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Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology
Biennial And Low-Frequency Components Of El Niño/Southern Oscillation, James Michael Ryan
Biennial And Low-Frequency Components Of El Niño/Southern Oscillation, James Michael Ryan
Theses and Dissertations
El Niño/Southern Oscillation (ENSO) is a coupled oscillation of sea surface temperatures (SSTs), winds, and air pressure in the eastern and central tropical Pacific, that repeats with quasi-regularity, every 2–7 years. Although the ENSO’s spectral peak is found at a 4–7-yr period, composite El Niño events, taken as the 84 months before and after the peak of each El Niño, show that the length of each event, and often the following La Niña if there is one, usually falls within a quasi-biennial (QB) range of around 18–42 months. We argue that the biennial range of ENSO events stems from the …
Multidecadal Variability In Climate Models And Observations, Alex Carl Oser
Multidecadal Variability In Climate Models And Observations, Alex Carl Oser
Theses and Dissertations
Climate change attribution and prediction using state-of-the-art models continue to garner an ever-growing focus amongst both the scientific community and public alike. Recent analyses showing discrepancies in the structure of modeled and observed decadal climate variability (DCV), therefore, have engendered efforts to not only diagnose the dynamics underpinning observed DCV, but also to characterize the behavior of DCV within climate models. In this thesis, we employ Multichannel Singular Spectrum Analysis (M-SSA) to show that while the DCV signal in observations is best described as a coherent oscillation with complex propagation across the globe, modeled DCV lacks this structure altogether. Specifically, …
Late Paleo-Indian Period Lithic Economies, Mobility, And Group Organization In Wisconsin, Ethan Adam Epstein
Late Paleo-Indian Period Lithic Economies, Mobility, And Group Organization In Wisconsin, Ethan Adam Epstein
Theses and Dissertations
The following dissertation focuses upon the organization of Pleistocene / Holocene period lithic technology in Wisconsin circa 10,000 – 10,500 years before present. Lithic debitage and flaked stone tools from the Plainview/Agate Basin components of the Heyrman I site (47DR381), the Dalles site (47IA374), and the Kelly North Tract site at Carcajou Point (47JE02) comprise the data set. These Wisconsin sites are located within a post glacial Great Lakes dune environment, an inland drainage/riverine environment, and an inland wetland/lacustrine environment. An assemblage approach is used to examine the structure of each site’s lithic economy. This broad approach to lithic organization …
Using A Semiprognostic Test To Elucidate Key Model Errors Of Warm Rain Processes Within A Unified Parameterization Of Clouds And Turbulence, Justin Kyle Weber
Using A Semiprognostic Test To Elucidate Key Model Errors Of Warm Rain Processes Within A Unified Parameterization Of Clouds And Turbulence, Justin Kyle Weber
Theses and Dissertations
The representation of clouds and turbulence remains one of the foremost challenges in modeling earth's climate system and continues to remain one of the greatest sources of uncertainty in future climate projections. Increased attention has been given to unifying cloud and turbulence parameterizations in order to avoid the artificial categorization of cloud and turbulence regimes. One such unified parameterization is known as the Cloud Layers Unified by Binormals (CLUBB). CLUBB is a single column model of clouds and turbulence that assumes subgrid scale variability can be represented by a joint probability density function (PDF) of temperature, moisture, momentum, and hydrometeors. …
Multi-Periodic Climate Dynamics: Spectral Analysis Of Instrumental, Short- And Long-Length Proxy Temperature Records, Michael David Madsen
Multi-Periodic Climate Dynamics: Spectral Analysis Of Instrumental, Short- And Long-Length Proxy Temperature Records, Michael David Madsen
Theses and Dissertations
Analyzing 26 short-length (less than 3000 years) instrumental and proxy temperature records and five long-length (greater than 3000 years) proxy temperature records using Discrete Fourier Transform has shown that as the length of significant periods increase in the time domain then so does the power at which the period is observed. A t-test verifies that a positive correlation exist between the length of the significant periods and the power with a confidence level of ∝ >0.05. Significant frequencies with period greater than 30 years are confirmed using Monte Carlo simulations, which were created using a nonlinear approach known as fractional …
Northern Hemisphere Sea Level Pressure Synchronization And Its Effect On Northern Hemisphere Temperature Variability, Joshua Daniel Verbeten
Northern Hemisphere Sea Level Pressure Synchronization And Its Effect On Northern Hemisphere Temperature Variability, Joshua Daniel Verbeten
Theses and Dissertations
We consider monthly anomalies of zonally averaged sea level pressure (SLP) in the Northern Hemisphere (NH) from two reanalysis products. A measure of synchronization utilizing correlation coefficient in a five-year sliding window across all latitude pairs is computed over this data. It is found that there have been two NH SLP synchronization episodes since the 1890s, which are significant to approximately three standard deviations. Similar statistically significant synchronization events are seen in simulations of 42 global climate models (GCM) with the dominant synchronization pattern in GCMs proving dynamically consistent with observations. Furthermore, a GCM-based NH temperature anomaly composite shows a …