First observations of mesospheric dynamics with a partial reflection radar in Hawaii (22°N, 160°W)

1992 ◽  
Vol 19 (4) ◽  
pp. 409-412 ◽  
Author(s):  
David C. Fritts ◽  
Joseph R. Isler
Keyword(s):  
Partial Reflection ◽  
Partial Reflection Radar

scholarly journals MESOSPHERIC ELECTRIC FIELD MEASUREMENTS WITH A PARTIAL REFLECTION RADAR

1999 ◽  
Vol 19 (2) ◽  
pp. 81-86
Author(s):  
S.I Martynenko ◽  
V.T. Rozumenko ◽  
A.M. Tsymbal ◽  
O.F. Tyrnov ◽  
A.M. Gokov
Keyword(s):  
Electric Field ◽  
Field Measurements ◽  
Partial Reflection ◽  
Electric Field Measurements ◽  
Partial Reflection Radar

scholarly journals Variations in mesospheric temperature during polar mesospheric summer echoes.

2020 ◽  
Author(s):  
S.M. Cherniakov ◽  
◽  
V.A. Turyansky ◽  
Keyword(s):  
Wave Amplitude ◽  
Physical Method ◽  
Ordinary Wave ◽  
Partial Reflection ◽  
Polar Geophysical Institute ◽  
Mesospheric Temperature ◽  
Murmansk Region ◽  
Amplitude Spectra ◽  
Summer Echoes ◽  
Partial Reflection Radar

The behavior of the ordinary radio wave amplitude at the frequency of 2.66 MHz of the partial reflection radar of the Polar Geophysical Institute (Tumanny observatory, Murmansk region, 69.0N, 35.7E) during the appearance of the polar mesospheric summer echoes on August 15, 2015 was considered. Using of radio physical method from the spectra of the amplitude at different heights the mesospheric temperature profile was calculated for the considered data. Significant reductionof temperature values near the heights of the mesopause corresponded to sharp changes in the amplitude spectra of the ordinary wave.

Climatologies of mean winds and tides observed by medium frequency radars at Tromsø (70°N) and Saskatoon (52°N) during 1987–1989

1991 ◽  
Vol 69 (8-9) ◽  
pp. 966-975 ◽  
Author(s):  
A. H. Manson ◽  
C. E. Meek
Keyword(s):  
Real Time ◽  
Theoretical Models ◽  
Temperature Gradients ◽  
Medium Frequency ◽  
Partial Reflection ◽  
Modal Composition ◽  
The Mean ◽  
Data Yield ◽  
Partial Reflection Radar ◽  
Mf Radar

A real-time winds system from Saskatoon has operated with the Tromsø medium frequency (MF) (partial reflection) radar (70°N, 20°E) since mid-1987. Although the system has a poorer data yield than usual, owing to smaller receiving antennas, it has proven possible over 2 years to obtain 12 month climatologies of mean winds and tides (70–75 to 100 km) with a 10 d resolution. These are compared with similar products from the Saskatoon MF radar (52°N, 107°W). The mean winds and tides generally show similar seasonal morphologies. However the mean winds are weaker, consistent with smaller meridional temperature gradients. Also, there are significant changes in the tidal wavelengths and amplitudes suggesting that considerable adjustments of modal composition have occurred. The tides are compared with recent numerical-theoretical models.

Detection of delamination in composites by using electromagnetic penetrating radar

2014 ◽  
Vol 5 (2) ◽  
pp. 151-156
Author(s):  
Z. Mechbal ◽  
A. Khamlichi
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Wave Reflection ◽  
Image Features ◽  
Partial Reflection ◽  
Straight Path ◽  
Reflected Signal ◽  
Short Time ◽  
Intervening Factors

Composites made from E-glass/epoxy or aramid/epoxy are frequently used in aircraft and aerospace industries. These materials are prone to suffer from the presence of delamination, which can reduce severely the performance of aircrafts and even threaten their safety. Since electric conductivity of these composites is rather small, they can propagate electromagnetic waves. Detection of delamination damage can then be monitored by using an electromagnetic penetrating radar scanner, which consists of emitting waves having the form of short time pulses that are centered on a given work frequency. While propagating, these waves undergo partial reflection when running into an obstacle or a material discontinuity. Habitually, the radar is moved at constant speed along a straight path and the reflected signal is processed as a radargram that gives the reflected energy as function of the two-way time and the antenna position.In this work, modeling of electromagnetic wave propagation in composites made from E-glass/epoxy was performed analytically. The electromagnetic wave reflection from a delamination defect was analyzed as function of key intervening factors which include the defect extent and depth, as well as the work frequency. Various simulations were performed and the obtained results have enabled to correlate the reflection pattern image features to the actual delamination defect characteristics which can provide quantification of delamination.

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