Mean winds and tides in the Arctic mesosphere and lower thermosphere

• Published in: Journal of Geophysical Research. A. Space Physics 2002-01, Vol.107 (A1), p.SIA 2-1-2-14
• Main Authors: Mitchell, N. J., Pancheva, D., Middleton, H. R., Hagan, M. E.
• Format: Article
• Language: English
• Subjects: Earth, ocean, space; Exact sciences and technology; External geophysics; Physics of the high neutral atmosphere; Tides, waves, convection, winds, turbulence
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2001JA900127

A new meteor radar has been deployed at Esrange (68°N, 21°E) near Kiruna in Sweden. The radar has been used to measure winds and tides in the Arctic mesosphere/lower thermosphere region over the interval August 1999 to July 2000. Conspicuous features of the measured mean winds include a strong shear of up to 5 m s−1 km−1 in the summer zonal flow, resulting in eastward flows of in excess of 30 m s−1 at the upper heights observed (97 km). An equatorward meridional flow is observed in summer and winter, which reaches maximum values of ∼13 m s−1 in a summer jet. Poleward flow in comparison is weak and only occurs at the equinoxes. The monthly mean and seasonal mean behaviors of the amplitudes and phases of the 12‐ and 24‐hour tides are examined and compared to the Global Scale Wave Model‐98. The observations are generally very close to the model predictions for the 24‐hour tide and for the 12‐hour tide in winter. In other seasons, particularly summer, the observed 12‐hour tidal amplitudes are significantly larger than those predicted. In spring and summer the wavelength of the 12‐hour tide is significantly larger than that predicted.