کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1777304 | 1523662 | 2010 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Seasonal variation of mesospheric waves at northern middle and high latitudes
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فیزیک زمین (ژئو فیزیک)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Seasonal variation of mesospheric waves at northern middle and high latitudes Seasonal variation of mesospheric waves at northern middle and high latitudes](/preview/png/1777304.png)
چکیده انگلیسی
The seasonal variation of the wave activity in the mesosphere/lower thermosphere is investigated using wind measurements with meteor and MF radars at Juliusruh (55°N, 13°E) and Andenes (69°N, 16°E), as well as on the basis of the simulated annual cycle using a gravity-wave resolving mechanistic general circulation model. For the observations, proxies for the activity of gravity waves (GWs) and waves with longer periods are computed from wind variances for defined bandwidths. Our corresponding proxy for the simulated GWs is the non-rotational kinetic energy due to the resolved mesoscales. Both observational and computational results show the strongest GW energy during winter and a secondary maximum during summer. Additional observational analysis of short-period GWs yields a more pronounced summer maximum. The semi-annual variation is consistent with the selective filtering of westward and eastward GWs by the mean zonal wind. The latitudinal dependence during summer is characterized by stronger GW energy between 65 and 85 km at middle latitudes than at polar latitudes, and a corresponding upward shift of the wind reversal towards the pole which is also reflected by the simulated GW drag. Also the observed oscillations with periods from 2 to 4 days show a latitudinal dependence and a clear seasonal cycle which is related to the mean zonal wind shear.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Atmospheric and Solar-Terrestrial Physics - Volume 72, Issues 14â15, September 2010, Pages 1068-1079
Journal: Journal of Atmospheric and Solar-Terrestrial Physics - Volume 72, Issues 14â15, September 2010, Pages 1068-1079
نویسندگان
Peter Hoffmann, Erich Becker, Werner Singer, Manja Placke,