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核心表面流量模型在与IGRF-14候选场模型相反时有什么变化?
1School of Earth and Environment, University of Leeds, Woodhouse, Leeds, LS2 9JT UK.
概括
新的国际地磁参考场 (IGRF-14) 模型完善了地球磁场的预测. 分析显示,候选模型的变化会影响核心流量预测,而更高的截断度可以提高准确性.
科学领域:
- 地质学和地球科学 地球物理学和地球科学
- 地磁主义和地球的磁场.
- 核心动力学和地力学理论
背景情况:
- 国际地磁参考场 (IGRF) 模拟了地球的大规模磁场,对导航,太空天气和资源勘探至关重要.
- 第14代 (IGRF-14) 提供了2020年的最终模型,2025年的预测,2025年的预测和2025年的世俗变化 (SV).
- 世俗变化 (SV) 与地球外核的流动有关,使得IGRF候选模型对研究核心动力学具有价值.
研究的目的:
- 用IGRF-14候选模型组合来研究预测的核心流量变化.
- 分析IGRF候选模型的差异如何影响推断的核心流量.
- 评估球体波切割度对 SV 预测和核心流量的影响.
主要方法:
- 使用了pygeodyn Python包,使用AR-1"密集"方法和71%的地质动力预测.
- 保持固定的反转参数,以隔离IGRF候选模型变化的核心流量影响.
- 与SV候选模型进行比较,SV候选模型在球体波13度与8度之间被截断.
主要成果:
- 虽然所有IGRF候选项都产生了类似的流量谱,但与中位数模型的较大偏差导致了较大的流量差异,主要是在小空间尺度上.
- 流速差异仍然低于平均模型最大流速的25%,太平洋和极地地区的不确定性最高.
- 将SV截断度提高到13改变了流量光谱能量,并将最大流速提高到31%,同时在流量图中保持高相关性.
结论:
- IGRF候选模型中的偏差显著影响推断的核心流量,突显了模型共识的重要性.
- 核心流的不确定性在磁场约束较弱的区域是最大的.
- 该研究支持将未来IGRF模型的SV组件的球体波切割度提高到13,以提高准确性.
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