First observations of large-scale wave structure and equatorial spread F using CERTO radio beacon on the C/NOFS satellite

2009 ◽  
Vol 36 (18) ◽  
Author(s):  
Smitha V. Thampi ◽  
Mamoru Yamamoto ◽  
Roland T. Tsunoda ◽  
Yuichi Otsuka ◽  
Takuya Tsugawa ◽  
...  
Keyword(s):  
Large Scale ◽  
Wave Structure ◽  
Equatorial Spread F ◽  
Spread F ◽  
Radio Beacon

scholarly journals Ionogram signatures of large-scale wave structure and their relation to equatorial spread F

2012 ◽  
Vol 117 (A8) ◽  
pp. n/a-n/a ◽  
Author(s):  
Smitha V. Thampi ◽  
Roland T. Tsunoda ◽  
Lijo Jose ◽  
Tarun Kumar Pant
Keyword(s):  
Large Scale ◽  
Wave Structure ◽  
Equatorial Spread F ◽  
Spread F

Evidence for a large scale electric field gradient at the onset of equatorial spread-F

1984 ◽  
Vol 46 (4) ◽  
pp. 355-362 ◽  
Author(s):  
R Raghavarao ◽  
J.N Desai ◽  
B.G Anandarao ◽  
R Narayanan ◽  
R Sekar ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Large Scale ◽  
Equatorial Spread F ◽  
Spread F

scholarly journals Wave structure and polarization electric field development in the bottomside F layer leading to postsunset equatorial spread F

2015 ◽  
Vol 120 (8) ◽  
pp. 6930-6940 ◽  
Author(s):  
M. A. Abdu ◽  
J. R. Souza ◽  
E. A. Kherani ◽  
I. S. Batista ◽  
J. W. MacDougall ◽  
...  
Keyword(s):  
Electric Field ◽  
Wave Structure ◽  
Equatorial Spread F ◽  
Field Development ◽  
Spread F ◽  
Polarization Electric Field

scholarly journals Phase calibration approaches for radar interferometry and imaging configurations: equatorial spread F results

2008 ◽  
Vol 26 (8) ◽  
pp. 2333-2343 ◽  
Author(s):  
J. L. Chau ◽  
D. L. Hysell ◽  
K. M. Kuyeng ◽  
F. R. Galindo
Keyword(s):  
Doppler Velocity ◽  
Equatorial Spread F ◽  
Radar Systems ◽  
Imaging Results ◽  
Phase Calibration ◽  
Spread F ◽  
Multiple Receiver ◽  
Calibration Techniques ◽  
Radio Beacon ◽  
Radio Stars

Abstract. In recent years, more and more radar systems with multiple-receiver antennas are being used to study the atmospheric and ionospheric irregularities with either interferometric and/or imaging configurations. In such systems, one of the major challenges is to know the phase offsets between the different receiver channels. Such phases are intrinsic to the system and are due to different cable lengths, filters, attenuators, amplifiers, antenna impedance, etc. Moreover, such phases change as function of time, on different time scales, depending on the specific installation. In this work, we present three approaches using natural targets (radio stars, meteor-head and meteor trail echoes) that allow either an absolute or relative phase calibration. In addition, we present the results of using an artificial source (radio beacon) for a continuous calibration that complements the previous approaches. These approaches are robust and good alternatives to other approaches, e.g. self-calibration techniques using known data features, or for multiple-receiver configurations constantly changing their receiving elements. In order to show the good performance of the proposed phase calibration techniques, we present new radar imaging results of equatorial spread F (ESF) irregularities. Finally we introduce a new way to represent range-time intensity (RTI) maps color coded with the Doppler information. Such modified map allows the identification and interpretation of geophysical phenomena, previously hidden in conventional RTI maps, e.g. the time and altitude of occurrence of ESF irregularities pinching off from the bottomside and their respective Doppler velocity.

scholarly journals Characterization of VHF radar observations associated with equatorial Spread F by narrow-band optical measurements

2004 ◽  
Vol 22 (9) ◽  
pp. 3129-3136 ◽  
Author(s):  
R. Sekar ◽  
D. Chakrabarty ◽  
R. Narayanan ◽  
S. Sripathi ◽  
A. K. Patra ◽  
...  
Keyword(s):  
Large Scale ◽  
Temporal Variations ◽  
Density Fluctuations ◽  
Optical Measurements ◽  
Small Scale ◽  
Upward Movement ◽  
Vhf Radar ◽  
Equatorial Spread F ◽  
Spread F ◽  
Airglow Intensity

Abstract. The VHF radars have been extensively used to investigate the structures and dynamics of equatorial Spread F (ESF) irregularities. However, unambiguous identification of the nature of the structures in terms of plasma depletion or enhancement requires another technique, as the return echo measured by VHF radar is proportional to the square of the electron density fluctuations. In order to address this issue, co-ordinated radar backscatter and thermospheric airglow intensity measurements were carried out during March 2003 from the MST radar site at Gadanki. Temporal variations of 630.0-nm and 777.4-nm emission intensities reveal small-scale ("micro") and large-scale ("macro") variations during the period of observation. The micro variations are absent on non-ESF nights while the macro variations are present on both ESF and non-ESF nights. In addition to the well-known anti-correlation between the base height of the F-region and the nocturnal variation of thermospheric airglow intensities, the variation of the base height of the F-layer, on occasion, is found to manifest as a bottomside wave-like structure, as seen by VHF radar on an ESF night. The micro variations in the airglow intensities are associated with large-scale irregular plasma structures and found to be in correspondence with the "plume" structures obtained by VHF radar. In addition to the commonly observed depletions with upward movement, the observation unequivocally reveals the presence of plasma enhancements which move downwards. The observation of enhancement in 777.4-nm airglow intensity, which is characterized as plasma enhancement, provides an experimental verification of the earlier prediction based on numerical modeling studies.

scholarly journals Concurrent observations at the magnetic equator of small-scale irregularities and large-scale depletions associated with equatorial spread F

2015 ◽  
Vol 120 (12) ◽  
pp. 10,883-10,896 ◽  
Author(s):  
Dustin A. Hickey ◽  
Carlos R. Martinis ◽  
Fabiano S. Rodrigues ◽  
Roger H. Varney ◽  
Marco A. Milla ◽  
...  
Keyword(s):  
Large Scale ◽  
Magnetic Equator ◽  
Small Scale ◽  
Equatorial Spread F ◽  
Spread F

scholarly journals NUMERICAL SIMULATIONS OF LARGE SCALE EQUATORIAL SPREAD F

1996 ◽  
Vol 45 (11) ◽  
pp. 1930
Author(s):  
HUANG CHAO-SONG ◽  
M.C.KELLEY
Keyword(s):  
Numerical Simulations ◽  
Large Scale ◽  
Equatorial Spread F ◽  
Spread F

scholarly journals The Brazil/Guará Equatorial Spread F Campaign: Results of the large scale measurements

1997 ◽  
Vol 24 (13) ◽  
pp. 1691-1694 ◽  
Author(s):  
J. LaBelle ◽  
J.-M. Jahn ◽  
R. F. Pfaff ◽  
W. E. Swartz ◽  
J. H. A. Sobral ◽  
...  
Keyword(s):  
Large Scale ◽  
Equatorial Spread F ◽  
Spread F
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