Magnetic Anomaly Grid and Associated Uncertainty From Marine Trackline Data: The Caribbean Alternative Navigation Reference Experiment (CANREx) Earth and Space Science

Crustal magnetic anomaly maps over oceanic regions are based largely on marine trackline surveys. These surveys, collected from the 1950s to the present, span a wide range of data quality and reliability. We discuss a methodology for constructing grids from these data with associated cell by cell estimates of grid uncertainty. The method is tested with a modern airborne survey for a representative region in the eastern Caribbean. The results are promising, producing an uncertainty estimate that is accurate to one standard deviation for the test area. As magnetic anomaly maps and grids are increasingly applied as constraints for geologic interpretation as well as for alternative navigation (e.g., navigation by magnetic field patterns in the absence of GPS), it is important to quantify the accuracy of these maps.

洋域地壳磁异常图（crustal magnetic anomaly maps）主要基于海洋测线调查（marine trackline surveys）。此类自1950年代至今收集的调查数据，其数据质量与可靠程度参差不齐。本文探讨了一种基于此类数据构建磁异常格网，并同步逐格网单元估算格网不确定性（grid uncertainty）的方法。本方法以加勒比海东部典型区域的现代航空测量（airborne survey）数据开展了测试，测试结果令人满意：所得不确定性估算值在试验区内的准确度可达一个标准差。鉴于磁异常图与格网正日益被用作地质解译的约束依据，以及替代导航方案（例如无GPS条件下依托磁场模式的导航）的应用场景，量化此类地图的精度已显得至关重要。