Spatial distributions of soluble salts in surface snow of East Antarctica

To better understand how sea salt reacts in surface snow of Antarctica, we collected and identified non-volatile particles in surface snow along a traverse in East Antarctica. Samples were obtained during summer 2012/2013 from coastal to inland regions within 69 degrees S to 80 degrees S and 39 degrees E to 45 degrees E, a total distance exceeding 800 km. The spatial resolution of samples is about one sample per latitude between 1500 and 3800m altitude. Here, we obtain the atomic ratios of Na, S and Cl, and calculate the masses of sodium sulphate and sodium chloride. The results show that, even in the coast snow sample (69 degrees S), sea salt is highly modified by acid (HNO3 or H2SO4). The fraction of sea salt that reacts with acid increases in the region from 70 degrees S to 74 degrees S below 3000m a.s.l., where some NaCl remains. At the higher altitudes (above 3300m a.s.l.) in the inland region (74 degrees S to 80 degrees S), the reaction uses almost all of the available NaCl.