Physical Sciences and Mathematics Commons^™

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1997, R J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagey

Reports

No abstract provided.

Semiclassical Representation Of Width-Weighted Spectra, M. W. Beims, V. Kondratovich, John B. Delos

Arts & Sciences Articles

We consider a system having decaying states with complex energies Ej−iΓj/2, and we define the “width-weighted spectrum” as DΓ(E)=ΣjΓjδ(E−Ej). We derive a semiclassical formula for this width-weighted spectrum, a formula which is analogous to the periodic-orbit representation of the density of states. The formula applies if classical motion is regular and if decay occurs by tunneling through a barrier. The semiclassical formula involves not periodic orbits or closed orbits, but action integrals associated with irreducible loops on the “extremal torus,” on which the particle climbs up the barrier and hangs at the top. Calculations confirm the validity of the formula.

Laser In-Situ Scattering And Transmissometer (Lisst) Observations In Support Of The Sensor Insertion System Duck, Nc October, 1997, Grace M. Massey, Carl T. Friedrichs

Reports

The objective of this portion of the study was to collect LIS ST time series at times corresponding to collection of pumped samples of suspended sediment across the width of the surf zone during a major field experiment called SandyDuck '97. The pumped samples were analyzed for total percent sand (>60 micron), total percent mud (0.8 - 60 micron), organic content and sand size distribution. The LISST measures the particle size distribution from 5-500 microns. The purpose was to provide a high quality data set of pumped samples with which to later test the sensitivity of indirect measurements of …

Public Policy: Integrated Approaches To Environmental Policy, Karla S. Havens, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Extracting Classical Trajectories From Atomic Spectra, M. R. Haggerty, Neal Spellmeyer, Daniel Kleppner, John B. Delos

Arts & Sciences Articles

We describe how to reconstruct individual classical trajectories from spectroscopic data. The ac dipole moment of a trajectory can be found from the effect of an oscillating field on the spectrum. The inverse Fourier transform of such data yields the component of the electron trajectory along the direction of the oscillating field. We demonstrate the method by experimentally extracting z(t) for two electron trajectories that influence the Stark spectrum of Rydberg lithium. Within the experimental resolution, the reconstructed orbits agree well with classical predictions.

Postimpact Deformation Associated With The Late Eocene Chesapeake Bay Impact Structure In Southeastern Virginia, Gerald H. Johnson, Sarah E. Kruse, Allison W. Vaughn, John K. Lucey, C. Hobbs, David S. Powars

VIMS Articles

Upper Cenozoic strata covering the Chesapeake Bay impact structure in southeastern Virginia record intermittent differential movement around its buried rim. Miocene strata in a graben detected by seismic surveys on the York River exhibit variable thickness and are deformed above the crater rim. Fan-like interformational and intraformational angular unconformities within Pliocene–Pleistocene strata, which strike parallel to the crater rim and dip2°–3° away from the crater center, indicate that deformation and deposition were synchronous.Concentric, large-scale crossbedded, bioclastic sand bodies of Pliocene age within ~20 km of the buried crater rim formed on offshore shoals, presumably as subsiding listric slump blocks rotated …

Scaled-Energy Floquet Spectroscopy In A Strong Electric Field: A Semiquantal Calculation Of The Recurrence Spectrum, V. Kondratovich, John B. Delos

Arts & Sciences Articles

We consider a hydrogen atom in a strong static electric field with a weak parallel radio-frequency (rf) field. We compute the photoabsorption spectrum by calculating the spectrum of Floquet states, including their quasienergies and their oscillator strengths. Our calculation is based upon “semiquantal” formulas: we calculate the discrete spectrum of quasienergy states by using a quantum adiabatic approximation combined with semiclassical (Bohr-Sommerfeld) quantization rules. We express this spectrum in a manner consistent with the method of scaled-variable spectroscopy, and then calculate the Fourier transform. These calculated absorption spectra and recurrence spectra are in good agreement with experiments on Li atoms. …

Semiclassical Formula For Oscillator Strengths Of Atomic Spectra In External Fields, V. Kondratovich, John B. Delos

Arts & Sciences Articles

In a previous Rapid Communication [Phys. Rev. A 56, R5 (1997)] we reported a semiclassical formula describing oscillator strengths for transitions to a high Rydberg state of a hydrogen atom in an electric field. The formula relates the oscillator strength for an atomic transition into a Rydberg state to the angular distribution of outgoing electron waves and to the density of classical tori. Here we give a derivation of that formula and we suggest some generalizations. We compare the formula with experimental measurements of the absorption spectrum of hydrogen in an electric field. This absorption spectrum consists of quasidiscrete resonances …

Status Of The Major Oyster Diseases In Virginia 1997 A Summary Of The Annual Monitoring Program, Lisa M. Ragone Calvo, Eugene M. Burreson

Reports

No abstract provided.

1998 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

1998 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

1998 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Temporal Variability In Dissolved Organic Carbon And Radiocarbon In The Eastern North Pacific Ocean, James E. Bauer

VIMS Articles

The factors regulating the steady state inventories and residence times of dissolved organic carbon (DOG) in the deep ocean are not well established. Previous studies of DOC have been limited to single time-point profiles that provide general information on the potential role of vertical advective-diffusive processes in controlling DOC distributions and mean apparent ages. We present results from a 2-year time series station in the eastern North Pacific (station M) where short-term (months) changes in inventories and Delta(14)C signatures of DOC as measured in deep profiles were examined in conjunction with changes in particulate organic carbon (POC) pools. Significant long-term …

Virginia Game Fish Tagging Program Annual Report 1997, C.M. Bain Iii, John A. Lucy, M. D. Arendt

Reports

The Virginia Game Fish Tagging Program (VGFI'P), a cooperative project of the Virginia Marine Resources Commission and the Virginia Institute of Marine Science (VIMS), set records for participation, fish tagged, and fish recaptured during its third year of operation.

In-Situ Impact Of Natural Sunlight And Tidal Action On The Composition And Toxicity Of Sediment-Associated Organic Pollutants, Robert Hale

Reports

Organic pollutants pose a haz.ard to living resources of the Chesapeake Bay and elsewhere. P AHs and other compounds present in creosote are major contaminants of concern. Polychlorinated terphenyls (PCTs), PCB-like compounds, have also been detected in high concentrations in sediments from several areas. Fates of these toxic compounds in-situ are poorly understood. In this study the impacts of physical processes operating in a tidal creek on the fate of creosote constituents (i.e. P AHs and heterocyclics) and PCTs were examined. Two representative sediments ( a coarse/low organic carbon (LOC) and a fine, high organic carbon (HOC)) were fortified with …

Remote Characterization Of Wetland Vegetation And Corresponding Relationship To Soils : Final Report On The Evaluation Of Imagery-Derived Terrain Attributes In The Coastal Zone, John E. Anderson, James E. Perry, Jill Meyer

Reports

To accomplish the goals of this study, a pristine coastal barrier island environment was selected that was free from influences of urban development. This provided the optimal situation that could be expected to be encountered by military strategists and base resource managers. The site selected was Parramore Island (Figure I). Parramore Island is the seventh island ( north to south) located on the seaward margin of the southeastern Delmarva Peninsula and is one of the most dynamic and least disturbed coastal landscapes remaining in North America (McCaffrey and Dueser, 1990). The island is centered at Latitude 37° 30' and Longitude …

Chincoteague Bay, Virginia, Effectiveness Of The Sav Sanctuary And Revegetation Of Sav Habitat Disturbed By Clam Dredging - Report To The Virginia Marine Resources Commission, Robert J. Orth, Ken Moore, David J. Wilcox, James R. Fishman

Reports

No abstract provided.

Data Report: Pump Sampling And Sediment Analysis In Support Of The Sensor Insertion System Duck, N.C. April And October, 1997, Grace M. Massey, Carl T. Friiedrichs, Amo De Kruif, Daan C. Rijks

Reports

The objectives of this study were to (i) construct a pumping system, (ii) operate the system and collect samples of suspended sediment across the width of the surf zone during two major field experiments planned for the SIS in 1997, and (iii) analyze the resulting samples for sand concentration, sand size distribution, total percent sand, total percent mud, and organic content. The purpose was to provide a high quality data set of pump samples with which to later test the sensitivity of indirect measurements of suspended sand concentration to the presence of suspended mud. The response of OBSs is known …

Environmental Studies Relative To Potential Sand Mining In The Vicinity Of The City Of Virginia Beach, Virginia, Carl H. Hobbs Iii

Reports

Part 1: Benthic Habitats and Biological Resources Off the Virginia Coast 1996 and 1997 / G. R. Cutter, Jr. and R. J. Diaz

Part 2: Preliminary Shoreline Adjustments to Dam Neck Beach Nourishment Project Southeast Virginia Coast / C. S. Hardaway, Jr., D. A. Milligan, G. R. Thomas, and C. H. Hobbs, III

Part 3: Nearshore Waves and Currents Observations and Modeling / J. D. Boon

Part 4: Coastal Currents A. Valle-Levinson

Part 5: Benthic Foraminifera and Ostracoda from Virginia Continental Shelf / T. M. Cronin, S. Ishman, R. Wagner, and G. R. Cutter, Jr