Uncertainty analysis of a model of wind-blown volcanic plumes.
Uncertainty analysis of a model of wind-blown volcanic plumes.
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DOI：
10.1007/s00445-015-0959-2
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发表时间：
2015
影响因子：
3.5
通讯作者：
Rougier JC
中科院分区：
文献类型：
--
作者：
Woodhouse MJ;Hogg AJ;Phillips JC;Rougier JC
自然过程的数学模型可以用作反演工具，从测量的量预测未观察到的属性。观测和模型制定的不确定性影响反建模的有效性。我们提出了一个一般的方法，历史匹配，可用于调查观测和模型的不确定性对反演建模研究的影响。我们展示了历史匹配的火山羽流的积分模型，用于估计源条件从观测的上升高度的羽流在冰岛的埃亚菲亚德拉冰盖，在2010年和格里姆火山，冰岛，在2011年爆发。不确定性的来源被确定和量化，并通过整体羽流模型传播。进行初步的敏感性分析，以确定强烈影响模型预测的不确定模型参数。模型预测是通过一个不可信性度量来评估的，该度量排除了在量化的不确定性下被认为是不可信的模型输入。我们证明，在火山源质量通量可以估计从羽流高度观测，但岩浆温度，出口速度和exsolved气体质量分数不能准确地确定。羽流高度观测和卷吸系数的不确定性导致源质量通量的大范围的合理值。我们的分析表明，更好的约束火山羽流的卷吸系数和更精确的观测羽流高度需要得到严格约束的源质量通量的估计。
Mathematical models of natural processes can be used as inversion tools to predict unobserved properties from measured quantities. Uncertainty in observations and model formulation impact on the efficacy of inverse modelling. We present a general methodology, history matching, that can be used to investigate the effect of observational and model uncertainty on inverse modelling studies. We demonstrate history matching on an integral model of volcanic plumes that is used to estimate source conditions from observations of the rise height of plumes during the eruptions of Eyjafjallajökull, Iceland, in 2010 and Grímsvötn, Iceland, in 2011. Sources of uncertainty are identified and quantified, and propagated through the integral plume model. A preliminary sensitivity analysis is performed to identify the uncertain model parameters that strongly influence model predictions. Model predictions are assessed against observations through an implausibility measure that rules out model inputs that are considered implausible given the quantified uncertainty. We demonstrate that the source mass flux at the volcano can be estimated from plume height observations, but the magmatic temperature, exit velocity and exsolved gas mass fraction cannot be accurately determined. Uncertainty in plume height observations and entrainment coefficients results in a large range of plausible values of the source mass flux. Our analysis shows that better constraints on entrainment coefficients for volcanic plumes and more precise observations of plume height are required to obtain tightly constrained estimates of the source mass flux.