A modelling study of HF radar coherent detection of irregularities in the high-latitude ionosphere
Ground-based coherent backscatter radar systems are extensively used to investigate small-scale dynamics in the earth's ionosphere and related geophysical process(es) in the magnetosphere. At high-latitudes, HF radars are used due to the requisite orthogonal condition with the earth's magn...
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ftleicester:oai:lra.le.ac.uk:2381/30604 2023-05-15T14:03:40+02:00 A modelling study of HF radar coherent detection of irregularities in the high-latitude ionosphere Zou, Li. 2014-12-15T10:40:45Z http://hdl.handle.net/2381/30604 en eng University of Leicester http://hdl.handle.net/2381/30604 U103791 a452398 Copyright © the author. All rights reserved. ProQuest Thesis Doctoral PhD 2014 ftleicester 2019-03-22T20:19:50Z Ground-based coherent backscatter radar systems are extensively used to investigate small-scale dynamics in the earth's ionosphere and related geophysical process(es) in the magnetosphere. At high-latitudes, HF radars are used due to the requisite orthogonal condition with the earth's magnetic field lines. Because of the effect of ionospheric refraction on the ray paths, the exact path of the radar signal through the ionosphere is then unknown. In practice, it is important to locate the radar echo sources given the echo parameters, such as group path, elevation angle, and azimuth angle. Furthermore, radar observations consist of direct backscatter from the ground. An uncertainty arises due to the difficulty in separating true ground backscatter from ionospheric scatter which fulfils the radar criteria based on the measured Doppler velocity and spectral width.;These problems are investigated in this research using a three-dimensional ray tracing computer programme, Jones3D (Jones and Stephenson, 1975). Some problems in the Jones3D code have been identified and corrected whilst modifications to the code have been made to suit the purpose of this research work. All modelling work presented in this thesis is based on two HF radars, the Halley HF radar in Antarctica and the CUTLASS HF radar in Finland. For the best comparison with radar observations, realistic ionospheric conditions are used. In the case study for the Halley HF radar in Antarctica, it is found that the radar's main propagation mode is one-hop propagation, and that the radar scatter is mostly organised in ranges in the order of E- region scatter, F- region scatter, and ground scatter. The range-bin statistical analysis suggests that the radar criteria based on the measured Doppler velocity and special width are not sufficient, and that the measured range (group path) parameter is important and should be used in separating radar ionospheric echoes from ground backscatter. Doctoral or Postdoctoral Thesis Antarc* Antarctica University of Leicester: Leicester Research Archive (LRA) Stephenson ENVELOPE(-69.133,-69.133,-72.133,-72.133) |
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Open Polar |
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University of Leicester: Leicester Research Archive (LRA) |
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ftleicester |
language |
English |
description |
Ground-based coherent backscatter radar systems are extensively used to investigate small-scale dynamics in the earth's ionosphere and related geophysical process(es) in the magnetosphere. At high-latitudes, HF radars are used due to the requisite orthogonal condition with the earth's magnetic field lines. Because of the effect of ionospheric refraction on the ray paths, the exact path of the radar signal through the ionosphere is then unknown. In practice, it is important to locate the radar echo sources given the echo parameters, such as group path, elevation angle, and azimuth angle. Furthermore, radar observations consist of direct backscatter from the ground. An uncertainty arises due to the difficulty in separating true ground backscatter from ionospheric scatter which fulfils the radar criteria based on the measured Doppler velocity and spectral width.;These problems are investigated in this research using a three-dimensional ray tracing computer programme, Jones3D (Jones and Stephenson, 1975). Some problems in the Jones3D code have been identified and corrected whilst modifications to the code have been made to suit the purpose of this research work. All modelling work presented in this thesis is based on two HF radars, the Halley HF radar in Antarctica and the CUTLASS HF radar in Finland. For the best comparison with radar observations, realistic ionospheric conditions are used. In the case study for the Halley HF radar in Antarctica, it is found that the radar's main propagation mode is one-hop propagation, and that the radar scatter is mostly organised in ranges in the order of E- region scatter, F- region scatter, and ground scatter. The range-bin statistical analysis suggests that the radar criteria based on the measured Doppler velocity and special width are not sufficient, and that the measured range (group path) parameter is important and should be used in separating radar ionospheric echoes from ground backscatter. |
format |
Doctoral or Postdoctoral Thesis |
author |
Zou, Li. |
spellingShingle |
Zou, Li. A modelling study of HF radar coherent detection of irregularities in the high-latitude ionosphere |
author_facet |
Zou, Li. |
author_sort |
Zou, Li. |
title |
A modelling study of HF radar coherent detection of irregularities in the high-latitude ionosphere |
title_short |
A modelling study of HF radar coherent detection of irregularities in the high-latitude ionosphere |
title_full |
A modelling study of HF radar coherent detection of irregularities in the high-latitude ionosphere |
title_fullStr |
A modelling study of HF radar coherent detection of irregularities in the high-latitude ionosphere |
title_full_unstemmed |
A modelling study of HF radar coherent detection of irregularities in the high-latitude ionosphere |
title_sort |
modelling study of hf radar coherent detection of irregularities in the high-latitude ionosphere |
publisher |
University of Leicester |
publishDate |
2014 |
url |
http://hdl.handle.net/2381/30604 |
long_lat |
ENVELOPE(-69.133,-69.133,-72.133,-72.133) |
geographic |
Stephenson |
geographic_facet |
Stephenson |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_source |
ProQuest |
op_relation |
http://hdl.handle.net/2381/30604 U103791 a452398 |
op_rights |
Copyright © the author. All rights reserved. |
_version_ |
1766274449583112192 |