eprintid: 1460140
rev_number: 30
eprint_status: archive
userid: 608
dir: disk0/01/46/01/40
datestamp: 2015-01-06 20:07:20
lastmod: 2020-04-13 03:58:30
status_changed: 2016-04-15 14:19:06
type: article
metadata_visibility: show
item_issues_count: 0
creators_name: Van De Kamp, M
creators_name: Pokhotelov, D
creators_name: Kauristie, K
title: TID characterised using joint effort of incoherent scatter radar and GPS
ispublished: pub
divisions: UCL
divisions: A01
divisions: B04
divisions: C06
note: Copyright © Author(s) 2014. This work is distributed
under the Creative Commons Attribution 3.0 License (https://creativecommons.org/licenses/by/3.0/).
abstract: Travelling Ionospheric Disturbances (TIDs), which are caused by Atmospheric Gravity Waves (AGWs), are detected and characterised by a joint analysis of the results of two measurement techniques: incoherent scatter radar and multiple-receiver GPS measurements. Both techniques to measure TIDs are already well known, but are developed further in this study, and the strengths of the two are combined, in order to obtain semi-automatic tools for objective TID detection. The incoherent scatter radar provides a good vertical range and resolution and the GPS measurements provide a good horizontal range and resolution, while both have a good temporal resolution. Using the combination of the methods, the following parameters of the TID can be determined: the time of day when the TID occurs at one location, the period length (or frequency), the vertical phase velocity, the amplitude spectral density, the vertical wavelength, the azimuth angle of horizontal orientation, the horizontal wavelength, and the horizontal phase velocity. This technique will allow a systematic characterisation of AGW-TIDs, which can be useful, among other things, for statistical analyses. 

The presented technique is demonstrated on data of 20 January 2010 using data from the EISCAT incoherent scatter radar in Tromsø and from the SWEPOS GPS network in Sweden. On this day around 07:00–12:00 UT, a medium-scale TID was observed from both data sets simultaneously. The TID had a period length of around 2 h, and its wave propagated southeastward with a horizontal phase velocity of about 67 m s−1 and a wavelength of about 500 km. The TID had its maximum amplitude in Tromsø at 10:00 UT. The period length detected from the GPS results was twice the main period length detected from the radar, indicating a different harmonic of the same wave. The horizontal wavelength and phase velocity are also estimated from the radar results using Hines' theory, using the WKB approximation to account for inhomogeneity of the atmosphere. The results of this estimate are higher than those detected from the GPS data. The most likely explanation for this is that Hines' theory overestimated the values, because the atmosphere was too inhomogeneous even for the WKB approximation to be valid.
date: 2014-12-17
official_url: http://dx.doi.org/10.5194/angeo-32-1511-2014
vfaculties: VMPS
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
article_type_text: Journal Article
verified: verified_manual
elements_source: Scopus
elements_id: 1001569
doi: 10.5194/angeo-32-1511-2014
lyricists_name: Pokhotelov, Dimitry
lyricists_id: DPOKH93
full_text_status: public
publication: Annales Geophysicae
volume: 32
number: 12
pagerange: 1511-1532
issn: 1432-0576
citation:        Van De Kamp, M;    Pokhotelov, D;    Kauristie, K;      (2014)    TID characterised using joint effort of incoherent scatter radar and GPS.                   Annales Geophysicae , 32  (12)   pp. 1511-1532.    10.5194/angeo-32-1511-2014 <https://doi.org/10.5194/angeo-32-1511-2014>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/1460140/1/TID%20characterised%20using%20joint%20effort%20of%20incoherent%20scatter%20radar%20and%20GPS.pdf