Statistics of sporadic iron layers and relation to atmospheric dynamics

At Rothera Research Station (67.3°S, 68.1°W), Antarctica, 296 h of day and nighttime Fe-Boltzmann temperature lidar data were accumulated in 2003. During this time, sporadic iron layers (FeS) were observed with an annual average occurrence probability of 14%. The peak altitude of the FeS layers was highest during the summer, with a fitted value of 103 km while during the winter the layer decreased in height to 90 km with an annual average of 97 km. The atmospheric temperature perturbations and potential energy density profiles computed from the same lidar data exhibited increased temperature but constant-with-height potential energy density when sporadic Fe layer occurred. Once sporadic Fe layers disappeared, the potential energy density decreased with height, indicating an energy loss due to atmospheric gravity wave breaking. These results suggest a link between FeS and atmospheric dynamics.