Assessment of Summer Trends of Tropospheric Radon Isotopes in a Coastal Antarctic Station (Terra Nova Bay)

This work reports the first results of atmospheric radon measurements performed at the Italian Antarctic station located at Terra Nova Bay (74.69°S; 164.12°E) during summer campaigns of 1995-96, 1996-97 and 1997-98. Mean222Rn concentrations was 0.51 - 0.43 Bq mm3 (median = 0.37 Bq mm3), and ranged from 0.01 to 2.74 Bq mm3 . On the average, these values were considered high, in comparison to results reported for other sites in Antarctica at equivalent latitudes. This could be explained by two causes: radon data for Terra Nova Bay were only for the summer period, when the ice-free area is at its maximum and thus the radon emission to the atmosphere; and by the larger ice-free area at Terra Nova Bay compared, for example, to measurements taken at another Antarctic site by the same technique (Ferraz station - 62°05'S; 058°23.5'W). The mean 222Rn to 220Rn activity ratio was 4.4 - 4.2, ranging between 0.1 and 45.3. The highest ratios indicated that some of observed surges of concentration of 222Rn could be attr...