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Articles 12931 - 12960 of 15698

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Twin Ice Cores From Greenland Reveal History Of Climate Change, More, R. Alley, Paul Andrew Mayewski, D. Peel, B. Stauffer May 1996

Twin Ice Cores From Greenland Reveal History Of Climate Change, More, R. Alley, Paul Andrew Mayewski, D. Peel, B. Stauffer

Earth Science Faculty Scholarship

Two projects conducted from 1989 to 1993 collected parallel ice cores—just 30 km apart— from the central part of the Greenland ice sheet. Each core is more than 3 km deep and extends back 110,000 years. In short, the ice cores tell a clear story: humans came of age agriculturally and industrially during the most stable climatic regime recorded in the cores. Change—large, rapid, and global—is more characteristic of the Earth's climate than is stasis.


Recent Climate Anomalies And Their Impact On Snow Chemistry At South Pole, 1987 - 1994, Jack E. Dibb, Sallie I. Whitlow May 1996

Recent Climate Anomalies And Their Impact On Snow Chemistry At South Pole, 1987 - 1994, Jack E. Dibb, Sallie I. Whitlow

Earth Sciences

Three 2-m deep snowpits sampled at South Pole in 1994 provide detailed (2-cm resolution) profiles of the concentrations of soluble ionic species for the period 1987 - 1994. The most prominent feature is a large concentration spike of SO4 = in snow deposited in 1992 reflecting fallout from the eruptions of Pinatubo and Hudson in 1991. Concentrations of MSA and values of the MSA/(non-sea-salt SO4 =) ratio are elevated for about three years centered on the prominent volcanic signal. These changes appear to be due to the extended 1991 - 1993 El Nino. The overlapping effects of the volcanic eruptions …


Identification Of Optimal Locations For Sampling Ground Water For Pesticides In The Mississippi Delta Region Of Eastern Arkansas, H. S. Lin, H. D. Scott, J. M. Mckimmey May 1996

Identification Of Optimal Locations For Sampling Ground Water For Pesticides In The Mississippi Delta Region Of Eastern Arkansas, H. S. Lin, H. D. Scott, J. M. Mckimmey

Technical Reports

Concerns about the presence of pesticides in the Mississippi River Valley alluvial aquifer in the Arkansas Delta have generated the need to develop a map of ground water vulnerability for this region comprised of approximately 10 million acres. Based on the availability of digital data and the scale of this study. we used a modified Pesticide DRASTIC model in a GRASS GIS environment to identify areas that were physically more sensitive to pesticide contamination than other areas within the Delta. Spatial distribution of pesticide loading was estimated from pesticide application rates in different crops and crop distribution map interpreted from …


Trace Element Analysis Of Selected Springs In The Virgin River Basin, Mary A. Yelken May 1996

Trace Element Analysis Of Selected Springs In The Virgin River Basin, Mary A. Yelken

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spring water from 23 springs in and near the Virgin River Basin (southwestern Utah, northwestern Arizona, and southeastern Nevada) was collected and analyzed for chemical concentrations. Trace elements and major ion chemistry was used to determine the potential for utilizing water chemistry to provide information on spring water source and flow pathways. Principal Component Analysis (PCA), rare earth element (REE) normalization patterns, and mineral equilibrium modeling (PHREEQE) techniques were used to analyze the data set. Four major spring water groups were displayed by the PCA, based on similarities in water chemistry. The analyses suggest that spring water chemistry is a …


Our Common Future, American Style (Reviewing President’S Council On Sustainable Development, Sustainable America (1996)), John C. Dernbach Apr 1996

Our Common Future, American Style (Reviewing President’S Council On Sustainable Development, Sustainable America (1996)), John C. Dernbach

John C. Dernbach

No abstract provided.


Potential Atmospheric Impact Of The Toba Mega‐Eruption ∼71,000 Years Ago, G. A. Zielinski, Paul Andrew Mayewski, L. D. Meeker, S. Whitlow, M. S. Twickler, K. Taylor Apr 1996

Potential Atmospheric Impact Of The Toba Mega‐Eruption ∼71,000 Years Ago, G. A. Zielinski, Paul Andrew Mayewski, L. D. Meeker, S. Whitlow, M. S. Twickler, K. Taylor

Earth Science Faculty Scholarship

An ∼6‐year long period of volcanic sulfate recorded in the GISP2 ice core about 71,100 ± 5000 years ago may provide detailed information on the atmospheric and climatic impact of the Toba mega‐eruption. Deposition of these aerosols occur at the beginning of an ∼1000‐year long stadial event, but not immediately before the longer glacial period beginning ∼67,500 years ago. Total stratospheric loading estimates over this ∼6‐year period range from 2200 to 4400 Mt of H2SO4 aerosols. The range in values is given to compensate for uncertainties in aerosol transport. Magnitude and longevity of the atmospheric loading may …


Report Of Significant Findings--Las Vegas Bay/Boulder Basin Investigations, James F. Labounty, Michael Horn, Bureau Of Reclamation Apr 1996

Report Of Significant Findings--Las Vegas Bay/Boulder Basin Investigations, James F. Labounty, Michael Horn, Bureau Of Reclamation

Publications (WR)

Field sampling was carried out between 0830 and 1500 beginning at the confluence of Las Vegas Wash and the Inner Las Vegas Bay. Ten (10) locations were sampled, each in a similar manner. Locations of sampling stations are in line from the Wash-Bay confluence to a point midway between Saddle and Black Islands. In addition, sampling was done at a location midway between Sentinel Island and the base of Fortification Hill, and at the buoy line in front of Hoover Dam. Sampling stations are labeled from LV01, at Wash-Bay confluence, to LV17 at Hoover Dam. A significant data collection point …


A One-Dimensional Model For Storm Breaching Of Barrier Islands, Cheol Shik Shin Apr 1996

A One-Dimensional Model For Storm Breaching Of Barrier Islands, Cheol Shik Shin

Civil & Environmental Engineering Theses & Dissertations

A set of numerical models is developed for simulating the four stages of barrier breaching characterized by one horizontal spatial dimension.

The SBEACH model is employed for the first stage of dune/beach erosion. The Lax-Wendroff two-step explicit scheme for Stage II is developed to simulate initiation of ocean flood propagation on initially dry barrier islands and the method of characteristics (MOC), is employed to compute additional boundary data. The development of the Preissmann implicit scheme for water motion and a forward time centered space explicit scheme for sediment motion in Stages III and IV provide a tool to study the …


Recruitment Of Blue Crab, Callinectes Sapidus, Postlarvae To The Back-Barrier Lagoons Of Virginia's Eastern Shore, Robert D. Brumbaugh Apr 1996

Recruitment Of Blue Crab, Callinectes Sapidus, Postlarvae To The Back-Barrier Lagoons Of Virginia's Eastern Shore, Robert D. Brumbaugh

OES Theses and Dissertations

Most research on the early life history of the blue crab, Callinectes sapidus, has been conducted in large partially stratified estuaries such as the Chesapeake Bay. In contrast, little is known about the recruitment dynamics or habitat requirements of blue crab postlarvae (megalopae) in shallow well-mixed lagoonal systems that make up a considerable part of the species' range. In Virginia's coastal lagoons, planktonic blue crab megalopae are most abundant at night on flooding tides, and are not abundant during the daytime or on ebbing tides. This appears to enhance retention within the lagoons, despite the short residence time of water …


Seasonal And Mesoscale Variability In The Distribution Of Antarctic Krill, Euphausia Superba, West Of The Antarctic Peninsula, Cathy Meyer Lascara Apr 1996

Seasonal And Mesoscale Variability In The Distribution Of Antarctic Krill, Euphausia Superba, West Of The Antarctic Peninsula, Cathy Meyer Lascara

OES Theses and Dissertations

Observations collected between November 1991 and September 1993 during four multidisciplinary cruises were analyzed to provide a description of seasonal and mesoscale variability in the distribution and abundance of Antarctic krill, Euphausia superba, within continental shelf waters west of the Antarctic Peninsula and to investigate possible relationships between variability in krill distributions and variability in selected environmental parameters. Acoustic measurements of krill were made each season at designated locations to estimate the abundance of krill, in terms of vertically-integrated krill biomass and the number of aggregations, characterize the depth distribution of krill, and provide a quantitative description of the size, …


Observation Of Shelfwater Overrunning The Southern Slope Sea, Ajoy Kumar Apr 1996

Observation Of Shelfwater Overrunning The Southern Slope Sea, Ajoy Kumar

OES Theses and Dissertations

Analyses of two years (1992 and 1993) of high resolution (1.47 km2) sea surface temperature satellite images of the southern Mid-Atlantic Bight (MAB), showed that unusually extensive overhang of shelf water occurs episodically, and coherently over along shelf distances of several hundred kilometers. These episodes are dubbed overrunning of the Slope Sea by shelf water. The overrunning volume has a "face" and a "back" (southern and northern limit). It transports substantial quantities of shelf water southward, and does not retreat onto the shelf, but eventually joins the western edge of the Gulf Stream in the vicinity of Chesapeake …


The Effects Of Environmental Variability On The Population Structure Of The Eastern Oyster (Crassostrea Virginica): A Modeling Study, Margaret Mcmanus Dekshenieks Apr 1996

The Effects Of Environmental Variability On The Population Structure Of The Eastern Oyster (Crassostrea Virginica): A Modeling Study, Margaret Mcmanus Dekshenieks

OES Theses and Dissertations

Three models were coupled to investigate the effects of changes in environmental conditions on the population structure of the Eastern oyster, Crassostrea virginica. The first model, a time-dependent model of the oyster population as described in Powell et al. (1992) and Hofmann et al. (1992, 1995), tracks the distribution, development, spawning, and mortality of sessile oyster populations. The post-settlement model incorporates mortality through parasitism, predation, food depletion and extremes in environmental conditions. The post-settlement model supplies the initial abundance of larvae spawned into the water column, and in turn is the recipient of cohorts of spawn which survive through metamorphosis. …


An Introduction To Lake And Reservoir Water Quality Modeling, Kenneth H. Reckhow Mar 1996

An Introduction To Lake And Reservoir Water Quality Modeling, Kenneth H. Reckhow

Technical Reports

No abstract provided.


A Century Of Accumulation And Temperature Changes In Dronning Maud Land, Antarctica, Elisabeth Isaksson, Wibjörn Karlén, Niels Gundestrup, Paul Andrew Mayewski, Sallie Whitlow, Mark Twickler Mar 1996

A Century Of Accumulation And Temperature Changes In Dronning Maud Land, Antarctica, Elisabeth Isaksson, Wibjörn Karlén, Niels Gundestrup, Paul Andrew Mayewski, Sallie Whitlow, Mark Twickler

Earth Science Faculty Scholarship

A mass balance program was initiated in the Vestfjella-Heimefrontfjella area of western Dronning Maud Land during the austral summer of 1988–1989. As a part of this program, spatial and temporal variations in snow accumulation and temperature/stable isotopes are measured using shallow firn cores. In this paper we present surface accumulation data and discuss the climatic implications of the stable isotope records from two shallow firn cores. One 30-m-deep core, obtained about 200 km from the coast at 700 m asl (73°36′S, 12°26′W), covers the period 1932–1991. The other core was drilled at about 500 km from the coast at 2900 …


Effects Of Water Stress On Soybean Productivity In Central India, Ajay K. Srivastava, Diwakar Naidu, A. S. R. A. S. Sastri, J. S. Urkurkar, B. Das Gupta Feb 1996

Effects Of Water Stress On Soybean Productivity In Central India, Ajay K. Srivastava, Diwakar Naidu, A. S. R. A. S. Sastri, J. S. Urkurkar, B. Das Gupta

Drought Network News (1994-2001)

In the Chhattisgarh plains in the agroclimatic region of central India (Figure 1), farms may be characterized by one of the following: unbunded lathyritic soils, bunded rice fields (rainfed), bunded rice fields (irrigated), unbunded black soils, or rice bunds. Under these five farming situations, different crop sequences have been in vogue. New crops and crop sequences are recommended by the Agricultural University from time to time based on experimental results.

In the unbunded black soils, farmers usually plant small millets and pigeon pea. However, based on experimental results, the University has recommended soybean followed by chickpea crop sequence under rainfed …


Drought Preparedness And Management Training Seminar Conducted For West Africa Feb 1996

Drought Preparedness And Management Training Seminar Conducted For West Africa

Drought Network News (1994-2001)

All of the World Meteorological Organization (WMO) member countries of western Africa were represented at a seminar conducted in Banjul, The Gambia, 4–9 September 1995. The Training Seminar on Drought Preparedness and Management for Western Africa was conducted to improve awareness of drought and appropriate mitigation and preparedness technologies to reduce impacts. The seminar was organized by WMO and sponsored by WMO and the UN Sudano-Sahelian Office.


Asian Influence Over The Western North Pacific During The Fall Season: Inferences From Lead 210, Soluble Ionic Species And Ozone, Jack E. Dibb, R. Talbot, Anthony Klemm, G L. Gregory, H B. Singh, J D. Bradshaw, S T. Sandholm Jan 1996

Asian Influence Over The Western North Pacific During The Fall Season: Inferences From Lead 210, Soluble Ionic Species And Ozone, Jack E. Dibb, R. Talbot, Anthony Klemm, G L. Gregory, H B. Singh, J D. Bradshaw, S T. Sandholm

Earth Sciences

Aerosol samples collected over the western Pacific during the NASA/Global Tropospheric Experiment Pacific Exploratory Mission (PEM-West A) expedition (September–October 1991) revealed mean 210Pb concentrations in the free troposphere in the 5–10 fCi m−3 STP range. Most soluble ionic aerosol-associated species were near detection limits [≪40 parts per trillion by volume (pptv)] in these same samples. The altitude distribution of O3 near Asia closely resembled that of 210Pb, while no relationship was found between the concentrations of O3 and 7Be. Free tropospheric air over the western Pacific was depleted in soluble aerosol-associated species but enriched …


Chemical Characteristics Of Continental Outflow From Asia To The Troposphere Over The Western Pacific Ocean During September-October 1991: Results From Pem-West A, R. Talbot, Jack E. Dibb, K I. Klemm, J D. Bradshaw, S T. Sandholm, D R. Blake, G W. Sachse, J E. Collins Jr, B J. Heikes, G L. Gregory, B E. Anderson, H B. Singh, D C. Thornton, J T. Merrill Jan 1996

Chemical Characteristics Of Continental Outflow From Asia To The Troposphere Over The Western Pacific Ocean During September-October 1991: Results From Pem-West A, R. Talbot, Jack E. Dibb, K I. Klemm, J D. Bradshaw, S T. Sandholm, D R. Blake, G W. Sachse, J E. Collins Jr, B J. Heikes, G L. Gregory, B E. Anderson, H B. Singh, D C. Thornton, J T. Merrill

Earth Sciences

An important objective of the Pacific Exploratory Mission-West A (PEM-West A) was the chemical characterization of the outflow of tropospheric trace gases and aerosol particles from the Asian continent over the western Pacific Ocean. This paper summarizes the chemistry of this outflow during the period September – October 1991. The vertical distributions of CO, C2H6, and NOxshowed regions of outflow at altitudes below 2 km and from 8 to 12 km. Mixing ratios of CO were ≈130 parts per billion by volume (ppbv), ≈1000 parts per trillion by volume (pptv) for C2H …


1996 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 1996

1996 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


Effects Of Channel Geometry On Cross Sectional Variation In Along Channel Velocity In Partially Stratified Estuaries, Carl T. Friedrichs, John M. Hamrick Jan 1996

Effects Of Channel Geometry On Cross Sectional Variation In Along Channel Velocity In Partially Stratified Estuaries, Carl T. Friedrichs, John M. Hamrick

VIMS Books and Book Chapters

Analytic solutions for along‐channel velocity through an estuarine cross‐section with laterally varying depth are compared to observations from an array of current meters deployed over a nearly triangular cross‐section of the James River estuary. Analytic results suggest that the transverse structure of along‐channel velocity at this cross‐section is primarily due to simple density‐driven circulation modified by bathymetry. Comparisons of analytic solutions for the amplitude and phase of tidal velocity to observations suggest that linear models which include realistic lateral depth variation should also incorporate across‐channel variation in eddy viscosity. Solutions for various contributions to mean velocity are then derived which …


Atmospheric Sampling Of Supertyphoon Mireille With Nasa Dc-8 Aircraft On September 27,1991, During Pem-West A, G W. Sachse, R E. Newall, W Hu, Z X. Wu, H Akimoto, B E. Anderson, E V. Browell, G L. Gregory, G W. Sachse, M C. Shipman, A S. Bachmeier, A R. Bandy, D C. Thornton, D R. Blake, F Sherwood Rowland, J D. Bradshaw, J H. Crawford, D D. Davis, S T. Sandholm, W Brockett, L Degreef, D Lewis, D Mccormick, E Monitz, J E. Collins Jr, B J. Heikes, J T. Merrill, K K. Kelly, S C. Liu, Y Kondo, M Koike, C M. Liu, F Sakama, H B. Singh, Jack E. Dibb, R. Talbot Jan 1996

Atmospheric Sampling Of Supertyphoon Mireille With Nasa Dc-8 Aircraft On September 27,1991, During Pem-West A, G W. Sachse, R E. Newall, W Hu, Z X. Wu, H Akimoto, B E. Anderson, E V. Browell, G L. Gregory, G W. Sachse, M C. Shipman, A S. Bachmeier, A R. Bandy, D C. Thornton, D R. Blake, F Sherwood Rowland, J D. Bradshaw, J H. Crawford, D D. Davis, S T. Sandholm, W Brockett, L Degreef, D Lewis, D Mccormick, E Monitz, J E. Collins Jr, B J. Heikes, J T. Merrill, K K. Kelly, S C. Liu, Y Kondo, M Koike, C M. Liu, F Sakama, H B. Singh, Jack E. Dibb, R. Talbot

Earth Sciences

The DC-8 mission of September 27, 1991, was designed to sample air flowing into Typhoon Mireille in the boundary layer, air in the upper tropospheric eye region, and air emerging from the typhoon and ahead of the system, also in the upper troposphere. The objective was to find how a typhoon redistributes trace constituents in the West Pacific region and whether any such redistribution is important on the global scale. The boundary layer air (300 m), in a region to the SE of the eye, contained low mixing ratios of the tracer species O3, CO, C2H6, C2H2, C3H8, C6H6and CS2 …


An Interdisciplinary Water Quality Curriculum For Middle School Students, Barbara Michelle Cleveland Jan 1996

An Interdisciplinary Water Quality Curriculum For Middle School Students, Barbara Michelle Cleveland

All Graduate Projects

An interdisciplinary curriculum correlating water quality with the disciplines of physical science and mathematics for 6th grade middle school students was developed. Literature examined indicates that the opportunity to explore key concepts and significant issues using an integrated approach provided greater opportunity to formulate meaningful connections between disciplines studied and that achievement was enhanced. The Learning units were developed for use at Wilson Middle School in Yakima, Washington.


Circulation Near Submarine Canyons: A Modeling Study, John M. Klinck Jan 1996

Circulation Near Submarine Canyons: A Modeling Study, John M. Klinck

CCPO Publications

Circulation near a submarine canyon is analyzed with a numerical model. Previous theoretical work indicated that stratification controlled the interaction of coastal flow with canyons, specifically, the ratio of canyon width to the internal radius of deformation. A wide canyon was thought to merely steer the flow, while a narrow canyon would create substantial cross-shelf exchange. Four cases are analyzed considering two directions of alongshore flow and two choices of initial stratification. The weakly stratified case has an internal radius about equal to the canyon width, while the strongly stratified case has one about 3 times the canyon width. The …


Modeling The Vertical Distribution Of Oyster Larvae In Response To Environmental Conditions, Margaret M. Dekshenieks, Eileen E. Hofmann, John M. Klinck, Eric N. Powell Jan 1996

Modeling The Vertical Distribution Of Oyster Larvae In Response To Environmental Conditions, Margaret M. Dekshenieks, Eileen E. Hofmann, John M. Klinck, Eric N. Powell

CCPO Publications

A size-structured, time and vertically-dependent model was used to investigate the effects of water column structure on the distribution of larvae of the oyster Crassostrea virginica. Formulations used to model larval growth and behavior are based upon laboratory studies. Simulated vertical larval distributions obtained for conditions representative of a well-mixed, partially stratified and strongly stratified water column illustrate the effect that salinity and temperature gradients have on moderating larval swimming and hence on larvae vertical location. For well-mixed conditions, smaller larvae are dispersed throughout most of the water column. For strongly stratified conditions, the smaller-sized larvae cluster within the …


Circulation, Winter 1996, Center For Coastal Physical Oceanography, Old Dominion University Jan 1996

Circulation, Winter 1996, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Winter 1996 issue of CCPO Circulation featuring article "The Ocean Mesoscale"


Illinois River Water Quality Automatic Sampler Installation, David G. Parker, Rodney Williams, Evan Teague Jan 1996

Illinois River Water Quality Automatic Sampler Installation, David G. Parker, Rodney Williams, Evan Teague

Technical Reports

No abstract provided.


Completion Report: Arkansas State Pesticides In Ground Water Monitoring Project Phase V: Vulnerable Areas In Jackson, Monroe, Lawrence And Lonoke Counties, T. Nichols, P. Vendrell, K. Steele, H. D. Scott, C. Armstrong Jan 1996

Completion Report: Arkansas State Pesticides In Ground Water Monitoring Project Phase V: Vulnerable Areas In Jackson, Monroe, Lawrence And Lonoke Counties, T. Nichols, P. Vendrell, K. Steele, H. D. Scott, C. Armstrong

Technical Reports

In 1996, sixty-seven water samples were drawn from 65 wells, including 62 new wells and 3 wells sampled previously . One Woodruff County well and two Pulaski County wells were resampled. Thirty-two samples were drawn from 30 wells in Monroe County (well #1 was sampled 3 times during this phase) . Ten wells in Jackson County, 12 wells in Lawrence County and 10 wells in Lonoke were also tested (Figures 1-5) . With the completion of Phase V, the number of wells tested has risen to 231 with a total of 258 samples analyzed . Initially, the wells were tested …


1996 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 1996

1996 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


John U. Lloyd Beach State Recreation Area Nature Guide, Nsu Oceanographic Center Jan 1996

John U. Lloyd Beach State Recreation Area Nature Guide, Nsu Oceanographic Center

Technical Reports

John U. Lloyd State Park is a 251 acre recreation area located on Ocean Drive in Dania, Broward County, Florida. The park is adjacent to Port Everglades and has a beach front park spanning 2.5 miles. It preserves some of south Florida's vanishing natural resources, while at the same time offers the public usage of beach and water recreational activities. Surf fishing, picknicking, and canoeing along the tidal waterway New River Sound or Whiskey Creek are just some of the activities the public can enjoy.

The recreation area was named in memory of the late John U. Lloyd, Broward County's …


Sea Turtle Conservation Program, Broward County, Fl 1996 Report, Curtis M. Burney, William E. Margolis Jan 1996

Sea Turtle Conservation Program, Broward County, Fl 1996 Report, Curtis M. Burney, William E. Margolis

Marine & Environmental Sciences Faculty Reports

Since 1978, the Broward County Environmental Protection Department (BCEPD) has provided for the conservation of endangered and threatened sea turtle species within its area of responsibility. Broward County is within the normal nesting areas of three species of sea turtles: the loggerhead sea turtle (Caretta caretta), the green sea turtle (Chelonia mydas) and the leatherback sea turtle (Dermochelys coriacea). The loggerhead is listed as a threatened species, while the green and leatherback are listed as endangered under the U.S. Endangered Species Act, 1973, and Chapter 370, F.S.

Since these statutes strictly forbid any disturbance …