Atmospheric Chemistry and Physics
www.atmos-chem-phys.net
1680-7316
1680-7324
8
18
2008
10.5194/acp-8-5627-2008
http://www.atmos-chem-phys.net/8/5627/2008/
http://www.atmos-chem-phys.net/8/5627/2008/acp-8-5627-2008.html
http://www.atmos-chem-phys.net/8/5627/2008/acp-8-5627-2008.pdf
5627
5634
2008-09-24
The interpretation of spikes and trends in concentration of nitrate in polar ice cores, based on evidence from snow and atmospheric measurements
E. W. Wolff
ewwo@bas.ac.uk
A. E. Jones
S. J.-B. Bauguitte
R. A. Salmon
British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
Nitrate is frequently measured in ice cores, but its interpretation remains
immature. Using daily snow surface concentrations of nitrate at Halley
(Antarctica) for 2004–2005, we show that sharp spikes (>factor 2) in
nitrate concentration can occur from day to day. Some of these spikes will
be preserved in ice cores. Many of them are associated with sharp increases
in the concentration of sea salt in the snow. There is also a close
association between the concentrations of aerosol nitrate and sea salt
aerosol. This evidence is consistent with many of the spikes in deposited
nitrate being due to the conversion or trapping of gas-phase nitrate, i.e. to
enhanced deposition rather than enhanced atmospheric concentrations of
NO<sub>y</sub>. Previously, sharp spikes in nitrate concentration (with
concentration increases of up to a factor 4 seen in probably just one
snowfall) have been assigned to sharp production events such as solar proton
events (SPEs). We find that it is unlikely that SPEs can produce spikes of
the kind seen. Taken together with our evidence that such spikes can be
produced depositionally, we find that it is not possible to track past SPEs
without carrying out a new multi-site and multi-analyte programme. Seasonal
and interannual trends in nitrate concentration in cores from any single
site cannot be interpreted in terms of production changes until the
recycling of nitrate from central Antarctica to coastal Antarctica is better
quantified. It might be possible to assess the interannual input of NO<sub>y</sub>
to the Antarctic lower troposphere by using a network of cores to estimate
variability in the total annual deposition across the continent (which we
estimate to be 9±2×10<sup>7</sup>kg/a – as NO<sub>3</sub><sup>−</sup>), but it will
first have to be established that the outflow across the coast can be ignored.
Arthern, R. J., Winebrenner, D. P., and Vaughan, D. G.: Antarctic snow accumulation mapped using polarization of 4.3-cm wavelength microwave emission, J. Geophys. Res., 111, D06107, doi:10.1029/2004JD005667, 2006.
Blunier, T., Floch, G. L., Jacobi, H. W., and Quansah, E.: Isotopic view on nitrate loss in Antarctic surface snow, Geophys. Res. Lett., 32, L13501, doi:10.1029/2005GL023011, 2005.
Clilverd, M. A., Seppala, A., Rodger, C. J., Thomson, N. R., Lichtenberger, J., and Steinbach, P.: Temporal variability of the descent of high-altitude NO<sub>x</sub> inferred from ionospheric data, J. Geophys. Res., 112, A09307, doi:10.1029/2006JA012085, 2007.
Davis, D., Chen, G., Buhr, M., Crawford, J., Lenschow, D., Lefer, B., Shetter, R., Eisele, F., Mauldin, L., and Hogan, A.: South Pole NO<sub>x</sub> chemistry: an assessment of factors controlling variability and absolute levels, Atmos. Environ., 38, 5375–5388, 2004.
Dibb, J. E. and Whitlow, S. I.: Recent climate anomalies and their impact on snow chemistry at South Pole, 1987–1994, Geophys. Res. Lett., 23, 1115–1118, 1996.
Fischer, H., Wagenbach, D., and Kipfstuhl, J.: Sulfate and nitrate firn concentrations on the Greenland ice sheet 2. Temporal anthropogenic deposition changes, J. Geophys. Res., 103, 21 935–21 942, 1998.
Fuhrer, K., Neftel, A., Anklin, M., Staffelbach, T., and Legrand, M.: High-resolution ammonium ice core record covering a complete glacial-interglacial cycle, J. Geophys. Res., 101, 4147–4164, 1996.
Grannas, A. M., Jones, A. E., Dibb, J., Ammann, M., Anastasio, C., Beine, H. J., Bergin, M., Bottenheim, J., Boxe, C. S., Carver, G., Chen, G., Crawford, J. H., Dominé, F., Frey, M. M., Guzmán, M. I., Heard, D. E., Helmig, D., Hoffmann, M. R., Honrath, R. E., Huey, L. G., Hutterli, M., Jacobi, H. W., Klán, P., McConnell, J., Plane, J., Sander, R., Savarino, J., Shepson, P. B., Simpson, W. R., Sodeau, J. R., von Glasow, R., Weller, R., Wolff, E. W., and Zhu, T.: An overview of snow photochemistry: Evidence, mechanisms and impacts, Atmos. Chem. Phys., 7, 4329–4373, 2007.
Herron, M. M.: Impurity sources of F$^-$, Cl$^-$, NO$_3^-$ and \chemSO_4^2- in Greenland and Antarctic precipitation, J. Geophys. Res., 87, 3052–3060, 1982.
Honrath, R. E., Peterson, M. C., Guo, S., Dibb, J. E., Shepson, P. B., and Campbell, B.: Evidence of NO<sub>x</sub> production within or upon ice particles in the Greenland snowpack, Geophys. Res. Lett., 26, 695–698, 1999.
Jones, A. E., Weller, R., Wolff, E. W., and Jacobi, H.-W.: Speciation and rate of photochemical NO and NO<sub>2</sub> production in Antarctic snow, Geophys. Res. Lett., 27, 345–348, 2000.
Jones, A. E., Wolff, E. W., Ames, D., Bauguitte, S. J.-B., Clemitshaw, K. C., Fleming, Z., Mills, G. P., Saiz-Lopez, A., Salmon, R. A., Sturges, W. T., and Worton, D. R.: The multi-seasonal NO<sub>y</sub> budget in coastal Antarctica and its link with surface snow and ice core nitrate: Results from the CHABLIS campaign, Atmos. Chem. Phys. Discuss., 7, 4127–4163, 2007.
Jones, A. E., Wolff, E. W., Salmon, R. A., Bauguitte, S. J.-B., Roscoe, H. K., Anderson, P. S., Ames, D., Clemitshaw, K. C., Fleming, Z., Bloss, W. J., Heard, D. E., Lee, J. D., Read, K. A., Hamer, P., Shallcross, D. E., Jackson, A., Walker, S., Lewis, A. C., Mills, G. P., Plane, J. M. C., Saiz-Lopez, A., Sturges, W. T., and Worton, D. R.: Chemistry of the Antarctic boundary layer and the interface with snow: an overview of the CHABLIS campaign, Atmos. Chem. Phys., 8, 3789–3803, 2008.
Jourdain, B. and Legrand, M.: Year-round records of bulk and size-segregated aerosol composition and HCl and HNO3 levels in the Dumont d'Urville (coastal Antarctica) atmosphere: Implications for sea-salt aerosol fractionation in the winter and summer, J. Geophys. Res., 107, 4645, doi:10.1029/2002JD002471, 2002.
König-Langlo, G., King, J., and Pettre, P.: Climatology of the three coastal Antarctic stations Dumont d'Urville, Neumayer and Halley, J. Geophys. Res., 103, 10 935–10 946, 1998.
Legrand, M., Wolff, E. W., and Wagenbach, D.: Antarctic aerosol and snowfall chemistry: implications for deep Antarctic ice core chemistry, Ann. Glaciol., 29, 66–72, 1999.
Legrand, M. R. and Kirchner, S.: Origins and variations of nitrate in south polar precipitation, J. Geophys. Res., 95, 3493–3507, 1990.
Legrand, M. R., Lorius, C., Barkov, N. I., and Petrov, V. N.: Vostok (Antarctica) ice core: atmospheric chemistry changes over the last climatic cycle (160 000 years), Atmos. Environ., 22, 317–331, 1988.
Mayewski, P. A., Lyons, W. B., Spencer, M. J., Twickler, M. S., Buck, C. F., and Whitlow, S.: An ice-core record of atmospheric response to anthropogenic sulphate and nitrate, Nature, 346, 554–556, 1990.
McCracken, K. G., Dreschhoff, G. A. M., Zeller, E. J., Smart, D. F., and Shea, M. A.: Solar cosmic ray events for the period 1561–1994 1. Identification in polar ice, 1561–1950, J. Geophys. Res., 106, 21 585–21 598, 2001.
McElroy, M. B.: Studies of polar ice: insights for atmospheric chemistry, in: The environmental record in glaciers and ice sheets, edited by: Oeschger, H. and Langway, C. C., Jr., John Wiley, Chichester, 363–377, 1989.
Mulvaney, R., Wagenbach, D., and Wolff, E. W.: Post-depositional change in snowpack nitrate from observation of year-round near-surface snow in coastal Antarctica, J. Geophys. Res., 103, 11 021–11 031, 1998.
Mulvaney, R. and Wolff, E. W.: Evidence for winter/spring denitrification of the stratosphere in the nitrate record of Antarctic ice cores, J. Geophys. Res., 98, 5213–5220, 1993.
Mulvaney, R. and Wolff, E. W.: Spatial variability of the major chemistry of the Antarctic ice sheet, Ann. Glaciol., 20, 440–447, 1994.
Palais, J. M., Chuan, R., and Spencer, M. J.: Soluble and insoluble impurities in snow samples from Ross Island, Antarctica, Ant. J. US, 24, 89–91, 1989.
Palmer, A. S., van~Ommen, T. D., Curran, M. A. J., and Morgan, V.: Ice-core evidence for a small solar-source of atmospheric nitrate, Geophys. Res. Lett., 28, 1953–1956, 2001.
Rankin, A. M. and Wolff, E. W.: A year-round record of size-segregated aerosol composition at Halley, Antarctica, J. Geophys. Res., 108, 4775, doi:10.1029/2003JD003993, 2003.
Röthlisberger, R., Hutterli, M. A., Sommer, S., Wolff, E. W., and Mulvaney, R.: Factors controlling nitrate in ice cores: evidence from the Dome C deep ice core, J. Geophys. Res., 105, 20 565–20 572, 2000.
Savarino, J., Kaiser, J., Morin, S., Sigman, D., and Thiemens, M. H.: Nitrogen and oxygen isotopic constraints on the origin of atmospheric nitrate in coastal Antarctica, Atmos. Chem. Phys., 7, 1925–1945, 2007.
Shea, M. A., Smart, D. F., and Dreschhoff, G. A. M.: Identification of major proton fluence events from nitrates in polar ice cores, Radiation Measurements, 30, 309–316, 1999.
Teinila, K., Kerminen, V. M., and Hillamo, R.: A study of size-segregated aerosol chemistry in the Antarctic atmosphere, J. Geophys. Res.-Atmos., 105, 3893–3904, 2000.
Vaughan, D. G., Bamber, J. L., Giovinetto, M., Russell, J., and Cooper, A. P. R.: Reassessment of net surface mass balance in Antarctica, J. Clim., 12, 933–946, 1999.
Vitt, F. M., Armstrong, T. P., Cravens, T. E., Dreschhoff, G. A. M., Jackman, C. H., and Laird, C. M.: Computed contributions to odd nitrogen concentrations in the Earth's polar middle atmosphere by energetic charged particles, J. Atmos. Sol.-Terr. Phy., 62, 669–683, 2000.
Wagenbach, D., Legrand, M., Fischer, H., Pichlmayer, F., and Wolff, E. W.: Atmospheric near-surface nitrate at coastal Antarctic sites, J. Geophys. Res., 103, 11 007–11 020, 1998.
Whitlow, S., Mayewski, P., Dibb, J., Holdsworth, G., and Twickler, M.: An ice-core-based record of biomass burning in the Arctic and Subarctic, 1750–1980, Tellus, 46B, 234–242, 1994.
Wolff, E. W.: Nitrate in Polar Ice, in: Ice core studies of global biogeochemical cycles, edited by: Delmas, R. J., Springer-Verlag, Berlin, 195–224, 1995.
Wolff, E. W., Fischer, H., Fundel, F., Ruth, U., Twarloh, B., Littot, G. C., Mulvaney, R., Rothlisberger, R., de Angelis, M., Boutron, C. F., Hansson, M., Jonsell, U., Hutterli, M. A., Bigler, M., Lambert, F., Kaufmann, P., Stauffer, B., Stocker, T. F., Steffensen, J. P., Siggaard-Andersen, M. L., Udisti, R., Becagli, S., Castellano, E., Severi, M., Wagenbach, D., Barbante, C., Gabrielli, P., and Gaspari, V.: Southern Ocean sea-ice extent, productivity and iron flux over the past eight glacial cycles, Nature, 440, 491–496, 2006.
Zeller, E. J. and Dreschhoff, G. A. M.: Anomalous nitrate concentrations in polar ice cores – do they result from solar particle injections into the polar atmosphere?, Geophys. Res. Lett., 22, 2521–2524, 1995.
Zeller, E. J., Dreschhoff, G. A. M., and Laird, C. M.: Nitrate flux on the Ross Ice Shelf, Antarctica and its relation to solar cosmic rays, Geophys. Res. Lett., 13, 1264–1267, 1986.