Data for Manuscript Submitted to Near Surface Geophysics Entitled “Diurnal observation and correction for spontaneous potential gradient measurement”

We selected two locations at 38 degrees north latitude and 45 degrees north latitude in China to conduct diurnal observation and correction surveys for spontaneous potential gradient measurement. In both study areas, the geoelectric diurnal data were processed with the following steps: (1) contrast correction, (2) background value correction, and (3) the calculation of diurnal norm and phase angle. At 45 degrees north, the geomagnetic diurnal data were processed with (1) background value correction only. The geomagnetic diurnal data were plotted together with simultaneously observed geoelectric diurnal data for analysis. Spontaneous potential gradient data were processed with the following steps: (1) contrast correction, (2) conversion to spontaneous potential, and (3) diurnal correction using the equations derived in the paper. After processing with the above methods, spontaneous potential contour maps for the entire study area can be obtained by interpolating the spontaneous potential data (before and after diurnal corrections) along all measuring lines on regularly spaced grids.

本团队精选我国北纬38度与45度两个地点，进行日际观测与修正调查，以测定自生电位梯度。在两个研究区域中，地电日际数据经过以下步骤进行处理：(1)对比度校正，(2)背景值校正，以及(3)日际规范值和相位角的计算。在北纬45度处，地磁日际数据仅进行(1)背景值校正。将地磁日际数据与同时观测的地电日际数据一同绘制，以便进行分析。自生电位梯度数据经过以下步骤进行处理：(1)对比度校正，(2)转换为自生电位，以及(3)利用论文中推导的方程进行日际校正。经上述方法处理之后，通过在规则间距网格上的所有测量线对自生电位数据进行插值，即可获得整个研究区域的自生电位等值线图。