解决具有可提取概率的地球物理倒置问题:线性高斯近似与相关的伪边际方法对比.
1Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland.
概括
这项研究引入了一种新的贝叶斯逆转方法,用于水地质学,该方法将不可观察的地球物理特性视为潜在变量. 大致高斯方法快速,但不那么准确,不确定性很高,与相关的伪边际方法不同.
科学领域:
- 地质物理学 地质物理学
- 水文地质学 水文地质学
- 贝叶斯的推理 贝叶斯的推理
背景情况:
- 地质学贝叶斯反转旨在从地质学数据中估计地下参数.
- 将地质参数与地质属性联系起来的石化物理关系往往表现出分散.
- 将中间地质物理特性视为潜变量可以解决这种不确定性.
研究的目的:
- 在潜在变量模型中开发和评估地质物理贝叶斯反转的方法.
- 给定地质物理数据,估计地质参数的难以处理的概率函数.
- 为了比较一个新的近似高斯方法与相关的伪边际方法.
主要方法:
- 使用基于局部线性化的高斯概率密度函数对概率函数的近似.
- 将石化物理关系噪声纳入数据共变矩阵.
- 与使用蒙特卡洛平均值对潜变量样本的一般相关伪边际方法进行比较.
主要成果:
- 这两种方法都为合成穿孔地面穿透雷达的旅行时间逆转提供了相似的估计,石化物理不确定性很低.
- 忽视石化物理的不确定性导致了偏见的估计.
- 线性高斯式方法的准确性随着石质散射的增加而下降,而相关的伪边际方法仍然准确.
结论:
- 相关的伪边际方法对于具有显著石化物理不确定性的地质物理逆转是可靠的.
- 线性高斯近似提供了计算效率,但对石化物理散射敏感.
- 准确的地质物理逆转需要考虑石质物理的不确定性.
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