This one-year project is aimed at comparing longitudinal differences that exist in the upper atmosphere and ionosphere. Through use of the large MU (Middle and Upper atmosphere) radar in Japan, the PIs will make comparisons on both an individual- experiment and climatological-average basis against the measurements from the Jicamarca, Arecibo, Millstone Hill, and Sondrestrom radars. In addition, the MU radar will extend the ionospheric-tilt studies to the American sector to determine their longitudinal consistency and to confirm hypotheses concerning their relation with global-scale dynamics. Finally, this research involves the development of a similar data base for MU radar data at Kyoto University.