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Simultaneous and Common-Volume Lidar Observations of the Mesospheric Fe and Na Layers at Boulder (40°N, 105°W)
Wentao Huang(1), Xinzhao Chu(1), Zhangjun Wang(1), Weichun Fong(1),
Zhibin Yu(1), John A. Smith(1), Brendan Roberts(1)
1. CIRES, Univ. of Colorado at Boulder, Boulder, CO 80309
The rich features of the mesospheric metal layers are produced by the complicated chemical and dynamical processes in the Upper Mesosphere/Lower Thermosphere region. Current chemical models with parameterized inputs are able to reproduce some large-scale structures but challenged in small-scale features. Simultaneous and common-volume observation of multiple species is an important
method to help reveal the determining mechanisms in small scales and validate the models. Such observations of Fe and Na layers are relatively rare, despite several reports based on one or a few nights of data, and one extensive study at Wuhan (30°N), China. In summer and fall 2010, we made over 16 nights of
such observations at Boulder (40°N, 105°W) with two resonance lidars: an Fe Boltzmann temperature lidar and a 3-frequency Na Doppler lidar. The data shows the primary characteristics of Fe vs. Na layers as reported in mid-latitude, e.g., higher Fe density and column abundance, lower Fe peak and centroid altitude, larger density gradient at the bottom of Fe layer etc. Their altitudes of lower boundaries are similar and closely follow each other through the night, while the upper boundary of Na layer normally extends to higher altitude. Moreover, we introduced the method using the relative density perturbations in analyzing the simultaneous measurements. Although this method reveals generally correlated density fluctuations in the main layers as well as in the sporadic layers, there are noticeable differences of the amplitude and phase in a few cases. On 11 August 2010, we also caught meteor trails of Perseids meteor shower, which may have increased the column abundance of both Fe and Na layers.
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