The purpose of this project is to develop a volcanic plume prediction model for volcanoes located in the Cook Inlet area, Alaska. Knowing where the ash plume is and predicting where it will go are important for public health and safety, as well as for flight operations and mitigating economic damage. For near-real-time plume prediction, acquisition of upper-air wind data is the essential part o...

This paper addresses detection and characterization of chemical vapor fugitive emissions in a nonscattering atmosphere by processing of remotely-sensed long-wavelength infrared spectra. The analysis approach integrates a parameterized signal model based on the radiative transfer equation with a statistical model for the infrared background. The maximum likelihood model parameter values are defi...

A time-accurate 2D axisymmetric Hybrid PIC-MCC model is used to simulate the plasma flow in the acceleration channel and near-field plume of a Hall thruster. The model is applied to the P5 Hall thruster due to known magnetic configuration and the availability of experimental data on the plasma properties in the interior and near-field plume for this thruster. Results for thruster performance an...

An end-to-end model is presented of the transient plume created by a micro laser-ablation plasma thruster. In this paper we describe a model of the plasma generation and expansion for a microlaser plasma thruster operated in transmission-mode (T-mode). The laser ablation and plasma formation processes are modeled using a kinetic ablation model. This procedure provides boundary conditions at the...

[1] Time‐dependent buoyant plumes form at the outflow of tidally dominated estuaries. When estuary discharge velocity exceeds plume internal wave speed c, a sharp front forms at the plume’s leading edge that expands from the time‐dependent source. Using observations of the Columbia River tidal plume from multiple tidal cycles we characterize time‐evolving plume structure and quantify front spee...

Following the collapse of the New York World Trade Center (WTC) towers on September 11, 2001, Local, State, and Federal agencies initiated numerous air monitoring activities to better understand the ongoing impacts of emissions from the disaster. The collapse of the World Trade Center towers and associated fires that lasted for several weeks resulted at times in a noticeable plume of material t...

The chemical evolution of the exhaust plumes of ocean-going ships in the cloud-free marine boundary layer is examined with a box model. Dilution of the ship plume via entrainment of background air was treated as in studies of aircraft emissions and was found to be a very important process that significantly alters model results. We estimated the chemical lifetime (defined as the time when diffe...

A mathematical model and computational code are validated for predicting shallow depth explosion plume behavior. The model is based on a generalized formulation of hydrodynamics and uses an incompressible liquid assumption. This formulation is well suited for predicting longtime bubble and plume dynamics. Initial conditions for the model are derived from spherically symmetric bubble theory, com...

[1] Aircraft measurements in the Hekla, Iceland volcanic plume in February 2000 revealed large quantities of hydrogen halides within the stratosphere correlated to volcanic SO2. Investigation of the longer-term stratospheric impact of these emissions, using the 3D chemical transport model, SLIMCAT suggests that volcanic enhancements of H2O and HNO3 increased HNO3 3H2O particle availability with...

Laboratory experiments are performed to examine the sedimentation of particles that initially rise in a plume, then spread radially and settle in uniformly stratified fluid. Using light attenuation, the depth of the sediment bed is measured nonintrusively as a function of radius from the center of the plume. To gain some insight into these dynamics, an idealized model is developed by adapting w...