A new technique for mapping of total electron content using GPS network in Japan

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Author(s)

Abstract

The dual frequency radio signals of the Global Positioning System (GPS) allow measurements of the total number of electrons, called total electron content (TEC), along a ray path from GPS satellite to receiver. We have developed a new technique to construct two-dimensional maps of absolute TEC over Japan by using GPS data from more than 1000 GPS receivers. A least squares fitting procedure is used to remove instrumental biases inherent in the GPS satellite and receiver. Two-dimensional maps of absolute vertical TEC are derived with time resolution of 30 seconds and spatial resolution of 0.15° × 0.15° in latitude and longitude. Our method is validated in two ways. First, TECs along ray paths from the GPS satellites are simulated using a model for electron contents based on the IRI-95 model. It is found that TEC from our method is underestimated by less than 3 TECU. Then, estimated vertical GPS TEC is compared with ionospheric TEC that is calculated from simultaneous electron density profile obtained with the MU radar. Diurnal and day-to-day variation of the GPS TEC follows the TEC behavior derived from MU radar observation but the GPS TEC is 2 TECU larger than the MU radar TEC on average. This difference can be attributed to the plasmaspheric electron content along the GPS ray path. This method is also applied to GPS data during a magnetic storm of September 25, 1998. An intense TEC enhancement, probably caused by a northward expansion of the equatorial anomaly, was observed in the southern part of Japan in the evening during the main phase of the storm.

Journal

  • Earth, Planets and Space

    Earth, Planets and Space 54(1), 63-70, 2002-01-01

    The Seismological Society of Japan, Society of Geomagnetism and Earth, Planetary and Space Sciences, The Volcanological Society of Japan , The Geodetic Society of Japan , The Japanese Society for Planetary Sciences

References:  24

Cited by:  16

Codes

  • NII Article ID (NAID)
    10008634190
  • NII NACSIS-CAT ID (NCID)
    AA11211921
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    13438832
  • NDL Article ID
    6062422
  • NDL Source Classification
    ZM41(科学技術--地球科学)
  • NDL Call No.
    Z54-J298
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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