Atmospheric Sciences Commons^™

Chemistry–Climate Model Simulations Of Twenty-First Century Stratospheric Climate And Circulation Changes, Neal Butchart, I. Cionni, V. Eyring, T. G. Shepherd, D. W. Waugh, H. Akiyoshi, J. Austin, C. Brühl, M. P. Chipperfield, Eugene C. Cordero, M. Dameris, R. Deckert, S. Dhomse, S. M. Frith, R. R. Garcia, A. Gettelman, M. A. Giorgetta, D. E. Kinnison, F. Li, E. Mancini, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, F. Sassi, J. F. Scinocca, K. Shibata, B. Steil, W. Tian

Faculty Publications, Meteorology and Climate Science

The response of stratospheric climate and circulation to increasing amounts of greenhouse gases (GHGs) and ozone recovery in the twenty-first century is analyzed in simulations of 11 chemistry–climate models using near-identical forcings and experimental setup. In addition to an overall global cooling of the stratosphere in the simulations (0.59 ± 0.07 K decade⁻¹ at 10 hPa), ozone recovery causes a warming of the Southern Hemisphere polar lower stratosphere in summer with enhanced cooling above. The rate of warming correlates with the rate of ozone recovery projected by the models and, on average, changes from 0.8 to 0.48 K decade …

Droughtscape, Fall 2010, Kelly Smith

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

CDC Issues Drought Guidance for Public Health

La Niña May Intensify Drought in South

Recent Workshops and Meetings

East Feels Impacts as Heat Intensifies Drought

New Products

Nicole Wall Co-Facilitates Republican River Basin Task Force

NDMC Climatologist on Ethiopia Team

Extensive Aerosol Optical Properties And Aerosol Mass Related Measurements During Tramp/Texaqs 2006 – Implications For Pm Compliance And Planning, Monica Elizabeth Wright, Dean B. Atkinson, Luke Ziemba, Robert Griffin, Naruki Hiranuma, Sarah D. Brooks, James Flynn, Ryan Perna, Bernhard Rappenglück, Winston Luke, Paul Kelley

Chemistry Faculty Publications and Presentations

Extensive aerosol optical properties, particle size distributions, and Aerodyne quadrupole aerosol mass spectrometer measurements collected during TRAMP/TexAQS 2006 were examined in light of collocated meteorological and chemical measurements. Much of the evident variability in the observed aerosol-related air quality is due to changing synoptic meteorological situations that direct emissions from various sources to the TRAMP site near the center of the Houston-Galveston-Brazoria (HGB) metropolitan area. In this study, five distinct long-term periods have been identified. During each of these periods, observed aerosol properties have implications that are of interest to environmental quality management agencies. During three of the periods, long …

A Three-Year Study Of The Magnetic Field Fluctuations In The Magnetospheric Cusp, Christina Seiman Chu

Master's Theses - Daytona Beach

The high-altitude magnetospheric cusps are regions of significant magnetic field turbulence. There are also magnetic field fluctuations that cannot be called turbulence. Some of the low frequency fluctuations observed in the cusp have been shown to be motion of the cusp structure by the spacecraft (back and forth motion of the boundaries surrounding the cusp); others are transient reconnection signatures or flux transfer events (FTEs). Turbulence is important to understand because it has been proposed as a mechanism for particle energization in the cusps to MeV levels. High resolution magnetic field data from the Fluxgate Magnetometer instruments on the Cluster …

Determining The Index Of Refraction Of An Unknown Object Using Passive Polarimetric Imagery Degraded By Atmospheric Turbulence, Milo W. Hyde Iv

Theses and Dissertations

In this research, an algorithm is developed to estimate the index of refraction of an unknown object using passive polarimetric images degraded by atmospheric turbulence. The algorithm uses a variant of the maximum-likelihood blind-deconvolution algorithm developed by LeMaster and Cain to recover the true object (i.e., the first Stokes parameter), the degree of linear polarization, and the polarimetric-image point spread functions. Nonlinear least squares is then used to find the value of the complex index of refraction which best fits the theoretical degree of linear polarization, derived using a polarimetric bidirectional reflectance distribution function, to the turbulence-corrected degree of linear …

Release Of Mercury Halides From Kcl Denuders In The Presence Of Ozone, Seth N. Lyman, Daniel A. Jaffe, Mae S. Gustin

USU Uintah Basin Faculty Publications

KCl-coated denuders have become a standard method for measurement of gaseous oxidized mercury, but their performance has not been exhaustively evaluated, especially in field conditions. In this study, KCl-coated and uncoated quartz denuders loaded with HgCl₂ and HgBr₂ lost 29–55% of these compounds, apparently as elemental mercury, when exposed to ozone (range of 6–100 ppb tested). This effect was also observed for denuders loaded with gaseous oxidized mercury at a field site in Nevada (3–37% of oxidized mercury lost). In addition, collection efficiency decreased by 12–30% for denuders exposed to 50 ppb ozone during collection of HgCl_{2 …}

Developing Tornado Climatology In The Southern Great Plains Per Phases Of Prominent Oceanic Oscillations, Nicholas M. Fillo

Geography and the Environment: Graduate Student Capstones

Meteorologists are continually working toward a greater understanding of which atmospheric environments are most conducive for tornado development. This Capstone project analyzed tornado occurrences across Texas, Oklahoma, Arkansas and Louisiana during the period 1950 through 2009 to determine if any correlation exists between the location and frequency of tornado activity and the phases of the El Nino-Southern Oscillation, the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation. While it was determined that no phase of any of the oscillations studied was significantly more dominant over the other(s) concerning frequency, this project does identify some spatial shifts in tornado activity depending …

The Production And Persistence Of Σrono2 In The Mexico City Plume, A E. Perring, T H. Bertram, D K. Farmer, Paul J. Wooldridge, Jack E. Dibb, N J. Blake, D R. Blake, H B. Singh, H Fuelberg, Glenn Diskin, G W. Sachse, Robert C. Cohen

Earth Sciences

Alkyl and multifunctional nitrates (RONO₂, ΣANs) have been observed to be a significant fraction of NO_y in a number of different chemical regimes. Their formation is an important free radical chain termination step ending production of ozone and possibly affecting formation of secondary organic aerosol. ΣANs also represent a potentially large, unmeasured contribution to OH reactivity and are a major pathway for the removal of nitrogen oxides from the atmosphere. Numerous studies have investigated the role of nitrate formation from biogenic compounds and in the remote atmosphere. Less attention has been paid to the role ΣANs may …

Wind Flow Modeling For Wind Energy Analysis Of The Nellis Dunes Area In Nevada, Upendra Rangegowda

UNLV Theses, Dissertations, Professional Papers, and Capstones

A wind energy analysis of the Nellis Dunes area in Nevada was conducted. A DEM file which contains the elevation data was used to generate the surface model and to create a 3-D mesh of the region. Local meteorological tower data collected for a period of one year was used to generate the diagnostic initial wind fields. Upper level wind fields were created using a surface boundary layer technique along with linear interpolation of the tower level wind fields. The vertical components of the velocities were adjusted using the equation of continuity. Mass consistent 3-D wind fields were then calculated …

Synthesis Of Satellite (Modis), Aircraft (Icartt), And Surface (Improve, Epa-Aqs, Aeronet) Aerosol Observations Over Eastern North America To Improve Modis Aerosol Retrievals And Constrain Surface Aerosol Concentrations And Sources, Easan Drury, Daniel J. Jacob, Robert J.D. Spurr, Jun Wang, Yohei Shinozuka, Bruce E. Anderson, A D. Clarke, Jack E. Dibb, Cameron Mcnaughton, Rodney J. Weber

Earth Sciences

We use an ensemble of satellite (MODIS), aircraft, and ground-based aerosol observations during the ICARTT field campaign over eastern North America in summer 2004 to (1) examine the consistency between different aerosol measurements, (2) evaluate a new retrieval of aerosol optical depths (AODs) and inferred surface aerosol concentrations (PM_2.5) from the MODIS satellite instrument, and (3) apply this collective information to improve our understanding of aerosol sources. The GEOS-Chem global chemical transport model (CTM) provides a transfer platform between the different data sets, allowing us to evaluate the consistency between different aerosol parameters observed at different times and …

Droughtscape, Summer 2010, Kelly Smith

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

Upcoming Workshops

Mild Drought Season Likely to Persist

Drought Impacts Intensify in Upper Midwest

Visiting Scientists

North Carolina Takes Drought Monitor Seriously

International Work- Murcia, Spain, June

A Differential Absorption Model For Remote Sensing Of Atmospheric Pressure, Shivam J. Shah

Electrical & Computer Engineering Theses & Dissertations

The goal of the project is to develop and test a "model based" radar processing strategy that is compatible with the concept of a "cognitive radar". The basic approach will be to develop a cognitive radar algorithm (genetic algorithm) based on the capabilities of an existing commercially available Software Radio. While the focus of this effort is the development of a candidate approach for genetic algorithm, the longer term goal would be to implement the approach using this software radio technology to provide a low cost radar processor. The proposed technology would use differential absorption radar working at the 50-56 …

Realistic Vertical Atmospheric Profiles And Effects From Limited Surface Observations, Dane P. Ranney

Theses and Dissertations

The ability to accurately describe the atmospheric conditions around us is not only important to the Air Force, but to anyone involved in signal propagation. The programs currently utilized to describe the atmosphere take into account a variety of measures. The LEEDR (Laser Environmental Effects Definition and Reference) program in particular, allows the user to select a location, aerosol and molecular effects model, numerous cloud and precipitation events, as well as other features. Even with the control that the user has, the output that the program provides can vary from actual conditions on a day to day basis. This is …

Atmospheric Airglow Fluctuations Due To A Tsunami‐Driven Gravity Wave Disturbance, Michael P. Hickey Ph.D., G. Schubert, R. L. Walterscheid

Publications

A spectral full‐wave model is used to study the upward propagation of a gravity wave disturbance and its effect on atmospheric nightglow emissions. Gravity waves are generated by a surface displacement that mimics a tsunami having a maximum amplitude of 0.5 m, a characteristic horizontal wavelength of 400 km, and a horizontal phase speed of 200 m/s. The gravity wave disturbance can reach F region altitudes before significant viscous dissipation occurs. The response of the OH Meinel nightglow in the mesopause region (∼87 km altitude) produces relative brightness fluctuations, which are ∼1% of the mean for overhead viewing. The wave …

The Arctic Research Of The Composition Of The Troposphere From Aircraft And Satellites (Arctas) Mission: Design, Execution, And First Results, D J. Jacob, J H. Crawford, H Maring, A D. Clarke, Jack E. Dibb, L K. Emmons, R A. Ferrare, C A. Hostetler, Phil Russell, H B. Singh, A M. Thompson, G E. Shaw, E Mccauley, Judith Pederson, Jenny Fisher

Earth Sciences

The NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission was conducted in two 3-week deployments based in Alaska (April 2008) and western Canada (June–July 2008). Its goal was to better understand the factors driving current changes in Arctic atmospheric composition and climate, including (1) influx of mid-latitude pollution, (2) boreal forest fires, (3) aerosol radiative forcing, and (4) chemical processes. The June–July deployment was preceded by one week of flights over California (ARCTAS-CARB) focused on (1) improving state emission inventories for greenhouse gases and aerosols, (2) providing observations to test and improve models …

Measurement And Interpolation Of Sea Surface Temperature And Salinity In The Tropical Pacific: A 9,000 Nautical Mile Research Odyssey, Amber Brooks

Earth and Soil Sciences

The purpose of this project was to compare spline and inverse distance weighting interpolation tools on data collected in the tropical Pacific Ocean by ship and data from a global network of CTD floats, known as Argo floats (fig.1), to provide evidence that technological advancement and integration is aiding our understanding of the ocean-atmosphere system of planet Earth. Thirty-one sea surface temperature and salinity samples were manually taken across a 9,000 nautical mile trek of the Pacific Ocean for the months of April, May and June 2008. Argo ASCII globally gridded monthly averaged sea surface temperature and salinity data, from …

Convective Distribution Of Tropospheric Ozone And Tracers In The Central American Itcz Region: Evidence From Observations During Tc4, M A. Avery, Cynthia Twohy, David Mccabe, J Joiner, Kurt Severance, E L. Atlas, D R. Blake, T P. Bui, John D. Crounse, Jack E. Dibb, Glenn Diskin, Paul Lawson, Matthew Mcgill, David Rogers, G W. Sachse, Eric Scheuer, A M. Thompson, Charles Trepte, Paul Wennberg, Jerald Ziemke

Earth Sciences

During the Tropical Composition, Clouds and Climate Coupling (TC4) experiment that occurred in July and August of 2007, extensive sampling of active convection in the ITCZ region near Central America was performed from multiple aircraft and satellite sensors. As part of a sampling strategy designed to study cloud processes, the NASA ER‐2, WB‐57 and DC‐8 flew in stacked “racetrack patterns” in convective cells. On July 24, 2007, the ER‐2 and DC‐8 probed an actively developing storm and the DC‐8 was hit by lightning. Case studies of this flight, and of convective outflow on August 5, 2007 reveal a significant anti‐correlation …

Evidence Of Nitric Acid Uptake In Warm Cirrus Anvil Clouds During The Nasa Tc4 Campaign, Eric Scheuer, Jack E. Dibb, Cynthia Twohy, David Rogers, Andrew J. Heymsfield, Aaron Bansemer

Earth Sciences

Uptake of HNO3 onto cirrus ice may play an important role in tropospheric NOx cycling. Discrepancies between modeled and in situ measurements of gas-phase HNO3 in the troposphere suggest that redistribution and removal mechanisms by cirrus ice have been poorly constrained. Limited in situ measurements have provided somewhat differing results and are not fully compatible with theory developed from laboratory studies. We present new airborne measurements of HNO3 in cirrus clouds from anvil outflow made during the Tropical Composition, Cloud, and Climate Coupling Experiment (TC4). Upper tropospheric (>9 km) measurements made during three flights while repeatedly traversing the same …

Intercomparison Of Prism And Daymet Temperature Interpolation From 1980 To 2003, Rebecca A. Scully

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As ecosystem modeling becomes increasingly integrated with Geographic Information Systems (GIS) there is a rise in demand for spatially and temporally continuous meteorological data. But in order to justify management decisions or to provide robust scientific insights, the accuracy of meteorological data used as model input must be thoroughly quantified. Current methods to create spatially continuous climate data from discrete weather station data include inverse distance weighting, geostatistical techniques such as kriging and splines, local regression models such as Parameter-Elevation Regression on Independent Slope Model (PRISM) and Daymet, and regional regression models. For the conterminous United States, PRISM and Daymet …

Reduction Of Rocket-Borne Atmospheric Density Measurements Using Monte Carlo Simulation, Travis Gaulden

All Theses

The HEX II atmospheric rocket experiment, conducted near 9:30 U.T. February 14, 2007 from the Poker Flat Rocket Range in Alaska was designed to lead to a better understanding of density and velocity gradients in the lower thermosphere. In a supporting role to this mission, cold cathode ionization gauges recorded composite density along three rocket payload trajectory paths from 90 km to 200 km. Rocket-borne instruments experience near sonic to hypersonic velocities and encounter a range of viscous, slipflow, and collisionless flow conditions at these heights. These variable conditions necessitate the use of tailored analytic expressions appropriate to the flow …