Thesis (Ph.D.) University of Alaska Fairbanks, 2021Airborne hazards either in gaseous form or particulate matter can originate from a variety of sources. The most common natural airborne hazards are ash and SO₂ released during volcanic eruptions, smoke emitted caused by wildfires and dust storms. Once released into the atmosphere they can have a significant impact on different parts of the environment e.g. air quality, soil and water, as well as air traffic and ground transportation networks. This latter field is an important aspect of everyday life that is affected during hazardous events. Aviation is one of the most critical ways of transport in this century. Even short interruptions in flight schedules can lead to major economic damages. Volcanic eruptions comprise one of the most important airborne hazards to aviation. These are considered rare as compared to severe weather, but with an extremely high impact. This dissertation focusses on dispersion modeling tools and how they can support emergency response during different phases of volcanic eruption events. The impact of the volcanic ash cloud on the prediction of meteorological parameters and furthermore the dispersion of the ash is demonstrated by applying the Weather Research Forecasting (WRF) model with on-line integrated chemical transport (WRF-Chem) to simulate the 2010 Eyjafjallajökull eruption in Iceland. Comprehensive observational data sets have been collected to evaluate the model and to show the added value of integrating direct-feedback processes into the simulations. The case of the Eyjafjallajökull eruption showed the necessity to further develop the volcanic emission preprocessor of WRF-Chem which has been extended for flexible and complex ash and SO₂ source terms. Furthermore, the thesis describes how scientists could support operational centers to mitigate hazards during a large volcanic eruption event. The author of the dissertation coordinated a large exercise including experts across all Europe within a project funded by the European Union. The exercise aimed to develop and test new tools, models, and data to support real-time decision making in aviation flight planning during a volcanic crisis event. New state-of-the-art modeling applications were integrated into a flight planning software during a fictitious eruption of the Etna volcano in Italy with contributions from scientists, the military and the aviation community.Cooperative Institute for Alaska Research, National Oceanic and Atmospheric Administration cooperative agreement NA13OAR4320056 with the University of AlaskaChapter 1: Introduction --1.1 Airborne hazards and their impact on the environment and aviation -- 1.2 The volcanic risk mitigation system for aviation -- 1.3 Dispersion models support emergency response -- 1.4 Composition of the dissertation -- References. Chapter 2: The effects of simulating volcanic aerosol radiative feedbacks with WRF-Chem during the Eyjafjallajökull eruption, April and May 2010 -- Abstract -- 2.1 Introduction -- 2.2. Simulations setup -- 2.2.1. Model setup and case specifications -- 2.2.2. Volcanic emission preprocessor -- 2.3. Spatial and temporal evaluation of the location of the volcanic plume -- 2.4. Evaluation of meteorological parameters close to the surface -- 2.4.1. Meteorological observations -- 2.4.2. Average meteorological parameters at ground level -- 2.5. Aerosol radiative feedback effects in the model simulations -- 2.5.1. Radiative feedback effects close to the surface -- 2.5.2. Vertical profiles of wind speed and temperature -- 2.5.3. Influence of the radiative feedback effects on the atmospheric stability -- 2.6. The influence of considering the direct effect on the dispersion of the ash cloud -- 2.7. Summary and conclusions -- 2.8. Acknowledgments -- References. Chapter 3: Extension of the WRF-Chem volcanic emission preprocessor to integrate complex source terms and evaluation for different emission scenarios of the Grimsvötn 2011 eruption -- Abstract -- 3.1 Introduction -- 3.2 Extension of the volcanic preprocessor of the WRF-Chem model -- 3.3 WRF-Chem model simulations -- 3.3.1 Model setup -- 3.3.2 Volcanic emission scenarios -- 3.3.3 Model inter-comparison of predicted ash considering aviation regulation aspects -- 3.4 Evaluation of WRF-Chem simulations with observations -- 3.4.1. Comparison of volcanic ash and SO₂ with satellite data -- 3.4.2 Comparison with ground-based observations -- 3.4.2.1 Lidar profiles at selected stations -- 3.4.2.2 Comparison with PM10 observations at selected ground stations -- 3.5. Conclusions -- 3.6 Acknowledgements -- Glossary -- Appendix -- References. Chapter 4: A volcanic-hazard demonstration exercise to assess and mitigate the impacts of volcanic ash clouds on civil and military aviation -- Abstract -- 4.1 Introduction -- 4.2 International exercises -- 4.3 Overview of the EUNADICS-AV demonstration exercise set-up -- 4.3.1 General approach -- 4.3.1.1 The volcanic-eruption scenario -- 4.3.1.2 Data sharing and visualization -- 4.4 Data sets used for the demonstration exercise -- 4.4.1 Artificial observations -- 4.4.1.1 Simulations of the artificial plume evolution -- 4.4.1.2 Generation of artificial observations from SILAM simulations -- 4.4.2 The early-warning system (EWS) -- 4.4.2.1 Volcano observatory, Sicily -- 4.4.2.2 Synthetic ACTRIS EARLINET data -- 4.4.2.3 Synthetic satellite data simulated for IASI and MODIS -- 4.4.3 Model ensemble -- 4.5 The impact of the ash cloud on aviation for the Etna eruption scenario -- 4.5.1 Air navigation service provider -- 4.5.2 Austrian Armed Forces (AAF) -- 4.5.3 Rerouting of flights -- 4.6 Conclusion -- 4.7 Acknowledgements -- Glossary -- References. Chapter 5: Dissertation Summary and Conclusions -- 5.1 Extension and evaluation of the WRF-Chem model -- 5.2 Future perspectives -- References
