Operational Modelling of Umbrella Cloud Growth in a Lagrangian Volcanic Ash Transport and Dispersion Model
| Autor: | B. J. Devenish, Larry G. Mastin, Alexa R. Van Eaton, David J. Thomson, Helen N. Webster |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Atmospheric Science
lateral spread 010504 meteorology & atmospheric sciences Meteorology umbrella cloud operational forecasting satellite observations Cloud computing Environmental Science (miscellaneous) lcsh:QC851-999 volcanic ash transport and dispersion model 010502 geochemistry & geophysics 01 natural sciences Dispersion (water waves) 0105 earth and related environmental sciences geography geography.geographical_feature_category Explosive eruption business.industry Volumetric flow rate Gravity current Volcano Environmental science Satellite lcsh:Meteorology. Climatology business Volcanic ash |
| Zdroj: | Atmosphere Volume 11 Issue 2 Atmosphere, Vol 11, Iss 2, p 200 (2020) |
| ISSN: | 2073-4433 |
| DOI: | 10.3390/atmos11020200 |
| Popis: | Large explosive eruptions can result in the formation of an umbrella cloud which rapidly expands, spreading ash out radially from the volcano. The lateral spread by the intrusive gravity current dominates the transport of the ash cloud. Hence, to accurately forecast the transport of ash from large eruptions, lateral spread of umbrella clouds needs to be represented within volcanic ash transport and dispersion models. Here, we describe an umbrella cloud parameterisation which has been implemented into an operational Lagrangian model and consider how it may be used during an eruption when information concerning the eruption is limited and model runtime is key. We examine different relations for the volume flow rate into the umbrella, and the rate of spreading within the cloud. The scheme is validated against historic eruptions of differing scales (Pinatubo 1991, Kelud 2014, Calbuco 2015 and Eyjafjallajö kull 2010) by comparing model predictions with satellite observations. Reasonable predictions of umbrella cloud spread are achieved using an estimated volume flow rate from the empirical equation by Bursik et al. and the observed eruption height. We show how model predictions can be refined during an ongoing eruption as further information and observations become available. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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