Meteorology Commons^™

Obscuration Analysis Of Camera Imagery For Aviation Applications, Patrick James Roelant

Theses and Dissertations

Image feature detection is a potent tool with many applications, such as fog identification, roadway conditions, etc. As part of the recent surge in machine learning applications, cloud detection has also become an increasingly engaged area of research. Identifying low clouds is especially useful with respect to aviation, particularly in regions of complex topography prone to visibility-related hazards such as haze or fog. To address this issue, a threshold-based semi-automated algorithm was developed and tested to determine whether or not an image is obscured by fog or haze. Images were obtained from a ground-based camera network in Southern California, the …

Using Asos Ceilings And Mesonet Relative Humidity To Improve General Aviation Flight Planning And Decision Making In Complex Terrain, Connor Hayden Welch

Theses and Dissertations

Despite the increasing availability of weather products and access to data, the issue of weather representativeness, especially in relation to terrain, persists in the aviation industry. Data-sparse regions pose a particular challenge, requiring focused research efforts to address this issue and reduce accident and fatality rates within the general aviation (GA) community. This thesis aims to tackle the specific problem of representing visibility conditions, with a focus on obscuration conditions in elevated terrain.

To achieve this goal, data from Automated Surface Observing System (ASOS) ceilometers and nearby mesonet relative humidity (RH) were analyzed to establish a relationship between the lowest …

Cloud Image Classification Using Machine Learning, Marcus Peter Cote

Theses and Dissertations

Machine learning is a rapidly expanding technology that has proven to be highly useful for image classification. Ground-based camera networks are an emerging resource for aviation weather information with near real-time imagery available online for public viewing and download. While raw web camera imagery can be analyzed by aviators, high pilot workload motivates the use of machine learning to autonomously interpret cloud type information from images that is relevant to aviation weather hazards. In particular, transfer learning is a machine learning approach by which elements of a pre-trained machine learning model are refitted for new tasks. By employing transfer learning …

A Probabilistic Approach To Generating Representative Wind Forcing And Wave Heights Within An Estuarine Environment, Vanessa Maria Haley

Theses and Dissertations

While wind driven waves affect erosion, sediment resuspension, and flow in shallow estuaries like the Indian River Lagoon (IRL), neither winds nor waves are well observed in this environment. In order to calculate accurate significant wave heights, the winds used for the calculation must be consistent with the observed winds over the lagoon. Given the complex land/water geometry and subsequent limited fetch, a probabilistic approach is used to produce a representative wind field over the IRL. Observed winds, near the IRL, are used to sample wind distributions obtained from 180 high resolution atmospheric model simulations in order to generate a …

Wind-Driven Setup, Roughness, And Drag Over A Depth- And Fetch-Limited Coastal Estuary, Jeffrey Allen Colvin

Theses and Dissertations

The understanding of the momentum exchange across the air-sea interface is critical to accurately model and forecast wind speed, wave properties, setup, and circulation. This is particularly true for a restricted estuary, such as the Indian River Lagoon (IRL), where wind is the driving force behind water movement due to the limited number of direct ocean connections. Current atmospheric and hydrodynamic models use formulations of the drag coefficient and/or roughness length based on open ocean studies in which wave properties are not considered. This dissertation develops two parameterizations – one for wind setup and one for the drag coefficient – …

Influence Of Ndbc Buoy Design On Sea Surface Temperature Trends In The Coastal United States, Alexander Keith Nickerson

Theses and Dissertations

The sea surface temperature (SST) record is the one of the oldest climate records, stretching back to 1662. Since that time, voluntary observing ships (VOSs) have been including these data in their ship‘s log. Due to the sparseness of VOS data, moored buoys were created to provide data at regular intervals in order to provide a more continuous record with data collection unaffected by human error. The SST sensor in National Data Buoy Center (NDBC) buoys is inside a hull and not in direct contact with the ocean. Thus, the design of the buoy may subject them to additional biases …

An Analysis Of The Moisture And Moist Static Energy Budgets In Amip Simulations, Kristine Adelaide Boykin

Theses and Dissertations

An analysis of the second phase of the Atmospheric Model Intercomparison Project (AMIP) simulations has been conducted to understand the physical processes that control precipitation in the tropics. This is achieved primarily through the analysis of the moisture and moist static energy budgets. Overall, there is broad agreement between the simulated and observed precipitation, although specific tropical regions such as the Maritime Continent poses challenges to these simulations. The models in general capture the latitudinal distribution of precipitation and key precipitating regions including the Inter-Tropical Convergence Zone (ITCZ) and the Asian Monsoon. The simulations portrayed the global patterns of evaporation …

Surface Cooling Due To Precipitation In The Tropics, Camila Gomes Martins Ramos

Theses and Dissertations

Precipitation is an important component of the global hydrological cycle. It affects the upper ocean salinity by adding freshwater to the ocean. In addition, precipitation plays a role in cooling the ocean and land surfaces, when the temperature of the raindrops is lower than the temperature of the surface. However, the surface cooling due to precipitation (QP) remains an overlooked feature and is not included in the Intergovernmental Panel on Climate Change (IPCC) models. One might expect that heavy precipitation events may lead to large QP, which can impact the surface temperature, surface energy balance, and local- to regional-scale circulations. …

Evaluating The Surface Layer Wind Profile In The Wrf, Robert Stephen James

Theses and Dissertations

The purpose of this thesis is to investigate how the surface vertical wind profile responds to different planetary boundary layer schemes in computer models. Local surface roughness is one of the elements represented in these schemes, and is used when interpolating winds down from the lowest model level to the surface, so this needs to be accurately represented in the model. Computer models rely on one bulk estimate of surface roughness for a given grid point, despite the complexity of surrounding terrain. Data for this research was gathered from local surface observations and computer simulations, which looked at two different …