Fig. 7From: Dependence of mesospheric Na and Fe distributions on electron density at AreciboThis figure shows the temporal variation of density ratio for Na (solid line) and Fe (dashed line) at two altitude levels calculated in a similar way as in Fig. 3. The ratio exceeds 1 for the case of Na during the sporadic event and is less than 1 for Fe throughout the night of 18–19 March 2004Back to article page