Abstract. Volcanic eruptions may generate volcanic ash and sulfur dioxide (SO₂) plumes with strong temporal and vertical variations. When simulating these changing volcanic plumes and the afar dispersion of emissions, it is important to provide the best available information on the temporal and vertical emission distribution during the eruption. The volcanic emission module of the chemical transport model WRF-Chem has been extended to allow integrating detailed temporally and vertically resolved input data from volcanic eruptions. The new emission pre-processor is tested and evaluated for the eruption of the Grimsvötn volcano in Iceland 2011. The initial ash plumes of the Grimsvötn eruption differed significantly from the SO₂ plumes posing challenges to simulate plume dynamics within existing modelling environments: observations of the Grimsvötn plumes revealed strong vertical wind shear that led to different transport directions of the respective ash and SO₂ clouds. Three source terms, each of them based on different assumptions and observational data are applied in the model simulations. The emission scenarios range from (i) a simple approach, which assumes constant emission fluxes and a pre-defined vertical emission profile, to (ii) a more complex approach, which integrates temporarily varying observed plume top heights and estimated emissions based on them, to (iii) the most complex method that calculates temporal and vertical variability of the emission fluxes based on satellite observations and inversion techniques. Comparisons between model results and independent observations from satellites, lidar and surface air quality measurements reveal best performance of the most complex source term.

中文翻译：

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扩展了WRF-Chem火山排放预处理器，以整合复杂的源术语和对Grimsvötn2011喷发不同排放情景的评估

摘要。火山喷发会产生火山灰和二氧化硫（SO ₂）羽，它们在时间和垂直方向上都有很大的变化。在模拟这些不断变化的火山羽和排放物的远处扩散时，重要的是在喷发期间提供关于时间和垂直排放物分布的最佳可用信息。化学运输模型WRF-Chem的火山排放模块已经扩展，可以整合来自火山喷发的详细的时间和垂直解析输入数据。测试了新的排放预处理器并评估了2011年冰岛格里姆斯沃特火山的喷发。格里姆斯沃特火山喷发的最初烟灰与SO ₂明显不同羽流对在现有建模环境中模拟羽流动力学提出了挑战：对Grimsvötn羽流的观察表明，强烈的垂直风切变导致相应灰分和SO _2的不同传输方向云。在模型仿真中应用了三个源项，每个源项基于不同的假设和观察数据。排放方案的范围从（i）一种简单的方法（假定恒定的排放通量和一个预先定义的垂直排放曲线）到（ii）一种更复杂的方法（将临时变化的观测烟羽顶部高度和基于它们的估计排放量整合在一起）组成， （iii）最复杂的方法，该方法基于卫星观测和反演技术来计算排放通量的时间和垂直变化。模型结果与卫星，激光雷达和地面空气质量测量结果的独立观测结果之间的比较表明，最复杂的源项的最佳性能。