Physical Sciences and Mathematics Commons^™

Sources Of Gravity Waves In The Lower Stratosphere Above South Pole, Zhenhua Li, Walter Robinson, Alan Liu

Zhenhua Li

No abstract provided.

A Study Of The Mesosphere-Lower Thermosphere: Noctilucent Cloud Observations And Rocket Borne Density Measurements, Shelton Simmons

All Theses

Herein, a study of a noctilucent cloud, NLC, display from 17 July 2007 is analyzed. A photogrammetric analysis was applied to time lapsed photographs taken from two observation sites, RŸgen and KŸhlungsborn, Germany. Both Kelvin-Helmholtz instabilities and internal gravity waves were identified during the NLC display based on the typical characteristics of such waves in the mesopause region. With the two observation sites, the location of details can be identified with an accuracy of ±0.125¡ longitude and ±0.5¡ latitude. A gravity wave with a wavelength of 50km and Kelvin-Helmholtz instability or gravity wave of wavelength 16.5km were observed. The 16.5km …

Observations Of Heterogeneous Reactions Between Asian Pollution And Mineral Dust Over The Eastern North Pacific During Intex-B, Cameron Mcnaughton, A D. Clarke, V Kapustin, Yohei Shinozuka, S G. Howell, B E. Anderson, E L. Winstead, Jack E. Dibb, Eric Scheuer, Ronald C. Cohen, Paul J. Wooldridge, A E. Perring, L Gregory Huey, S Kim, Jose L. Jimenez, E J. Dunlea, P F. Decarlo, Paul Wennberg, John D. Crounse, Andrew Weinheimer, F Flocke

Earth Sciences

In-situ airborne measurements of trace gases, aerosol size distributions, chemistry and optical properties were conducted over Mexico and the Eastern North Pacific during MILAGRO and INTEX-B. Heterogeneous reactions between secondary aerosol precursor gases and mineral dust lead to sequestration of sulfur, nitrogen and chlorine in the supermicrometer particulate size range.

Simultaneous measurements of aerosol size distributions and weak-acid soluble calcium result in an estimate of 11 wt% of CaCO3 for Asian dust. During transport across the North Pacific, ∼5ĝ€ "30% of the CaCO3 is converted to CaSO4 or Ca(NO 3)2 with an additional ∼4% consumed through reactions with HCl. The …

Instability In Leapfrog And Forward–Backward Schemes, Wen-Yih Sun

Department of Earth, Atmospheric, and Planetary Sciences Faculty Publications

No abstract provided.

Acid Rain: The Effects, Torrey Mortimer

Social Sciences

In a world experiencing increasing population, urbanization, and developing nations looking to compete on a global market with post-industrial nations, the effects of acid precipitation require greater consideration. As the world’s energy demand rises, and with the cheapest and most abundant source of energy being coal, the occurrence of acid precipitation is on the rise.

The goal of my project is to research and report on the effects of acid deposition on humans, animals and the environment that surrounds them. When I have completed my project, I hope to be able to explain the impacts that acid deposition has on …

Intra-Annual Comparison Of Mesospheric Gravity Waves Over Halley And Rothera Stations, Antarctica, Jonathan Pugmire, Michael J. Taylor, K. Nielsen, A. Wall, J. Thompson, P. D. Pautet

Graduate Student Posters

No abstract provided.

Gravity Wave Ducting In The Upper Mesosphere And Lower Thermosphere Duct System, R. L. Walterscheid, Michael P. Hickey Ph.D.

Publications

We report on a numerical study of gravity wave propagation in a pair of ducts located in a region where dramatic changes in the airglow most likely associated with ducted wave trains are observed. We examine ducting in an upper mesosphere inversion (INV) and an always present lower thermosphere stable layer (LTD) for a range of phase speeds and horizontal wavelengths characteristic of ducting events. We analyze the propagation and modal structure of ducted waves for backgrounds with increasing realism, starting with a climatological temperature profile where only the LTD is present. In succession, we add the INV based on …

Droughtscape- Fall 2009, Kelly Smith

Droughtscape, Quarterly Newsletter of NDMC, 2007-

Drought Monitor Forum to be in Austin, Oct. 7-8

El Niño Likely to Bring More Needed Precipitation

NDMC Welcomes Visiting Chinese Scientist

TX, CA Feeling Worst of Impacts

Grant to Bring Climate Change Ed to Teachers

Speaking of Drought ...

NDMC Takes Message Across Nebraska and World

Sparticus: Small Particles In Cirrus Science And Operations Plan, J. Mace, E. Jensen, G. Mcfarquhar, J. Comstock, T. Ackerman, David L. Mitchell, X. Liu, T. Garrett

Publications (E)

From a mass-weighted perspective, cirrus clouds exert an enormous influence on the radiative energy budget of the earth?s climate system. Owing to their location in the cold upper troposphere, cirrus can significantly reduce the outgoing longwave radiation while, at the same time, remaining relatively transmissive to solar energy. Thus, cirrus clouds are the only cloud genre that can exert a direct radiative warming influence on the climate system (Ackerman et al. 1988). It is not surprising, therefore, that general circulation models (GCMs) are especially sensitive to the presence of cirrus in the model atmosphere. Lohmann and Roeckner (1995), for instance, …

Impacts Of Meteorological Factors On Modis-Observed Fire Activity In The North American Boreal Forest: The Role Of Lightning, David A. Peterson

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

The meteorological impact on wildfire activity in the North American boreal forest during the fire seasons of 2000 – 2006 is statistically analyzed through an integration of the following data sets: the MODerate Resolution Imaging Spectroradiometer (MODIS) level 2 fire products, the 3-hourly 32-km gridded meteorological data from North American Regional Reanalysis (NARR), the instantaneous lightning data collected by the Canadian Lightning Detection Network (CLDN), and the Alaska Lightning Detection Network (ALDN). Positive anomalies of the 500 hpa geopotential height field, convective available potential energy (CAPE), number of cloud-to-ground lightning strikes, and the number of consecutive dry days are found …

Tb202: Composition And Biomass Of Forest Floor Vegetation In Experimentally Acidified Paired Watersheds At The Bear Brook Watershed In Maine, Peter Kenlan, G. B. Wiersma, A. S. White, I. J. Fernandez

Technical Bulletins

The percentage cover (abundance), frequency of occurrence, biomass, species richness, and species diversity of understory herbs was measured on a paired watershed ecosystem in eastern Maine, USA. This paired watershed site (Bear Brook Watershed in Maine, BBWM) has had the West Bear Brook Watershed treated bi-monthly with granular ammonium sulfate at a rate of 28.8 kg S ha-1 yr-1 and 25.2 kg N ha-1 yr-1 since 1989. East Bear Brook Watershed serves as the reference site. More than 100 plots were randomly located across the two watersheds. The data suggest that there is generally a lower frequency of occurrence of …

Atmospheric Mercury Concentrations And Speciation Measured From 2004 To 2007 In Reno, Nevada, Usa, Seth N. Lyman, Mae Sexauer Gustin

USU Uintah Basin Faculty Publications

Atmospheric elemental, reactive and particulate mercury (Hg) concentrations were measured north of downtown Reno, Nevada, USA from November 2004 to November 2007. Three-year mean and median concentrations for gaseous elemental Hg (Hg0) were 1.6 and 1.5 ng m−3 (respectively), similar to global mean Hg0 concentrations. The three-year mean reactive gaseous Hg (RGM) concentration (26 pg m−3) was higher than values reported for rural sites across the western United States. Well defined seasonal and daily patterns in Hg0 and RGM concentrations were observed, with the highest Hg0 concentrations measured in winter and early morning, and RGM concentrations being greatest in the …

Analysis And Modeling Of Ducted And Evanescent Gravity Waves Observed In The Hawaiian Airglow, D. B. Simkhada, J. B. Snively, M. J. Taylor, S. J. Franke

Publications

Short-period gravity waves of especially-small horizontal scale have been observed in the Maui, Hawaii airglow. Typical small-scale gravity wave events have been investigated, and intrinsic wave propagation characteristics have been calculated from simultaneous meteor radar wind measurements. Here we report specific cases where wave structure is significantly determined by the local wind structure, and where wave characteristics are consistent with ducted or evanescent waves throughout the mesopause region. Two of the documented events, exhibiting similar airglow signatures but dramatically different propagation conditions, are selected for simple numerical modeling case studies. First, a Doppler-ducted wave trapped within relatively weak wind flow …

Effects Of Non-Equilibrium Plasma On Eukaryotic Cells (Final Report: Grant Fa9550-06-1-0004), Mounir Laroussi, Fred C. Dobbs, Old Dominion University

Electrical & Computer Engineering Faculty Publications

This document is our final report describing the research activities carried out under AFOSR Grant FA9550-06-1-0004. First, descriptions of our cold plasma generation systems are presented. Two systems, developed with past and present AFOSR support, are available in our laboratory. The first is a pulsed device capable of emitting a cold plasma plume in room air. The second is an air plasma generator the core of which is a dielectric barrier discharge excited by a high AC voltage. Following these brief descriptions we first present the effects of an atmospheric pressure air plasma on four different types of eukaryotic microalgae. …

Propagation Of Tsunami-Driven Gravity Waves Into The Thermosphere And Ionosphere, Michael P. Hickey, G. Schubert, R. L. Walterscheid

Publications

Recent observations have revealed large F-region electron density perturbations (~100%) and total electron content (TEC) perturbations (~30%) that appear to be correlated with tsunamis. The characteristic speed and horizontal wavelength of the disturbances are ~200 m/s and ~400 km. We describe numerical simulations using our spectral full-wave model (SFWM) of the upward propagation of a spectrum of gravity waves forced by a tsunami, and the interaction of these waves with the F-region ionosphere. The SFWM describes the propagation of linear, steady-state acoustic-gravity waves in a nonisothermal atmosphere with the inclusion of eddy and molecular diffusion of heat and momentum, ion …

Analysis Of The Neutral Wind Profiles From The Hex Ii Experiment, Tyler Scott

All Theses

The HEX II sounding rocket experiment was carried out on February 14, 2007, during active geomagnetic conditions. Three rockets released trimethyl aluminum (TMA) chemical tracer trails to measure the neutral winds. Three neutral wind profiles obtained from the upleg trails are presented. The profiles are characterized by a strong wind peak around 113 km altitude in the northwestward direction. Below the peak, the winds exhibit strong shear and a smaller wind peak at around 103 km in the southeastward direction. The wind magnitudes are too strong to be attributed to tidal forcing. Above 120 km the winds are consistently to …

Testing And Application Of Surrogate Surfaces For Understanding Potential Gaseous Oxidized Mercury Dry Deposition, Seth N. Lyman, Mae Sexauer Gustin, Eric M. Prestbo, Phillip I. Kilner, Eric Edgerton, Ben Hartsell

USU Uintah Basin Faculty Publications

Currently there is no standard method for measurement of atmospheric mercury dry deposition. While all operationally defined forms of atmospheric mercury (elemental, oxidized, and particulate) can be dry deposited, oxidized forms are of concern due to high deposition velocities, water solubility, and reactivity. This paper describes the development of a surrogate surface for characterizing potential dry deposition of gaseous oxidized mercury (GOM). Laboratory tests showed that the surface collected HgCl2, HgBr2, and HgO with equal efficiency, and deposition was not significantly influenced by temperature, humidity, or ozone concentrations. Deposition of mercury to surfaces in field deployments was correlated with GOM …

Droughtscape- Summer 2009, Kelly Smith

Droughtscape, Quarterly Newsletter of NDMC, 2007-

U.S. Drought Monitor Forum, 2009

El Niño Could Bring Wet Winter After Hot Summer

Around the World

Agriculture Hit Hard in California, Texas

Predictable Patterns in Missouri River Basin?

Seeking Low-Flow Effects in Colorado, Southeast

VegDRI Began Coast-to-Coast Coverage in May

Balloonsat: Design, Implementation, And Application Of A Low-Cost Tethered Weather Balloon Remote Sensing Station, John Saghri, Dustin Blackwell, John Hupton, Robert Hursig, Jessica Kiefer, Matt Schlutz, Scott Seims

Honors Undergraduate Research Journal

No abstract provided.

Impact Of The Intraseasonal Variability Of Large-Scale Circulation Over The Western North Pacific On The Characteristics Of Tropical Cyclone Track, T. C. Chen, Shih-Yu (Simon) Wang, M. C. Yen, A. J. Clark

Plants, Soils, and Climate Faculty Publications

The life cycle of the Southeast Asian–western North Pacific monsoon circulation is established by the northward migrations of the monsoon trough and the western Pacific subtropical anticyclone, and is reflected by the intraseasonal variations of mo nsoon westerlies and trad e easterlies in the form of an east–west seesaw oscillation. In this paper, an effort is made to disclose the influence of this monsoon circulation on tropical cyclone tracks during its different ph ases using composite charts of large-scale circulation for certain types of tracks. A majority of straight-moving (recurving) tropical cyclones appear during weak (strong) monsoon west- erlies and …

Intra-Annual Comparison Of Mesospheric Gravity Waves Over Halley And Rothera Stations, Antarctica., Jonathan R. Pugmire, Mike J. Taylor, Kim Nielsen

Jonathan Pugmire

As part of a collaborative program between British Antarctic Survey and Utah State University, we present an intra-annual study of short-period, mesospheric gravity wave events observed over Antarctica in the near infrared OH emission. The measurements were made using an all-sky airglow imager operated at either Halley Station on the Brunt Ice Shelf, or Rothera Station, situated on the Antarctic Peninsula. A total of six austral winter seasons have been analyzed (2000-2006). This study comprises the first detailed winter seasonal investigation of short-period mesospheric gravity waves at high-Antarctic latitudes. Distributions of their observed wave parameters were found to be similar …

The Spread-F Experiment (Spreadfex): Program Overview And First Results, David C. Fritts, M. A. Abdu, B. R. Batista, I. S. Batista, P. P. Batista, R. Buriti, B. R. Clemesha, T. Dautermann, E. De Paula, B. J. Fechine, Bela Fejer, D. Gobbi, J. Haase, F. Kamalabadi, B. Laughman, L. M. Lima, H. L. Liu, A. Medeiros, Pierre-Dominique Pautet, D. M. Riggin, F. São Sabbas, J. H. A. Sobral, P. Stamus, H. Takahashi, Michael J. Taylor, Sharon L. Vadas, C. M. Wrasse

Publications

We performed an extensive experimental campaign (the spread F Experiment, or SpreadFEx) from September to November 2005 to attempt to define the role of neutral atmosphere dynamics, specifically wave motions propagating upward from the lower atmosphere, in seeding equatorial spread F and plasma bubbles extending to higher altitudes. Campaign measurements focused on the Brazilian sector and included ground-based optical, radar, digisonde, and GPS measurements at a number of fixed and temporary sites. Related data on convection and plasma bubble structures were also collected by GOES 12 and the GUVI instrument aboard the TIMED satellite. Initial results of our analyses of …

Rayleigh-Lidar Observations Of Mesospheric Gravity Wave Activity Above Logan, Utah, Durga N. Kafle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A Rayleigh-scatter lidar operated from Utah State University (41.7°N, 111.8°W) for a period spanning 11 years ― 1993 through 2004. Of the 900 nights observed, data on 150 extended to 90 km or above. They were the ones used in these studies related to atmospheric gravity waves (AGWs) between 45 and 90 km. This is the first study of AGWs with an extensive data set that spans the whole mesosphere. Using the temperature and temperature gradient profiles, we produced a climatology of the Brunt-Väisälä (buoyancy) angular frequency squared, N² (rad/s)². The minimum and maximum values of N …

Droughtscape- Spring 2009, Kelly Smith

Droughtscape, Quarterly Newsletter of NDMC, 2007-

U.S. Drought Monitor Publishes Map 500!

Weakening La Niña May Mean Relief for Texas

Upcoming Workshops

Drought Impacts Worst in California, Texas

CoCoRaHS to Request Drought Impact Data, Too

NDMC Adds Researcher

K-12 Students Learn About Drought

High Time Resolution Pfisr And Optical Observations Of Naturally Enhanced Ion Acoustic Lines, R G. Michell, K A. Lynch, C J. Heinselman, H C. Stenbaek-Nielsen

Dartmouth Scholarship

Observations of naturally enhanced ion acoustic lines (NEIALs) taken with the Poker Flat Incoherent Scatter Radar (PFISR) using a mode with very high time resolution are presented. The auroral event took place over Poker Flat, Alaska on 8 February 2007 at 09:35 UT (∼22:00 MLT), and the radar data are complemented by common-volume high- resolution auroral imaging. The NEIALs occurred during only one of the standard 15-s integration periods. The raw data of this time show very intermittent NEIALs which oc- cur only during a few very short time intervals (≤1 s) within the 15-s period. The time sampling of …

Rayleigh-Lidar Observations Of Mesospheric Instabilities, Gabriel C. Taylor, Durga N. Kafle, Vincent B. Wickwar

Posters

From 1993 to 2004 the Utah State University Rayleigh lidar, known as the USU green laser, collected 900 nights of data from the mesosphere (45-90 km). From these observations profiles of relative neutral densities and absolute temperatures were derived. Usually, the atmosphere is horizontally stratified with a balance between gravitational and pressure forces. When this balance is perturbed, it leads to the generation of buoyancy or “gravity” waves. An example of these is clear air turbulence, which can have dramatic effects on airplanes. As these waves propagate upward, the decrease in atmospheric density and conservation of energy combine to give …

Assessment Of Weather Sensitivities And Air Force Weather (Afw) Support To Tactical Lasers In The Lower Troposphere, Francesco J. Echeverria

Theses and Dissertations

ATL scientists need to develop a full understanding of the interaction effects between a high-energy laser beam and the atmosphere through which it propagates. Achieving this understanding is important for many reasons. In particular, the high cost of DE weapons systems makes each propagation event expensive. Having an understanding of the atmosphere in which a high-energy laser propagates will increase efficiency and effectiveness of the ATL weapon system, which in turn will decrease cost of operation. A tool that allows for the ATL war-fighter to determine the atmospheric effects on laser propagation currently does not exist. This study creates a …

A Computational Tool For Evaluating Thz Imaging Performance In Brownout Conditions At Land Sites Throughout The World, Seth L. Marek

Theses and Dissertations

This study quantifies terahertz (THz) or sub-millimeter imaging performance during simulated rotary-wing brownout or whiteout environments based on geographic location and recent/current atmospheric weather conditions. The atmospheric conditions are defined through the Air Force Institute of Technology Center for Directed Energy (AFIT/CDE) Laser Environmental Effects Definition and Reference or LEEDR model. This model enables the creation of vertical profiles of temperature, pressure, water vapor content, optical turbulence, and atmospheric particulates and hydrometeors as they relate to line-by-line layer extinction coefficient magnitude at wavelengths from the UV to the RF. Optical properties and realistic particle size distributions for the brownout and …

Demonstration And Verification Of A Broad Spectrum Anomalous Dispersion Effects Tool For Index Of Refraction And Optical Turbulence Calculations, J. Jean Cohen

Theses and Dissertations

An atmospheric optical turbulence strength model with a broad wavelength range of 355nm (ultraviolet) to 8.6m (radio frequencies) has been created at AFIT and implemented into the High Energy Laser End-to-End Operational Simulation tool (HELEEOS). This modeling and simulation tool is a first principles atmospheric propagation and characterization model. Within HELEEOS lies the High-Resolution Transmission Molecular Absorption (HITRAN) database, containing 1,734,469 spectral lines for 37 different molecules as of version 12.0 (2004). HITRAN affords HELEEOS incredible accuracy for electromagnetic (EM) propagation prediction. A full understanding of optical turbulence is needed to successfully predict EM radiation propagation, particularly within the application …

The Noctilucent Cloud (Nlc) Display During The Ecoma/Mass Sounding Rocket Flights On 3 August 2007: Morphology On Global To Local Scales, G. Baumgarten, J. Fiedler, K. H. Fricke, M. Gerding, M. Hervig, P. Hoffmann, N. Müller, Pierre-Dominique Pautet, M. Rapp, C. Robert, D. Rusch, C. Von Savigny, W. Singer

Publications

During the ECOMA/MASS rocket campaign large scale NLC/PMC was observed by satellite, lidar and camera from polar to mid latitudes. We examine the observations from different instruments to investigate the morphology of the cloud. Satellite observations show a planetary wave 2 structure. Lidar observations from Kühlungsborn (54° N), Esrange (68° N) and ALOMAR (69° N) show a highly dynamic NLC layer. Under favorable solar illumination the cloud is also observable by ground-based cameras. The cloud was detected by cameras from Trondheim (63° N), Juliusruh (55° N) and Kühlungsborn. We investigate planetary scale morphology and local scale gravity wave structures, important …