Oceanography and Atmospheric Sciences and Meteorology Commons^™

Simulation Of The Recent Multidecadal Increase Of Atlantic Hurricane Activity Using An 18-Km-Grid Regional Model, Thomas R. Knutson, Joseph J. Sirutis, Stephen T. Garner, Isaac M. Held, Robert E. Tuleya

CCPO Publications

In this study, a new modeling framework for simulating Atlantic hurricane activity is introduced. The model is an 18-km-grid nonhydrostatic regional model, run over observed specified SSTs and nudged toward observed time-varying large-scale atmospheric conditions (Atlantic domain wavenumbers 0-2) derived from the National Centers for Environmental Prediction (NCEP) reanalyses. Using this "perfect large-scale model" approach for 27 recent August-October seasons (1980-2006), it is found that the model successfully reproduces the observed multidecadal increase in numbers of Atlantic hurricanes and several other tropical cyclone (TC) indices over this period. The correlation of simulated versus observed hurricane activity by year varies from …

Influences Of Winter Haze On Fog/Low Cloud Over The Indo-Gangetic Plains, Ritesh Gautam, N. C. Hsu, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The aerosol loading in south Asia has increased considerably because of the growing population, urbanization, and industrialization in recent years. To understand the effects of aerosols on cloud properties in this region, we have analyzed an extensive collection of aerosol and cloud properties, obtained from the Moderate resolution Imaging Spectroradiometer (MODIS) data, over the Indian subcontinent during winter 2000–2006. During these winter months, the Indo-Gangetic (IG) plains, in the northern part of India, are subjected to dense haze and fog on the basis of MODIS climatology of aerosol optical depth and cloud properties (cloud effective radius, cloud top pressure, and …

The Effect Of Water Droplet Oscillations On The Scavenging Efficiency Of Micron Sized Particles, Raymond Mcdonnell

All Theses

It has been hypothesized that drop oscillations and vortex shedding within the droplet wake affect the scavenging efficiency, E, of particles. However, no conclusive results have been presented on the effect these phenomena might have on particle scavenging. To address this need, experiments were conducted using oscillating water drops and water drops damped by the addition of glycerol. The scavenging efficiencies were measured for millimeter-sized droplets scavenging micron-sized particles. These results show that E is increased by drop oscillations where the particle diameter is large, but E is decreased by these oscillations when the particle diameter is small.

Stratospheric Variability And Trends In Models Used For The Ipcc Ar4, P. M. De F. Forster, Eugene Cordero

Faculty Publications, Meteorology and Climate Science

Atmosphere and ocean general circulation model (AOGCM) experiments for the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) are analyzed to better understand model variability and assess the importance of various forcing mechanisms on stratospheric trends during the 20th century. While models represent the climatology of the stratosphere reasonably well in comparison with NCEP reanalysis, there are biases and large variability among models. In general, AOGCMs are cooler than NCEP throughout the stratosphere, with the largest differences in the tropics. Around half the AOGCMs have a top level beneath ~2 hPa and show a significant cold bias in their …

Mercury Exchange Between The Atmosphere And Low Mercury Containing Substrates, Mae Sexauer Gustin, Mark Engle, Jody Ericksen, Seth N. Lyman, Jelena Stamenkovic, Mei Xin

USU Uintah Basin Faculty Publications

Mercury is emitted to the air from Hg-enriched and low Hg-containing (natural background) substrates. Emitted Hg can be geogenic, or can be derived from the re-emission of Hg that was previously deposited to the soil from the atmosphere. Atmospheric Hg can be derived from natural and/or anthropogenic sources and can be deposited by wet or dry processes. It is important to understand the relative magnitude of emission, deposition, and re-emission of Hg associated with terrestrial ecosystems with natural background soil Hg concentrations because these landscapes cover large terrestrial surface areas. This information is also important for developing biogeochemical mass balances, …

Assessment Of Temperature, Trace Species, And Ozone In Chemistry-Climate Model Simulations Of The Recent Past, V. Eyring, N. Butchart, D. W. Waugh, H. Akiyoshi, J. Austin, S. Bekki, G. E. Bodeker, B. A. Boville, C. Brühl, M. P. Chipperfield, E. Cordero, M. Dameris, M. Deushi, V. E. Fioletov, S. M. Frith, R. R. Garcia, A. Gettelman, M. A. Giorgetta, V. Grewe, L. Jourdain, D. E. Kinnison, E. Mancini, E. Manzini, M. Marchand, D. R. Marsh, T. Nagashima, P. A. Newman, J. E. Nielsen, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, M. Schraner, T. G. Shepherd, K. Shibata, R. S. Stolarski, H. Struthers, W. Tian, M. Yoshiki

Faculty Publications, Meteorology and Climate Science

[1] Simulations of the stratosphere from thirteen coupled chemistry-climate models (CCMs) are evaluated to provide guidance for the interpretation of ozone predictions made by the same CCMs. The focus of the evaluation is on how well the fields and processes that are important for determining the ozone distribution are represented in the simulations of the recent past. The core period of the evaluation is from 1980 to 1999 but long-term trends are compared for an extended period (1960–2004). Comparisons of polar high-latitude temperatures show that most CCMs have only small biases in the Northern Hemisphere in winter and spring, but …

In Situ Evidence For Renitrification In The Arctic Lower Stratosphere During The Polar Aura Validation Experiment (Pave), Jack E. Dibb, Eric Scheuer, Melody A. Avery, G W. Sachse

Earth Sciences

In-situ measurements of nitric acid (HNO₃), ozone (O₃), and nitrous oxide (N₂O) were made from the NASA DC-8 during the Polar Aura Validation Experiment in January/February 2005. In the lower stratosphere (9–12.5 km, potential temperature 300–350 K) characteristic compact relationships were observed between all three gases. The ratio HNO₃/O₃ averaged 3.5 (±0.7) ppt/ppb. Samples with enhanced HNO₃/O₃ (>4.0) were most abundant under the edge of the Arctic Polar vortex in airmasses with enhanced mixing ratios of both gases (>400 ppb O₃ and >2000 ppt HNO …

The Influence Of North Pacific Atmospheric Blocking On Colorado Lee Cyclogenesis, Diana S. Dickey

All-Inclusive List of Electronic Theses and Dissertations

North Pacific atmospheric blocking is an upper tropospheric phenomenon that occurs modally in the northwestern quadrant of the North American cyclogenetic region primarily during the winter season. In this study, Colorado lee cyclones, which develop to the east of the Rocky Mountains, are investigated to see if differing strengths of North Pacific atmospheric blocking influences cyclone frequency, intensity and tracks during the study period 1965-1995. Three blocking categories, strong blocking, anti-blocking and weak-index blocking were created based on indices provided by previously published research. Additionally, an analysis of upper tropospheric circulation during strong blocking and anti-blocking winter seasons was made …

Observations Of Hono By Laser-Induced Fluorescence At The South Pole During Antci 2003, W Liao, A T. Case, J Mastromarino, D Tan, Jack E. Dibb

Earth Sciences

Observations of nitrous acid (HONO) by laser-induced fluorescence (LIF) at the South Pole taken during the Antarctic Troposphere Chemistry Investigation (ANTCI), which took place over the time period of Nov. 15, 2003 to Jan. 4, 2004, are presented here. The median observed mixing ratio of HONO 10 m above the snow was 5.8 pptv (mean value 6.3 pptv) with a maximum of 18.2 pptv on Nov 30th, Dec 1st, 3rd, 15th, 17th, 21st, 22nd, 25th, 27th and 28th. The measurement uncertainty is ±35%. The LIF HONO observations are compared to concurrent HONO observations performed by mist chamber/ion chromatography (MC/IC). The …

Magnetic Coupling Between A “Hot Jupiter” Extrasolar Planet And Its Pre-Main-Sequence Central Star, Brooke E. Alarcon

Master's Theses - Daytona Beach

In order to understand the short-period pile-up of extrasolar planets, the magnetic torque of a pre-main-sequence central star on a single orbiting "hot Jupiter" planet is calculated. The star's magnetic field is modeled as a dipole magnetic field. The time-dependent stellar radius is calculated for four different stellar mass sizes; 2Msum \.5Msum \Msum and 0.5Msurt. The minimum planetary ionization for the giant gas planet to be nearly frozen to the magnetic field lines is calculated. The changing angular momentum of an orbiting body was balanced with the magnetic torque of the central star to provide …

Comparative Investigations Of Equatorial Electrodynamics And Low-To-Mid Latitude Coupling Of The Thermosphere-Ionosphere System, M J. Colerico, M Mendillo, C G. Fesen, J Meriwether

Dartmouth Scholarship

The thermospheric midnight temperature maxi-

mum (MTM) is a highly variable, but persistent, large scale

neutral temperature enhancement which occurs at low lati-

tudes. Its occurrence can impact many fundamental upper

atmospheric parameters such as pressure, density, neutral

winds, neutral density, and F-region plasma. Although the

MTM has been the focus of several investigations employ-

ing various instrumentation including photometers, satellites,

and Fabry-Perot interferometers, limited knowledge exists

regarding the latitude extent of its influence on the upper at-

mosphere. This is largely due to observational limitations

which confined the collective geographic range to latitudes

within ±23◦. This paper investigates the …

Radiometric Analysis Of Daytime Satellite Detection, Katherine B. Lilevjen

Theses and Dissertations

A radiometric model for daylight satellite detection is developed and used to evaluate the effects of various parameters on signal-to-noise ratio (SNR). Detection of reflected sunlight from a low-earth orbit, diffuse, planar satellite by a single-pixel infrared photovoltaic detector is considered. Noise considered includes photon noise from the background and signal, as well as thermal noise. Parameters considered include atmospheric conditions, optical parameters, and detector parameters. The Phillips Laboratory Expert-assisted User System, an atmospheric modeling tool that employs the MODTRAN and FASCODE transmission codes, is used to model wavelength-dependent atmospheric transmission and background radiance. The SNR is found to increase …

Comparison Of Ray Tracing Through Ionospheric Models, Shayne C. Aune

Theses and Dissertations

A comparison of ray tracing predictions for transionospheric electromagnetic wave refraction and group delays through ionospheric models is presented. Impacted applications include over-the-horizon RADAR, high frequency communications, direction finding, and satellite communications. The ionospheric models used are version 2.1 of Utah State University's Global Assimilation of Ionospheric Measurements (USU GAIM) model and the 2001 version of the International Reference Ionosphere (IRI) model. In order to provide ray tracing results applicable to satellite communications for satellites at geosynchronous orbit (GEO), a third ionospheric model is used to extend the sub-2000-km USU GAIM and IRI ionospheric specifications to 36540 km in altitude. …

A Climatological Study Of Equatorial Gps Data And The Effects On Ionospheric Scintillation, Katharine A. Wicker

Theses and Dissertations

Ionospheric scintillation is detrimental to radio signals, especially those from the global positioning system. Such scintillation is caused when a signal permeates the ionosphere through plasma bubbles. The signal’s phase and amplitude can be altered, and a receiver on the ground can lose lock on the GPS signal. Measured using a zero to one index known as S4, scintillation severity is based upon season, solar cycle, time of day, location and frequency. The most severe scintillation occurs at the equatorial anomaly, or fifteen degrees north and south of the equator. Seven years of data from fifteen different locations around the …

Iron In Ice Cores From Law Dome: A Record Of Atmospheric Iron Deposition For Maritime East Antarctica During The Holocene And Last Glacial Maximum, Ross Edwards, Peter N. Sedwick, Vin Morgan, Claude Boutron

OES Faculty Publications

Total dissolvable iron (TDFe) was measured in sections of ice cores recovered from Law Dome on the coast of Wilkes Land, East Antarctica. These samples include ice dating from the Last Glacial Maximum (LGM), the Last Deglaciation, and the early and mid Holocene as well as samples from the Anthropocene that have been dated with seasonal to annual resolution. Combining our TDFe concentration data with estimates of the ice accumulation rate, we estimate the atmospheric iron deposition for Law Dome and the adjacent Southern Ocean during these periods. Our results indicate that the atmospheric iron deposition flux to this region …

Role Of Anomalous Warm Gulf Waters In The Intensification Of Hurricane Katrina, Menas Kafatos, D. Sun, Ritesh Gautam, Z. Boybeyi, Ruixin Yang, G. Cervone

Mathematics, Physics, and Computer Science Faculty Articles and Research

The year 2005 experienced several strong hurricanes intensifying in the Gulf of Mexico before making landfall that severely damaged the Gulf States, especially Hurricane Katrina. Remarkable similarities between sea surface temperature anomaly (SSTA) and major hurricane (categories 3 and higher) activity over the Gulf are identified. However, the intensification of individual hurricanes may not necessarily be temporally and spatially coincident with the distribution of warm waters or high sea surface temperature (SST). High SST values are found in advance of significant intensification of Hurricane Katrina. We emphasize that high SSTA which occurred at the right time and right place was …

Rocket And Radar Investigation Of Background Electrodynamics And Bottom-Type Scattering Layers At The Onset Of Equatorial Spread F, D. L. Hysell, M. F. Larsen, C. M. Swenson, A. Barjatya, T. F. Wheeler, T. W. Bullett, Et. Al.

Publications

Sounding rocket experiments were conducted during the NASA EQUIS II campaign on Kwajalein Atoll designed to elucidate the electrodynamics and layer structure of the postsunset equatorial F region ionosphere prior to the onset of equatorial spread F (ESF). Experiments took place on 7 and 15 August 2004, each comprised of the launch of an instrumented and two chemical release sounding rockets. The instrumented rockets measured plasma number density, vector electric fields, and other parameters to an apogee of about 450 km. The chemical release rockets deployed trails of trimethyl aluminum (TMA) which yielded wind profile measurements. The Altair radar was …

Observations Of Triboelectric Charging Effects On Langmuir-Type Probes In Dusty Plasma, Aroh Barjatya, Charles M. Swenson

Publications

Investigation of Earth’s mesosphere using sounding rockets equipped with a myriad of instruments has been a highly active field in the last 2 decades. This paper presents data from three separate instruments: an RF impedance probe, a DC fixed bias Langmuir probe, and an electric field probe, that were flown on a mesospheric sounding rocket flight investigating the presence of charged dust within and/or around a sporadic metal layer. The combined data set indicates a case of payload surface charging, the causes of which are investigated within this paper. A generic circuit model is developed to analyze payload charging and …

Estimation Of Iron Solubility From Observations And A Global Aerosol Model, Chao Luo, N. M. Mahowald, N. Meskhidze, Y. Chen, R. L. Siefert, A. R. Baker, Anne M. Johansen

All Faculty Scholarship for the College of the Sciences

Mineral aerosol deposition is the dominant source of iron to the open ocean. Soil iron is typically insoluble and understanding the atmospheric processes that convert insoluble iron to the more soluble forms observed over the oceans is crucial. In this paper, we model several proposed processes for the conversion of Fe(III) to Fe(II), and compare with cruise observations. The comparisons show that the model results in similar averaged magnitudes of iron solubility as measured during 8 cruises in 2001–2003. Comparisons show that results of cases including cloud, SO₂ and hematite processing are better than the other approaches used using …

Coupled Oceanic-Atmospheric Variability And U.S. Streamflow, Glenn A. Tootle, Thomas C. Piechota, Ashok Singh

Civil and Environmental Engineering and Construction Faculty Research

A study of the influence of interdecadal, decadal, and interannual oceanic-atmospheric influences on streamflow in the United States is presented. Unimpaired streamflow was identified for 639 stations in the United States for the period 1951–2002. The phases (cold/negative or warm/positive) of Pacific Ocean (El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)) and Atlantic Ocean (Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation (NAO)) oceanic-atmospheric influences were identified for the year prior to the streamflow year (i.e., long lead time). Statistical significance testing of streamflow, based on the interdecadal, decadal, and interannual oceanic-atmospheric phase (warm/positive or cold/negative), was performed by …

Acoustic Waves Generated By Gusty Flow Over Hilly Terrain, R. L. Walterscheid, Michael P. Hickey Ph.D.

Publications

We examine the generation of acoustic waves by gusty flow over hilly terrain. We use simple theoretical models of the interaction between terrain and eddies and a linear model of acoustic-gravity wave propagation. The calculations presented here suggest that over a dense array of geographically extensive sources orographically generated vertically propagating acoustic waves can be a significant cause of thermospheric heating. This heating may account in good part for the thermospheric hot spot near the Andes reported by Meriwether et al. (1996, 1997).

A New Pathway For Communicating The 11-Year Solar Cycle Signal To The Qbo, Eugene C. Cordero, Terrence R. Nathan

Faculty Publications, Meteorology and Climate Science

[1] The response of the equatorial quasi-biennial oscillation (QBO) to zonal-mean ozone perturbations consistent with the 11-year solar cycle is examined using a 2 1/2 dimensional model of the tropical stratosphere. Unique to this model are wave-ozone feedbacks, which provide a new, nonlinear pathway for communicating solar variability effects to the QBO. Model simulations show that for zonal-mean ozone perturbations representative of solar maximum (minimum), the diabatic heating due to the wave-ozone feedbacks is primarily responsible for driving a slightly stronger (weaker) QBO circulation and producing a slightly shorter (longer) QBO period. These results, which are explained via an analytical …

Mass Loading Measurements In Amargosa Valley, John C. Sagebiel, Alan W. Gertler, Amy J. Smiecinski, David Shafer

Publications (YM)

This work will be conducted under Task DRI-FI-001, “Mass Loading Measurements in Amargosa Valley.” The objective of this task is to measure, with known accuracy, the levels of atmospheric mass loading (mass concentration of suspended particulates) accompanying soil surface disturbing activities in Amargosa Valley. Mass loading is used in the biosphere model to calculate inhalation exposure for the human receptor, the maximally reasonably exposed individual (RMEI). The mass loading currently used in the biosphere model is based on literature data from the analog sites rather than on site-specific conditions. This work is subject to the Nevada System of Higher Education …

Antiphase Oh And Oi Airglow Emissions Induced By A Short-Period Ducted Gravity Wave, Jonathan B. Snively, Victor P. Pasko

Publications

"Numerical simulation of a ducted gravity wave event suggests that OH (8,3) and O(1S) 557.7 nm airglow emissions layers may exhibit opposite-phase intensities when perturbed by a short-period wave undergoing vertical reflection. This effect arises due to the time and temperature dependance of the OH excitation reaction, coupled with the linear polarization properties of vertically-standing waves."

Physical Processes In Acoustic Wave Heating Of The Thermosphere, G. Schubert, Michael P. Hickey Ph.D., R. L. Walterscheid

Publications

Upward propagating acoustic waves heat the atmosphere at essentially all heights due to effects of viscous dissipation, sensible heat flux divergence, and Eulerian drift work. Acoustic wave-induced pressure gradient work provides a cooling effect at all heights, but this is overwhelmed by the heating processes. Eulerian drift work and wave-induced pressure gradient work dominate the energy balance, but they nearly cancel at most altitudes, leaving their difference, together with viscous dissipation and sensible heat flux divergence to heat the atmosphere. Acoustic waves are very different from gravity waves which cool the upper atmosphere through the effect of sensible heat flux …

A Measure Of The Hurst Exponent Variability On Ground Based Magnetometer Data For Quiet And Active Magnetospheric Periods, Dario O. Cersosimo

Master's Theses - Daytona Beach

Ground-based magnetometer data were analyzed for the period of 1991-2001. The data were classified into periods of quiet and active magnetospheric activity. Those periods classified as quiet required that Kp < 1 for not less than 48 consecutive hours and active periods required a Kp > 4 for not less than 24 consecutive hours. Detrended fluctuation analysis was employed to analyze 40 events. A monofractal approach was used to identify differences in the Hurst exponent of quiet and active events. No statistical differences were found using this approach since both types of events displayed quasirandom walk behavior. A second approach determined the temporal variations in the Hurst exponent for each event. The Hurst exponent is temporally …

Planetary Wave Activity Observed In Polar Mesospheric Clouds, David A. Mackler

Master's Theses - Daytona Beach

In this paper, the Solar Backscatter UV spectrometer (SBUV) Polar Mesospheric Cloud (PMC) dataset was investigated for planetary wave activity following the earlier study by Merkel [2002]. To counter the sparse nature of the data, four separate methods of analysis are used in determining if planetary waves are present and how they effect PMC formation. The four methods are histograms (both in frequency of occurrence and mean albedo), periodograms using the Lomb-Scargle method, frequency-wavenumber analysis using a 2D Lomb-Scargle method from Wu et. al [1995], and a temporal (yearly) analysis of the 5, 6.5, and 10 day wave amplitudes. The …

Rocket Borne Measurements Of A Near-Infrared Vehicle Induced Emission With A Newly Designed Spectrograph, Damon Burke

Master's Theses - Daytona Beach

In order to broaden current knowledge of a particular vehicle induced atmospheric glow, a modified Ebert-Fastie Spectrograph was designed and built at Embry-Riddle Aeronautical University for rocket borne observations of this glow. This instrument became a piggy-back payload on the Terrier-Orion SAMPLER 41.025 rocket payload launched from White Sands Missile Range in July, 2003. A photodiode detector array measured the mesospheric hydroxyl airglow emissions during the initial ascent as well as the vehicle induced glow through the mesopause at eight discreet bandpasses. Data collected shows moderate agreement with previous measurements by Murtagh et al. [1997] and Lopez-Moreno et al. [1985] …

Rocket-Borne Instrument Design To Observe Peak Oh Meinel Band Vibrational Emission Profiles, Joshua T. Bryson

Master's Theses - Daytona Beach

The effects of density-dependent molecular quenching produce a unique, altitude dependent emission profile of the vibrational emission band for each OH v' value in the mesosphere. Previous rocket flights using broad band sensors have been able to detect a 1-2 km altitude gap between the peak emissions of Av6. An instrument design is presented which will directly measure the individual peak OH vibrational emission altitudes for the v' = 2, 3, 4, 6, 7, and 8 transitions radiating from the mesosphere. This high altitude resolution altitude profile information will enhance the ability to observe vertical propagation of atmospheric gravity waves …

Local Adjustment Of The Background Error Correlation For Surface Analyses Over Complex Terrain, David T. Myrick, John D. Horel, Steven M. Lazarus

Aeronautics Faculty Publications

The terrain between grid points is used to modify locally the background error correlation matrix in an objective analysis system. This modification helps to reduce the influence across mountain barriers of corrections to the background field that are derived from surface observations. This change to the background error correlation matrix is tested using an analytic case of surface temperature that encapsulates the significant features of nocturnal radiation inversions in mountain basins, which can be difficult to analyze because of locally sharp gradients in temperature. Bratseth successive corrections, optimal interpolation, and three-dimensional variational approaches are shown to yield exactly the same …