the reaction of N<sub>2</sub>O with O($^1$D) and its implications for the stratospheric N<sub>2</sub>O isotope signature, J. Geophys. Res., 107, 4214, doi:10.1029/2001JD001506, 2002a.
Kaiser, J., Röckmann, T., and Brenninkmeijer, C. A. M.: Temperature dependence of isotope fractionation in N<sub>2</sub>O photolysis, Phys. Chem. Chem. Phys., 4, 4220–4230, doi:10.1039/B204837J, 2002b.
Kaiser, J., Röckmann, T., and Brenninkmeijer, C. A. M.: Complete and accurate mass-spectrometric isotope analysis of tropospheric nitrous oxide, J. Geophys. Res., 108, 4476, doi:10.1029/2003JD003613, 2003a.
Kaiser, J., Röckmann, T., Brenninkmeijer, C. A. M., and Crutzen, P. J.: Wavelength dependence of isotope fractionation in N<sub>2</sub>O photolysis, Atmos. Chem. Phys., 3, 303–313, 2003b.
Kaiser, J., Park, S., Boering, K. A., Brenninkmeijer, C. A. M., Hilkert, A. W., and Röckmann, T.: Mass-spectrometric method for the absolute calibration of the intramolecular nitrogen isotope distribution in nitrous oxide, Anal. Bioanal. Chem., 378, 256–269, doi:10.1007/s00216-003-2233-2, 2004a.
Kaiser, J., Röckmann, T., and Brenninkmeijer, C. A. M.: Contribution of mass-dependent fractionation to the oxygen isotope anomaly of atmospheric nitrous oxide, J. Geophys. Res., 109, D03305, doi:10.1029/2003JD004088, 2004b.
Kaiser, J. and Röckmann, T.: Absence of isotope exchange in the reaction of N<sub>2</sub>O + O($^1$D) and the global $\Delta ^17$O budget of nitrous oxide, Geophys. Res. Lett., 32, L15808, doi:10.1029/2005GL023199, 2005.
Kaye, J. A.: Mechanisms and observations for isotope fractionation of molecular species in planetary atmospheres, Rev. Geophys., 25, 1609–1658, 1987.
Keeling, C. D.: The concentration and isotopic abundance of atmospheric carbon dioxide in rural areas, Geochim. Cosmochim. Acta, 13, 322–334, 1958.
Kim, K.-R. and Craig, H.: Nitrogen-15 and oxygen-18 characteristics of nitrous oxide: A global perspective, Science, 262, 1855–1857, 1993.
McLinden, C. A., Prather, M. J., and Johnson, M. S.: Global modeling of the isotopic analogues of N<sub>2</sub>O: Stratospheric distributions, budgets, and the $^17$O-$^18$O mass-independent anomaly, J. Geophys. Res., 108, 4233, doi:10.1029/2002JD002560, 2003.
Michelsen, H. A., Manney, G. L., Gunson, M. R., Rinsland, C. P., and Zander, R.: Correlations of stratospheric abundances of CH<sub>4</sub> and N<sub>2</sub>O derived from ATMOS measurements, Geophys. Res. Lett., 25, 2777–2780, 1998.
Minschwaner, K., Salawitch, R. J., and McElroy, M. B.: Absorption of solar radiation by O<sub>2</sub>: Implications for O<sub>3</sub> and lifetimes of N<sub>2</sub>O, CFCl<sub>3</sub>, and CF<sub>2</sub>Cl<sub>2</sub>, J. Geophys. Res., 98, 10 543–10 561, 1993.
Moore, H.: Isotopic measurement of atmospheric nitrogen compounds, Tellus, 26, 169–174, 1974.
Morgan, C. G., Allen, M., Liang, M. C., Shia, R. L., Blake, G. A., and Yung, Y. L.: Isotopic fractionation of nitrous oxide in the stratosphere: Comparison between model and observations, J. Geophys. Res., 109, D04305, doi:10.1029/2003JD003402, 2004.
Park, S., Atlas, E. L., and Boering, K. A.: Measurements of N<sub>2</sub>O isotopologues in the stratosphere: Influence of transport on the apparent enrichment factors and the isotope fluxes to the troposphere, J. Geophys. Res., 109, D01305, doi:10.1029/2003JD003731, 2004.
Patra, P. K., Lal, S., Venkataramani, S., and Chand, D.: Halogen Occultation Experiment (HALOE) and balloon-borne in situ measurements of methane in stratosphere and their relation to the quasi-biennial oscillation (QBO), Atmos. Chem. Phys., 3, 1051–1062, 2003.
Plumb, R. A., Waugh, D. W., and Chipperfield, M. P.: The effects of mixing on tracer relationships in the polar vortices, J. Geophys. Res., 105, 10 047–10 062, 2000.
Prather, M., Ehhalt, D., Dentener, F., Derwent, R., Dlugokencky, E., Holland, E., Isaksen, I., Katima, J., Kirchhoff, V., Matson, P., Midgley, P., and Wang, M.: Atmospheric chemistry and greenhouse gases, in: Climate Change 2001: The Scientific Basis, edited by: Houghton, J. T., Ding, Y., Griggs, D. J., et al., 239–287, Cambridge University Press, 2001.
Prinn, R. G., Weiss, R. F., Fraser, P. J., Simmonds, P. G., Cunnold, D. M., Alyea, F. N., O'Doherty, S., Salameh, P., Miller, B. R., Huang, J., Wang, R. H. J., Hartley, D. E., Harth, C., Steele, L. P., Sturrock, G., Midgley, P. M., and McCulloch, A.: A history of chemically and radiatively important gases in air deduced from ALE/GAGE/AGAGE, J. Geophys. Res., 105, 17 751–17 792, 2000.
Rahn, T. and Wahlen, M.: Stable isotope enrichment in stratospheric nitrous oxide, Science, 278, 1776–1778, 1997.
Rahn, T., Zhang, H., Wahlen, M., and Blake, G. A.: Stable isotope fractionation during ultraviolet photolysis of N<sub>2</sub>O, Geophys. Res. Lett., 25, 4489–4492, 1998.
Röckmann, T., Kaiser, J., Brenninkmeijer, C. A. M., Crowley, J. N., Borchers, R., Brand, W. A., and Crutzen, P. J.: The isotopic enrichment of nitrous oxide ($^15$N$^14$NO, $^14$N$^15$NO, $^14$N$^14$N$^18$O) in the stratosphere and in the laboratory, J. Geophys. Res., 106, 10 403–10 410, 2001.
Röckmann, T., Kaiser, J., and Brenninkmeijer, C. A. M.: The isotopic fingerprint of the pre-industrial and the anthropogenic N<sub>2</sub>O source, Atmos. Chem. Phys., 3, 315–323, 2003a.
Röckmann, T., Kaiser, J., Brenninkmeijer, C. A. M., and Brand, W. A.: Gas-chromatography/isotope-ratio mass spectrometry method for high-precision position-dependent $^15$N and $^18$O measurements of atmospheric nitrous oxide, Rapid Commun. Mass Spectrom., 17, 1897–1908, 2003b.
Röckmann, T. and Levin, I.: High-precision determination of the changing isotopic composition of atmospheric N<sub>2</sub>O from 1990 to 2002, J. Geophys. Res., 110, D21304, doi:10.1029/2005JD006066, 2005.
Schmidt, U., Kulessa, G., Klein, E., Roth, E. P., Fabian, P., and Borchers, R.: Intercomparison of balloon-borne cryogenic whole air samplers during the MAP/GLOBUS 1983 campaign, Planet. Space Sci., 35, 647, 1987.
Selwyn, G. S. and Johnston, H. S.: Ultraviolet absorption spectrum of nitrous oxide as function of temperature and isotopic substitution, J. Chem. Phys., 74, 3791–3803, 1981.
Sowers, T., Rodebaugh, A., Yoshida, N., and Toyoda, S.: Extending records of the isotopic composition of atmospheric N<sub>2</sub>O back to 1800 A.D. from air trapped in snow at the South Pole and the Greenland Ice Sheet Project II ice core, Global Biogeochem. Cycles, 16, 1129, doi:10.1029/2001GB001911, 2002.
Toyoda, S. and Yoshida, N.: Determination of nitrogen isotopomers of nitrous oxide on a modified isotope ratio mass spectrometer, Anal. Chem., 71, 4711–4718, 1999.
Toyoda, S., Yoshida, N., Urabe, T., Aoki, S., Nakazawa, T., Sugawara, S., and Honda, H.: Fractionation of N<sub>2</sub>O isotopomers in the stratosphere, J. Geophys. Res., 106, 7515–7522, 2001.
Toyoda, S., Yoshida, N., Urabe, T., Nakayama, Y., Suzuki, T., Tsuji, K., Shibuya, K., Aoki, S., Nakazawa, T., Ishidoya, S., Ishijima, K., Sugawara, S., Machida, T., Hashida, G., Morimoto, S., and Honda, H.: Temporal and latitudinal distributions of stratospheric N<sub>2</sub>O isotopomers, J. Geophys. Res., 109, D08308, doi:10.1029/2003JD004316, 2004.
Volk, C. M., Elkins, J. W., Fahey, D. W., Dutton, G. S., Gilligan, J. M., Loewenstein, M., Podolske, J. R., Chan, K. R., and Gunson, M. R.: Evaluation of source gas lifetimes from stratospheric observations, J. Geophys. Res., 102, 25 543–25 563, 1997.
von Hessberg, P., Kaiser, J., Enghoff, M. B., McLinden, C. A., Sorensen, S. S., Röckmann, T., and Johnson, M. S.: Ultra-violet absorption cross sections of isotopically substituted nitrous oxide species: $^14$N$^14$NO, $^15$N$^14$NO, $^14$N$^15$NO and $^15$N$^15$NO, Atmos. Chem. Phys., 4, 1237–1253, 2004.
Yoshida, N., Morimoto, H., and Matsuo, S.: UV photolysis and microbial reduction as major sinks of nitrous oxide with emphasis on kinetic nitrogen isotope discrimination, Eos Trans. AGU, 71, 933–934, 1990.
Yoshida, N. and Toyoda, S.: Constraining the atmospheric N<sub>2</sub>O budget from intramolecular site preference in N<sub>2</sub>O isotopomers, Nature, 405, 330–334, 2000.
Yung, Y. L. and Miller, C. E.: Isotopic fractionation of stratospheric nitrous oxide, Science, 278, 1778–1780, 1997.