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Observations of mesospheric sporadic sodium layers with the MU radar and sodium lidars

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The dynamical structure of the atmosphere around the sporadic sodium layer at mid-latitude (35°N) below 100 km was studied by simultaneous observation with the MU radar at Shigaraki (34.9°N, 136.1°E), and two Na lidars at Shigaraki and in Hachioji (35.6°N, 139.4°E). In the lidar data, fifteen Nas (sporadic sodium layer) events were detected. Wind shear, temperature, and stability indices, at around the time and height of Nas were observed with the MU radar. Strong total wind shear correlated well with Nas, especially when sporadic Es did not accompany. However, no other clear correlations, such as correlations with temperature etc., were found. The result is similar to the report of the lidar observations in Hawaii during the ALOHA-93 campaign (Qian et al., 1998), and suggests a similar generation mechanism between 20°N and 35°N.


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Correspondence to Hirohisa Miyagawa.

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  • Lidar
  • Wind Shear
  • Richardson Number
  • Lidar Observation
  • Mesopause Region