Impurity sources Of F, Cl, NO3 and SO4 2− in Greenland and Antarctic precipitation


  • Michael M. Herron


Five polar impurity sources are proposed: anthropogenic NO3 and SO42− in recent Greenland but not Antarctic snow; marine aerosols, the dominant Cl source; volcanic eruptions, which produce detectable but variable peaks in SO42−, F, and/or Cl concentrations; biogenic sulfurous gases from soil and coastal waters, the dominant source for SO42− in nonvolcanic strata; an unidentified source of background nitrate which is more active in the northern hemisphere and which displays a summer concentration maximum. Solar activity and supernova events do not modulate NO3 concentrations in Greenland snow.