Dusty, Dense, Bright, Dark, Narrow, and Broad: the Rings in our Solar System and a Few of the Things They Can Tell Us

The observations of planetary rings acquired by the Cassini and Voyager missions and from the Earth have launched large advancements in our knowledge of planetary ring formation, evolution, and dynamics. Today, the study of the ring systems around our giant planets has evolved further into using the rings themselves as a tool to learn about their home planetary systems. In Chapter moonlets we use two of the narrow rings of Uranus to probe for unseen nearby small moons who gravitationally interact with the rings and produce wake-like structures. These small moons both provide a possible solution for the confinement of their neighboring narrow rings and may represent a subset of the upper end of the ring particle size distribution. In Chapter eta we detect the effects of a resonant induced radial mode in the Uranian eta ring. The amplitude of the radial oscillations observed in the eta ring allow us to estimate the mass of the perturbing moon Cressida. This is the first such measurement of small inner Uranian moon's mass and density. In Chapter roche we track the presence and strength of periodic brightness variations in Saturn's dusty Roche Division and find that they are most likely caused by the seasonally varying planetary period oscillations of Saturn's magnetic field. This is just one of many ways in which the rings of Saturn have been found to be interacting with their magnetospheric environment.doctoral, Ph.D., Physics -- University of Idaho - College of Graduate Studies, 2019-1

Toward improved crop management using spectral sensing with unmanned aerial systems

Remote sensing applications in agriculture are established for large-scale monitoring with satellite and airborne imagery, but unmanned aerial systems (UAS) are poised to bring in-field mapping capabilities to the hands of individual farmers. UAS imaging holds several advantages over traditional methods, including centimeter-scale resolution, reduced atmospheric absorption, flexible timing of data acquisitions, and ease of use. In this work, we present two studies using UAS imaging of specialty crops in upstate New York to work towards improved crop management applications. The first study is an investigation of multispectral imagery obtained over table beet fields in Batavia, NY during the 2018 and 2019 seasons to be used in root yield modeling. We determined optimal growth stages for future observations and establish the importance of quantifying early growth via determination of canopy area, a feature unattainable with lower resolution imaging. We developed models for root mass and count based on area-augmented imagery of our raw study plots and their corresponding ground truth data for practical testing with independent data sets. The second study was designed to determine an optimal subset of wavelengths derived from hyperspectral imagery that are related to grapevine nutrients for improved vineyard nutrient monitoring. Our ensemble wavelength selection and regression algorithm chose wavelengths consistent with known absorption features related to nitrogen content in vegetation. Our model achieved a leave-one-out cross-validation root-mean-squared error of 0.17% nitrogen in our dried vine-leaf samples with 2.4-3.6% nitrogen. This is an improvement upon published studies of typical UAS multispectral sensors used to assess grapevine nitrogen status. With further testing on new data, we can determine consistently selected wavelengths and guide the design of specialty multispectral sensors for improved grapevine nutrient management