Location of Repository

The interpretation of spikes and trends in concentration of nitrate in polar ice cores, based on evidence from snow and atmospheric measurements

By Eric Wolff, Anna E. Jones, S.J.-B. Bauguitte and Rhian Anya Salmon


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 NOy. 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 NOy 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 x 10(7) kg/a - as NO3-), but it will first have to be established that the outflow across the coast can be ignored

Topics: Meteorology and Climatology, Glaciology, Atmospheric Sciences, Chemistry
Publisher: Copernicus Publications
Year: 2008
DOI identifier: 10.5194/acp-8-5627-2008
OAI identifier: oai:nora.nerc.ac.uk:11667

Suggested articles



  1. (2003). A year-round record of sizesegregated aerosol composition at Halley,
  2. (1990). An ice-core record of atmospheric response to anthropogenic sulphate and nitrate,
  3. (1994). An ice-core-based record of biomass burning doi
  4. (2007). An overview of snow photochemistry: Evidence, mechanisms and impacts,
  5. (1995). Anomalous nitrate concentrations in polar ice cores – do they result from solar particle injections into the polar atmosphere?, doi
  6. (1999). Antarctic aerosol and snowfall chemistry: implications for deep Antarctic ice core chemistry,
  7. (2006). Antarctic snow accumulation mapped using polarization of 4.3-cm wavelength microwave emission,
  8. (1998). Atmospheric near-surface nitrate at coastal Antarctic sites, doi
  9. (2008). Chemistry of the Antarctic boundary layer and the interface with snow: an overview of the CHABLIS campaign,
  10. (1998). Climatology of the three coastal Antarctic stations Dumont d’Urville,
  11. (2000). Computed contributions to odd nitrogen concentrations in the Earth’s polar middle atmosphere by energetic charged particles, doi
  12. (1993). Evidence for winter/spring denitrification of the stratosphere in the nitrate record of Antarctic ice cores,
  13. (1999). Evidence of NOx production within or upon ice particles in the Greenland snowpack, doi
  14. (2000). Factors controlling nitrate in ice cores: evidence from the Dome C deep ice core,
  15. (1996). High-resolution ammonium ice core record covering a complete glacial-interglacial cycle, doi
  16. (2001). Ice-core evidence for a small solar-source of atmospheric nitrate,
  17. (1999). Identification of major proton fluence events from nitrates in polar ice cores,
  18. Impurity sources of F−, Cl−,
  19. (1986). Nitrate flux on the Ross Ice Shelf, Antarctica and its relation to solar cosmic rays, doi
  20. (1995). Nitrate in Polar Ice, in: Ice core studies of global biogeochemical cycles, edited by:
  21. (2007). Nitrogen and oxygen isotopic constraints on the origin of atmospheric nitrate in coastal Antarctica,
  22. (2006). Ocean sea-ice extent, productivity and iron flux over the past eight glacial cycles, doi
  23. (1990). Origins and variations of nitrate in south polar precipitation,
  24. (1998). Post-depositional change in snowpack nitrate from observation of year-round near-surface snow in coastal Antarctica,
  25. (1999). Reassessment of net surface mass balance in Antarctica,
  26. Recent climate anomalies and their impact on snow chemistry at South Pole, doi
  27. (2001). Solar cosmic ray events for the period 1561– 1994 1. Identification in polar ice, 1561–1950,
  28. (1989). Soluble and insoluble impurities in snow samples from Ross Island, Antarctica,
  29. (2004). South Pole NOx chemistry: an assessment of factors controlling variability and absolute levels, doi
  30. (1994). Spatial variability of the major chemistry of the Antarctic ice sheet,
  31. (2000). Speciation and rate of photochemical NO and NO2 production in Antarctic snow, doi
  32. (1989). Studies of polar ice: insights for atmospheric chemistry, in: The environmental record in glaciers and ice sheets, edited by: Oeschger,
  33. (1998). Sulfate and nitrate firn concentrations on the Greenland ice sheet 2. Temporal anthropogenic deposition changes, doi
  34. (2005). Temporal variability of the descent of high-altitude NOx inferred from ionospheric data, doi
  35. (2007). The multi-seasonal NOy budget in coastal Antarctica and its link with surface snow and ice core nitrate: Results from the CHABLIS campaign,
  36. (1988). Vostok (Antarctica) ice core: atmospheric chemistry changes over the last climatic cycle (160 000 years),
  37. (2008). Wolff et al.: Nitrate in polar ice

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.