Scavenging of atmospheric ions and aerosols by drifting snow in Antarctica

TL;DR

This study investigates how drifting snow in Antarctica scavenges atmospheric ions and aerosols, revealing that ion concentrations decrease with wind speed while aerosol size distributions shift, highlighting snow's role in atmospheric particle removal.

Contribution

It provides detailed measurements of ion and aerosol size distributions during drifting snow, demonstrating the scavenging effects of snow particles on atmospheric ions and aerosols in Antarctica.

Findings

Ion concentrations decrease with increasing wind speed.

Aerosol size distributions shift with wind speed.

Large particles increase while small particles decrease in concentration.

Abstract

Measurements of the small,intermediate, and large ion concentrations and the airearth current density along with simultaneous measurements of the concentration and size-distribution of aerosol particles in the size ranges 4.4 to 163 nm and 0.5 to 20 micrometer diameters are reported for a drifting snow period after the occurrence of a blizzard at a coastal station, Maitri, Antarctica. Ion concentrations of all categories and the airearth current simultaneously decrease by approximately an order of magnitude as the wind speed increases from 5 to 10 meter per sec. The rate of decrease is the highest for large ions, lowest for small ions and in between the two for intermediate ions. Total aerosol number concentration decreases in the 4.4 to 163 nm size range but increases in 0.5 to 20 micrmetr size range with wind speed. Size distribution of the nanometer particles show a dominant maximum at 30 nm diameter throughout the period of observations and the height of the maximum decreases with wind speed. However, larger particles show a maximum at 0.7 micrometer diameter but the height of the maximum increases with increasing wind speed. The results are explained in terms of scavenging of atmospheric ions and aerosols by the drifting snow particles.