Atmospheric Sciences Commons^™

Atmospheric Remote Sensing Using X-Band Radar In The Marine Atmospheric Surface Layer, Daniel P. Greenway

Electronic Theses and Dissertations

Atmospheric remote sensors have always offered promising technological advancements for measuring atmospheric properties over large spatial areas at high spatiotemporal resolution – a feat not currently possible with present atmospheric measurement technologies. However, remote sensors do not measure these atmospheric properties directly; they rely on robust calibrations or conversions, complex mathematical inversion methods, and/or machine learning to retrieve these properties. These inverse methods rely on the selection of an objective function, a machine learning technique, and an accurate parameterization for atmospheric property estimation. By leveraging inverse methods to improve the characterization of properties measured by remote sensors, this work enables …

Error Analysis Of Numerical Weather Prediction Forecasts And Remotely Sensed Air Properties, Caleb R. Sease

Honors Theses

Communication and sensing technologies are influenced by atmospheric properties such as the air’s index of refraction, humidity, and temperature in the marine atmospheric surface layer (MASL). Recent research has demonstrated that radar can remotely sense the index of refraction in the MASL and, sometimes, numerical weather prediction models (NWP) can be used to aid this process. These developments are important because they allow for larger spatial coverage and finer temporal resolution than is possible with in-situ atmospheric sensors. More recently, on-going research is working toward extending this remote sensing capability to humidity using refraction as an intermediary. In order to …

Characteristics Of Refractivity And Sea State In The Marine Atmospheric Surface Layer And Their Influence On X-Band Propagation, Douglas Matthew Pastore

Electronic Theses and Dissertations

Predictions of environmental conditions within the marine atmospheric surface layer (MASL) are important to X-band radar system performance. Anomalous propagation occurs in conditions of non-standard atmospheric refractivity, driven by the virtually permanent presence of evaporation ducts (ED) in marine environments. Evaporation ducts are commonly characterized by the evaporation duct height (EDH), evaporation duct strength, and the gradients below the EDH, known as the evaporation duct curvature. Refractivity, and subsequent features, are estimated in the MASL primarily using four methods: in-situ measurements, numerical weather and surface layer modeling, boundary layer theory, and inversion methods.

The existing refractivity estimation techniques often assume …

Mapping The Spatial Footprint Of Sea Breeze Winds In The Southeastern United States, Shaowu Bao, Leonard Pietrafesa, Paul Gayes, Stephen Noble, Brian Viner, Jian-Hua Qian, David Werth, Grant Mitchell, Savannah Burdette

Marine Science

Sea breeze winds are observed at various locations worldwide, but the spatially continuous mapping of sea breeze winds is rare. We have developed a scheme to map the areas of the southeastern United States (SEUS) coast influenced by sea breeze winds using a range of surface re-analysis data to identify their occurrence. Changes in wind direction and dew point temperature are both used to detect a potential sea breeze signature, which is then confirmed by cumuliform clouds seen in satellite images or coastal fronts shown as cohesive lines in radar reflectivity images. Filters are employed to remove onshore winds not …

Arctic Sea Ice Loss In The Pacific Sector And Its Impacts On Sudden Stratospheric Warming Events, Jiarong Zhang

Electronic Theses and Dissertations

The Arctic sea ice is a critical indicator of climate change. The extent of sea ice coverage over the Arctic Ocean has dramatically declined over the past few decades. The impact has been extensively studied through observations suggesting a linkage between the anomalously warm Arctic surface associated with the Arctic sea ice loss and the mid-latitude surface cooling in the subsequent boreal winter. This linkage could involve the wintertime stratospheric circulation by enhancing the upward planetary wave activity and weakening the polar vortex. With recent advances in climate model, more relevant studies relied on numerical simulations and some suggested that …

Improving Near Surface Refractivity Estimates In Marine Environments, Sarah Evelyn Wessinger

Electronic Theses and Dissertations

This study utilizes in-situ measurements and numerical weather prediction datasets collected during the Coupled Air-Sea Processes Electromagnetic Ducting Research East field campaign to assess how thermodynamic properties in the marine atmospheric surface layer influence evaporation duct shape and to develop a simple near-surface modified refractivity estimation method. This study utilizes a logarithmic linear parametric model, which describes evaporation ducts via three main parameters: evaporation duct height, evaporation duct curvature, and mixed layer slope. Notably, most studies utilizing this type of model assume the curvature, C0, to be a theoretical value derived assuming neutral atmospheric stability; a thermodynamic regime that is …

Eastward-Propagating Planetary Waves In The Middle Atmosphere During Major Sudden Stratospheric Warming Events, Christian Todd Rhodes

Electronic Theses and Dissertations

No abstract provided.

Parametric Model Development For Heterogeneous Atmospheric Conditions, Daniel Paul Greenway

Electronic Theses and Dissertations

No abstract provided.

Impact Of Data Selection On The Accuracy Of Atmospheric Refractivity Inversions Performed Over Marine Surfaces, Ian Joseph Matsko

Electronic Theses and Dissertations

Within the Earth’s atmosphere there is a planetary boundary layer that extends from the surface to roughly 1 km above the surface. Within this planetary boundary layer exists the marine atmospheric boundary layer, which is a complex turbulent surface layer that extends from the sea surface to roughly 100 m in altitude. The turbulent nature of this layer combined with the interactions across the air-sea interface cause ever changing environmental conditions within it, including atmospheric properties that affect the index of refraction, or atmospheric refractivity. Variations in atmospheric refractivity lead to many types of anomalous propagation phenomena of electromagnetic (EM) …

The Clean Air Act And Its Impact On Ground Level Ozone Pollution Levels In Los Angeles, California, Rebecca Ford

Bridges: A Journal of Student Research

Ozone (O3) occurs as a photochemically produced pollutant in the troposphere and its emission and concentration is regulated by the Clean Air Act (CAA) of 1970. The Los Angeles area is an example of how O3 can be a public health hazard and taint a city’s aesthetics and quality of life through photochemical smog. This study was conducted to observe the overall effectiveness of the CAA. I explored daily O3 concentrations from 1980 to the present at three air quality monitoring stations in LA from the AirData database of the U.S. Environmental Protection Agency. National O3 standards were only exceeded …

The Clean Air Act And Its Impact On Ground Level Ozone Pollution Levels In Los Angeles, California, Rebecca G. Ford

Honors Theses

Ozone (O₃) occurs naturally as a protective, ultraviolet radiation-shielding “Ozone Layer” in the Stratosphere and as a photochemically produced pollutant in the Troposphere. The Clean Air Act (CAA) of 1970 regulates the emission and concentration of O₃ and five other atmospheric pollutants. Since the signing of the CAA, the ongoing question has been whether or not the National Ambient Air Quality Standards (NAAQS) and regulatory policies have had an effect on decreasing O₃ concentration. The Los Angeles metropolitan area is a prime example of how O₃ can be a public health hazard, and taint a …