منابع مشابه
Climatic trends in E-region critical frequency and virtual height above Tromsø (70 N, 10 E)
We have examined the long time series of observations of E-region virtual height (1948–2006) and critical frequency (1935-2006) hitherto made by the Tromsø ionosonde at 70 N, 19 E. Combining a simplistic trend analysis with a rigorous treatment of errors we identify a negative trend in critical frequency. While a similar analysis of the virtual height hE also suggests a negative trend, a closer...
متن کاملLong-term trends in foF2: their estimating and origin
This paper deals with two problems, methods of foF2 trend determination and origin of trends in foF2, both being controversial in current literature. We found that various regression-based methods and artificial neural networkbased method of Yue et al. (2006) provided comparable results within uncertainties caused mainly by various ways of removing/suppressing the dominant solar cycle effect. T...
متن کاملLong-term trends in the relation between daytime and nighttime values of foF2
The data from the vertical ionospheric sounding for 12 stations over the world were analyzed to find the relation between the values of foF2 for 02:00 LT and 14:00 LT of the same day. It is found that, in general, there exists a negative correlation between foF2(02) and foF2(14). The value of the correlation coefficient R(foF2) can be in some cases high enough and reach minus 0.7–0.8. The value...
متن کاملTrends : above - Ic Integration and Mm - Wave
The 7GHz unlicensed band around 60GHz provides the possibility of gigabit-per-second wireless communications. In addition to satisfying speed-intensive applications, such high data rates can also reduce the energy dissipated per bit because the power consumption of RF transceivers has historically increased sublinearly with the data rate. Moreover, the millimeter wavelength permits the integrat...
متن کاملLetter to the editor Spatial and seasonal variations of the foF2 long-term trends
Using a method suggested by the authors earlier, the long-term trends of the F2-layer critical frequency, foF2 are derived for a set of ionospheric stations with a wide latitudinal and longitudinal coverage. All the trends are found to be negative. A pronounced dependence on geomagnetic latitude is found, the trend magnitude increasing with the latter. No globe scale longitudinal eect in trend...
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ژورنال
عنوان ژورنال: Geophysical Research Letters
سال: 2002
ISSN: 0094-8276
DOI: 10.1029/2002gl016259