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.

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

The 4.6 mb,Lg Northeastern Kentucky Earthquake of September 7, 1988

1993 ◽  
Vol 64 (3-4) ◽  
pp. 187-199 ◽  
Author(s):  
R. Street ◽  
K. Taylor ◽  
D. Jones ◽  
J. Harris ◽  
G. Steiner ◽  
...  
Keyword(s):  
Surface Wave ◽  
Seismic Moment ◽  
Wave Amplitude ◽  
Linear Trend ◽  
Source Parameters ◽  
Strike Slip ◽  
Source Depth ◽  
Nodal Plane ◽  
Amplitude Spectra ◽  
Conjugate Fault

Abstract Source parameters for the September 7, 1988 northeastern Kentucky earthquake have been estimated from the analysis of surface-wave amplitude spectra. The source that best fits the observed data had a seismic moment of 2.0 × 1022 dyne-cm, a mechanism with strike = 198° ± 10°, dip = 51° ± 11°, and slip = −178° ± 17°, (T) trend = 160°, plunge = 25°, (P) trend = 55°, plunge = 28°, and source depth of 4 to 7 km. Thirty-two aftershocks were recorded during 2 weeks of monitoring following the mainshock; 23 of the aftershocks were locatable and fall on a roughly NW-SE linear trend. This trend is subparallel with the NW-SE nodal plane of the mainshock. Our analysis shows the 1988 event to be different from the July 27, 1980 mb,Lg = 5.3 earthquake located 11 km to the northwest. First, the 1988 event is considerably shallower (4 to 7 km) than the 1980 event (14 to 22 km). Second, data from the 1988 event suggest the motion is on a conjugate fault and is in contrast with the 1980 event, which had right-lateral strike-slip on a southeast-dipping plane.

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.

scholarly journals An Experimental Study of Focusing Wave Generation with Improved Wave Amplitude Spectra

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2521 ◽  
Author(s):  
Guochun Xu ◽  
Hongbin Hao ◽  
Qingwei Ma ◽  
Qinqin Gui
Keyword(s):  
Wave Energy ◽  
Wave Amplitude ◽  
Wave Spectrum ◽  
Amplitude Spectrum ◽  
Wave Frequency ◽  
Wave Crest ◽  
Wave Component ◽  
Frequency Wave ◽  
Motion Signal ◽  
Amplitude Spectra

We experimentally investigate the generating results of space-time focusing waves based on two new wave spectra, i.e., the quasi constant wave amplitude spectrum (QCWA) and the quasi constant wave steepness spectrum (QCWS), in which amplitude and steepness for each wave component can be adjusted with fixed wave energy. The wavemaker signal consists of a theoretical wavemaker motion signal and two different auxiliary functions at two ends of the signal. By testing a series of focusing waves in a physical wave tank, we found that with given wave energy, the QCWA spectrum can produce a focusing wave with larger crest elevation and farther focusing location from the wavemaker flap, as compared with the QCWS spectrum. However, both spectra lead to larger focusing wave crests when the wave frequency bandwidth was narrowed down and a positive correlation between the generated relative wave crest elevation and the input wave elevation parameter. The two spectra produce different focusing wave positions for the same wave frequency range. We also found that the focusing time strongly relates to the energy of the highest-frequency wave component of the wave spectrum.

Sign in / Sign up

Export Citation Format

Share Document