Results 21 to 30 of about 413,548 (214)

Doppler shifts of HF radio waves along oblique propagation paths in the ionosphere

Вісник Харківського національногоуніверситету імені В.Н. Каразіна. Серія: Радіофізика та електроніка, 2023
Urgency. The ionosphere is widely used as a channel for radar, radioastronomy, radio navigation, communication links, and space-based  sounding the Earth.
L. F. Chernogor, Y. H. Zhdanko
doaj   +1 more source

HF Bistatic Ocean Doppler Spectra: Simulation Versus Experimentation [PDF]

IEEE Transactions on Geoscience and Remote Sensing, 2014
We simulate the Doppler spectra that can be obtained under experimental conditions from bistatic high-frequency oceanic radar. For this, we combine the bistatic second-order theory with the characteristics of the full radar system, such as antenna patterns, range attenuation, and postprocessing of the received signal.
Grosdidier, Samuel, Forget, Philippe, Barbin, Yves, Guérin, Charles-Antoine   +3 more
openaire   +3 more sources

Long-distance HF radio waves propagation during the April 2023 geomagnetic storm by measurements in Antarctica, in Europe, and aboard RV Noosfera

Український антарктичний журнал, 2023
The paper aims at an experimental study of the mechanisms of long-distance high-frequency (HF) propagation and spatial and temporal variations of the ionospheric parameters during the first hours of a severe geomagnetic storm of April 23, 2023 by ...
A. Zalizovski, Y. Yampolski, I. Stanislawska, O. Koloskov, O. Budanov, O. Bogomaz, B. Gavrylyuk, A. Sopin, A. Reznychenko, A. Kashcheyev, S. Kashcheyev, V. Lisachenko   +11 more
doaj   +1 more source

Typical disturbances of the daytime equatorial F region observed with a high-resolution HF radar [PDF]

Annales Geophysicae, 1998
HF radar measurements were performed near the magnetic equator in Africa (Korhogo 9°24'63''N–5°37'38''W) during the International Equatorial Electrojet Year (1993–1994). The HF radar is a high-resolution zenithal radar.
E. Blanc, E. Houngninou
doaj   +1 more source

On the relationship between the velocity of E-region HF echoes and E B plasma drift [PDF]

, 2005
International audienceIn this study, velocities of E-region HF echoes observed by the Stokkseyri HF radar are compared with ExB plasma drifts in the F-region measured by the DMSP satellites.
D. W. Danskin, Koustov, A. V., J. D. Gorin, Makarevitch, R. A., Gorin, J. D., A. V. Koustov, R. A. Makarevitch, Danskin, D. W.   +7 more
core   +2 more sources

Periodic oscillations of Doppler frequency excited by the traveling ionospheric disturbances associated with the Tonga eruption in 2022

Earth, Planets and Space, 2023
The explosive eruption of the Hunga Tonga-Hunga Ha’apai volcano on 15 January 2022 generated atmospheric waves traveling around the Earth, which caused ionospheric disturbances on various spatio-temporal scales.
Hiroyuki Nakata, Keisuke Hosokawa, Susumu Saito, Yuichi Otsuka, Ichoro Tomizawa   +4 more
doaj   +1 more source

Comparison of D-region Doppler drift winds measured by the SuperDARN Finland HF radar over an annual cycle using the Kiruna VHF meteor radar [PDF]

, 2003
The SuperDARN chain of oblique HF radars has provided an opportunity to generate a unique climatology of horizontal winds near the mesopause at a number of high latitude locations, via the Doppler shifted echoes from sources of ionisation in the D-region.
N. F. Arnold (7589813), T. R. Robinson (7590257), P. A. Cook, Chapman, Peter J., N. Mitchell, P. A. Cook (7692134), Lester, M., Mitchell, N., Mitchell, Nick, P. J. Chapman, Arnold, Neil E., Robinson, T. R., Chapman, P. J., M. Lester, Cook, Peter A., M. Lester (7589660), P. J. Chapman (7590299), Arnold, N. F., Cook, P. A., T. R. Robinson, Lester, Mark, N. Mitchell (7692137), N. F. Arnold   +22 more
core   +2 more sources

Electrodynamics of the equatorial F-region ionosphere during pre-sunrise period [PDF]

Annales Geophysicae, 2009
The electrodynamics of the pre-sunrise equatorial F-region is investigated using HF Doppler radar and digital ionosonde. The observations are limited to those days for which the radar probing frequency is below the foF2 value.
S. R. Prabhakaran Nayar, T. J. Mathew, C. V. Sreehari, S. G. Sumod, C. V. Devasia, S. Ravindran, V. Sreeja, T. Kumar Pant, R. Sridharan   +8 more
doaj   +1 more source

Phenomena in the ionosphere-magnetosphere system induced by injection of powerful HF radio waves into nightside auroral ionosphere [PDF]

, 2005
International audienceExperimental results from three ionospheric HF pumping experiments in overdense E or F regions are summarized. The experiments were conducted by the use of the EISCAT HF Heating facility located near Tromsø, Norway, allowing HF ...
N. F. Blagoveshchenskaya, Bösinger, T., Rietveld, M. T., B. Thidé, Thidé, B., Borisova, T. D., T. D. Borisova, M. T. Rietveld, Kosch, M. J., V. A. Kornienko, M. J. Kosch, Blagoveshchenskaya, N. F., Kornienko, V. A., T. Bösinger   +13 more
core   +2 more sources

ULF wave occurrence statistics in a high-latitude HF Doppler sounder [PDF]

Annales Geophysicae, 1999
Ultra low frequency (ULF) wave activity in the high-latitude ionosphere has been observed by a high frequency (HF) Doppler sounder located at Tromsø, Norway (69.7°N, 19.2°E geographic coordinates).
D. M. Wright, T. K. Yeoman, T. B. Jones
doaj   +1 more source