Source effects and the interpretation of geomagnetic sounding data at sub‐auroral latitudes
Source effects and the interpretation of geomagnetic sounding data at sub‐auroral latitudes
复制标题
亚极光纬度地磁探测数据的源效应和解释
DOI：
10.1111/j.1365-246x.1981.tb02736.x
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
M. Mareschal
中科院分区：
文献类型：
--
作者：
M. Mareschal
总结
传统的地磁测深技术使用垂直场到水平场变化的函数来估计地球内电导率的水平分层或横向不连续性。当电导率仅随深度变化时，梯度法也可用于估计穿透深度处的环境电导率。
在亚极光区和15-60分钟的周期范围内，这两种方法的源场均匀性基本假设并不总是成立，解释技术变得可疑。
使用三维源模型（电射流+场对准电流），我们展示了源的接近程度如何扭曲传递函数估计，从而扭曲Z/H比。源场梯度的估计似乎是不太容易在高纬度地区比标准的解释内外场比的错误。
Summary
Conventional techniques of geomagnetic deep sounding use functions of vertical to horizontal field variations to estimate either horizontal layering or lateral discontinuities in conductivity within the Earth. When the conductivity varies with depth alone, gradient methods are also used to estimate the ambient conductivity at depth of penetration.
In sub-auroral regions and in the period range 15-60 min, the assumption of source field uniformity basic to both methods does not always hold and the techniques of interpretation become questionable.
Using three-dimensional source models (electrojet + field-aligned currents), we show how the closeness of the source can distort transfer function estimates and thus Z/H ratios. Estimates of source field gradients appear to be less error prone at high latitudes than standard interpretations of internal-external field ratios.