Open AccessSome characteristics of atmospheric gravity waves observed by radio-interferometry
Author(s) -
C. Mercier
Publication year - 1996
Publication title -
annales geophysicae
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.522
H-Index - 93
eISSN - 1432-0576
pISSN - 0992-7689
DOI - 10.1007/s00585-996-0042-6
Subject(s) - daytime , azimuth , physics , radio wave , geodesy , sky , total electron content , interferometry , tec , atmospheric sciences , ionosphere , geology , astrophysics , geophysics , astronomy , quantum mechanics
Observations of atmospheric acoustic-gravitywaves (AGWs) are considered through their effect on the horizontal gradient Gof the slant total electron content (slant TEC), which can be directly obtainedfrom two-dimensional radio-interferometric observations of cosmic radio-sourceswith the Nançay radioheligraph (2.2°E, 47.3°N).Azimuths of propagation can be deduced (modulo 180°). The totaldatabase amounts to about 800 h of observations at various elevations, localtime and seasons. The main results are:
a) AGWs are partially directive, confirming our previousresults.
b) The propagation azimuths considered globally are widelyscattered with a preference towards the south.
c) They show a bimodal time distribution with preferentialdirections towards the SE during daytime and towards the SW during night-time(rather than a clockwise rotation as reported by previous authors).
d) The periods are scattered but are larger during night-timethan during daytime by about 60%.
e) The effects observed with the solar radio-sources aresignificantly stronger than with other radio-sources (particularly at higherelevations), showing the role of the geometry in line of sight-integratedobservations