scholarly journals VIRGINIA BEACH SAND SIZE AS BASIS FOR DESIGN OF ON-SHORE DREDGED MATERIAL DISPOSA

1986 ◽  
Vol 1 (20) ◽  
pp. 84
Author(s):  
Cyril Galvin ◽  
James W. Holton ◽  
Ronald G. Vann
Keyword(s):  
Atlantic Ocean ◽  
Shoreline Change ◽  
Beach Sand ◽  
Dredged Material ◽  
Virginia Beach ◽  
Median Diameter ◽  
Northern Segment ◽  
Ocean Shore ◽  
Sand Size

Analyses of sand samples collected along and across the Atlantic Ocean shore of Virginia Beach, Virginia, suggest that sand placed on the shore should have a minimum median diameter of 0.20 mm to efficiently benefit the beach. Size analyses and shoreline change data show that the existing long-term beach replenishment by mechanical bypassing across Rudee Inlet and by truck-hauled sand from land sources is effective and necessary to maintain the shore along the commercial segment of Virginia Beach. The data also indicate that the northern segment of Virginia Beach shore, occupying more than half the distance between Rudee Inlet and Fort Story, is gaining sand. About two million cubic meters of sand to be dredged from the Atlantic Ocean Channel offshore of Virginia Beach will be suitable for placement on the beach.

scholarly journals FIELD INVESTIGATION OF SEDIMENT TRANSPORT PATTERN IN A CLOSED SYSTEM

1976 ◽  
Vol 1 (15) ◽  
pp. 72
Author(s):  
Tsuguo Sunamura ◽  
Kiyoshi Horikawa
Keyword(s):  
Sediment Transport ◽  
Closed System ◽  
Shoreline Change ◽  
Field Investigation ◽  
Depositional Environments ◽  
Aerial Photographs ◽  
Beach Sand ◽  
Sieve Analysis ◽  
Alongshore Sediment Transport

In order to elucidate the transport pattern of sediment in a closed system, a pocket beach was chosen and investigated from various aspects. This investigation included the following studies: (1) bathymetric survey by an echo sounder, (2) survey of submarine geology using an acoustic probe, (3) observation of nearshore current systems using floats, (4) documentation of the transport pattern of suspended sediment by aerial photographs, (5) examination of depositional environments of bottom and beach material by sieve analysis, (6) inference of long-term alongshore sediment transport pattern from the grain size properties of beach sand, and measurement of short-term trends by use of fluorescent sand, and (7) examination of long-term shoreline change using old and recent maps.

scholarly journals Fate of the Arterial Origin of Major Aortopulmonary Collateral Arteries After Unifocalization

2021 ◽  
Vol 12 (2) ◽  
pp. 230-233
Author(s):  
P.C. van de Woestijne ◽  
J.A.A.E. Cuypers ◽  
W.A. Helbing ◽  
A.J.J.C. Bogers
Keyword(s):  
Pulmonary Atresia ◽  
Descending Aorta ◽  
Major Aortopulmonary Collateral Arteries ◽  
Collateral Arteries ◽  
Collateral Artery ◽  
Median Diameter ◽  
Aortopulmonary Collateral ◽  
Median Interval

Background: During unifocalization procedures for pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries, collateral arteries are either ligated or detached. Not much is known of the fate of the remaining arterial origins in the long term. Available computed tomography (CT) or magnetic resonance (MR) imaging of the intrathoracic arteries was examined to investigate possible abnormalities at the former position of the collateral arteries as well as ascending aortic diameters. Methods: From 1989 to 2018, we performed 66 unifocalization procedures in 39 patients. One hundred and twenty-nine collateral arteries were ligated or detached. In 52% (15) of the surviving patients (with a total of 55 ligated or detached collaterals), sufficient imaging of the thoracic aorta from CT (11) and/or MR (9) was available for evaluation. Results: The median interval between unifocalization procedure and imaging was 15 years (interquartile range [IQR]: 9-19 years). In 93% (14) of the scanned patients, 18 blunt ends were detected at the location of a former collateral artery. No aneurysm formation of the descending aorta was observed. The median diameter of the ascending aorta was 35 mm (IQR: 31-40 mm). During follow-up, no aortic dissection or rupture occurred. Conclusions: Aortic imaging late after unifocalization showed abnormalities in 93% of the scanned patients. Abnormalities consisted mostly of blunt ends of the former collateral artery. We recommend to include routine imaging of the aorta during late follow-up to detect eventual future abnormalities and monitor aortic diameters. Ascending aortic diameters showed slight dilatation with no clinical implications so far.

scholarly journals Storm Driven Migration of the Napatree Barrier, Rhode Island, USA

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 330
Author(s):  
Bryan A. Oakley
Keyword(s):  
Rhode Island ◽  
Shoreline Change ◽  
Aerial Photographs ◽  
Tropical Storms ◽  
Lower Intensity ◽  
Storm Activity ◽  
The Impact ◽  
Washover Fan

Napatree Point, an isolated barrier in southern Rhode Island, provides a case study of barrier spit migration via storm driven overwash and washover fan migration. Documented shoreline changes using historical surveys and vertical aerial photographs show that the barrier had little in the way of net change in position between 1883 and 1939, including the impact of the 1938 hurricane. The barrier retreated rapidly between 1945 and 1975, driven by both tropical and extra-tropical storms. The shoreline position has been largely static since 1975. The removal of the foredune during the 1938 hurricane facilitated landward shoreline migration in subsequent lower intensity storms. Dune recovery following the 1962 Ash Wednesday storm has been allowed due to limited overwash and barrier migration over the last several decades. Shoreline change rates during the period from 1945–1975 were more than double the rate of shoreline change between 1939 and 2014 and triple the rate between 1883 and 2014, exceeding the positional uncertainty of these shoreline pairs. The long-term shoreline change rates used to calculate coastal setbacks in Rhode Island likely underestimate the potential for rapid shoreline retreat over shorter time periods, particularly in a cluster of storm activity. While sea-level rise has increased since 1975, the barrier has not migrated, highlighting the importance of storms in barrier migration.

scholarly journals A 12-year long global record of optical depth of absorbing aerosols above the clouds derived from the OMI/OMACA algorithm

2018 ◽  
Vol 11 (10) ◽  
pp. 5837-5864 ◽  
Author(s):  
Hiren Jethva ◽  
Omar Torres ◽  
Changwoo Ahn
Keyword(s):  
Atlantic Ocean ◽  
Optical Depth ◽  
Frequency Of Occurrence ◽  
Cloud Optical Depth ◽  
Low Level ◽  
Aerosol Cloud ◽  
Aerosol Absorption ◽  
The World ◽  
Absorbing Aerosols

Abstract. Aerosol–cloud interaction continues to be one of the leading uncertain components of climate models, primarily due to the lack of adequate knowledge of the complex microphysical and radiative processes of the aerosol–cloud system. Situations when light-absorbing aerosols such as carbonaceous particles and windblown dust overlay low-level cloud decks are commonly found in several regions of the world. Contrary to the known cooling effects of these aerosols in cloud-free scenario over darker surfaces, an overlapping situation of the absorbing aerosols over the cloud can lead to a significant level of atmospheric absorption exerting a positive radiative forcing (warming) at the top of the atmosphere. We contribute to this topic by introducing a new global product of above-cloud aerosol optical depth (ACAOD) of absorbing aerosols retrieved from the near-UV observations made by the Ozone Monitoring Instrument (OMI) onboard NASA's Aura platform. Physically based on an unambiguous “color ratio” effect in the near-UV caused by the aerosol absorption above the cloud, the OMACA (OMI above-cloud aerosols) algorithm simultaneously retrieves the optical depths of aerosols and clouds under a prescribed state of the atmosphere. The OMACA algorithm shares many similarities with the two-channel cloud-free OMAERUV algorithm, including the use of AIRS carbon monoxide for aerosol type identification, CALIOP-based aerosol layer height dataset, and an OMI-based surface albedo database. We present the algorithm architecture, inversion procedure, retrieval quality flags, initial validation results, and results from a 12-year long OMI record (2005–2016) including global climatology of the frequency of occurrence, ACAOD, and aerosol-corrected cloud optical depth. A comparative analysis of the OMACA-retrieved ACAOD, collocated with equivalent accurate measurements from the HSRL-2 lidar for the ORACLES Phase I operation (August–September 2016), revealed a good agreement (R = 0.77, RMSE = 0.10). The long-term OMACA record reveals several important regions of the world, where the carbonaceous aerosols from the seasonal biomass burning and mineral dust originated over the continents are found to overlie low-level cloud decks with moderate (0.3 < ACAOD < 0.5, away from the sources) to higher levels of ACAOD (> 0.8 in the proximity to the sources), including the southeastern Atlantic Ocean, southern Indian Ocean, Southeast Asia, the tropical Atlantic Ocean off the coast of western Africa, and northern Arabian sea. No significant long-term trend in the frequency of occurrence of aerosols above the clouds and ACAOD is noticed when OMI observations that are free from the “row anomaly” throughout the operation are considered. If not accounted for, the effects of aerosol absorption above the clouds introduce low bias in the retrieval of cloud optical depth with a profound impact on increasing ACAOD and cloud brightness. The OMACA aerosol product from OMI presented in this paper offers a crucial missing piece of information from the aerosol loading above cloud that will help us to quantify the radiative effects of clouds when overlaid with aerosols and their resultant impact on cloud properties and climate.

scholarly journals Correction to “Modeling storms improves estimates of long-term shoreline change”

2010 ◽  
Vol 37 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
L. Neil Frazer ◽  
Tiffany R. Anderson ◽  
Charles H. Fletcher
Keyword(s):  
Shoreline Change

Post-Dorian shoreline change at Cape Hatteras National Seashore: 2019 report

2021 ◽  
Author(s):  
Lisa Baron
Keyword(s):  
High Tide ◽  
Monitoring Program ◽  
Shoreline Change ◽  
The United States ◽  
United States Geological Survey ◽  
Vital Signs Monitoring ◽  
Cape Hatteras ◽  
Cape Hatteras National Seashore ◽  
National Seashore

In 2018 and 2019 the Southeast Coast Network (SECN), with assistance from park staff, collected long-term shoreline monitoring data at Cape Hatteras National Seashore as part of the National Park Service (NPS) Vital Signs Monitoring Program. Monitoring was conducted following methods developed by the NPS Northeast Coastal and Barrier Network and consisted of mapping the high-tide swash line using a Global Positioning System unit in the spring of each year (Psuty et al. 2010). Shoreline change was calculated using the Digital Shoreline Analysis System (DSAS) developed by the United States Geological Survey (USGS; Himmelstoss et al. 2018). Following the same field methods used for monitoring long-term shoreline change, geospatial data were collected as part of the Hurricane Dorian (or Dorian) Incident Response from September 12–16, 2019. This report summarizes the post-Dorian data and the previous two shoreline data collection efforts (spring 2019 and fall 2018).

Creep behavior in Virginia Beach sand

2013 ◽  
Vol 50 (11) ◽  
pp. 1159-1178 ◽  
Author(s):  
Hamid Karimpour ◽  
Poul V. Lade
Keyword(s):  
Triaxial Compression ◽  
Initial Response ◽  
Grain Structure ◽  
Beach Sand ◽  
Static Fatigue ◽  
Compression Tests ◽  
Time Effects ◽  
Grain Crushing ◽  
Virginia Beach ◽  
Confining Pressures

Triaxial compression tests were performed on dense specimens of Virginia Beach sand at low and high confining pressures to study time effects that relate to grain crushing due to static fatigue or delayed fracture. Experiments to study effects of loading strain rate on subsequent creep showed negligible time effects and no grain crushing at low confining pressures, while tests at high confining pressures indicated increasing amounts of creep with increasing initial loading strain rates and with increasing deviator stress at creep. Investigation of effects of grain-size distribution indicated stiffer initial response and smaller amounts of creep for more uniformly graded soils at high confining pressures. The experimental results showed that structuration effects were not present in the dense Virginia Beach sand. A long-term creep test at high confining pressure indicated continuous creep with no indication of its termination. Sieve analyses following each triaxial test showed that grain crushing, as quantified by Hardin’s relative breakage factor, was proportional to energy input and amount of creep observed for each soil specimen. The creep is due to the time-dependent static fatigue by which the grains crush and cause rearrangement of the grain structure, and this is the reason behind the time effects in granular materials.

Sign in / Sign up

Export Citation Format

Share Document