Berlin 2005 – wissenschaftliches Programm
EP 2.10: Vortrag
Freitag, 4. März 2005, 17:15–17:30, TU BH349
Mean wind and gravity wave trends in the upper mesosphere and lower thermosphere deduced from Collm LF D1 drift measurements 1984-2003 — •Christoph Jacobi1, Dierk Kürschner2, and Nikolai Gavrilov3 — 1Institut für Meteorologie, Universität Leipzig, Stephanstr. 3, 04103 Leipzig, Germany — 2Institut für Geophysik und Geologie, Universität Leipzig, Collm Observatory, 04779 Wermsdorf, Germany — 3St. Petersburg State University, Atmospheric Physics Department, 1 Ul’yanovskaya Street, Petrodvorets, Saint Petersburg, 198904, Russia
Gravity wave activity and mean horizontal winds obtained from LF drift measurements on 177 kHz in the height range 85-110 km at 52.1∘N, 13.2∘E during 1984-2003 are presented, allowing the analysis of long-term trends, interannual and decadal variations of the upper middle atmosphere wind field. Besides a long-term increase of the westerly mean winds in the lower thermosphere, an 11-year solar cycle signal is found in the summer months, which is strongest in the mesosphere and decreasing with height. Time series of seasonal (3-monthly) mean gravity wave activity show maximum amplitudes around 1989-1991 and 2000-2002, which is concomitant with the solar activity maxima within the 11-year solar cycle, and the time intervals of increased mean wind shear on a decadal scale.