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Comparative climatological study of large‐scale traveling ionospheric disturbances over North America and China in 2011–2012
Author(s) -
Ding Feng,
Wan Weixing,
Li Qiang,
Zhang Rui,
Song Qian,
Ning Baiqi,
Liu Libo,
Zhao Biqiang,
Xiong Bo
Publication year - 2014
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2013ja019523
Subject(s) - solstice , earth's magnetic field , ionosphere , climatology , china , geology , terminator (solar) , geography , latitude , geodesy , geophysics , physics , archaeology , quantum mechanics , magnetic field
This paper describes a comparative study of the climatology of large‐scale traveling ionospheric disturbances (LSTIDs) over North America and China based on observations obtained in 2011–2012 using two GPS networks characterized by dense regional coverage. We identified a total of 390 LSTIDs in China and 363 events in North America. These can be categorized into three types, namely south, north, and westward propagating LSTIDs. The southward LSTIDs over North America show similar diurnal and seasonal variations to those of geomagnetic disturbances, but the southward LSTIDs over China do not show such variations. The occurrence of southward LSTIDs over China increases at ~1–2 h after the time of geomagnetic activity maximum; this increase lasts several hours until the geomagnetic minimum, which happens during the local evening. The southward LSTIDs over North America show a semiannual variation with two peaks in March and October, while the southward LSTIDs over China show a major peak in January. Northward LSTIDs occur much less frequently than their southward counterparts, and they are mainly observed in China. They mostly occur during geomagnetic activity maximum, indicating a possible relation with the degree of geomagnetic activity. Westward LSTIDs are seen in both regions during local sunrise and may be excited by the moving solar terminator. No relationship was found between these latter LSTIDs and the geomagnetic disturbances. The propagation direction of westward events changed from northwestward during winter solstice to southwestward at summer solstice. This is consistent with the seasonal orientation of the solar terminator.