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Oceanography and Atmospheric Sciences and Meteorology

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1997

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Articles 61 - 90 of 132

Full-Text Articles in Physical Sciences and Mathematics

Beaver Lake Water Quality Enhancement Project Data Analysis, Thomas Soerens, Brian E. Haggard, David G. Parker Mar 1997

Beaver Lake Water Quality Enhancement Project Data Analysis, Thomas Soerens, Brian E. Haggard, David G. Parker

Technical Reports

No abstract provided.

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Wetland Loss In The Northern Gulf Of Mexico: Multiple Working Hypotheses, R. Eugene Turner Mar 1997

Wetland Loss In The Northern Gulf Of Mexico: Multiple Working Hypotheses, R. Eugene Turner

Faculty Publications

I examined four hypotheses about causes for the dramatically high coastal wetland losses (0.86% yr−1) in the northern Gulf of Mexico: an extensive dredged canal and spoil bank network, a decline in sediments in the Mississippi River during the 1950s, Mississippi River navigation and flood protection levees, and salinity changes. Natural factors contributing to these habitat changes include eustatic sea-level rise and geological compaction, which appear to have remained relatively constant this century, although variation does occur. These four hypotheses were tested using data on land-to-water changes in 15-min quadrangle maps inventoried for four intervals between the 1930s and 1990. …

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An Examination Of The Hanson Contrail Forecast Algorithm Under Low Relative Humidity Conditions, Robert P. Asbury Iii Mar 1997

An Examination Of The Hanson Contrail Forecast Algorithm Under Low Relative Humidity Conditions, Robert P. Asbury Iii

Theses and Dissertations

Accurate forecasts of contrail occurrence are essential to military aircrews. Although classical forecast methods have been reasonably successful predicting contrails, there is need for improvement at low ambient relative humidity. This thesis examines the performance of the Hanson method, which was developed to provide better contrail forecasts under drier atmospheric conditions. As a secondary objective, the forecast methods of Schumann and Hanson are compared to the algorithm currently in use by the Air Force Global Weather Central. Data used to validate the algorithms were collected at Wright-Patterson AFB, OH and Edwards AFB, CA. Theoretical contrail forecasts were made for each …

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An Atmospheric Sensitivity And Validation Study Of The Variable Terrain Radio Parabolic Equation Model (Vtrpe), Matthew K. Doggett Mar 1997

An Atmospheric Sensitivity And Validation Study Of The Variable Terrain Radio Parabolic Equation Model (Vtrpe), Matthew K. Doggett

Theses and Dissertations

The Variable Terrain Radio Parabolic Equation (VTRPE) computer model is a powerful and flexible program that provides calculations of the radar propagation conditions of the atmosphere. It is limited however, by the accuracy and resolution of the input data. This study quantifies the sensitivity of the VTRPE model to the accuracy and resolution of the atmospheric parameters that go into it. Also, two case studies are examined to test the utility of VTRPE in operational use. The sensitivity to measurements of pressure, temperature, and humidity was found to be dependent on the meteorological environment. In standard and subrefractive environments, average …

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Optimization Of The Velocity Azimuth Display (Vad) Algorithm's Adaptable Parameters In The Wsr-88d System, Donald R. Farris Mar 1997

Optimization Of The Velocity Azimuth Display (Vad) Algorithm's Adaptable Parameters In The Wsr-88d System, Donald R. Farris

Theses and Dissertations

Meteorologists have encountered problems with the Velocity Azimuth Display (VAD) algorithm in the Weather Surveillance Radar - 1988 Doppler (WSR-88D) System. Under certain meteorological conditions, forecasters have observed differences between the radar's wind profiles and wind profiles from rawinsonde upper-air soundings, or wind profilers. One of the main causes of this problem is inversions in the atmosphere which cause the radar beam to subrefract or superefract, causing the VAD winds to be inaccurately reported at a particular height. This thesis used the WSR-88D Algorithm Testing and Display System (WATADS) to compare VAD winds from recorded Level 2 NEXRAD data at …

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Validation Of The Air Force Global Weather Center Relocatable Window Model Total Cloud Forecast, Edward C. Harris Mar 1997

Validation Of The Air Force Global Weather Center Relocatable Window Model Total Cloud Forecast, Edward C. Harris

Theses and Dissertations

Air Force Global Weather Center's (AFGWC) Relocatable Window Model (RWM) total cloud forecasts were validated using data for selected days in May, June, and July, 1996. Forecasts were generated twice daily (00 UTC and 12 UTC) to determine the RWM's ability to accurately forecast total cloud cover during the late spring and early summer. The RWM forecasts were post-processed using the Slingo cloud forecast algorithm and compared against AFGWC's operational real time nephanalysis (RTNEPH) cloud analysis model. As a minimal-skill baseline comparison to the RWM's total cloud forecast, the RTNEPH initial analysis hour was persisted and evaluated against the same …

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Quantification Of Weather Effects On Imaging Laser Radar, Clifton D. Stargardt Mar 1997

Quantification Of Weather Effects On Imaging Laser Radar, Clifton D. Stargardt

Theses and Dissertations

The Air Force is investigating the use of imaging laser radar systems as autonomous guidance systems on future precision guided munitions. The Air Force's Wright Laboratory is currently testing a 1.06 micron wavelength laser radar (ladar) at Eglin Air Force Base. Since laser radiation can be susceptible to propagation problems through weather, quantitative understanding of these effects is important to the development of this weapon system. Ladar image degradation, in the form of target dropouts and false returns, was evaluated in various weather conditions. Statistical analysis of the images presented expected degrees of degradation according to visibility and rain fall …

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Moisture Sensitivity Of Contrail Forecast Algorithms, Allen C. Rabayda Mar 1997

Moisture Sensitivity Of Contrail Forecast Algorithms, Allen C. Rabayda

Theses and Dissertations

This thesis looked at using new relative humidity (RH) climatologies to improve the Air Force Global Weather Center's (AFGWC) contrail forecasts. To study the effect of the new RH climatolgies, the currently used empirical relative humidity (RH) profile is replaced with a more accurate climatological one, the Stratospheric And Gaseous Experiment II (SAGE II). The study begins by examining accuracy and bias of forecast contrail bases generated by the empirical and SAGE II RH profiles on 42 days. Both sets of forecast bases are shown to be statistically similar with a series of hypothesis tests. Additional RH profiles, from 0% …

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Effects Of Ghost Crab (Ocypode Quadrata) Invasion On Loggerhead Sea Turtle (Caretta Caretta) Nests At Hillsboro Beach, Florida, Terri S. Schmidt, Curtis M. Burney Mar 1997

Effects Of Ghost Crab (Ocypode Quadrata) Invasion On Loggerhead Sea Turtle (Caretta Caretta) Nests At Hillsboro Beach, Florida, Terri S. Schmidt, Curtis M. Burney

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

No abstract provided.

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A Validation Study Of The Ssm/I Temperature Algorithm And Comparison With The Cal/Val Land Surface Temperatures, Ronald L. Comoglio Mar 1997

A Validation Study Of The Ssm/I Temperature Algorithm And Comparison With The Cal/Val Land Surface Temperatures, Ronald L. Comoglio

Theses and Dissertations

The USAF operational cloud model, the Real-Time Nephanalysis (RTNEPH), requires infrared and visual scene scans as well as input from the Special Sensor Microwave Imager (SSM/I), featured on the Defense Meteorological Satellite Program (DMSP) polar orbiters. Additionally, SSM/I provides input to the Air Force Global Weather Center (AFGWC) surface temperature model (SFCTMP). The global surface temperatures are required for identifying which pixel of a scene is cloud and which is ground and as a first guess input to initialize NWP models. The SSM/I provides brightness temperatures sampled at four discrete: frequencies and dual polarizations to produce surface temperatures. Two algorithms …

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Development And Implementation Of An Isentropic Potential Vorticity Algorithm For Use At Air Force Global Weather Center, Jay B. Desjardins Jr. Mar 1997

Development And Implementation Of An Isentropic Potential Vorticity Algorithm For Use At Air Force Global Weather Center, Jay B. Desjardins Jr.

Theses and Dissertations

This thesis presents and validates methods for calculating isentropic potential vorticity (IPV) and applies these methods in software programs planned for implementation at the Air Force Global Weather Center (AFGWC). The IPV programs will provide Air Force Weather forecasters additional tools to diagnose atmospheric kinematics and understand atmospheric dynamics. A FORTRAN program is recommended using mandatory-level isobaric data projected to be available on AFGWC computer systems, specifically, from the Navy Operational Global Atmosphere Prediction System and Medium Range Forecast models. Program development and analysis consists of three main steps: (1) data retrieval; (2) IPV calculations; and, (3) interpolation to an …

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Adaption Of The Air Weather Service Fog Model To Forecast Radiation Fog Events In The Southeast United States, Andrew C. Goodnite Mar 1997

Adaption Of The Air Weather Service Fog Model To Forecast Radiation Fog Events In The Southeast United States, Andrew C. Goodnite

Theses and Dissertations

This research examined the performance of the Air Weather Service (AWS) Fog Model and the potential for using it in the Southeast United States for predicting fog. This task was accomplished in four separate steps. First, a correlation study was performed by comparing different weather elements in observations that met radiational cooling conditions to the observed visibility. This correlation study showed that the 22 UTC dewpoint depression was correlated (0.60) with early morning fog and no other weather elements that are commonly observed had significant correlation with early morning fog. Second, a verification study was conducted on the Saint Louis …

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Automatic Digital Processing For Calibration Data Of Open Skies Treaty Sensors, Donna D. Keating Mar 1997

Automatic Digital Processing For Calibration Data Of Open Skies Treaty Sensors, Donna D. Keating

Theses and Dissertations

The Open Skies Treaty provides guidelines allowing participants to fly in air space over other participants' countries to monitor strategic military placement and development. The treaty restricts the ground size of the smallest detail recorded by these aerial imaging systems to any size larger than 30 cm. This restriction is enforced by placing a lower limit on the altitude at which a participating aircraft can fly and it is computed as the value of Hmin. Current techniques rely on human photographic interpreters to select the value of Hmin for every calibration pass and is very resource intensive. The Open Skies …

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The Columbia Slough, Scott A. Wells Mar 1997

The Columbia Slough, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

This report was written in an attempt to provide the public and Bureau of Environmental Services Staff with a summary of work accomplished on the Columbia Slough system by Portland State University and other consultants working on the Slough over the last 6 years. An attempt was made to create an easy-to-read report with important overviews of the "big picture", glossary of definitions, index, and further details to assist in technology transfer.

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A 200-Year 210pb Record From Greenland, Jack E. Dibb, Henrick B. Clausen Feb 1997

A 200-Year 210pb Record From Greenland, Jack E. Dibb, Henrick B. Clausen

Earth Sciences

A continuous profile of 210Pb activity extending back to 1766 has been developed for a firn/ice core collected at Site D in central Greenland in 1984. Unexpectedly high activities of 210Pb were found at the base of this core (0.032 pCi kg−1 in samples more than 200 years old), calling into question the common assumption that supported 210Pb can be neglected when constructing chronologies in glacial snow and ice. It is problematic to assert that all of the 210Pb measured at depth should be attributed to the supported fraction, given previous estimates of dust loading …

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Announcements: February 1997 Feb 1997

Announcements: February 1997

Drought Network News (1994-2001)

Contents:

Local Authorities Confronting Disasters and Emergencies-Third International Conference

1997 National Conference on Delivering Health and Medical Services in Catastrophic Disasters

Book: Policy Making in an Era of Global Environmental Change

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Famine And Drought: The Question Of Food Security In Zimbabwe, Joshua Chigodora Feb 1997

Famine And Drought: The Question Of Food Security In Zimbabwe, Joshua Chigodora

Drought Network News (1994-2001)

From the time that the London Missionary Society first took Zimbabwean rainfall records at Hope Fountain in 1888, the worst droughts on record are the consecutive dry spells from 1911 to 1914, the 1946–47 drought, the 1960 drought, and the 1972–73 rainy season, which was the driest period of colonial Zimbabwe. The country also had serious food shortages in 1903, 1916, 1922, 1933, and 1942. Although the people of precolonial Zimbabwe experienced recurrent droughts, they generally had well-developed coping mechanisms that prevented high death tolls (Iliffe, 1990).

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Drought In The United States: 1996 Summary And Historical Perspective, William O. Brown, Richard R. Heim Jr. Feb 1997

Drought In The United States: 1996 Summary And Historical Perspective, William O. Brown, Richard R. Heim Jr.

Drought Network News (1994-2001)

Considerable variation in moisture conditions, on both a spatial and temporal basis, occurred in the contiguous United States during 1996. A tenth or more of the country experienced severe to extreme short-term (i.e., monthly) precipitation deficits during nearly half of the months (Figure 1), but in many months there were also large areas of excessive precipitation, which resulted in overall national conditions averaging near normal to wetter than normal (again, see Figure 1). From a national perspective, long-term drought peaked at mid-year (Figure 2), when severe drought plagued the South and Southwest.

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Climatic Uncertainties And Recent Experiences In Medium-Range Weather Forecasting Over Kashmir, Badrul Hasan, Rehana Habib Kanth Feb 1997

Climatic Uncertainties And Recent Experiences In Medium-Range Weather Forecasting Over Kashmir, Badrul Hasan, Rehana Habib Kanth

Drought Network News (1994-2001)

Successful crop management and production require a precise and thorough understanding of agroclimatic conditions of a region. A crop experiences a range of weather conditions during its vegetative and reproductive phases. Although the agronomic inputs at optimum levels decide satisfactory and stable crop yields, the range of weather and climatic optimum prevalent at important crop stages determine the ultimate yields. Thus, even with all inputs at our disposal, we cannot afford to ignore the environmental conditions experienced by the crop. Systematic and continuous measurements of weather elements provide basic data input for tuning any type of computer-based forecasting system. This …

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Changing Climatic Scenarios And Strategies For Drought Management In The Indian Arid Region, A. S. Rao, J. P. Gupta, A. S. Faroda Feb 1997

Changing Climatic Scenarios And Strategies For Drought Management In The Indian Arid Region, A. S. Rao, J. P. Gupta, A. S. Faroda

Drought Network News (1994-2001)

Western Rajasthan constitutes 62% of the 0.32 million km2 that make up the hot Indian arid region (Figure 1). The average annual rainfall of the area varies from less than 100 mm (coefficient of variation [CV] = 70%) in the western parts to just above 500 mm (CV = 40%) in the eastern parts of arid Rajasthan. During July and August, the eastern parts of the arid region have an assured crop growing period of 12–15 weeks, whereas the western parts mostly depend on the vagaries of the southwest monsoon. The annual potential evapotranspiration rates are 3–8 times higher …

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From The Director: February 1997, Donald A. Wilhite Feb 1997

From The Director: February 1997, Donald A. Wilhite

Drought Network News (1994-2001)

In the October issue of Drought Network News, I briefly discussed two policy initiatives that developed in response to the severe and widespread drought that affected the Southwest and southern Great Plains states in the United States during 1996. The first of these activities, a multistate workshop (and its subsequent report), was coordinated by the Federal Emergency Management Agency. This report was submitted to President Clinton in late August; it contained a series of recommendations that focused on short- and long-term issues. The second initiative, under the leadership of the Western Governors’ Association (WGA), was not available in final …

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Core-Log-Seismic Integration As A Framework For Determining The Basin-Wide Significance Of Regional Reflectors In The Eastern Equatorial Pacific, Stephen F. Bloomer, Larry A. Mayer Feb 1997

Core-Log-Seismic Integration As A Framework For Determining The Basin-Wide Significance Of Regional Reflectors In The Eastern Equatorial Pacific, Stephen F. Bloomer, Larry A. Mayer

Affiliate Scholarship

ODP Leg 138 in the eastern equatorial Pacific (EEP) provided a unique opportunity to understand the paleoceanographic significance of seismic reflectors in this climatically sensitive region. Carefully offset multiple cores were spliced into a complete stratigraphic section for the upper 250 m at each site and accurate, astronomically tuned time scales were generated from these composites. Well log data provided a means to correct composite depths to true depths as well as density and velocity data for the generation of synthetic seismograms. These synthetic seismograms were used to determine the paleoceanographic significance of regionally traceable reflectors by linking variations in …

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The Influence Of The Wastewater Drainage From The Las Vegas Valley On The Limnology Of Boulder Basin, Lake Mead, Nevada-Arizona, James F. Labounty, Michael J. Horn, Bureau Of Reclamation Jan 1997

The Influence Of The Wastewater Drainage From The Las Vegas Valley On The Limnology Of Boulder Basin, Lake Mead, Nevada-Arizona, James F. Labounty, Michael J. Horn, Bureau Of Reclamation

Publications (WR)

Lake Mead, Colorado River, Arizona-Nevada, is one of the most heavily used reservoirs in the western United States, providing abundant recreational opportunities as well as downstream domestic and agricultural water for over 22 million users. Based on average nutrient levels and productivity, Lake Mead is classified as mildly mesotrophic. The interflow of the Colorado River dominates the limnology of much of the 106 km-long reservoir, and may still be identified at Hoover Dam under certain conditions. The lower basin of Lake Mead ending at Hoover Dam is known as Boulder Basin and is near the Las Vegas metropolitan area. Las …

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Application Of A Flow-Through Absorption Tube For Remotely Estimating Water-Quality Parameters, Charles Bostater, Melissa Keller, Manuel Gimond Jan 1997

Application Of A Flow-Through Absorption Tube For Remotely Estimating Water-Quality Parameters, Charles Bostater, Melissa Keller, Manuel Gimond

Ocean Engineering and Marine Sciences Faculty Publications

A flow through absorption tube is described and applied. The tube is similar in concept to a 50 cm pathlength cylindrical cuvette described previously by Bostater and Gimond.' The new absorption tube allows for continuous, underway measurements of water absorption signatures. Water is allowed to flow through the tube, and in this way the spectral change or track ofabsorption can be measured as a function oftime or space when operated from a stationary or moving platform. Data gathered from various environments ranging from very turbid to clear water is analyzed and described. Concentrations of chlorophyll-a, suspended matter, and dissolved organic …

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1997 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 1997

1997 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

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Glaciochemical Studies At Siple Dome, West Antarctica, During The 1996–1997 Season, Karl J. Kreutz, Paul Andrew Mayewski, Mark S. Twickler, Sallie I. Whitlow, L. David Meeker Jan 1997

Glaciochemical Studies At Siple Dome, West Antarctica, During The 1996–1997 Season, Karl J. Kreutz, Paul Andrew Mayewski, Mark S. Twickler, Sallie I. Whitlow, L. David Meeker

Earth Science Faculty Scholarship

Deep ice cores collected from the interior of the west antarctic ice sheet and the interice stream ridges along the Siple Coast potentially contain long time-series records of Southern Hemisphere environmental change. One such location is Siple Dome, an approximately l20-kilometer (km) x 250-km ice dome located between ice streams C and D (figure 1). Because of promising results from reconnaissance glaciochemical (Mayewski, Twickler, and Whitlow 1995) and geophysical (Raymond et al. 1995) research, current U.S. deep ice-coring efforts are focused in the area. Drilling at Siple Dome is advantageous for several reasons, including the site's relatively simple geometry and …

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Spatial Analysis Of The Cause Of Mercury Contamination Of Fish In Arkansas - A Report Submitted To The Arkansas Mercury Task Force, H. S. Lin, H. D. Scott Jan 1997

Spatial Analysis Of The Cause Of Mercury Contamination Of Fish In Arkansas - A Report Submitted To The Arkansas Mercury Task Force, H. S. Lin, H. D. Scott

Technical Reports

There have been concerns about mercury (Hg) contamination in fish in Arkansas since the discovery of the problem in the Ouachita River in 1992 (Armstrong et aI., 1995). Of the more than 170 lakes and streams sampled by the Mercury Task Force from 1992 through 1994, 23% had fish with Hg concentrations exceeding the FDA Action Level of 1 ppm (Armstrong et aI., 1995). Cause of the fish Hg contamination, however, is unknown. Given the economic, human-health and environmental costs associated with fish Hg contamination, it is critical that the cause of this widely-spread problem be identified. Determination of the …

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Investigation Of The Statistical And Spatial Distributions Of Mercury Contaminated Fish, Surface Waters And Soils In Arkansas, H. D. Scott, J. M. Mckimmey Jan 1997

Investigation Of The Statistical And Spatial Distributions Of Mercury Contaminated Fish, Surface Waters And Soils In Arkansas, H. D. Scott, J. M. Mckimmey

Technical Reports

Mercury (Hg) contamination of fish is a widespread problem throughout much of the United States and the world (Louisiana WWW page, 1997). Levels ofHg in fish suffic1ent to exceed the FDA action level of 1 mg kg-1 have been found in many water bodies, including some in Arkansas and Louisiana. As a result of the serious public health ramifications for developing fetuses and for people that subsist on native fish, fish consumption advisories due to Hg contamination have been issued in 29 states. Contamination of surface water bodies by Hg results from deforestation, forest fires, fossil fuels, mining, natural emissions …

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1997 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 1997

1997 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

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Chesapeake Bay Hall Dedication, Virginia Institute Of Marine Science, School Of Marine Science, College Of William And Mary Jan 1997

Chesapeake Bay Hall Dedication, Virginia Institute Of Marine Science, School Of Marine Science, College Of William And Mary

Miscellaneous

Dedication: April 25, 1997. Invitation to dedication ceremony and program booklet. List of research laboratories provided.

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