Seasonal trends of nighttime plasma density enhancements in the topside ionosphere

International audienceIn situ registrations of electron density from the Langmuir probe on board Detection ofElectro-Magnetic Emissions Transmitted from Earthquake Regions satellite are used to study spatialand temporal evolution of nighttime plasma density enhancements (NPDEs). The study introduces thenormalized density difference index INDD in order to provide global estimates of the phenomenon. In thevalidation test, in situ data are compared with synthetic data set generated with the International ReferenceIonosphere model. We find signatures of two most common examples of NPDEs, the Weddell Sea Anomaly(WSA) and midlatitude nighttime summer anomaly (MSNA) with proposed index, in the topside ionosphere.The study provides evidence that the occurrence of the WSA and MSNA is not limited to the local summerconditions. Analyzed annual trend of INDD and in particular spatial pattern obtained during equinoxessuggest that mechanisms governing the behavior of the equatorial ionosphere cannot be neglected in theexplanation of the development of NPDEs

Examples of unusual ionospheric observations made by the DEMETER satellite over seismic regions

International audienceThe micro-satellite DEMETER was launched on June 29, 2004 in a polar and circular orbit with an altitude of ∼710 km. It is a CNES mission controlled from Toulouse in France. The main objective of DEMETER is to search and characterize ionospheric perturbations that can be associated with the seismic activity in order to better understand the generation mechanism of such perturbations. Its scientific payload allows us to measure waves in a broad frequency range and also some important plasma parameters (ion composition, electron density and temperature, energetic particles). This paper is a preliminary report of unusual observations recorded by DEMETER over seismic regions prior to earthquakes. The main purpose of the project is to perform a statistical analysis with many events in order to determine the necessary conditions to observe such seismo-electromagnetic effects. It is too early to perform such statistics but data recorded during selected events and shown here are useful since they may point out sensitive parameters which must be particularly surveyed in the statistical analysis

The effects of the strong thunderstorms seen in the ionosphere above Poland by DEMETER and Swarm satellites.

International audienceLightnings and particularly TLEs (sprites, jets, elves, halos) are associated with the electromagnetic connections and interactions between atmosphere, ionosphere and magnetosphere. DEMETER was a low-altitude microsatellite, it operated from June 2004 till December 2010 on a polar, circular orbit which altitude at the beginning was 710km but it was decreased to 660 km. DEMETER measured variations of the electric field in low frequency range from 0 to 20 kHz. The plasma analyzer instrument measured variations of the ion density 4 s time resolution. Langmuir probe gave the value of the electron temperature and density. A detector of energetic particle measured electrons and protons with energies from 70 keV to 2.34MeV every 4 s in survey mode and 1 s in burst mode. DEMETER has clearly shown, that thunderstorms and TLE can affected the ionosphere even at altitude of its orbit (680km). It registered many strong thunderstorms in Poland during its time of operation. The Swarm constellation comprises 3 identical satellites launched on 22 November 2013 into a near-polar orbit. This set of satellites is still operating. Two of them are operating on the circular, polar orbits with initial altitude 460. Third one has also circular orbit, but with altitude 530. The orbits of the first 2 satellites are in almost the same plane, but third one is close to be perpendicular to the first two. The payload containing Vector Field Magnetometer, Absolute Scalar Magnetometer and Electric Field Instrument among other allows to study the effects in the ionosphere generated by thunderstorms. The measurements performed during flights over thunderstorms areas in Poland will be discussed in our presentation. The discussion of the cross correlation between the ground based registrations (PERUN and VERA systems) and DEMETER and Swarm measurements of the ULF/ELF/VLF waves, electron density and temperature variations in the ionosphere related to the strong thunderstorms in Poland will be presented. This work was supported by grant NCN 2017/27/B/ST10/02285 and ESA Contract No:4000112769/14/NL/FF/g

The effects of the strong thunderstorms seen in the ionosphere above Poland by DEMETER and Swarm satellites. Michel Parrot (6)

International audienceLightnings and particularly TLEs (sprites, jets, elves, halos) are associated with the electromagnetic connections and interactions between atmosphere, ionosphere and magnetosphere. DEMETER was a low-altitude microsatel-lite, it operated from June 2004 till December 2010 on a polar, circular orbit which altitude at the beginning was 710km but it was decreased to 660 km. DEMETER measured variations of the electric field in low frequency range from 0 to 20 kHz. The plasma analyzer instrument measured variations of the ion density 4 s time resolution. Langmuir probe gave the value of the electron temperature and density. A detector of energetic particle measured electrons and protons with energies from 70 keV to 2.34MeV every 4 s in survey mode and 1 s in burst mode. DEMETER has clearly shown, that thunderstorms and TLE can affected the ionosphere even at altitude of its orbit (680km). It registered many strong thunderstorms in Poland during its time of operation. The Swarm constellation comprises 3 identical satellites launched on 22 November 2013 into a near-polar orbit. This set of satellites is still operating. Two of them are operating on the circular, polar orbits with initial altitude 460. Third one has also circular orbit, but with altitude 530. The orbits of the first 2 satellites are in almost the same plane, but third one is close to be perpendicular to the first two. The payload containing Vector Field Magnetometer, Absolute Scalar Magnetometer and Electric Field Instrument among other allows to study the effects in the ionosphere generated by thunderstorms. The measurements performed during flights over thunderstorms areas in Poland will be discussed in our presentation. The discussion of the cross correlation between the ground based registrations (PERUN and VERA systems) and DEMETER and Swarm measurements of the ULF/ELF/VLF waves, electron density and temperature variations in the ionosphere related to the strong thunderstorms in Poland will be presented

The effects of the strong thunderstorms seen in the ionosphere above Poland by DEMETER and Swarm satellites.

International audienceLightnings and particularly TLEs (sprites, jets, elves, halos) are associated with the electromagnetic connections and interactions between atmosphere, ionosphere and magnetosphere. DEMETER was a low-altitude microsatellite, it operated from June 2004 till December 2010 on a polar, circular orbit which altitude at the beginning was 710km but it was decreased to 660 km. DEMETER measured variations of the electric field in low frequency range from 0 to 20 kHz. The plasma analyzer instrument measured variations of the ion density 4 s time resolution. Langmuir probe gave the value of the electron temperature and density. A detector of energetic particle measured electrons and protons with energies from 70 keV to 2.34MeV every 4 s in survey mode and 1 s in burst mode. DEMETER has clearly shown, that thunderstorms and TLE can affected the ionosphere even at altitude of its orbit (680km). It registered many strong thunderstorms in Poland during its time of operation. The Swarm constellation comprises 3 identical satellites launched on 22 November 2013 into a near-polar orbit. This set of satellites is still operating. Two of them are operating on the circular, polar orbits with initial altitude 460. Third one has also circular orbit, but with altitude 530. The orbits of the first 2 satellites are in almost the same plane, but third one is close to be perpendicular to the first two. The payload containing Vector Field Magnetometer, Absolute Scalar Magnetometer and Electric Field Instrument among other allows to study the effects in the ionosphere generated by thunderstorms. The measurements performed during flights over thunderstorms areas in Poland will be discussed in our presentation. The discussion of the cross correlation between the ground based registrations (PERUN and VERA systems) and DEMETER and Swarm measurements of the ULF/ELF/VLF waves, electron density and temperature variations in the ionosphere related to the strong thunderstorms in Poland will be presented. This work was supported by grant NCN 2017/27/B/ST10/02285 and ESA Contract No:4000112769/14/NL/FF/g