کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5487474 | 1523586 | 2017 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Characteristics of the anomalous refractive conditions in Nigeria
ترجمه فارسی عنوان
خصوصیات شرایط انکساری غیر طبیعی در نیجریه
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کلمات کلیدی
شیب، بی نظیر، مجاز انتشار
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فیزیک زمین (ژئو فیزیک)
چکیده انگلیسی
The thirty six years (1979-2014) meteorological data needed to calculate refractivity gradient is obtained from Era interim build on IFS CY31r2 model. Diurnal cycle of ducting occurrence for four seasons in Nigeria were analysed from refractivity gradient. Percentage occurrence of anomalous propagation in thirty locations across Nigeria were estimated. It is discovered that ducting is more frequent at mid night and early morning which also vary seasonally and regionally across the country. Highest percentage of 94 % of ducting and zero occurrence of sub refractive is obtained in Lagos. Highest percentage of 34.24 % and 45.62 % of super refractive and sub refractive are obtained in Sapele and Oban hill, respectively. Minimum percentage of 21.9 % and 4.33 % of ducting and super refractive were obtained for Calabar and Gashua, respectively. The minimum frequency for a radio wave to be trapped within Nigeria troposphere varies between 0.045Â GHz and 0.11Â GHz. The occurrence of anomalous propagation condition, such as ducts, super refractive and sub refractive provide valuable information about the propagation of radio waves over Nigeria, which will assist the radio engineer in their planning and designing of radio circuitry.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Atmospheric and Solar-Terrestrial Physics - Volume 164, November 2017, Pages 215-221
Journal: Journal of Atmospheric and Solar-Terrestrial Physics - Volume 164, November 2017, Pages 215-221
نویسندگان
I. Emmanuel, B. Adeyemi, E.O. Ogolo, A.T. Adediji,