Atmospheric dust in polar ice and the background aerosol.

We have measured insoluble particle size distributions covering the radius range 0.05-1.31 micrometer for 15 samples from a 3-year (1782-1785) section of ice core from Crete, central Greenland, and for a 2500 year old, 2-year section of south pole ice. We predict that 60% of all the insoluble particles in this range in the northern hemisphere background areosol are in the radius range 0.05 - 0.13 micrometer, 30% are in the range 0.13 - 0.38 micrometer, and 10% are in the range 0.38 - 1.31 micrometer. The corresponding values for the southern hemisphere are 74, 22, and 4%. Also, we have found that the small and large particle profiles for our Crete ice core section show similar variability features, but peaks in the large particles are much more pronounced.-Authors