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Relationship Between Wavenumber 4 Pattern of Sporadic E Layer Intensity and Eastward Propagating Diurnal Tide With Zonal Wavenumber 3 in Low Latitude Region
Author(s) -
Niu J.
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028985
Subject(s) - wavenumber , ionosphere , longitude , latitude , amplitude , geology , northern hemisphere , radio occultation , southern hemisphere , atmospheric sciences , middle latitudes , geophysics , climatology , geodesy , physics , optics
Ionospheric sporadic E layers are irregularities with enhanced plasma density which occur in the ionosphere E region. In the present work, we have focused on an interesting wavenumber 4(WN4) pattern of sporadic E layer based on the Constellation Observing System for Meteorology, Ionosphere and Climate radio occultation S4 indices observation. It is found that amplitude of WN4 pattern has a significant seasonal dependency with the maximum appearing in summer/autumn and minimum in winter. The seasonal variation of the WN4 pattern is basically consistent with the eastward propagating diurnal tide with zonal wavenumber 3 (DE3) tide features. Inconsistencies, mainly an anomalous weak amplitude during the summer in southern hemisphere and propagation direction (speed), are also found. By removing the zonal ion drift factor effect, WN4 pattern of sporadic E layers exhibits a closer relation with the DE3 tide with larger amplitude in the northern hemisphere and ∼90° shift in longitude on average during autumn in the southern hemisphere. In general, it is reasonable to conclude that DE3 tide greatly contributes to this WN4 pattern of sporadic E layers.