Earthquake Science

, Volume 23, Issue 4, pp 349–355 | Cite as

Variations of electron density and temperature in ionosphere based on the DEMETER ISL data

  • Yufei He
  • Dongmei YangEmail author
  • Rong Zhu
  • Jiadong Qian
  • M Parrot


Observations of the Langmuir Probe Instrument (ISL, Instrument Sonde de Langmuir) onboard the DEMETER satellite during four years from 2006 to 2009 were used to analyze the tempo-spatial variations of electron density (Ne) and temperature (Te) in the ionosphere. Twenty four research bins with each covering an area with 10° in longitude and 2° in latitude were selected to study the spatial distributions of Ne and Te. The results indicate that both Ne and Te have strong annual variations in the topside ionosphere at 660 km altitude. The semiannual anomaly and equinoctial asymmetry which are usually well known as the features of F-layer also exist in the topside ionosphere at low- and mid-latitudes. The yearly variation of Ne is opposite to the peak electron density of the F2-layer (NmF2) at higher latitudes in daytime and both are similar in nighttime. Also the yearly variations of Te at low-latitude are contrary to that at 600 km in daytime and similar in nighttime. An interesting feature of nighttime Te at low-latitude is an obvious annual variation in the northern hemisphere and semiannual variation in the southern hemisphere. The yearly variations of Te in daytime have negative and positive correlation with Ne at mid- and high-latitudes, respectively. Both Ne and Te in the neighborhood bins at the same latitude have a high correlation. In ionospheric events analyzing, this information may help to understand the characteristics of the variation and to distinguish the reliable abnormality from the normal background map.

Key words

seasonal variation annual variation spatial distribution Ne Te DEMETER satellite 

CLC number



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Copyright information

© The Seismological Society of China and Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Yufei He
    • 1
  • Dongmei Yang
    • 1
    Email author
  • Rong Zhu
    • 1
  • Jiadong Qian
    • 2
  • M Parrot
    • 3
  1. 1.Institute of GeophysicsChina Earthquake AdministrationBeijingChina
  2. 2.Institute of Earthquake ScienceChina Earthquake AdministrationBeijingChina
  3. 3.Laboratoire de Physique et Chimie de l’EnvironmentCentre National de la Recherche ScientifiqueOrleansFrance

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