Abstract

The gravity database for the IAG African Geoid Project contains significantly large data gaps. These large data gaps affect the interpolation precision of the reduced gravity anomalies needed for the determination of the gravimetric geoid for Africa. Our aim is to develop a suitable interpolation technique that can be used for a proper gravity interpolation within large data gaps. A gap of 10° × 5° in the latitude and longitude directions, respectively, located at the high lands of Ethiopia has been artificially created within the gravity data set for Africa. The rest of the data set has been used to interpolate the gravity values at the gap points; then a comparison between the interpolated and the actual data values at the artificial data gap has been carried-out to determine the accuracy of the used interpolation technique. The unequal weight least-squares prediction (with the optimum curvature parameter at the origin) with an underlying grid at the gap areas computed by the satellite-only GO CONS GCF 2 DIR R5 model till degree and order 300, has been proposed as the developed interpolation approach. For comparison purpose, the Kriging interpolation technique has also been tested. Both the classical residual terrain modeling reduction and the window technique, suggested earlier by the authors to get rid of the double consideration of the topographic-isostatic masses within the data window in the framework of the remove-restore technique, have been used for the reduction process. A comparison between the data and interpolated values of the gravity at the gap points has been carried out. The results show that the developed interpolation technique gives better interpolation accuracy at the artificial data gap.

中文翻译：

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适用于非洲大数据空白的重力插值技术

摘要

IAG非洲大地水准项目的重力数据库包含很大的数据空白。这些巨大的数据缺口影响了确定非洲重力重力大地水准面所需的重力重力降低的内插精度。我们的目标是开发一种适合的插值技术，该技术可用于在大数据间隙内进行适当的重力插值。在非洲的重力数据集中，人为地创建了位于埃塞俄比亚高地的纬度和经度方向分别为10°×5°的间隙。其余数据集已用于在间隙点处插入重力值。然后在人工数据间隙处进行插值和实际数据值之间的比较，以确定所用插值技术的准确性。已经提出了由纯卫星GO CONS GCF 2 DIR R5模型计算出的度数和阶数为300时在间隙区域具有底层网格的不等权最小二乘预测（在原点具有最佳曲率参数）的建议。插值法。为了进行比较，还测试了克里格插值技术。作者较早前建议的经典残余地形建模简化和窗口技术均已消除了在删除-还原技术框架中对数据窗口内的地形等静质量的双重考虑，处理。在间隙点处的重力数据和插值之间进行了比较。