Open AccessIonogram signatures of large‐scale wave structure and their relation to equatorial spread F
Author(s) -
Thampi Smitha V.,
Tsunoda Roland T.,
Jose Lijo,
Pant Tarun Kumar
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2012ja017592
Subject(s) - ionosonde , ionogram , geology , ionosphere , upwelling , geophysics , geodesy , scale (ratio) , reflection (computer programming) , radius , latitude , physics , electron density , oceanography , computer security , quantum mechanics , computer science , programming language , electron
Observations of signatures of the large‐scale wave structure (LSWS) and subsequent development of equatorial spread F (ESF) by using data from a newly installed digital ionosonde at Trivandrum (8.5°N; 77°E; 0.5°N magnetic dip latitude) are presented. The LSWS signatures are observed using the ionograms with echo directions. The ‘satellite’ traces are shown as echoes from oblique directions, when an upwelling (associated with LSWS) is not directly over the ionosonde location. When an upwelling is centered overhead, and the radius of curvature of the isodensity contours matches the height of reflection, signals from various directions can add in phase to enhance the ionospheric reflection coefficient, and produce another ionogram signature, referred to as multireflected echoes (MREs). It is also shown that the generation of ESF is related to the presence of LSWS. The skymaps also show the presence of small‐scale wave structures in the bottomside F region. The investigation also indicates that the range spread F (RSF) occurs because of the reflections from the embedded smaller‐scale structures within the large‐scale upwelling.