Relationship between mesospheric Na and Fe layers from simultaneous and common-volume lidar observations at Arecibo

摘要

We compare the mesospheric Na and Fe layers by using simultaneous and commonvolume lidar measurements made at the Arecibo Observatory (18.3°N, 66.75°W), Puerto Rico, in 2003. The temporal variations of the two species are highly correlated at practically all heights, although not always positively. Positive correlations occur in the bottom and top sides while negative correlation is observed in a relatively narrow region in the middle part. Chemical and dynamical effects are discussed to interpret this particular relationship between Na and Fe layers. It is shown that gas phase chemistry determines the structure of the Na and Fe layers after the metals are ablated from meteoroids entering the atmosphere. The observed region of negative correlation appears to be slightly lower than that of the expected region of negative correlation based on inert response to dynamics. It appears that such a differencemay be due to temperature-dependent chemistry. Overall, the observed correlations between Na and Fe layers can be well explained by their responses to wave dynamics.