scholarly journals Global morphology of ionospheric sporadic E layer from the FormoSat-3/COSMIC GPS radio occultation experiment

GPS Solutions ◽  
2018 ◽  
Vol 22 (4) ◽  
Author(s):  
Lung-Chih Tsai ◽  
Shin-Yi Su ◽  
Chao-Han Liu ◽  
Harald Schuh ◽  
Jens Wickert ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Gps Radio Occultation ◽  
Sporadic E Layer ◽  
Sporadic E

Global Sporadic E Layer Characteristics Obtained from GPS Radio Occultation Measurements

2013 ◽  
pp. 207-221 ◽  
Author(s):  
Christina Arras ◽  
Jens Wickert ◽  
Christoph Jacobi ◽  
Georg Beyerle ◽  
Stefan Heise ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Gps Radio Occultation ◽  
Sporadic E Layer ◽  
Sporadic E

scholarly journals Tidal wind shear observed by meteor radar and comparison with sporadic E occurrence rates based on GPS radio occultation observations

2019 ◽  
Vol 17 ◽  
pp. 213-224
Author(s):  
Christoph Jacobi ◽  
Christina Arras
Keyword(s):  
Wind Shear ◽  
Radio Occultation ◽  
Signal To Noise Ratio ◽  
Lower Thermosphere ◽  
Horizontal Component ◽  
Meteor Radar ◽  
Good Correspondence ◽  
Gps Radio Occultation ◽  
Middle Latitudes ◽  
Sporadic E

Abstract. We analyze tidal (diurnal, semidiurnal, terdiurnal, quarterdiurnal) phases and related wind shear in the mesosphere/lower thermosphere as observed by meteor radar over Collm (51.3∘ N, 13.0∘ E). The wind shear phases are compared with those of sporadic E (Es) occurrence rates, which were derived from GPS radio occultation signal-to-noise ratio (SNR) profiles measured by the COSMIC/FORMOSAT-3 satellites. At middle latitudes Es are mainly produced by wind shear, which, in the presence of a horizontal component of the Earth's magnetic field, leads to ion convergence in the region where the wind shear is negative. Consequently, we find good correspondence between radar derived wind shear and Es phases for the semidiurnal, terdiurnal, and quarterdiurnal tidal components. The diurnal tidal wind shear, however, does not correspond to the Es diurnal signal.

Global ionosonde and GPS radio occultation sporadic-E intensity and height comparison

2020 ◽  
Vol 199 ◽  
pp. 105200
Author(s):  
Joshua Y. Gooch ◽  
Jonah J. Colman ◽  
Omar A. Nava ◽  
Daniel J. Emmons
Keyword(s):  
Radio Occultation ◽  
Gps Radio Occultation ◽  
Sporadic E

Simulated GPS radio occultation signals from sporadic-E layers

2020 ◽  
Author(s):  
Daniel Emmons
Keyword(s):  
Radio Occultation ◽  
Plasma Frequency ◽  
Signal Amplitude ◽  
Scintillation Index ◽  
Gps Radio Occultation ◽  
Multiple Phase ◽  
Maximum Variance ◽  
Sporadic E Layers ◽  
Sporadic E ◽  
Screen Model

<p>A multiple phase screen model is used to simulate GPS radio occultation signals through varying sporadic-E layers.  The length, vertical extent, and plasma frequency of the sporadic-E layers are varied to analyze the effect on the signal received by a low earth orbiting satellite.  A nonlinear relationship between the maximum variance in the signal amplitude and the plasma frequency is observed.  For certain frequency ranges, the predictions match previous studies that have used the S<sub>4 </sub>scintillation index to predict fbEs values. Additionally, the spectra of the signals are analyzed as a function of the different parameters providing an alternative approach for extracting sporadic-E parameters from GPS radio occultation measurements. </p>

scholarly journals Semidiurnal tidal signature in sporadic E occurrence rates derived from GPS radio occultation measurements at higher midlatitudes

2009 ◽  
Vol 27 (6) ◽  
pp. 2555-2563 ◽  
Author(s):  
C. Arras ◽  
C. Jacobi ◽  
J. Wickert
Keyword(s):  
Global Positioning System ◽  
Zonal Wind ◽  
Radio Occultation ◽  
Positioning System ◽  
Semidiurnal Tide ◽  
Meteor Radar ◽  
Global Positioning ◽  
Sporadic E Layer ◽  
Sporadic E ◽  
Wind Shears

Abstract. GPS (Global Positioning System) Radio occultation (RO) measurements from CHAMP, GRACE and FORMOSAT-3/COSMIC satellites at Northern Hemisphere midlatitides (50°–55° N) are analysed to obtain the diurnal variation of sporadic E layer occurrence frequency in 2006 and 2007. Interconnections with zonal wind shears measured by meteor radar at Collm (51.3° N, 13° E), Germany, are investigated. According to theory, maximum Es occurrence is expected when the zonal wind shear, which is mainly produced by the semidiurnal tide in midlatitudes, is negative. This is confirmed by the present measurements and analysis.

Effect of sporadic E clouds on GPS radio occultation signals

2010 ◽  
Vol 37 (18) ◽  
pp. n/a-n/a ◽  
Author(s):  
Z. Zeng ◽  
S. Sokolovskiy
Keyword(s):  
Radio Occultation ◽  
Gps Radio Occultation ◽  
Sporadic E

scholarly journals Comparison of Seasonal foEs and fbEs Occurrence Rates Derived from Global Digisonde Measurements

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1558
Author(s):  
Dawn K. Merriman ◽  
Omar A. Nava ◽  
Eugene V. Dao ◽  
Daniel J. Emmons
Keyword(s):  
Southern Hemisphere ◽  
Lower Limit ◽  
Northern Hemisphere ◽  
Radio Occultation ◽  
Austral Summer ◽  
Peak Frequency ◽  
Boreal Summer ◽  
Gps Radio Occultation ◽  
Drastic Decrease ◽  
Sporadic E

A global climatology of sporadic-E occurrence rates (ORs) based on ionosonde measurements is presented for the peak blanketing frequency, fbEs, and the ordinary mode peak frequency of the layer, foEs. ORs are calculated for a variety of sporadic-E frequency thresholds: no lower limit, 3, 5, and 7 MHz. Seasonal rates are calculated from 64 Digisonde sites during the period 2006–2020 using ionograms either manually or automatically scaled with ARTIST-5. Both foEs and fbEs ORs peak in the Northern Hemisphere during the boreal summer, with a decrease by roughly a factor of 2–3 in fbEs rates relative to foEs rates without a lower threshold on the sporadic-E intensity. This ratio of foEs to fbEs OR increases with increasing sporadic-E intensity, up to a factor of 5 for the 7 MHz threshold. An asymmetry is observed with the Southern Hemisphere peaks during the austral summer, with slightly lower rates compared with the Northern Hemisphere during the boreal summer. A drastic decrease in ORs is observed for the higher intensity thresholds, such that the fbEs occurrence rates for 7 MHz are nearly zero during most locations and seasons. These updated occurrence rates can be used for future statistical comparisons with GPS radio occultation-based sporadic-E occurrence rates.

scholarly journals Modulation of sporadic E layers by small-scale atmospheric waves in Earth’s high-latitude ionosphere

2019 ◽  
Vol 5 (3) ◽  
pp. 116-129
Author(s):  
Владимир Губенко ◽  
Vladimir Gubenko ◽  
Иван Кириллович ◽  
Ivan Kirillovich
Keyword(s):  
High Latitude ◽  
Radio Occultation ◽  
Small Scale ◽  
Polar Cap ◽  
Atmospheric Waves ◽  
Sporadic E Layers ◽  
High Latitude Ionosphere ◽  
Sporadic E Layer ◽  
Sporadic E ◽  
Good Agreement

We have used radio occultation measurements of the satellite CHAMP (Challenging Minisatellite Payload) to examine sporadic E layers (altitudes 90–130 km) in Earth’s high-latitude ionosphere. We have developed a new method for determining characteristics of internal atmospheric waves based on the use of inclined sporadic E layers of Earth’s ionosphere as a detector. The method relies on the fact that an internal wave propagating through the initially horizontal sporadic E layer causes the plasma density gradient to rotate in the direction of the wave vector, which leads to the fact that the layer ionization plane is set parallel to the phase wave front. The developed method enables us to study the interrelations between small-scale internal waves and sporadic E layers in Earth’s ionosphere and significantly expands the capabilities of traditional radio occultation monitoring of the atmosphere. We have found that the internal atmospheric waves under study have periods from 35 to 46 min and vertical phase speeds from 1.2 to 2.0 m/s, which are in good agreement with the results of independent experiments and simulation data on sporadic E layers at a height of ~100 km in Earth’s polar cap.

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