Longitudinal Structure in the Altitude of the Sporadic E Observed by COSMIC in Low-Latitudes

The longitudinal structure in the altitude of the Sporadic E (Es) was investigated for the first time based on the S4 index provided by the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) in low latitudes. The longitudinal structure is identified as a symmetrically located wavenumber-4 (WN4) pattern within 30°S–30°N. The WN4 occurs primarily during the daytime at the June solstice and equinoxes, with the largest amplitude at the September equinox and the smallest one at the March equinox. It moves eastward with a speed of ~90°/day. The strongest WN4 appears within 10–20°N and 5–15°S in the Northern and Southern hemispheres, respectively. At the June solstice and the September equinox, the WN4 is stronger in the Northern hemisphere than in the Southern hemisphere, while the situation is reversed at the March equinox. The altitude distribution of the convergence null in the diurnal eastward non-migrating tide with zonal wavenumber-3 (DE3) for the zonal wind is similar to that of the WN4. This and other similar features, such as the seasonal variation, eastward speed, and the symmetrical locations, support the dominant role of the DE3 tide for the formation of the WN4 structure.

[1]  C. Haldoupis,et al.  On the altitude dependence and role of zonal and meridional wind shears in the generation of E region metal ion layers , 2021 .

[2]  C. Haldoupis.  A Tutorial Review on Sporadic E Layers , 2011 .

[3]  X. Xue,et al.  The global climatology of the intensity of the ionospheric sporadic E layer , 2019, Atmospheric Chemistry and Physics.

[4]  D. Marsh,et al.  Interhemispheric transport of metallic ions within ionospheric sporadic E layers by the lower thermospheric meridional circulation , 2021 .

[5]  Ze Gao,et al.  A New Empirical Model of NmF2 Based on CHAMP, GRACE, and COSMIC Radio Occultation , 2019, Remote. Sens..

[6]  I. Batista,et al.  Simulations of blanketing sporadic E-layer over the Brazilian sector driven by tidal winds , 2017 .

[7]  I. Batista,et al.  The influence of tidal winds in the formation of blanketing sporadic e-layer over equatorial Brazilian region , 2017 .

[8]  G. Didebulidze,et al.  Formation of sporadic E (Es) layer by homogeneous and inhomogeneous horizontal winds , 2020 .

[9]  Xinan Yue,et al.  Case study on complex sporadic E layers observed by GPS radio occultations , 2014 .

[11]  J. Plane,et al.  Atmospheric chemistry of meteoric metals. , 2003, Chemical reviews.

[12]  Dora Pancheva,et al.  Ionogram height–time–intensity observations of descending sporadic E layers at mid-latitude , 2006 .

[13]  Yen-Hsyang Chu,et al.  Coordinated sporadic E layer observations made with Chung-Li 30 MHz radar, ionosonde and FORMOSAT-3/COSMIC satellites , 2011 .

[14]  Hermann Lühr,et al.  A statistical analysis of longitudinal dependences of upper thermospheric zonal winds at dip equator latitudes derived from CHAMP , 2007 .

[15]  T. Nygrén,et al.  The role of electric field and neutral wind direction in the formation of sporadic E-layers , 1984 .

[16]  T. Yu,et al.  Comparison of global morphologies of vertical ion convergence and sporadic E occurrence rate , 2019, Advances in Space Research.

[17]  I. Batista,et al.  Study of sporadic E layers based on GPS radio occultation measurements and digisonde data over the Brazilian region , 2018 .

[18]  Chen Zhou,et al.  The seasonal distribution of sporadic E layers observed from radio occultation measurements and its relation with wind shear measured by TIMED/TIDI , 2018, Advances in Space Research.

[19]  J. Wickert,et al.  Estimation of ionospheric sporadic E intensities from GPS radio occultation measurements , 2017, Journal of Atmospheric and Solar-Terrestrial Physics.

[20]  Jens Wickert,et al.  Semidiurnal tidal signature in sporadic E occurrence rates derived from GPS radio occultation measurements at higher midlatitudes , 2009 .

[21]  H. Lühr,et al.  Nonmigrating tidal signals in the upper thermospheric zonal wind at equatorial latitudes as observed by CHAMP , 2009 .

[22]  C. Meek,et al.  Seasonal variability and descent of mid-latitude sporadic E layers at Arecibo , 2009 .

[23]  I. Batista,et al.  Simulation of the sporadic E layer response to prereversal associated evening vertical electric field enhancement near dip equator , 2007 .