English  |  正體中文  |  简体中文  |  Items with full text/Total items : 67783/67783 (100%)
Visitors : 23030387      Online Users : 840
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Tips:
  • please add "double quotation mark" for query phrases to get precise results
  • please goto advance search for comprehansive author search
  • Adv. Search
    HomeLoginUploadHelpAboutAdminister Goto mobile version

    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/27363

    Title: A new aspect of ionospheric E region electron density morphology
    Authors: Chu,YH;Wu,KH;Su,CL
    Contributors: 太空科學研究所
    Date: 2009
    Issue Date: 2010-06-29 18:37:02 (UTC+8)
    Publisher: 中央大學
    Abstract: From global measurements of ionospheric electron density profiles made by the FORMOSAT-3/COSMIC satellites, the morphology of E region electron density is investigated. Seasonal, latitudinal, and diurnal variations in daytime E region electron density are well described by the Chapman theory, and the E layer peak electron density NmE and its peak height h(m)E are governed by the solarzenith angle chi in accordance with relations relations NmE alpha(cos chi)(p) and h(m)E alpha ln(sec chi), respectively. However, it is revealed that there are three geomagnetic latitude regions where striking enhancements of the E region electron density occur. One of them is located at the geomagnetic equator with relatively narrow latitude extent of about 6 degrees-10 degrees, and the other two with much wider latitude extent of about 10 degrees-20 degrees appear on both sides of the geomagnetic equator in latitude regions +/- 20 degrees-30 degrees, respectively. The locations of these E region density enhancements are asymmetrical about the geomagnetic equator in solstice seasons, and they have a salient tendency to shift toward (away from) the summer (winter) hemisphere. The off-equator E region electron density enhancements are closely connected with the bottomside of the F region equatorial anomaly crests, where the component of the electron density parallel to the magnetic field line is maximum. It appears that the off-equator E region electron density enhancements are very likely the footprints of the F region equatorial anomaly crests. The morphologies of the exponent n and coefficient K in the power law relation between chi and f(o)E (E region critical frequency) are also examined. There is a tendency for the n and K values to be larger in local winter than in local summer seasons in the latitudinal regions the same as the off-equator electron density enhancements. In addition, it is found that a minor peak in the K values is nearly continuously present in all seasons over the geomagnetic equator. A comparison shows significant discrepancies in the E region electron density morphologies between COSMIC measurement and IRI model prediction. Furthermore, compelling evidence is provided to show the presences of longitudinal wave number 3 and 4 structures of the electron density in the height region 100-200 km, which are in coincident with the longitudinal structures of equatorial electrojet. It is believed that these longitudinal 3-and 4-peak structures are very likely associated with nonmigrating diurnal tides propagating eastward in ionospheric E region.
    Appears in Collections:[太空科學研究所 ] 期刊論文

    Files in This Item:

    File Description SizeFormat

    All items in NCUIR are protected by copyright, with all rights reserved.

    社群 sharing

    ::: Copyright National Central University. | 國立中央大學圖書館版權所有 | 收藏本站 | 設為首頁 | 最佳瀏覽畫面: 1024*768 | 建站日期:8-24-2009 :::
    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - Feedback  - 隱私權政策聲明