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Ionospheric structures correlated with Anatolian surface features
Author(s) -
Garner T. W.,
Slack C. M.,
Mehta K.,
Scholze A.,
Mahrous A. M.
Publication year - 2011
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/2011rs004653
Subject(s) - tec , geology , ionosphere , ripple marks , amplitude , orographic lift , geodesy , latitude , atmospheric sciences , ripple , trough (economics) , seismology , geophysics , meteorology , physics , precipitation , optics , quantum mechanics , voltage , macroeconomics , economics
A UHF/VHF beacon receiver located in Helwan, Egypt, frequently observes structures in ΔTEC/Δ t measurements (where TEC is total electron count), where the F region (300 km) intercept of the radio rays crosses the steep topographic gradients associated with the Anatolian Plateau. There are three classes of structures: bumps, ripples and waves. A bump is defines as a single spatial ΔTEC/Δ t peak with a peak‐to‐trough amplitude of at least 0.01 TECU/s (1 TEC unit (TECU) = 10 16 electrons/m 2 ) that is at least 1° wide in F region latitude. A ripple is a bump with smaller structures on either side of the central bump. Finally, waves have amplitudes ≥0.01 TECU/s with several roughly equal peaks. These features were observed repeatedly in a number passes from 31 August to 30 November 2008. Over half of passes had either a bump (34.6%), a ripple (18.2%) or a wave (6.3%). Most of these structures occur near areas with large orographic gradients. The prevailing surface wind blows across the mountains when bumps and ripples are observed. These correlations suggest that the local ionosphere is affected by the ground topography, most likely through the orographic lifting and the associated gravity waves.