Oceanography and Atmospheric Sciences and Meteorology Commons^™

Assessment Of The Effects Of Plasma Bubbles On Gaim-Gm, Kenneth R. Fenton

Theses and Dissertations

Plasma bubbles are regions of depleted plasma density generated in the post-sunset equatorial region of the ionosphere. Bubbles significantly affect total electron count (TEC) and consequently alter communication and navigation capabilities. Here, the Global Assimilation of Ionospheric Measurements Gauss-Markov (GAIM-GM) model is studied in order to assess its capability to accurately model equatorial plasma bubbles. GAIM-GM uses the Ionospheric Forecast Model (IFM) as a background state modified through the application of a Kalman Filter to incorporate ionospheric observations such as Global Positioning System (GPS) total electron content (TEC) values. GPS TEC values representative of plasma bubble conditions are modeled and …

Verification Of Global Assimilation Of Ionospheric Measurements Gauss Markov (Gaim-Gm) Model Forecast Accuracy, Paul H. Domm

Theses and Dissertations

GAIM-GM is an operational Kalman filter data assimilation model of the ionosphere that can assimilate data from GPS total electron content (TEC), ionosonde electron density profiles, and satellite based in situ electron densities. The Air Force Weather Agency (AFWA) uses GAIM-GM to specify and forecast the ionosphere. An in depth investigation into the accuracy of these forecasts has not been completed. GAIM-GM output obtained from four cases run from combinations of geomagnetic and solar activity was used to determine GAIM-GM forecast accuracy. Forecast accuracy was determined through the use of a skill score as well as other statistical tools to …

Effect Of Storm Enhanced Densities On Geo-Location Accuracy Over Conus, Lindon H. Steadman

Theses and Dissertations

Storm enhanced densities (SEDs) are ionospheric plasma enhancements that disrupt radio communications in the near-Earth space environment, degrading the Global Positioning System (GPS) and other key technologies. Accurate GPS/total electron content (TEC) correction maps produced by ionosphere models can mitigate degradations from SEDs. An artificial SED was created and ingested via slant TEC measurements into the Global Assimilation of Ionospheric Measurements Gauss-Markov Kalman Filter Model to determine how many ground GPS receivers are needed to produce reliable GPS/TEC correction maps over the continental United States during geomagnetic storming. It was found that 110 well-positioned GPS receivers produced the best overall …

Sources Of Gaseous Oxidized Mercury And Mercury Dry Deposition At Two Southeastern U.S. Sites, Peter S. Weiss-Penzias, Mae S. Gustin, Seth N. Lyman

USU Uintah Basin Faculty Publications

Wet deposition measurements have shown that relative to other parts of the US, the southeastern region has the highest mercury (Hg) inputs. The source of this Hg has been investigated by multiple researchers and is suggested to be derived from local, regional and global sources. Here we focus on trying to understand potential sources of Hg to this area during periods dominated by dry gaseous oxidized mercury (GOM) deposition. Dry deposition of GOM to a surrogate surface was measured in conjunction with speciated atmospheric Hg, and ancillary parameters from September 2007 through September 2008 at two sites located within 25 …

Hyperspectral-Based Adaptive Matched Filter Detector Error As A Function Of Atmospheric Profile Estimation, Allan W. Yarbrough

Theses and Dissertations

Hyperspectral imagery is collected as radiance data. This data is a function of multiple variables: the radiation profile of the light source, the reflectance of the target, and the absorption and scattering profile of the medium through which the radiation travels as it reflects off the target and reaches the imager. Accurate target detection requires that the collected image matches as closely as possible the known "true" target in the classification database. Therefore, the effect of the radiation source and the atmosphere must be removed before detection is attempted. While the spectrum of solar light is relatively stable, the effect …

Observations Of Hydroxyl And Peroxy Radicals And The Impact Of Bro At Summit, Greenland In 2007 And 2008, J Liao, L Gregory Huey, D Tanner, N Brough, Steve Brooks, Jack E. Dibb, J Stutz, J L. Thomas, Barry Lefer, C Haman, K Gorham

Earth Sciences

The Greenland Summit Halogen-HO_x (GSHOX) Campaign was performed in spring 2007 and summer 2008 to investigate the impact of halogens on HO_x (= OH + HO₂) cycling above the Greenland Ice Sheet. Chemical species including hydroxyl and peroxy radicals (OH and HO₂+ RO₂), ozone (O₃), nitrogen oxide (NO), nitric acid (HNO₃), nitrous acid (HONO), reactive gaseous mercury (RGM), and bromine oxide (BrO) were measured during the campaign. The median midday values of HO₂ + RO₂ and OH concentrations observed by chemical ionization mass spectrometry (CIMS) were …

Rehabilitation Of Srrl Aerosol Optical Depth Photometer Data, Elin Deeb, Daryl Myers, Afshin Andreas

STAR Program Research Presentations

NREL’s Solar Radiation Research Laboratory (SRRL) utilizes a Prede POM-01 Photometer to collect aerosol optical depth (AOD) information, necessary for determining the performance of solar collector systems. Inconsistencies and errors exist in SRRL’s AOD data due to errors in the calibration factors as well as the data reduction algorithms. Langley plots of five of the channels were performed to calibrate the necessary constants for AOD calculations. Clear sky data was determined based on the ratio of direct to global radiation and on the scatter between morning and afternoon TWC 500 nm photometer (an NREL custom photometer) data. Plots of calculated …

A Climatology Of High-Wind Events Associated With Post-Tropical Cyclones In The United States, Joshua M. Gilliland

Masters Theses & Specialist Projects

During 1951-2009, 47% of all tropical systems (TSs) within the Atlantic Basin transitioned to post-tropical (PTC) extratropical classification. These systems have shown the capability of producing hurricane-force winds and gusts for portions of the eastern United States. This study provides a climatological foundation for high-wind observations that were contributed from PTCs. In this study, 76 PTC systems were identified and tracked using six hourly observations from the National Hurricane Center’s HURDAT dataset. Mean wind radii buffers were calculated and used to determine the high-wind observations attributed by PTCs. High-wind climatology was developed by using hourly surface wind data from the …

On The Variation Of Gravity Wave Activity Through The Solar Cycle At The South Pole, Ryan Matthew Agner

Doctoral Dissertations and Master's Theses

Atmospheric dynamics comprise of a multitude of phenomena from various sources that affect the entire climate of the globe. Some of these phenomena include Atmospheric Gravity Waves which are ubiquitous features around the planet. They are important mechanisms for the transport of momentum and energy from the lower atmosphere to the upper atmosphere. The sun is the ultimate source of energy for the earth and the primary driver of atmospheric dynamics. The 11-year solar cycle of the sun has had a noticeable effect on the overall climate of the earth in the past. More recent work has seen the diurnal …

Particle‐In‐Cell Simulation Of Incoherent Scatter Radar Spectral Distortions Related To Beam‐Plasma Interactions In The Auroral Ionosphere, M. A. Diaz, M. Oppenheim, J. L. Semeter, M. Zettergren

Publications

An electrostatic parallel particle‐in‐cell (EPPIC) code that allows for particle beam injections and multiple boundary conditions is used to investigate the beam‐plasma interaction and its manifestations in the incoherent scatter (IS) spectrum. Specifically, the code is used to investigate anomalous enhancements in the ion acoustic line through the destabilization of the plasma by injection (or precipitation) of low‐energy electron beams. This enhancement of the ion acoustic line is a form of IS distortion commonly observed in the vicinity of auroral arcs called the naturally enhanced ion‐acoustic line (NEIAL). Simulations confirm the parametric decay of Langmuir waves as a plausible mechanism, …

Do Wind Turbines Affect Weather Conditions?: A Case Study In Indiana, Meghan F. Henschen, Brittany Herrholtz, Lacey Rhudy, Kathryn Demchak, Brian Doogs, Joshua Holland, Erik Larson, Johnny Martin, Matthew Rudkin

The Journal of Purdue Undergraduate Research

Wind turbines are becoming increasingly widespread in the United States as the world looks for cleaner sources of energy. Scientists, policymakers, and citizens have strong opinions regarding the positive and negative effects of wind energy projects, and there is a great deal of misinformation about wind energy circulating on the Web and other media sources. The purpose of this study is to gain a better understanding of how the rotation of hundreds of turbines can influence local weather conditions within a wind farm and in the surrounding areas. This experiment measures temperature, atmospheric pressure, wind speed, wind direction, relative humidity, …

Mesospheric Temperature Variability And Seasonal Characteristics Over The Andes, Jonathan Pugmire, Yucheng Zhao, Michael J. Taylor, P D. Pautet

Graduate Student Posters

The Utah State University CEDAR Mesospheric Temperature Mapper (MTM) is a high-quality CCD imager capable of remote sensing faint optical emissions from the night sky to determine mesospheric temperature and its variability at an altitude of ~87 km. The MTM was operated at the new Andes Lidar Observatory (ALO)located at Cerro Pachon, Chile (30.2° S, 70.7° W) since August 2009 to investigate the seasonal characteristic of the mesopause at mid-latitudes. Measurement were made alongside a powerful lidar capable of height sounding the mesosphere. In this study, the MTM data have been analyzed to determine night to night variability and seasonal …

The World's Most Sensitive Rayleigh-Scatter Lidar, Leda Sox, V. B. Wickwar, J P. Herron, Marcus J. Bingham, Lance W. Peterson

Posters

No abstract provided.

Droughtscape, Summer 2011, Kelly Smith

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

New NDMC Website

Drought May Improve in Southeast and Southwest

Impacts Summary: Fire, Crop Loss and More

International Activities

NDMC Launches Ranch Planning Tool

Serving Data to Order

Workshop Builds Drought Planning Community

The Effect Of An Offshore Wind Turbine Array On Circulation In An Idealized Coastal Ocean, Mahmoud Kamel

OES Theses and Dissertations

The effect of arrays of wind turbines on circulation in the coastal ocean is analyzed with a coastal numerical model applied to a shallow coastal area like the Mid Atlantic Bight (MAB). A simplified model domain is specified with a linearly deepening shelf along a straight coastline. The initial density structure is a quasi-two layer situation with a sharp thermocline. Wind stress in most of the cases is either upwelling or downwelling favorable with constant amplitude continuing after a smooth start. There are two cases where oscillating wind forcing is used. Simulations consider wind arrays having different widths, different locations …

Identifying Changes In Climatic Trends And The Fingerprints Of Landuse And Landcover Changes In The High Plains Of The Usa, Denis Mutiibwa

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Human activities such as conversion of natural ecosystem to croplands and urban-centers, deforestation and afforestation impact biophysical properties of land surface such as albedo, energy balance, and surface roughness. Alterations in these properties affect the heat and moisture exchanges between the land surface and atmospheric boundary layer. The objectives of this research were; (i) to quantitatively identify the High plains’ regional climate change in temperatures over the period 1895 to 2006, (ii) detect the signatures of anthropogenic forcing of LULC changes on the regional climate change of the High Plains, and (iii) examine the trends in evolving regional latent heat …

Excitation Of Zero-Frequency Magnetic Field-Aligned Currents By Ionospheric Heating, A V. Streltsov, T R. Pedersen

Dartmouth Scholarship

Time-dependent, three-dimensional numerical simulations of the reduced MHD model describing shear Alfve ́n waves in the magnetosphere provide an interesting prediction superficially similar to results of several iono- spheric heating experiments conducted at high altitudes. In these experiments, heating of the ionospheric F-region with a constant/zero-frequency beam of HF waves causes luminous structures in the ionosphere in the form of a ring or a solid spot with a characteristic size comparable to the size of the heated spot. Simulations suggest that spots/rings or similar optical appearance might be associated with a magnetic field- aligned current system produced by the ionospheric …

The 2009 Samoa And 2010 Chile Tsunamis As Observed In The Ionosphere Using Gps Total Electron Content, David A. Galvan, Attila Komjathy, Michael P. Hickey Ph.D., Anthony J. Mannucci

Publications

Ground‐based Global Positioning System (GPS) measurements of ionospheric total electron content (TEC) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following two recent seismic events: the Samoa earthquake of 29 September 2009 and the Chile earthquake of 27 February 2010. Both earthquakes produced ocean tsunamis that were destructive to coastal communities near the epicenters, and both were observed in tidal gauge and buoy measurements throughout the Pacific Ocean. We observe fluctuations in TEC correlated in time, space, and wave properties with these tsunamis using the Jet Propulsion Laboratory’s Global Ionospheric Mapping software. These TEC measurements were …

The Use Of Large-Scale Climate Data To Predict Drought, River Flows, And Vegetation Over Central-Southwest Asia, Matthew Barlow

2011 Symposium on Data-Driven Approaches to Droughts

Central-Southwest Asia is a semi-arid, economically stressed region where droughts have severe societal impacts in terms of agriculture, farming, access to fresh water for drinking, and sanitation. There are two sources of drought predictability for this area: the influence of predictable modes of large-scale climate variability at both seasonal and intraseasonal timescales, and the importance of the snow pack to warm season river flows and vegetation. Local data scarcity is a critical problem for the region, both for historical analysis and for real-time monitoring. However, analysis shows that satellite data can be used to provide a considerable amount of high-resolution …

Building An Enhanced Drought Early Warning System (Dews): Tools And Services For Decision Support, Mark Svoboda

2011 Symposium on Data-Driven Approaches to Droughts

Perhaps no other hazard lends itself as well to the need for a diligent early warning system (DEWS) than drought. Droughts typically evolve slowly, but have the potential to cover very large areas compared to hazards like hurricanes, tornadoes and floods, which have a much smaller geographic footprint. The U.S. took first steps in 2006 toward developing coordinated and integrated DEWS through the creation of the National Integrated Drought Information System, or NIDIS. More recently, the National Drought Mitigation Center (http://drought.unl.edu) has been working with NIDIS and other international parties (WMO, GEO, United Nations, etc.) with a goal of developing …

Group Velocity And Energy Flux In The Thermosphere: Limits On The Validity Of Group Velocity In A Viscous Atmosphere, R. L. Walterscheid, Michael P. Hickey Ph.D.

Publications

The response to wave forcing of finite duration comprises a transient forerunner and the steady state signal (or simply the signal). It is the latter that carries information on the spectral content of the forcing, and the signal velocity is the velocity at which wave energy flows. To the extent that group velocity is a good measure of the energy flow velocity, the ray‐tracing formalism is a valid description of signal propagation. We have examined vertical group velocities as a measure of vertical energy flow velocity for gravity and acoustic waves propagating into the dissipative lower thermosphere. We find that …

Building A Sustainable Network Of Drought Communities, Deborah J. Bathke, Nicole Wall, Jeff Nothwehr, Kelly Helm Smith, Donna L. Woudenberg, Tonya K. Bernadt, Crystal Bergman, Joseph P. Robine, Michael Hayes, Mark Svoboda, Lisa Darby, Roger S. Pulwarty, The National Drought Mitigation Center, The National Integrated Drought Information System Program Office

High Plains Regional Climate Center: Staff Publications

The first step in managing large-scale (national) collaborations and networks is to consider and address how a group and a potential partnership may match up (Luther, 2005). To explore this concept and many other collaborative concepts, the National Integrated Drought Information System (NIDIS) hosted a workshop, “Building a Sustainable Network of Drought Communities,” which was facilitated by the National Drought Mitigation Center (NDMC) in Chicago, IL, June 8-9, 2011.

The workshop explored current examples of good communication and lessons learned within the realm of drought planning in order to address a future NIDIS Engaging Preparedness Communities (EPC) working group that …

Fabry-Perot Observations Of Midlatitude Neutral Winds And Atmospheric Gravity Wave Activity, Marjory Anne Katon

Doctoral Dissertations and Master's Theses

The mesosphere and lower thermosphere displays a wide range of dynamical phenomena resulting in a complex and variable regions. Governed primarily by fluid dynamics, the motion of the upper atmosphere is modulated by a number of atmospheric waves propagating upward from various sources in the lower atmosphere. Among these are atmospheric gravity waves which have been recognized as a major source of momentum and energy in the mesosphere and lower thermosphere as well as a major factor in the dynamic coupling between the troposphere and lower thermosphere. A Fabry-Perot interferometer possessed by the Space Physics Research Laboratory at the Embry-Riddle …

In Situ Measurements Of Tropospheric Volcanic Plumes In Ecuador And Colombia During Tc, S A. Carn, K D. Froyd, B E. Anderson, Paul Wennberg, John D. Crounse, K Spencer, Jack E. Dibb, N A. Krotkov, E V. Browell, Jonathan Hair, Glenn S. Diskin, G W. Sachse

Earth Sciences

A NASA DC‐8 research aircraft penetrated tropospheric gas and aerosol plumes sourced from active volcanoes in Ecuador and Colombia during the Tropical Composition, Cloud and Climate Coupling (TC4 ) mission in July–August 2007. The likely source volcanoes were Tungurahua (Ecuador) and Nevado del Huila (Colombia). The TC4 data provide rare insight into the chemistry of volcanic plumes in the tropical troposphere and permit a comparison of SO2 column amounts measured by the Ozone Monitoring Instrument (OMI) on the Aura satellite with in situ SO2 measurements. Elevated concentrations of SO2, sulfate aerosol, and particles were measured by DC‐8 instrumentation in volcanic …

Modeling Chemistry In And Above Snow At Summit, Greenland – Part 1: Model Description And Results, J L. Thomas, J Stutz, Barry Lefer, L Gregory Huey, K Toyota, Jack E. Dibb, R Von Glasow

Earth Sciences

Sun-lit snow is increasingly recognized as a chemical reactor that plays an active role in uptake, transformation, and release of atmospheric trace gases. Snow is known to influence boundary layer air on a local scale, and given the large global surface coverage of snow may also be significant on regional and global scales. We present a new detailed one-dimensional snow chemistry module that has been coupled to the 1-D atmospheric boundary layer model MISTRA. The new 1-D snow module, which is dynamically coupled to the overlaying atmospheric model, includes heat transport in the snowpack, molecular diffusion, and wind pumping of …

Spatial Patterns Of Drought Triggers And Indicators, Joseph P. Robine

Department of Environmental Studies: Undergraduate Student Theses

Drought is a reoccurring phenomenon with widespread economic, social, and environmental impacts. Unlike other disasters, a drought cannot be easily detected. In addition, droughts are widespread and develop slowly over time making it difficult to detect its onset and monitor its severity and impacts. To assist in monitoring the severity and spatial extent of droughts, drought managers frequently use indicators and triggers. Drought indicators are meteorological or hydrological variables or indices that quantify or describe the level of drought severity. A drought trigger is a value of an indicator that initiates management and response actions. Despite the clear importance of …

Searching For Melting-Induced Cold-Pool Circulations In An Oklahoma Winter Storm, Gabriel Susca-Lopata

Atmospheric & Environmental Sciences

This paper investigates the thermodynamic and dynamic impacts of melting precipitation through a case study of an Oklahoma winter storm. On 28 January 2005 a rain and snow event affected the state of Oklahoma. A combination of radiosonde data, wind profiler data, radar imagery and Oklahoma Mesonet surface data show that latent cooling from melting caused the surface temperatures to fall in western Oklahoma while evaporation caused surface cooling in central and eastern Oklahoma. The wind and surface pressure fields in western Oklahoma are analyzed along with radar data from Frederick Air Force Base, and some limited evidence for melting-driven …

Analysis Of Banding In 26-27 December 2010 East Coast Blizzard, Sara Ganetis

Atmospheric & Environmental Sciences

Blizzard conditions occurred in the New York City metropolitan area and portions of adjacent southern New England on 26-27 December 2010 in conjunction with a strong coastal cyclone. Parts of New Jersey received over 80 cm of snow while Long Island and coastal Connecticut observed wind gusts of over 30 ms-1. The heaviest snow was concentrated along a north-south oriented mesoscale snowband that extended from coastal New Jersey northward through the New York City metropolitan area. This mesoscale snowband, which remained quasi-stationary for approximately 12 h, was associated with strong low and mid-level frontogenetical forcing. In addition to the primary …

A Preliminary Climatology Of Tropical Moisture Exports In The Southern Hemisphere, Alicia M. Bentley, Lance F. Bosart, Jason M. Cordeira

Atmospheric & Environmental Sciences

Heavy precipitation events in the midlatitudes can be supported by the poleward transport of tropical air masses within the warm sector of extratropical cyclones. Previous studies have established a climatology of the four preferred pathways of tropical moisture export (TME) events into the midlatitudes over the Northern Hemisphere (NH). The present study constructs a similar climatology of TME timing and frequency over the Southern Hemisphere (SH), highlighting three preferential regions for tropicalmidlatitude interaction. These regions correspond to the locations of the: (i) South Pacific convergence zone (Pacific Ocean pathway, PO), (ii) South Atlantic convergence zone (South American pathway, SA), and …

Surface Morphology Implications On Langmuir Probe Measurements, Padmashri Suresh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Langmuir probes are extensively employed to study the plasmas in space and laboratory environments. Successful measurements require a comprehensive modeling of both the plasma environment and the probe conditions in the form of current collection models. In this thesis, the surface morphology implications on the probe current collection are investigated. This problem is applied and solved in the context of a CubeSat regime. The first problem that is investigated is the consequence of surface structural variability on the current measurements. A new model for dealing with non-uniformity of the probe surface structure is developed in this paper. This model is …