Results 171 to 180 of about 413,548 (214)

Using HF-Doppler Detector to Analyze Infrasonic Disturbances

2007 International Conference on Microwave and Millimeter Wave Technology, 2007
We have been observing infrasonic disturbances by our HF-Doppler detector. Through analyzing their spectrum structures, we can conclude local features of infrasonic disturbances occurring in our area.
Chen Jixiang, Zhang Yinghui
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Ionospheric HF Doppler indication of GNSS positioning errors

2023
The HF Doppler ionospheric measurements can along with identification of medium scale wave activity provide also estimation of the level of the related GNSS positioning errors. The paper demonstrates the rise of GNSS positioning error with increasing wave activity at ionospheric heights and with changing parameters representing ionospheric waves ...
Urbar, J., Rejfek, L., Chum, J., Truhlik, V., Rusz, J., Baše, J., Horký, J., Šimůnek, J., Mošna, Z., Kouba, D., Obrazová, D.   +10 more
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HF ionospheric doppler studies

1976
Thesis (Ph.D.) -- La Trobe University, 1976.; Submitted to the Division of Theoretical and Space Physics.
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Observations of a coastal buoyant jet with HF Doppler radar

OCEANS 96 MTS/IEEE Conference Proceedings. The Coastal Ocean - Prospects for the 21st Century, 2002
Currents on the inner shelf respond to a combination of forcing by intrusions of ocean fronts, eddies and internal waves as well as winds, surface gravity waves and topographic rectifications. To quantify the effect that the interaction of these processes has on inner shelf flows, a shore-based, 25.4 MHz (High Frequency) Ocean Surface Current Radar ...
B.K. Haus, H.C. Graber, L.K. Shay
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Temporal impulsive noise excision in the range-Doppler map of HF radar

Proceedings 2003 International Conference on Image Processing (Cat. No.03CH37429), 2004
In this paper we present an effective scheme to excise impulsive noise pixels from a range-Doppler image or map. The temporal impulses in high frequency ocean surveillance radar (HFOSR) Doppler spectrum image arise due to local lightning discharges or man-made sources.
Xiaoli Lu, R. Lynn Kirlin, Jian Wang
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Use of HF Doppler radars for the investigation of the wind-current relationship

International Journal of Remote Sensing, 1986
Abstract The theoretical behaviour of the near-surface wind-driven currents is strongly dependent upon the models used to describe the mixed surface layer (especially the kinematic viscosity profile). This paper investigates measurements of ocean currents by HF Doppler radars in order to shed some light on this problem.
P. Broche, J. C. De maistre, P. Forget
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HF Doppler Measurements of Mesospheric Gravity Wave Momentum Fluxes

Journal of the Atmospheric Sciences, 1983
Abstract Recent theoretical studies have emphasized the probable importance of internal gravity waves in balancing the momentum budget of the mesosphere. In this paper, we propose a method by which the vertical flux of horizontal momentum can be measured by ground based radars.
Vincent, R., Reid, I.
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Modeling HF Doppler effects of geomagnetic sudden commencements

Journal of Geophysical Research, 1976
A model has been proposed to explain the ionospheric effects of the sudden commencements as measured with a Doppler sounder. The model consists of two different sources of electric fields generated in the ionosphere during the sudden commencement: a westward electromagnetically induced electric field generated in the F region due to the change of ...
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Use of global ionospheric maps for HF Doppler measurements interpretation

Advances in Space Research, 2018
Abstract The HF Doppler technique, a method of measurement of Doppler frequency shift of ionospheric signal, is one of the well-known and widely used techniques of ionosphere research. It allows investigation of various disturbances in the ionosphere.
Petrova I., Bochkarev V., Latypov R.
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Saturation Processes in Doppler-Broadened HF Vibrational Transition

1984
We have experimentally determined the frequency dependent shapes of Doppler-broadened HF vibrational transitions in the presence of a frequency stabilized, single-mode, saturating radiation field. We find that the transitions saturate homogeneously with no effective hole-burning observable.
Rolf W. F. Gross, John G. Coffer
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