Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Connecting microburst precipitation to its scattering mechanism(Montana State University - Bozeman, College of Letters & Science, 2019) Shumko, Mykhaylo Sergeevich; Chairperson, Graduate Committee: John Sample; Drew L. Turner, T. P. O'Brien, Seth G. Claudepierre, John Sample, D. P. Hartley, Joseph Fennell, J. Bernard Blake, Matina Gkioulidou and Donald G. Mitchell were co-authors of the article, 'Evidence of microbursts observed near the equatorial plane in the outer Van Allen Radiation Belt' in the journal 'Geophysical research letters' which is contained within this thesis.; John Sample, Arlo Johnson, Bern Blake, Alex Crew, Harlan Spence, David Klumpar, Oleksiy Agapitov and Matthew Handley were co-authors of the article, 'Microburst scale size derived from multiple bounces of a microburst simultaneously observed with the Firebird-II cubesats' in the journal 'Geophysical research letters' which is contained within this thesis.; A.T. Johnson, J.G. Sample, B.A. Griffith, D.L. Turner, T.P. OBrien, O. Agapitov, J.B. Blake and S. G. Claudepierre were co-authors of the article, 'Microburst size distribution derived with Aerocube-6' submitted to the journal 'Geophysical research letters' which is contained within this thesis.We will review the main structures in the magnetosphere, the motion of charged particles in electric and magnetic fields, how particles are accelerated and lost in the magnetosphere, and asses the current state of our understanding of microbursts. Then the rest of this dissertation expands our knowledge of microbursts. In Chapter 2 we will investigate and model the scattering mechanism responsible for microbursts observed inside the outer radiation belt, near the magnetic equator. Then in Chapters 3 and 4 we will investigate the microburst scattering mechanism indirectly by estimating the microburst footprint size in low Earth orbit and the magnetic equator (near where microburst electrons are believed to be scattered) and compare it to sizes of chorus waves estimated in prior literature.Item Broadening participation in atmospheric science through a program needs assessment(Montana State University - Bozeman, Graduate School, 2016) Rockwell, Alison B.; Chairperson, Graduate Committee: Peggy Taylor.The National Science Foundation (NSF) Lower Atmosphere Observing Facilities (LAOF) Educational Deployment Program is a short-term facilities deployment program designed to strengthen STEM-related education. It provides access to eight separate research facilities for authentic instruction in the field of observational meteorology and engineering. Facilities are available for graduate, undergraduate, and K-12 education, and can be deployed to a College or University for up to three weeks. Anomalies were found in the diversity of requested facilities and requesting Principal Investigators (PIs) in the 46 education deployments from the calendar years of 2008-2015. A needs assessment was conducted to determine actual program performance, identify performance gaps in the program, and to determine the desired program performance. The needs assessment resulted in a data-driven recommendation action plan to close the gaps that when implemented, will increase the diversity of requesting PIs and the requested facilities, thereby increasing diversity within the education program.Item Operating characteristics and calibration of thermocouple psychrometers at low temperatures and potentials near zero(Montana State University - Bozeman, College of Agriculture, 1975) Degn, Roy MadsenItem Agricultural implications of weather control(Montana State University - Bozeman, College of Agriculture, 1954) Pavelis, George A.Item Development of Spring Creek data acquisition system(Montana State University - Bozeman, College of Engineering, 1974) Williams, Robert MatthewItem Modification of micrometeorological parameters by full-awned, half-awned, and nonawned isogenic barley(Montana State University - Bozeman, College of Agriculture, 1971) Benci, John FrankItem Geographic knowledge discovery techniques for exploring historical weather and avalanche data(Montana State University - Bozeman, College of Letters & Science, 2004) McCollister, Christopher Michael; Chairperson, Graduate Committee: Katherine J. Hansen; Karl Birkeland (co-chair)Many ski areas, backcountry avalanche centers, highway departments, and helicopter ski operations record and archive daily weather and avalanche data. The objective of this thesis is to present probabilistic techniques that allow avalanche forecasters to better utilize weather and avalanche data by incorporating a Geographic Information System with a modified meteorological nearest neighbors approach. This nearest neighbor approach utilizes evolving concepts related to visualizing geographic information stored in large databases. The resulting interactive database tool, Geographic Weather and Avalanche Explorer, allows the investigation of the relationships between specific weather parameters and the spatial pattern of avalanche activity. In order to validate these new techniques, two case studies are presented using over 10,000 individual avalanche events from the past 23 years that occurred at the Jackson Hole Mountain Resort. The first case study explores the effect of new snowfall, wind speed, and wind direction on the spatial patterns of avalanche activity. Patterns exist at the slide path scale, and for groups of adjacent slide paths, but not for either the entire region as a whole or when slide paths are grouped by aspect. Since wind instrumentation is typically located to measure an approximation of the free air winds, specific topography around a given path, and not aspect, is more important when relating wind direction to avalanche activity. The second case study explores the spatial variability of hard slab and dry loose avalanches, and characterizes these avalanche types with respect to their geographic location and associated weather conditions. I analyzed these data with and without the incorporation of three weather parameters (wind speed, 24-hour maximum temperature, and new snow density). Slide paths near each other often had similar proportions of hard slabs and a higher proportion of hard slabs occurred on exposed ridges. The proportion of loose avalanches also was similar for adjacent slide paths, and these paths were typically sheltered from strong winds. When I incorporated the three weather parameters I found significant increases in the average proportion of hard slabs with increases in new snow density, but not for changes in the 24-hour maximum temperature or wind speed. When I analyzed the proportion of loose avalanches associated with the three weather parameters I found a more direct relationship than with hard slabs. Changes in both wind speed and density significantly changed the average proportion of loose avalanches, with low wind and low density resulting in higher proportions of loose avalanches. My results quantify what operational avalanche forecasters have long known: Geographic location and weather are both related to the proportion of hard slab and dry loose avalanches.