GAS-PHASE MEASUREMENTS OF HYDROGEN-PEROXIDE IN GREENLAND AND THEIR MEANING FOR THE INTERPRETATION OF H2O2 RECORDS IN ICE CORES

The gas phase concentration of hydrogen peroxide at Summit, Central Greenland, has been measured continuously during June/July 1990 using a coil scrubber technique combined with liquid phase fluorometry. The concentrations ranged between 0.3 ppbv and 3.5 ppbv, which is considerably higher than expected from model calculations and can be explained by low deposition rates. The record shows pronounced diurnal variations with minimum concentrations during night and maximum concentrations in the afternoon. The nocturnal minima can be explained by scavenging of H2O2 by hoarfrost. The scavenging mechanisms of H2O2 by snow and the redistribution of H2O2 during firnification are discussed. There is indirect evidence, that H2O2 is uniformly distributed in the ice lattice and that the fractionation between H2O2 and H2O is small during diffusional crystal growth from the vapor phase (co-condensation).