کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1768870 | 1020244 | 2007 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
High-resolution observations of mesospheric layers with the Jicamarca VHF radar
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم فضا و نجوم
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چکیده انگلیسی
We report new results from the 50-MHz Jicamarca radar in Peru (12°S, 77°W), which is able to observe backscatter from the daytime mesosphere on any given day. Since 2005, the radar has been operated in a high-power MST-ISR mode for 3-day runs four times per year to study the seasonal variation of mesospheric echoes. Doppler spectra are obtained with 1 min and 150-m nominal resolution yielding power, horizontal and vertical winds, and spectral width. The rich echo structures contain braids and billows suggestive of Kelvin-Helmholtz instability (KHI). We present three cases; (1) a short sequence of billows growing in height and becoming unstable; (2) a long train of billows showing high levels of turbulence at two different locations; and (3) a series of billows passing only slowly through the field of view. In all cases, the layers were associated with strong wind shears, mature billows were 1-1.5 km tall, and separation of KH phase fronts was 8-10 km. We compare our observations with OH imager observation and numerical simulations.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Advances in Space Research - Volume 40, Issue 6, 2007, Pages 734-743
Journal: Advances in Space Research - Volume 40, Issue 6, 2007, Pages 734-743
نویسندگان
G.A. Lehmacher, L. Guo, E. Kudeki, P.M. Reyes, A. Akgiray, J.L. Chau,