ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Springer Verlag Göttingen, Germany 10.1007/s00585-999-0405-x Diurnal and semidiurnal tide in the upper middle atmosphere during the first year of simultaneous MF radar observations in northern and southern Japan (45°N and 31°N) Hocke K. 1 2 Igarashi K. 1 Communication Research Laboratory, Tokyo, Japan Present address: DLR, Kalkhorstweg 53, 17235 Neustrelitz, Germany, E-mail: hocke@nz.dlr.de 31 03 1999 17 3 405 414 Copyright: © 1999 K. Hocke 1999 © European Geosciences Union 1999 This article is available from https://angeo.copernicus.org/articles/17/405/1999/angeo-17-405-1999.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/17/405/1999/angeo-17-405-1999.pdf

The climatology of mean wind, diurnal and semidiurnal tide during the first year (1996-1997) of simultaneous wind observations at Wakkanai (45.4°N, 141.7°E) and Yamagawa (31.2°N, 130.6°E) is presented. The locations of the radars allow us to describe the latitudinal dependence of the tides. Tidal amplitude and phase profiles are compared with those of the global scale wave model (GSWM). While the observed amplitude profiles of the diurnal tide agree well with the GSWM values, the observed phase profiles often indicate longer vertical wavelengths than the GSWM phase profiles. In contrast to the GSWM simulation, the observations show a strong bimodal structure of the diurnal tide, with the phase advancing about 6 hours from summer to winter.<br><br><b>Key words. </b>Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)