Dense Gas Dispersion and Modelling at Fagradalsfjall, Iceland

冰岛 Fagradalsfjall 的稠密气体扩散和建模

• 批准号: NE/W004852/1
• 负责人: Ralph Burton
• 金额: $ 6.43万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FW004852%2F1
• 关键词: Dense; Gas; Dispersion; Modelling; Fagradalsfjall

The ongoing eruption at Fagradalsfjall in Iceland presents an outstanding and rare opportunity to observe and model the behaviour of dense volcanic gases. Sulphur Dioxide (SO2) is the principal emission from lava-rich eruptions such as at Fagradalsfjall. With more than double the molecular weight of air, this is prone to exhibiting dense gas dispersion characteristics such as settling, with the potential to significantly affect the dispersion over scales of hundreds of kilometers. This can lead to enhanced concentrations at low levels with consequences for air quality and human health. This project aims to (a) collect a surface air quality and meteorological dataset and (b) produce a modelling framework capable of simulating dense gas and validate it against (a). Such a framework does not exist at present. This is a significant, time-limited and accessible eruption event which, if responded to now, can lead to major advances in both scientific understandings and in the management of future, possibly larger, eruptions from which there is a serious gas hazard. (A) We will enhance existing air quality observations in the vicinity of Fagradalsfjall, creating a network to provide a comprehensive assessment of dense volcanic gas dispersion on a scale of 50-100 km. This unique dataset will provide the first independent verification for a full meteorological prediction model with dense gas capability coupled with surface heating (see below).(B) Recent model development work has demonstrated effective volcanic gas dispersion predictions using an adapted version of the NCAR Weather Research and Forecasting (WRF) model. This system was used to successfully interpret aircraft measurements of CO2 dispersion from the (subglacial) Katla volcano in Iceland and to explain quantitatively, for the first time, the dense gas CO2 behaviour which led to the Lake Nyos disaster in 1986 that saw dense CO2 pooling and draining down valleys, causing ~1700 deaths. Neither of these applications considered (or required) a heated surface. However, the Fagradalsfjall eruption is now in a phase where lava fountains have been reported, and so the effect of surface heating will need to be considered in any modelling, to include the complex interactions and feedbacks between a dense gas, a heated surface, and the underlying meteorology. The model, after development and verification, will be available in the future as an operational hazard prediction system and and could lead to significant improvements in the UK national capability to respond to dense gas releases. This includes anthropogenic releases, for example industrial accidents and fires.

冰岛Fagradalsfjall正在进行的喷发为观察和模拟致密火山气体的行为提供了一个杰出而难得的机会。二氧化硫（SO2）是富熔岩喷发的主要排放物，如在Fagradalsfjall。由于分子量是空气的两倍以上，这很容易表现出稠密气体的分散特性，如沉降，有可能在数百公里的尺度上显著影响分散。这可能导致低浓度的浓度增加，对空气质量和人类健康造成影响。该项目的目的是（a）收集地面空气质量和气象数据集，（B）制作一个能够模拟稠密气体的建模框架，并对照（a）进行验证。这样的框架目前并不存在。这是一个重大的、有时限的和可以接触到的喷发事件，如果现在就作出反应，可以在科学认识和管理未来可能更大规模的喷发方面取得重大进展，这些喷发会产生严重的气体危险。(A)我们将加强Fagradalsfjall附近现有的空气质量观测，建立一个网络，全面评估50-100公里范围内的密集火山气体扩散情况。这一独特的数据集将为一个完整的气象预测模型提供第一个独立的验证，该模型具有致密气体能力，并结合了表面加热（见下文）。(B)最近的模型开发工作证明，使用NCAR天气研究和预报（WRF）模型的改编版本进行有效的火山气体扩散预测。该系统被用来成功地解释了飞机测量的冰岛卡特拉火山（冰下）的二氧化碳扩散，并首次定量解释了导致1986年尼奥斯湖灾难的致密气体二氧化碳行为，该灾难导致了致密的二氧化碳汇集和排放山谷，造成约1700人死亡。这些应用都没有考虑（或需要）加热表面。然而，Fagradalsfjall火山喷发现在正处于熔岩喷泉的报告阶段，因此在任何建模中都需要考虑表面加热的影响，以包括致密气体，加热表面和底层气象之间的复杂相互作用和反馈。该模型在开发和验证后，将在未来作为一个操作性的危险预测系统，并可能导致英国国家能力的显着改善，以应对密集气体释放。这包括人为排放，例如工业事故和火灾。