Oceanography and Atmospheric Sciences and Meteorology Commons^™

Modeling Environmental Effects On Msx Prevalence And Intensity In Eastern Oyster (Crassostrea Virginica) Populations, Michelle Christine Paraso

OES Theses and Dissertations

An oyster population model coupled with a model for Haplosporidium nelsoni, the causative agent of the oyster disease MSX, was used with salinity time-series constructed from Delaware River flow measurements to study environmentally-induced variations in the annual cycle of this disease. Simulations with this model were designed to investigate the effect of increased or decreased spring freshwater discharge, the timing of high freshwater runoff, the presence or absence of a fall or late spring phytoplankton bloom, and the occurrence of a warm winter on MSX prevalence and intensity in Delaware Bay oyster populations. Model simulations for the lower Bay site …

Full-Wave Modeling Of Small-Scale Gravity Waves Using Airborne Lidar And Observations Of The Hawaiian Airglow (Aloha-93) O(¹S) Images And Coincident Na Wind/Temperature Lidar Measurements, Michael P. Hickey Ph.D., Michael J. Taylor, Chester S. Gardner, Christian R. Gibbons

Publications

Measurements were made of mesospheric gravity waves in the OI (5577 Å) nightglow observed from Maui, Hawaii, during the Airborne Lidar and Observations of Hawaiian Airglow (ALOHA-93) campaign. Clear, monochromatic gravity waves were observed on several nights. By using a full-wave model that realistically includes the major physical processes in this region, we have simulated the propagation of four waves through the mesopause region and calculated the O(¹S) nightglow response to the waves. Mean winds derived from Na wind/temperature lidar observations were employed in the computations. Wave amplitudes were calculated based on the requirement that the observed and …

Sand Body Geometry Of The Wax Lake Outlet Delta Atchafalaya Bay, Louisiana, Susan Majersky Fitzgerald

LSU Historical Dissertations and Theses

Deltas forming in Atchafalaya Bay, L-ouisiana, are the result of delta switching by the Mississippi River. The larger Lower Atchafalaya River delta has been heavily manipulated by dredging for navigation, but the Wax Lake Outlet delta is largely undisturbed and an excellent example of a 'bayhead' delta. Combining stratigraphy, aerial photography and digital terrain model data sets, the developmental history of this delta is presented. The Wax Lake Outlet delta is comprised of a typical upward-coarsening sequence, although its prodelta unit is extremely limited. Its plan-view form is typical of deltas developing in low-energy, unstratified, shallow basins. Early developmental processes …

An Analytical Study Of Ozone Feedbacks On Kelvin And Rossby–Gravity Waves: Effects On The Qbo, Eugene Cordero, Terrence R. Nathan, Robert S. Echols

Faculty Publications, Meteorology and Climate Science

An equatorial beta-plane model of the middle atmosphere is used to analytically examine the effects of radiative cooling and ozone heating on the spatial and temporal evolution of the quasi-biennial oscillation (QBO). Under the assumption that the diabatic heating is weak and the background fields of wind, temperature, and ozone are slowly varying, a perturbation analysis yields expressions describing the vertical spatial modulation of Kelvin and Rossby–gravity waves in the presence of ozone. These expressions show that wave-induced changes in the diabatic heating arising from the advection of basic-state ozone reduce the local radiative damping rate by up to 15% …

Inventory And Characterization Of The Riparian Zone Of The Current And Jacks Fork Rivers, Jonathan Lyon, Cynthia L. Sagers

Arkansas Water Resources Center Technical Reports

The ecological, recreational, and economic value of the 134 mile (216 km) riparian corridor within the Ozark National Scenic Riverways (ONSR) is of great interest to land managers and conservationists. Recent interest in applying ecosystem management to forest systems has necessitated a fresh look at the tools and methods in use to assess existing patterns of plant community structure and diversity. The purpose and objective of the study described in this report was to initiate a series of vegetation studies that could be integrated with existing research and management infonnation on the riparian vegetation in the ONSR. Defining the compositional …

How To Reduce Drought Risk, Cody Knutson, Mike Hayes, Tom Phillips

National Drought Mitigation Center: Faculty Publications

This guide describes a practical step-by-step process for identifying actions that can be taken to reduce potential drought-related impacts before a drought occurs. Step 1 begins with making sure that the right people are brought together and supplied with adequate data to make informed and equitable decisions during the process. Steps 2 and 3 narrow the focus of the study by identifying high priority drought-related impacts that are relevant to the user’s location or activity. Step 4 demonstrates that in order to reduce the potential for the identified impacts to occur in the future, it is necessary to understand the …

Azimuth And Range Optimization Of The Velocity Azimuth Display (Vad) Algorithm In The Wsr-88d, David L. Craft

Theses and Dissertations

The Velocity Azimuth Display (VAD) algorithm occasionally produces inaccurate wind estimates for the VAD Wind Profile (VWP) product of the Weather Surveillance Radar 1988 Doppler (WSR-88D) System. Weather forecasters have observed differences between the radar's wind profiles and wind profiles produced by rawinsondes and vertical wind profilers, when radiation and subsidence inversions in the atmosphere caused the radar beam to super refract. This thesis sought to improve the operational use of the VWP product for the WSR-88D near Denver, CO, by finding the optimal VAD algorithm Azimuth and Range parameter settings to overcome data contamination by hills located at the …

Calibrated Probabilistic Quantitative Precipitation Forecasts Based On The Mrf Ensemble, Frederick Anthony Eckel

Theses and Dissertations

Probabilistic quantitative precipitation forecasts (PQPF) based on the medium range forecast (MRF) ensemble are currently in operational use below their full potential quality (i.e., accuracy and reliability). This unfulfilled potential is due to the MRF ensemble being adversely affected by systematic errors which arise from an imperfect model and less than ideal ensemble initial perturbations. This thesis sought to construct a calibration to account for these systematic errors and thus produce higher quality PQPF. Systematic errors were explored with the use of the verification rank histogram, which tracks the performance of the ensemble. The information in these histograms was then …

Evaluation Of Satellite Microwave Derived Surface Temperature Algorithms For The Period August 1996 To February 1997, Charles H. Harris

Theses and Dissertations

The Air Force Weather Agency (AFWA) has two operational algorithms that derive surface temperatures from microwave observations taken by the Special Sensor Microwave Imager (SSM/I) which rides aboard space platforms of the Defense Meteorological Satellite Program (DMSP). The algorithm called Temperature from Satellite Microwave Imager (TS) is used to analyze global cloud coverage. The second algorithm is fittingly called Calibration and Validation (CV), as it was the algorithm used to calibrate and validate the first SSM/I in 1987. Multiple linear regression defined the algorithms from empirically gathered brightness temperatures and simultaneous surface temperatures. The key questions were how much data …

Nowcasting Thunderstorms At Cape Canaveral, Florida, Using An Improved Neumann-Pfeffer Thunderstorm Index, Cindy L. Howell

Theses and Dissertations

The Neumann-Pfeffer Thunderstorm Index (NPTI) is used daily by the 45th Weather Squadron during the convective season to estimate the probability of afternoon thunderstorms. The current I , developed by Charles J. Neumann in the 1960s, i based on only 13 years of data taken over 30 years ago. The index was in desperate need of an upgrade. Following the multiple regression techniques outlined by Neumann, this thesis examines whether or not including additional data would improve the performance of the NPTI. After performing the multiple regressions and retuning the regression coefficients, both NPTs were validated using a 2-year independent …

A Comparison Of Advect Cloud Model And Fifth-Generation Mesoscale Model Total Fractional Cloud Forecasts, Brian D. Pukall

Theses and Dissertations

Total fractional cloudiness (FC) forecasts from the advect cloud (ADVCLD) model and total FC forecasts diagnosed from the relative humidity and total cloud condensate (snow, ice, rain water, and cloud water) fields from the fifth generation mesoscale model (MM5) were statistically and subjectively compared to determine which model produced the better total FC forecasts from August through November 1997 for a forecast window centered on Bosnia. The real time nephanalysis (RTNFPH) model was used to represent the true state of the atmosphere. ADVCLD and MM5 forecasts were also compared against a persistence forecast to provide a minimal skill baseline. The …

Analyzing Horizontal Distances Between Wsr-88d Thunderstorm Centroids And Cloud-To-Ground Lightning Strikes, Steve L. Renner

Theses and Dissertations

On April 29, 1996, lightning struck the airfield at Hurlburt Field, FL, killing one Airmen and injuring ten others. This cloud to ground lightning strike hit eight minutes after a lightning advisory was canceled. At the time of the strike, thunderstorms were observed 7 to 10 miles north and south of the airfield. The incident raised questions about Air Force Weather Agency's lightning criteria. Soon after the incident, a Lightning Safety Review Panel was assembled to determine the adequacy of lightning advisories. One of the questions posed to the panel was could an incident like Hurlburt happen again? The review …

Improving Cape Canaveral's Day-2 Thunderstorm Forecasting Using Meso-Eta Numerical Model Output, Christian S. Wohlwend

Theses and Dissertations

The 45th Weather Squadron (WS) is responsible for the protection of billions of dollars worth of Air Force and NASA equipment from weather hazards. They produce a seven day planning forecast as one tool to support the space launch community. Improving this forecast can potentially save millions of dollars of government funds. This research focuses on the feasibility of improving the day two thunderstorm forecast by applying Meso Eta numerical forecasts to the Neumann-Pfeffer Thunderstorm Index (NPTI). The NPTI is currently used by the 45th WS for same day thunderstorm probability forecasting utilizing the morning radiosonde as input. The perfect …

Regression Analysis Of Radar Measured Optical Turbulence With Synoptic Scale Meteorological Variables, Diana L. Hajek

Theses and Dissertations

A key issue to the USAF's Airborne Laser (ABL) program is the ability to accurately predict the level of optical turbulence that the ABL will encounter at its flight levels. The optical turbulence must be characterized so that the range and range variation of the ABL can be determined. Gravity wave spectra resulting from frontal or jet stream passage are presumed to cause layers of optical turbulence; however, exact relationships between optical turbulence and synoptic scale meteorological phenomena are unclear. This study assesses the statistical relationship between optical turbulence and synoptic scale variables through multiple linear regression. The optical turbulence …

Forecasting Wet Microbursts Associated With Summertime Airmass Thunderstorms Over The Southeastern United States, James B. Mackey

Theses and Dissertations

Microbursts are intense downbursts from thunderstorms that affect an area less than 4 km and have a lifespan less than 10 minutes. Wet microbursts are associated with heavy precipitation and are common in the eastern and southeastern part of the country. The greatest threat from microbursts is to low flying aircraft, where the rapid fluctuations in horizontal and vertical airflow create tremendous shear zones. Microbursts have been determined to be the causal factor behind at least three major aircraft accidents resulting in numerous fatalities. Due to the short lifespan of microbursts, they often strike without warning and pose a serious …

A Validation Study Of The Air Force Weather Agency (Afwa) Jetrax Contrail Forecast Algorithm, Jeffrey D. Shull

Theses and Dissertations

Accurate contrail forecasts allow pilots to avoid levels of the atmosphere which are conducive to contrail formation, reducing their likelihood of being visually detected by enemy forces. The primary objective of this thesis is to evaluate the performance of the JETRAX contrail forecast algorithm currently used by the Air Force Weather Agency to support military air operations. A total of 397 ground-based contrail observations were collected at Wright-Patterson Air Force Base on 27 different days. Observations were collected with the aid of air traffic control radar, which greatly facilitated the positive identification of overflying aircraft and provided necessary information such …

Air-Snow Exchange Of Hno3 And Noy At Summit, Greenland, Jack E. Dibb, R. Talbot, J W. Munger, Daniel J. Jacob, S M. Fan

Earth Sciences

Ice core records of NO₃⁻ deposition to polar glaciers could provide unrivaled information on past photochemical status and N cycling dynamics of the troposphere, if the ice core records could be inverted to yield concentrations of reactive N oxides in the atmosphere at past times. Limited previous investigations at Summit, Greenland, have suggested that this inversion may be difficult, since the levels of HNO₃ and aerosol-associated NO₃⁻ over the snow are very low in comparison with those of NO₃⁻ in the snow. In addition, it appears that some fraction of the NO_{3 …}

Spring Crops In Bulgaria Damaged By 1996 Summer Drought, Nikola Slavov, Vesselin Alexandrov

Drought Network News (1994–2001)

Studies suggest there is a decreasing trend in precipitation in both north and south Bulgaria because of precipitation deficiencies in the 1940s and since the 1970s. Bulgaria has experienced several summer drought episodes during the last century, most notably in the 1940s and 1980s. There has been a decreasing trend in precipitation during the potential crop-growing season since the end of the 1970s, and the number of 10-day dry spells during this season has increased since the beginning of the 1970s. In the course of the last 3 decades, there was a decreasing trend in precipitation during the non-growing season …

Announcements: February 1998

Drought Network News (1994–2001)

Contents:

Hazards and Sustainability: Contemporary Issues in Risk Management

Hazards–98: Seventh International Symposium on Natural and Man-made Hazards

Water: A Looming Crisis? International Conference on World Water Resources at the Beginning of the 21st Century

Disaster Forum ’98

National Conference on Lifesaving Intervention

New Book: Reaching the Unreached: Challenges for the 21st Century

Droughts In Poland, 1951-90, R. Farat, M. Kepinska - Kasprzak, P. Kowalczak, P. Mager

Drought Network News (1994–2001)

One of the negative features of Poland’s climate is the periodic occurrence of atmospheric droughts. The most frequent source of this phenomenon is the occurrence of long-term (sometimes lasting several weeks) rainless periods. The occurrence of these periods is connected with the persistence of a stationary east European high that joins with the Azores anticyclone via central Europe. In such situations, with the accompanying lack or insufficiency of atmospheric precipitation, a drought begins to develop gradually. First, a soil drought appears, followed by hydrologic drought. During a hydrologic drought, a decrease in the ground water flow into surface waters is …

India, Indonesia Experiencing Opposite Effects From 1997 El Niño, R. H. Kripalani, Ashwini Kulkarni

Drought Network News (1994–2001)

It is now well recognized that the El Niño/Southern Oscillation (ENSO) phenomenon is the single most important cause of year-to-year climatic variability. Several studies have documented that a majority of the warm extremes (El Niño events) cause below-normal rainfall over Indonesia, while cold extremes (La Niña events) cause above-normal rainfall over India.

During the current ongoing El Niño episode, temperature anomalies in the Niño 1+2, Niño 3, and Niño 3.4 regions have been the largest values observed in the last 50 years. The pattern of anomalous tropical convection with enhanced activity across the central and eastern equatorial Pacific and suppressed …

Planning For The Next Drought: A National Drought Mitigation Center Workshop Sponsored By The U.S. Bureau Of Reclamation And The National Governors’ Association

Drought Network News (1994–2001)

The drought that gripped the Southwest and southern Great Plains states in 1996 was the most recent reminder of the nation’s continuing and apparently increasing vulnerability to drought. Although drought is a common feature in the West, it is a normal part of the climate of each region of the United States: drought struck the Southeast in 1986; most of the country, especially the Midwest and Plains states, in 1988–89; the West from 1987 to 1992; and the Northeast in 1995. Experiences from each of these droughts reinforce the need for advance planning. Even though drought is a slow-onset disaster, …

Quarterly Report Provides Assessment Of Western Water Supply Indicators

Drought Network News (1994–2001)

A new quarterly report, Western Climate and Water Status, provides decision makers in the western United States with a comprehensive assessment of water supply indicators that can give early warning of emerging droughts. A product of the Western Drought Coordination Council, the report is an important new connection between scientists and policy makers.

From The Director: February 1998, Donald A. Wilhite

Drought Network News (1994–2001)

If it seems like considerable time has elapsed since you received the last issue of Drought Network News, it is not just your imagination. After much discussion, we decided not to publish the newsletter in October 1997. First, we had a limited number of submissions to include. Second, the task of editing the manuscript for a new drought book was an overwhelming task that was involving much of my time and that of my publications specialist, Deborah Wood. She is also responsible for Drought Network News. With more submissions and the near completion of the drought book, I …

China’S Drought Climate Monitoring System, Zhu Changhan, Zhang Qiang, Wu Hong

Drought Network News (1994–2001)

In China, about 50% of the country is in arid and semiarid regions. Drought is the most severe climate disaster to affect China, and it causes significant reductions in grain yields. The area affected annually by drought has been estimated at about 20 million ha, which accounts for 59% of the total area affected by disasters. When severe droughts occur, they can affect as much as 33 million ha.

To monitor the occurrence and development of droughts efficiently and provide information on the strength and range of droughts and floods, the China Drought–Flood Climate Monitoring System was developed by the …

Hydrology Of Two Interdunal Valleys In The Nebraska Sand Hills, Steve Drda

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

Two neighboring interdunal valleys are compared within a study area of about 15 square miles in the Nebraska Sand Hills. One is a subirrigated wet meadow drained by a manmade ditch. The other is topographically lower, but dry at the surface. The goal of this study is to identify the factors responsible for the hydrologic regime present in each valley, and to discern the reasons for the differences between the two valleys. Water levels in 39 piezometers positioned at different locations across both valleys, and at different depths were monitored for two-and-a-half years to determine groundwater flow paths, gradients, and …

Sea Turtle Conservation Program, Broward County, Fl 1998 Report, Curtis M. Burney, William E. Margolis

Marine & Environmental Sciences Faculty Reports

No abstract provided.

Inventory Of Sub-Catchments Within The Wilson Inlet Catchment, B Radys

Resource management technical reports

The release of the "Salinity Action Plan for Western Australia' in December 996 highlighted the need for catchment scale planning and coordinated actions to reverse salinity trends.

A separate report has been produced for each major catchment area. Each report contains and inventory of all sub-catchments. with information on area, degradation risks and group activities with each catchment.

Mud Creek Urban Nonpoint Source Demonstration, Paul Vendrell, K. Teague

Arkansas Water Resources Center Technical Reports

Northwest Arkansas is the seventh fastest developing area in the nation. The conversion of rolling pastureland into paved city streets, parking lots, and buildings within this rapidly urbanizing region is reducing infiltration and intensifying stormwater runoff. In the city of Fayetteville alone, the population increased from 42,099 to 58,163 between 1990 and 1999, moving the city across the population threshold which will require the Phase II Stormwater Permit process. Approximately half of Fayetteville is included in the Illinois River Watershed, which has been identified as the third highest priority watershed in need of restoration in the state of Arkansas. Mud …

Chapter 2 Climate, Donald A. Wilhite, Kenneth G. Hubbard

National Drought Mitigation Center: Faculty Publications

The broad climatic patterns of the Sand Hills region are also characteristic of the central Great Plains environment. The spatial and temporal patterns of these climatic variables have a significant effect on the natural resources of the region.