ANNUAL AND SEMIANNUAL CHANGES OF THE QUIET DAILY VARIATIONS (SQ) IN THE GEOMAGNETIC-FIELD AT NORTH-AMERICAN LOCATIONS
ANNUAL AND SEMIANNUAL CHANGES OF THE QUIET DAILY VARIATIONS (SQ) IN THE GEOMAGNETIC-FIELD AT NORTH-AMERICAN LOCATIONS
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DOI：
10.1029/ja087ia02p00785
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发表时间：
1982-01-01
影响因子：
2.8
通讯作者：
CAMPBELL, WH
中科院分区：
文献类型：
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作者：
CAMPBELL, WH
本文给出了1965年北美地区地磁场平静日变的解析表达式，其日变幅度的平均误差小于10%。H、D和Z的场的24小时、12小时、8小时和6小时傅立叶分量的逐月变化具有显著的年度和半年变化。在赤道，Sq（H）的半年变化对所有傅立叶分量都是占主导地位的。在15° ~ 50°纬度范围内，Sq（D）的24小时分量年变化是该区域电离层电流涡旋的主要季节变化。日场的24小时分量在高纬度地区有很大的增强，在70°纬度以上，H、D、和Z的年变化在夏季有很强的最大值。总的来说，这些结果与对所有区域电离层电流源的预期一致。
An analytic representation of the quiet daily variation of the geomagnetic field (Sq) was obtained for 1965 in the North American region, with a mean error of less than 10% of the daily variation range. The month‐by‐month 24‐, 12‐, 8‐, and 6‐hour Fourier components of the field inH, D,andZhad significant annual and semiannual changes. At the equator theSq(H) semiannual change was dominant for all Fourier components. From 15° to 50° latitude the 24‐hour component annual change ofSq(D) was the principal seasonal variation in this region of the ionospheric current vortex. Great enhancements of the 24‐hour component of the daily field occurred at high latitude, with strong summertime maxima in the annual variation ofH, D,, andZabove 70° latitude. The results, in general, agreed with the expectation for ionospheric current sources in all regions.