“Follow the Water”: Determination of Unfrozen Water Content and Mechanisms Of Its Survival In Soils of the Dry Valleys of Antarctica by Nuclear Magnetic Resonance

Alaska has more than 100 volcanoes, 40 of them active, which make up about 80 percent of all active volcanoes in the United States (USGS Volcano Hazard Program). Volcanic eruptions can cause many hazards, the most significant being the volcanic ash clouds that are released into the atmosphere and transported thousands of kilometers away by wind (Ram and Gayley 1991). Volcanic ash plumes pose a significant threat to aviation safety, a fact that was recently learned by many after the Mt. Redoubt eruption in March 2009. Alaska Airlines was forced to cancel more than 100 flights on its Alaska routes as a safety precaution. General aviation, which is a critical component of transportation in Alaska, was also greatly disrupted. Over the past decades, many volcanic ash transport and dispersion (VATD) models have been developed to predict volcanic ash transport and dispersion in the atmosphere, providing a scientific basis for authorities to plan hazard responses. However, their wider applications are often limited due to challenge in prediction accuracy. The difficulties in obtaining eruption source parameters cause a lack of accurate physical descriptions of the initial eruptive plumes, which can introduce considerable errors. Errors are also accumulated in calculating ash particle trajectories that represent evolution of volcanic ash plumes. A novel method was recently developed to provide a new prediction tool that is able to overcome some limitations on the existing VATD models (Peng and Peterson, 2011).

The method is based on a multidisciplinary approach that applies a theory in dynamics systems to volcanic ash transport. To be more specific, the method uses the finite time Lyapunov exponents to identify coherent structures in the wind field that attract volcanic ash particles. In contrast to the previous methods that simulate the evolution of a single eruption event, the new method focuses on the overall properties of the wind field in which volcanic particles are transported. It is able to correlate particle transport with the underlining attracting structures that dictate the wind field. These structures, which predict hazard zones of volcanic ash plumes, are independent of particle source parameters and are less prone to errors of wind velocity field. Therefore, the new method provides a robust and accurate way to predict the hazard zones of volcanic ash in the atmosphere. In the proposed study, the new prediction method will be further developed and implemented. The method will be validated by a case study through comparisons with satellite images of volcanic ash plumes. Its advantages will be demonstrated by comparison with predictions from the existing VATD models. An additional feature will be added to the model that uses information from satellite image analysis to update prediction and further improve its accuracy. A software package will be developed to provide interested researchers easy access and application of the new method. In addition, a separate web-based application will also be created to provide real-time predictions in events of volcano eruptions. Through the advance of the new method, the proposed study will provide knowledge to help better understand the physics of volcanic ash transport in the atmosphere. The software and the web application developed in the proposed study will have broad impacts.

They allow wider application of the method in scientific research. They also provide guidance to aviation authorities to reroute flights and to close airspace in response to volcanic eruptions.