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

The dynamical structure of the atmosphere around the sporadic sodium layer at mid-latitude (similar to 35 degrees N) below 100 km was studied by simul taneous observation with the MU radar at Shigaraki (34.9 degrees N, 136.1 d egrees E), and two Na lidars at Shigaraki and in Hachioji (35.6 degrees N, 139.4 degrees E). In the lidar data, fifteen Na-s (sporadic sodium layer) e vents were detected. Wind shear, temperature, and stability indices, at aro und the time and height of Na-s were observed with the MU radar. Strong tot al wind shear correlated well with Na-s, especially when sporadic Es did no t accompany. However, no other clear correlations, such as correlations wit h 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., 199 8), and suggests a similar generation mechanism between 20 degrees N and 35 degrees N.