Atmospheric Sciences Commons^™

Development Of A Passive Sampler For Gaseous Mercury, Mae S. Gustin, Seth N. Lyman, P. Kilner, E. Prestbo

USU Uintah Basin Faculty Publications

Here we describe work toward development of the components of a cost effective passive sampling system for gaseous Hg that could be broadly deployed by nontechnical staff. The passive sampling system included an external shield to reduce turbulence and exposure to precipitation and dust, a diffusive housing that directly protects the collection surface during deployment and handling, and a collection surface. A protocol for cleaning and deploying the sampler and an analytical method were developed. Our final design consisted of a polycarbonate external shield enclosing a custom diffusive housing made from expanded PTFE tubing. Two collection surfaces were investigated, gold …

Droughtscape, Fall 2011, Kelly Smith

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

Drought Preparedness Community Options

Drought Likely to Persist, Intensify Across South

Database Will Help Planners Find Options

Impacts: Ag Losses, Fire, Water Restrictions

NDMC Welcomes International Visitors

New Drought Impact Reporter Online

Sim-Drought, Available Now at Select Agencies

Longpath Doas Observations Of Surface Bro At Summit, Greenland, J Stutz, J L. Thomas, S C. Hurlock, M Schneider, R Von Glasow, M Piot, K Gorham, John F. Burkhart, Luke D. Ziemba, Jack E. Dibb, Barry Lefer

Earth Sciences

Reactive halogens, and in particular bromine oxide (BrO), have frequently been observed in regions with large halide reservoirs, for example during bromine catalyzed coastal polar ozone depletion events. Much less is known about the presence and impact of reactive halogens in areas without obvious halide reservoirs, such as the polar ice sheets or continental snow.

We report the first LP-DOAS measurements of BrO at Summit research station in the center of the Greenland ice sheet at an altitude of 3200 m. BrO mixing ratios in May 2007 and June 2008 were typically between 1–3 pmol mol⁻¹, with maxima …

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 …

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 …

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

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 …

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 …

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 …