Physical Sciences and Mathematics Commons^™

Comparison Of Multidecadal Variability In Climate Reanalyses And Global Models, Andrew A. Westgate

Theses and Dissertations

Superimposed on the linear upward trend of observed global surface air temperature anomalies since the late nineteenth century is, what appears to be, a multidecadal undulation. However, this undulation is either muted or virtually absent in both the previous and current generations of the state-of-the-art climate models used to not only simulate past climates but also predict future climates. One possibility is that this signal is due to a series of complex responses to the global climate forcing; an alternative is that this signal is contained within the internal variability and teleconnected via atmospheric channels. Either way, the existential threat …

Authigenic Minerals In Volcaniclastics From An Eastern African Paleolake: A Proxy For Paleoenvironment, Kaitlyn Truss

Theses and Dissertations

Olduvai Gorge exposes the stratigraphy of Paleolake Olduvai, an often saline-alkaline rift lake that records volcanism from the Ngorongoro Volcanic Highlands. In 2014, cores retrieved from the study area revealed new stratigraphy, including the lacustrine Naibor Soit Formation (Fm) and the volcaniclastic Ngorongoro Fm. In the Ngorongoro Fm part of the cores, mineralogy and geochemistry are the best paleoenvironmental proxies, since under saline-alkaline conditions, volcanic glass alters into specific authigenic minerals (e.g., zeolite, feldspar). This study employs X-Ray Diffraction, X-Ray Fluorescence, and Scanning Electron Microscopy to analyze authigenic mineralogy and geochemistry. The lower Ngorongoro Fm experienced the most alteration, with …

Analytic Approximations Of Higher Order Moments In Terms Of Lower Order Moments, Sven Detlef Bergmann

Theses and Dissertations

The Cloud Layers Unified By Binormals (CLUBB) model uses the sum of two normal probability density function (pdf) components to represent subgrid variability within a single grid layer of an atmospheric model. This binormal approach, while computationally efficient, restricts the model’s ability to capture the full spectrum of potential shapes encountered inreal-world atmospheric data.

This thesis proposes to introduce a third normal pdf component strategically positioned between the existing two, significantly enhancing the model’s representational flexibility. This trinormal representation allows for a wider range of grid-layer shapes while permitting analytic solutions for certain higher order moments.

The core of this …

Predictability Of The Overland Reintensification Of North Atlantic Tropical Cyclone Erin (2007), Ariel Tickner-Ernst

Theses and Dissertations

Tropical cyclones (TC) typically decrease in intensity upon interacting with land because of increased surface roughness and decreased surface evaporation. However, several studies have documented cases in which TCs maintain their intensity or even intensify over land within non- or weakly baroclinic environments. Yet, our understanding of the precise physical processes that support maintenance or intensification over land in non- or weakly baroclinic environments remains limited, and the predictive skill for these outcomes has yet to be quantified.

We begin this process by quantifying the predictive skill and forecast uncertainty of the overland intensification of North Atlantic Tropical Storm Erin …

An Assessment Of The High-Resolution Rapid Refresh Model’S Ability To Resolve The Great Lakes Marine Atmospheric Boundary Layer And Lake-Breeze Front, Collin Paul Deyoung

Theses and Dissertations

We determined the ability of the High-Resolution Rapid Refresh (HRRR) mesoscale model to predict the lake-breeze front’s structure and faithfully represent the marine atmospheric boundary layer (MABL) behind it. First, two field missions were completed during the 2023 warm season over Lake Michigan to characterize the spatiotemporal evolution of the MABL and validate HRRR forecasts. We found the Lake Michigan MABL was characterized by minimal thermodynamic and kinematic variability on diurnal time scales, regardless of the stability or flow regime. Additionally, the HRRR was able to resolve MABL thermodynamic structures effectively but underestimated the vertical temperature distribution, leading to a …