Atmospheric Sciences Commons^™

Improving Multiple Surface Range Estimation Of A 3-Dimensional Flash Ladar In The Presence Of Atmospheric Turbulence, Brian J. Neff

Theses and Dissertations

Laser Radar sensors can be designed to provide two-dimensional and three-dimensional (3-D) images of a scene from a single laser pulse. Currently, there are various data recording and presentation techniques being developed for 3-D sensors. While the technology is still being proven, many applications are being explored and suggested. As technological advancements are coupled with enhanced signal processing algorithms, it is possible that this technology will present exciting new military capabilities for sensor users. The goal of this work is to develop an algorithm to enhance the utility of 3-D Laser Radar sensors through accurate ranging to multiple surfaces per …

Winter Climatology Of Short-Period Mesospheric Gravity Waves Over Alaska, Michael Negale, Kim Nielsen, Michael J. Taylor, Dominique Pautet

Physics Student Research

Momentum deposition by short-period (<1 h) gravity waves is known to play a major role in the global circulation in the mesosphere and lower thermosphere (MLT) region ~80-100 km (e.g. Fritts and Alexander, 2003). Observations of these waves over the Arctic region are few and their impact on the Arctic MLT region is of high interest, but has yet to be determined. The Mesospheric Airglow Imaging and Dynamics (MAID) project was initiated in January 2011 to investigate short-period gravity wave dynamics over central Alaska.

In this poster, we focus on quantifying the climatology of short-period gravity waves during two winter seasons (2011-2012) over central Alaska

Discontinuities And Alfvenic Fluctuations In The Solar Wind, G. Paschmann, S. Haaland, B. Sonnerup, T. Knetter

Dartmouth Scholarship

We examine the Alfvenicity of a set of 188 solar wind directional discontinuities (DDs) identified in the Cluster data from 2003 by Knetter (2005), with the objective of separating rotational discontinuities (RDs) from tangential ones (TDs). The DDs occurred over the full range of solar wind velocities and magnetic shear angles. By performing the Walen test in the de Hoffmann–Teller (HT) frame, we show that 77 of the 127 crossings for which a good HT frame was found had plasma flow speeds exceeding 80 % of the Alfven speed at an average angular deviation of 7.7◦; 33 cases had speeds …

Climate Change Tipping Points: A Point Of No Return?, Elise Lequire

Joint Fire Science Program Digests

Summer 2012 saw records fall for intensity of drought and number, size, and cost of wildfires in the Central and Western United States, and the climate forecast calls for more of the same in the near and distant future. When wildfire breaks out, emergency responders decide their immediate strategy based on past experience and quick judgment calls. But in the long term, land managers need to plan for a warmer climate on a time scale of decades, or even a century or more, to better reflect the life span of trees and forests. Studies supported by the Joint Fire Science …

Middle Atmosphere Temperature Results From A New, High-Powered, Large-Aperture Rayleigh Lidar, Leda Sox, Vincent B. Wickwar, Joshua P. Herron

Conference publications

In June–July 2012, observations were carried out using the recently upgraded, large-aperture, Rayleigh-scatter lidar system located at the Atmospheric Lidar Observatory (ALO) on the campus of Utah State University, in Logan, UT (41.7 N, 111.8 W). This time period was significant because it enabled us to observe the annual temperature minimum in the upper mesosphere-lower thermosphere region. The data collected during the campaign were analyzed for temperatures between ~70–109 km. The results above ~95 km are the first obtained with a Rayleigh-scatter lidar, extending the technique well into the lower thermosphere. A great deal of variability from night-to-night is evident …

On The Export Of Reactive Nitrogen From Asia: NoX Partitioning And Effects On Ozone, T H. Bertram, Paul J. Wooldridge, Jack E. Dibb, Robert C. Cohen, A E. Perring

Earth Sciences

The partitioning of reactive nitrogen (NO_y was measured over the remote North Pacific during spring 2006. Aircraft observations of NO, NO₂, total peroxy nitrates (ΣPNs), total alkyl and multi-functional nitrates (ΣANs) and nitric acid (HNO₃, made between 25° and 55° N, confirm a controlling role for peroxyacyl nitrates in NO_x production in aged Asian outflow. ΣPNs account for more than 60% of NO_y above 5 km, while thermal dissociation limits their contribution to less than 10% in the lower troposphere. Using simultaneous observations of NO_x, ΣPNs, ΣANs, HNO₃ and average …

Acting To Address The Ocean-Related Impacts Of Climate Change On Human And National Security, With Recommendations For Priority Actions Drawn From The Discussions Of The Global Conference On Oceans, Climate And Security At The University Of Massachusetts Boston, Robbin Peach, Felix Dodds, Michael Strauss, Collaborative Institute For Oceans, Climate And Security, University Of Massachusetts Boston

Collaborative Institute for Oceans, Climate and Security Publications

In the course of the past calendar year the United States has been struck by a series of droughts, tornadoes, hurricanes, blizzards, wildfires, and floods whose size and path of resulting damage defy previously established patterns. The U.S. thus joins nations on every continent that have increasingly experienced extreme and extremely damaging weather events over the past two decades.

At the same time, the world’s oceans have been exhibiting a less-visible but equally dangerous sequence of temperature rise, acidification increase, fish kills, coastal erosion, salinity shifts, algae blooms, and steady decreases in commercially available fish and shellfish species.

Those impacts …

An Examination Of The Mechanisms And Environments Supportive Of Bow Echo Mesovortex Genesis, George Limpert

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Low-level mesovortices are associated with enhanced surface wind gusts and high-end wind damage in quasi-linear thunderstorms. Although damage associated with mesovortices can approach that of moderately strong tornadoes, skill in forecasting mesovortices is low. The overarching goal of this work is to understand mesovortices and how they develop, to improve the skill in forecasting them. This was done by developing a climatology of mesovortices, which required a tracking algorithm, and numerical simulations were conducted to answer questions that could not be answered through the observational data. A climatology of mesovortices was constructed from 44 events during 2009 and 2010 to …

Lunar Tidal Effects In The Electrodynamics Of The Low-Latitude Ionosphere, Brian David Tracy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In order to model and perform better forecasts of the upper atmosphere, we have studied variations in the equatorial ionosphere due to lunar tidal forcing. We used extensive measurements made by the Jicamarca Unattended Long-Term Investigations of the Ionosphere and Atmosphere (JULIA) and Incoherent Scatter Radar (ISR) systems at Jicamarca, Peru during geomagnetic quiet conditions to determine the season, local time, and lunar age-dependent lunar tidal effects on equatorial vertical plasma drifts. The amplitudes and phases of the semimonthly and monthly lunar tidal perturbations were derived using a least squares method. Our results indicate that, as expected, lunar tidal effects …

The Effects Of Climate Science Literacy And Cultural Polarization Around Climate Change Risk Perception, Gabriel R. Young, Helen R. Neill

Graduate Research Symposium (2010 - 2017)

Science communicators have struggled to provide meaningful information about climate change due to the complex nature of the problem and the polarized political and media landscapes, and yet, a well informed public is a crucial element to both public acceptance and policy initiatives aimed at climate change mitigation. Current literature suggests that scientific literacy actually increases cultural polarization around the issue of climate change (Kahan, 2012). This study adds to the literature by testing the hypothesis that climate change risk perception is more heavily tied to climate science literacy than general science literacy when controlling for cultural worldviews. We use …

Resolving Ionospheric E-Region Modeling Challenges: The Solar Photon Flux Dependence, Joseph B. Jensen, Jan J. Sojka, Michael David, Kent Tobiska, Robert W. Schunk, Tom Woods, Frank Eparvier

Browse All Undergraduate research

The EVE instrument of the NASA Solar Dynamics Observatory (SDO) provides for the first time EUV and XUV measurements of the solar irradiance that adequately define the major source of ionization of the atmosphere. In our study we modeled the E-region of the ionosphere and analyzed how it is affected by the solar irradiance data obtained by EVE and contrast this with the S2000 Solar Irradiance model, used previously. The ionosphere has two major layers, the E-layer at 100 km, and the F-layer at 300 km. The difference in solar irradiances are small except at some wavelength bands, it is …

Resolving Ionospheric E-Region Modeling Challenges: The Solar Photon Flux Dependence, Joseph B. Jensen, Jan J. Sojka, Michael David, Kent Tobiska, Robert W. Schunk, Tom Woods, Frank Eparvier

Student Showcase

No abstract provided.

Design, Development, And In-Flight Testing Of A Pointer/Tracker For In-Flight Experiments To Measure Aero-Optical Effects Over A Scaled Turret, Matthew J. Krizo, Salvatore J. Cusumano, Steven T. Fiorino, Ryan Heap, Victor Velten, Joshua Brown, Richard J. Bartell

Faculty Publications

We address the design, development, and testing of a pointer/tracker as a probe beam for the purpose of making high-speed, aero-optical measurements of the flow over a scaled beam director turret. The tracker uses retro-reflection of the probe beam off of a Reflexite annulus surrounding the turret. The constraints of the design required a near-total-commercial off the shelf system that could be quickly installed and removed in a rented aircraft. Baseline measurements of environmental vibrations are used to predict pointing performance; mitigation of line-of-sight jitter on the probe beam is achieved through passive isolation and the design of relay optics. …

The Production Of Organic Nitrates In Portland Oregon And The Columbia River Gorge, Holly Ann Neill

Dissertations and Theses

This work studied the production of aerosol-phase organic nitrates in both Portland and the Columbia River Gorge (CRG). Ozone and NO_x species were investigated for correlation with organic nitrate aerosol, as they function as precursors to the production of organic nitrates. These ambient gas-phase measurements were collected in the same locations as high-volume (Hi-Vol) filters samples, in an urban and rural gorge setting to investigate correlations at the origin of the pollution plume and downwind. A novel Soxhlet extraction method for Hi-Vol filters was developed based on literature and EPA standard methods. Analysis for nitrate production was done by …

Ionospheric Induced Scintillation: A Space Weather Enigma, Jan Josef Sojka

All Physics Faculty Publications

The effect of scintillation on radio signals whose propagation path involves the Earth’s ionosphere is analogous to the allies of World War II receiving radio messages that had passed through the Enigma machine. In both these cases, man-made information has been encrypted and transmitted via radio. The two encryption methods are shown in Figure 1. The right panel shows a World War II Enigma machine used extensively by German U-boats to convey encrypted messages transmitted by radio [Perera, 2010]. The left panel gives an extreme example of a mapping of ionospheric irregularities at 3 m, which creates very severe scintillation …

Droughtscape, Spring 2013, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

Director’s report

First quarter climate summary and outlook

Impacts: Crop indemnities set records in 2012; water conflicts escalating

International meeting recommends countries have drought policies

NDMC plays key role in international drought policy meeting

EDEN and VOAD guide helps build community drought capacity

Svoboda, other experts and policymakers focus on food and water security

New Mexico ranching workshop set for May 29 in Socorro

Ranch planning updates: archived webinars, new publications

Tune in to the US Drought Monitor Forum, April 16-18

Archived webinar looks at using drought simulations in planning

CoCoRaHS WxTalk on drought

Evaluation Of A Wind-Wave System For Ensemble Tropical Cyclone Wave Forecasting. Part I: Winds, Steven M. Lazarus, Samuel T. Wilson, Michael E. Splitt, Gary A. Zarillo

Aeronautics Faculty Publications

A computationally efficient method of producing tropical cyclone (TC) wind analyses is developed and tested, using a hindcast methodology, for 12 Gulf of Mexico storms. The analyses are created by blending synthetic data, generated from a simple parametric model constructed using extended best-track data and climatology, with a first-guess field obtained from the NCEP-NCAR North American Regional Reanalysis (NARR). Tests are performed whereby parameters in the wind analysis and vortex model are varied in an attempt to best represent the TC wind fields. A comparison between nonlinear and climatological estimates of the TC size parameter indicates that the former yields …

Bottled Sky, Ioannis Michalou(Di)S

The Transdisciplinary STEAM+ Journal

Cloud-hunter Ioannis ΜICHALOU(di)S, lies in wait of air streams, grapping pieces of sky, shaping them, molding them, and baptizing them as ‘aerosculptures’. MICHALOU(di)S is the first visual artist worldwide to use art and science in a unique way. His latest Art-Science achievement is ‘Bottled Sky’. He states:

“In October 2001, while I was trying to create a cubic nephele, in the Visual Arts Research Centre of Massachusetts Institute of Technology (MIT), I came upon the silica aerogel for the first time... It is a space technology material, intangible -consisting of 99.9% air and 0.1% glass - which has been recently …

On The Lack Of Stratospheric Dynamical Variability In Low‐Top Versions Of The Cmip5 Models, Andrew J. Charlton-Perez, Mark P. Baldwin, Thomas Birner, Robert X. Black, Amy H. Butler, Natalia Calvo, Nicholas A. Davis, Edwin P. Gerber, Nathan Gillett, Steven Hardiman, Junsu Kim, Kirsten Krüger, Yun-Young Lee, Elisa Manzini, Brent A. Mcdaniel, Lorenzo Polvani, Thomas Reichler, Tiffany A. Shaw, Michael Sigmond, Seok-Woo Son, Matthew Toohey, Laura Wilcox, Shigeo Yoden, Bo Christiansen, François Lott, Drew Shindell, Seiji Yukimoto, Shingo Watanabe

Faculty Articles

We describe the main differences in simulations of stratospheric climate and variability by models within the fifth Coupled Model Intercomparison Project (CMIP5) that have a model top above the stratopause and relatively fine stratospheric vertical resolution (high-top), and those that have a model top below the stratopause (low-top). Although the simulation of mean stratospheric climate by the two model ensembles is similar, the low-top model ensemble has very weak stratospheric variability on daily and interannual time scales. The frequency of major sudden stratospheric warming events is strongly underestimated by the low-top models with less than half the frequency of events …

Bulk Partitioning The Growing Season Net Ecosystem Exchange Of Co2 In Siberian Tundra Reveals The Seasonality Of Its Carbon Sequestration Strength, Benjamin R. K. Runkle, T. Sachs, C. Wille, E.-M. Pfeiffer, L. Kutzbach

Biological and Agricultural Engineering Faculty Publications and Presentations

This paper evaluates the relative contribution of light and temperature on net ecosystem CO2 uptake during the 2006 growing season in a polygonal tundra ecosystem in the Lena River Delta in Northern Siberia (72°22´ N, 126°30´ E). The occurrence and frequency of warm periods may be an important determinant of the magnitude of the ecosystem's carbon sink function, as they drive temperature-induced changes in respiration. Hot spells during the early portion of the growing season, when the photosynthetic apparatus of vascular plants is not fully developed, are shown to be more influential in creating positive mid-day surface-to-atmosphere net ecosystem CO2 …