15:30 〜 15:45
[PEM12-16] Equatorial Sporadic E layers as seen from GNSS radio occultations
★Invited Papers
キーワード：Ionosphere, sporadic E layer, GNSS radio occultation
The GNSS radio occultation (RO) technique has been established successfully during the previous two decades. It evolved into a valuable observation tool for precise atmospheric and ionospheric vertical profiling. Radio occultation measurements provide globally distributed precise profiles of the refractivity of the Earth’s atmosphere that can be converted into profiles of temperature, pressure, and water vapor in the lower neutral atmosphere and into electron density values in the ionosphere. The main advantage of this technique is that it provides the profiles in a very high vertical resolution covering the whole globe. Until today, there are about 14 million RO recordings available.
GNSS RO signals are very sensitive to vertical electron density gradients in the Earth’s ionosphere. This becomes visible as strong fluctuations in, e.g., signal-to-noise ratio recordings, which allow detecting ionospheric disturbances like sporadic E (Es) layers in the lower ionospheric E region. Due to the geometry of the GNSS RO technique, it enables for the first time receiving a global and comprehensive picture of the occurrence and the properties of Es layers in a high spatial resolution.
In this presentation, we like to focus on the difference between midlatitude and low-latitude sporadic E properties. We observed that the Es occurrence rate shows a pronounced depression directly at the magnetic equator. Further, the equatorial Es altitudes show a strong longitudinal variability which is not the case at midlatitudes. We will give and explanation attempt for the observed features in the equatorial region using equatorial electric field data provided by the Swarm satellites.
GNSS RO signals are very sensitive to vertical electron density gradients in the Earth’s ionosphere. This becomes visible as strong fluctuations in, e.g., signal-to-noise ratio recordings, which allow detecting ionospheric disturbances like sporadic E (Es) layers in the lower ionospheric E region. Due to the geometry of the GNSS RO technique, it enables for the first time receiving a global and comprehensive picture of the occurrence and the properties of Es layers in a high spatial resolution.
In this presentation, we like to focus on the difference between midlatitude and low-latitude sporadic E properties. We observed that the Es occurrence rate shows a pronounced depression directly at the magnetic equator. Further, the equatorial Es altitudes show a strong longitudinal variability which is not the case at midlatitudes. We will give and explanation attempt for the observed features in the equatorial region using equatorial electric field data provided by the Swarm satellites.