FPLUME-1.0: An integral volcanic plume model accounting for ash aggregation

Geoscientific Model Development

G.Macedonio¹  A.Folch¹  A.Costa¹ 

DOI  :  10.5194/gmd-9-431-2016

学科分类：天文学(综合)

来源: Copernicus Publications

【 摘 要 】

Eruption source parameters (ESP) characterizing volcanic eruption plumes arecrucial inputs for atmospheric tephra dispersal models, used for hazardassessment and risk mitigation. We present FPLUME-1.0, a steady-state 1-D(one-dimensional) cross-section-averaged eruption column model based on thebuoyant plume theory (BPT). The model accounts for plume bending by wind, entrainment ofambient moisture, effects of water phase changes, particle fallout andre-entrainment, a new parameterization for the air entrainment coefficientsand a model for wet aggregation of ash particles in the presence of liquid wateror ice. In the occurrence of wet aggregation, the model predicts aneffective grain size distribution depleted in fines with respect to thaterupted at the vent. Given a wind profile, the model can be used to determinethe column height from the eruption mass flow rate or vice versa. Theultimate goal is to improve ash cloud dispersal forecasts by betterconstraining the ESP (column height, eruption rate and vertical distributionof mass) and the effective particle grain size distribution resultingfrom eventual wet aggregation within the plume. As test cases we apply themodel to the eruptive phase-B of the 4 April 1982 El Chichón volcanoeruption (México) and the 6 May 2010 Eyjafjallajökull eruption phase(Iceland). The modular structure of the code facilitates the implementationin the future code versions of more quantitative ash aggregationparameterization as further observations and experiment data will beavailable for better constraining ash aggregation processes.

【 授权许可】

Unknown