Spatial variability of the major chemistry of the Antarctic ice sheet

Abstract

A compilation of reliable data for sodium, nitrate, chloride and sulphate has been made. NO 3 concentrations arc remarkably consistent across Antarctica, though there appears to be some correlation with altitude and accumulation rate. Post-depositional loss of NO 3 - is important at low-accumulation sites. Cl concentration (either measured directly or calculated from Na + via the sea salt ratio) decreases with distance from the coast, though the decline is less rapid if the coastal topography is not steep or mountainous. Excess sulphate ( xs SO 4 2 ) concentration (here calculated from normal sea-salt ratios with Na + or Cl) also declines with distance from the coast, though less quickly than Cl - . Fractionation of sea-salt ions makes the calculation of SO 4 2- uncertain.