scholarly journals Rip current evidence by hydrodynamic simulations, bathymetric surveys and UAV observation

2017 ◽  
Author(s):  
Guido Benassai ◽  
Pietro Aucelli ◽  
Giorgio Budillon ◽  
Massimo De Stefano ◽  
Diana Di Luccio ◽  
...  
Keyword(s):  
Grain Size ◽  
High Resolution ◽  
Numerical Simulations ◽  
Current System ◽  
Current Evidence ◽  
Rip Current ◽  
Rip Currents ◽  
Transport Pathways ◽  
Fine Sediments ◽  
Scientific Challenge

Abstract. The prediction of the formation, spacing and location of rip currents is a scientific challenge that can be achieved by means of different complementary methods. In this paper the analysis of numerical and experimental data, including UAV observation, allowed to detect the presence of rip currents and rip channels at the mouth of Sele river, in the Gulf of Salerno, southern Italy. The dataset used to analyze these phenomena consisted of two different bathymetric surveys, a detailed sediment 5 analysis and a set of high-resolution wave numerical simulations, completed with satellite and UAV observation. The grain size trend analysis and the numerical simulations allowed to identify the rip current system, forced by topographically constrained channels incised on the seabed, which were detected by high resolution bathymetric surveys. The study evidenced that on the coastal area of the Sele mouth grain-size trends are controlled by the contribution of fine sediments, which exhibit suspended transport pathways due to rip currents and longshore currents. The results obtained were confirmed by satellite and UAV 10 observations in different years.

scholarly journals Rip current evidence by hydrodynamic simulations, bathymetric surveys and UAV observation

2017 ◽  
Vol 17 (9) ◽  
pp. 1493-1503 ◽  
Author(s):  
Guido Benassai ◽  
Pietro Aucelli ◽  
Giorgio Budillon ◽  
Massimo De Stefano ◽  
Diana Di Luccio ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Southern Italy ◽  
Current Evidence ◽  
Rip Current ◽  
Rip Currents ◽  
Hydrodynamic Simulations ◽  
Aircraft Systems ◽  
Remotely Piloted Aircraft ◽  
Scientific Challenge ◽  
Grain Size Trend Analysis

Abstract. The prediction of the formation, spacing and location of rip currents is a scientific challenge that can be achieved by means of different complementary methods. In this paper the analysis of numerical and experimental data, including RPAS (remotely piloted aircraft systems) observations, allowed us to detect the presence of rip currents and rip channels at the mouth of Sele River, in the Gulf of Salerno, southern Italy. The dataset used to analyze these phenomena consisted of two different bathymetric surveys, a detailed sediment analysis and a set of high-resolution wave numerical simulations, completed with Google EarthTM images and RPAS observations. The grain size trend analysis and the numerical simulations allowed us to identify the rip current occurrence, forced by topographically constrained channels incised on the seabed, which were compared with observations.

scholarly journals Occurrence features of Rip current at Ha My (Dien Ban district) and Tam Thanh (Tam Ky city) beaches, Quang Nam province

2019 ◽  
Vol 19 (4A) ◽  
pp. 43-53
Author(s):  
Le Dinh Mau ◽  
Nguyen Van Tuan ◽  
Nguyen Chi Cong ◽  
Tran Van Binh ◽  
Pham Ba Trung ◽  
...  
Keyword(s):  
Wave Energy ◽  
Surf Zone ◽  
Transition Period ◽  
Current System ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Rip Current ◽  
Rip Currents ◽  
Open Sea ◽  
Study Results

Rip current is a relatively strong, narrow current flowing outward from the beach through the surf zone and presenting a hazard to swimmers. This paper presents some occurrence features of Rip current at main swimming beaches in Quang Nam province, Central Vietnam. Study results show that most of swimming beaches along Quang Nam province coast are directly opposed to open sea and strongly affected by swell. Therefore, Rip current system can occur at any time in the year with large dimension and intensity. During Northeast monsoon (November to March) beach morphology is considerably changed by strong wave action, thus the strongest rip current is formed. However, in this period careful swimmers can easily identify where that rip current occurs along the beach. During the transition period from Northeast monsoon to Southwest monsoon (April to May) wave energy is reduced, thus Rip current intensity is also decreased. During Southwest monsoon (June to August) wave energy is not strong and beach is accreted, therefore some Rip currents remain at reasonable morphology places along the beach. During the transition period from Southwest monsoon to Northeast monsoon (September to October) Rip current can occur at deep places along the beach with characteristics of narrow dimension, thus causing more danger to swimmer. Especially, dangerous rip current is caused by swell which comes from active region of tropical cyclone in open sea. In this period wave field in the nearshore region is not rough, thus most of swimmers are not cautious when swimming at dangerous rip current places.

scholarly journals Paleoenvironments from robust loess stratigraphy using high-resolution color and grain-size data of the last glacial Krems-Wachtberg record (NE Austria)

2020 ◽  
Vol 248 ◽  
pp. 106602
Author(s):  
Tobias Sprafke ◽  
Philipp Schulte ◽  
Simon Meyer-Heintze ◽  
Marc Händel ◽  
Thomas Einwögerer ◽  
...  
Keyword(s):  
Grain Size ◽  
High Resolution ◽  
Last Glacial ◽  
Size Data ◽  
The Last Glacial

scholarly journals High-Resolution Atmospheric Sensing of Multiple Atmospheric Variables Using the DataHawk Small Airborne Measurement System

2013 ◽  
Vol 30 (10) ◽  
pp. 2352-2366 ◽  
Author(s):  
Dale A. Lawrence ◽  
Ben B. Balsley
Keyword(s):  
High Resolution ◽  
Measurement System ◽  
Current System ◽  
Low Cost ◽  
Structure Constant ◽  
Turbulence Structure ◽  
Quality Of Data ◽  
Airborne Measurement ◽  
Atmospheric Measurement ◽  
Atmospheric Variables

Abstract The DataHawk small airborne measurement system provides in situ atmospheric measurement capabilities for documenting scales as small as 1 m and can access reasonably large volumes in and above the atmospheric boundary layer at low cost. The design of the DataHawk system is described, beginning with the atmospheric measurement requirements, and articulating five key challenges that any practical measurement system must overcome. The resulting characteristics of the airborne and ground support components of the DataHawk system are outlined, along with its deployment, operating, and recovery modes. Typical results are presented to illustrate the types and quality of data provided by the current system, as well as the need for more of these finescale measurements. Particular focus is given to the DataHawk's ability to make very-high-resolution measurements of a variety of atmospheric variables simultaneously, with emphasis given to the measurement of two important finescale turbulence parameters, (the temperature turbulence structure constant) and ɛ (the turbulent energy dissipation rate). Future sensing possibilities and limitations using this approach are also discussed.

Rip current rescues on unguarded beaches

Shore & Beach ◽  
2021 ◽  
pp. 41-45
Author(s):  
Aubrey Litzinger ◽  
Stephen Leatherman
Keyword(s):  
Young Person ◽  
Red Cross ◽  
Rip Current ◽  
Rip Currents ◽  
Water Ring ◽  
The U.S

Rip currents are the greatest danger at surf beaches. Professional lifeguards rescue tens of thousands of people every year at U.S. beaches, but only a small percentage of the nation’s beaches are guarded. Oftentimes it is a young person who is caught in a rip current, and a bystander will attempt a rescue without a flotation device. The U.S. Lifesaving Association strongly suggests that this kind of rescue should not be undertaken because too often the rescuer will drown. Some coastal towns such as Cocoa Beach in Florida are now posting ring buoys on their unguarded beaches with the warning to throw, but not to go into the water. Ring buoys of two different weights were tested for efficiency when thrown in terms of distance and accuracy. The participants threw the ring buoys two different ways: one way of their choosing (un-instructed) and second by Red Cross recommendation (instructed). The buoyancy was also tested for each buoy. While these flotation devices have some merit, they clearly have limitations.

scholarly journals Radial migration in barred galaxies

2012 ◽  
Vol 10 (H16) ◽  
pp. 355-355
Author(s):  
P. Di Matteo ◽  
M. Haywood ◽  
F. Combes ◽  
B. Semelin ◽  
C. Babusiaux ◽  
...  
Keyword(s):  
High Resolution ◽  
Numerical Simulations ◽  
Disk Galaxies ◽  
List Type ◽  
Stellar Content ◽  
Radial Migration ◽  
Barred Galaxies ◽  
Corotation Radius ◽  
Low Activity ◽  
Metallicity Distribution

AbstractIn this talk, I will present the result of high resolution numerical simulations of disk galaxies with various bulge/disk ratios evolving isolated, showing that: •Most of migration takes place when the bar strength is high and decreases in the phases of low activity (in agreement with the results by Brunetti et el. 2011, Minchev et al. 2011).•Most of the stars inside the corotation radius (CR) do not migrate in the outer regions, but stay confined in the inner disk, while stars outside CR can migrate either inwards or outwards, diffusing over the whole disk.•Migration is accompanied by significative azimuthal variations in the metallicity distribution, of the order of 0.1 dex for an initial gradient of ~-0.07 dex/kpc.•Boxy bulges are an example of stellar structures whose properties (stellar content, vertical metallicity, [α/Fe] and age gradients, ..) are affected by radial migration (see also Fig. 1).

scholarly journals DOC sources and DOC transport pathways in a small headwater catchment as revealed by carbon isotope fluctuation during storm events

2014 ◽  
Vol 11 (11) ◽  
pp. 3043-3056 ◽  
Author(s):  
T. Lambert ◽  
A.-C. Pierson-Wickmann ◽  
G. Gruau ◽  
A. Jaffrezic ◽  
P. Petitjean ◽  
...  
Keyword(s):  
High Resolution ◽  
High Flow ◽  
Published Data ◽  
Storm Events ◽  
Transport Pathways ◽  
Relative Contribution ◽  
Temporal And Spatial ◽  
High Flow Period ◽  
Doc Flux ◽  
Headwater Catchment

Abstract. Monitoring the isotopic composition (δ13CDOC) of dissolved organic carbon (DOC) during flood events can be helpful for locating DOC sources in catchments and quantifying their relative contribution to stream DOC flux. High-resolution (< hourly basis) δ13CDOC data were obtained during six successive storm events occurring during the high-flow period in a small headwater catchment in western France. Intra-storm δ13CDOC values exhibit a marked temporal variability, with some storms showing large variations (> 2 ‰), and others yielding a very restricted range of values (< 1 ‰). Comparison of these results with previously published data shows that the range of intra-storm δ13CDOC values closely reflects the temporal and spatial variation in δ13CDOC observed in the riparian soils of this catchment during the same period. Using δ13CDOC data in conjunction with hydrometric monitoring and an end-member mixing approach (EMMA), we show that (i) > 80% of the stream DOC flux flows through the most superficial soil horizons of the riparian domain and (ii) the riparian soil DOC flux is comprised of DOC coming ultimately from both riparian and upland domains. Based on its δ13C fingerprint, we find that the upland DOC contribution decreases from ca.~30% of the stream DOC flux at the beginning of the high-flow period to < 10% later in this period. Overall, upland domains contribute significantly to stream DOC export, but act as a size-limited reservoir, whereas soils in the wetland domains act as a near-infinite reservoir. Through this study, we show that δ13CDOC provides a powerful tool for tracing DOC sources and DOC transport mechanisms in headwater catchments, having a high-resolution assessment of temporal and spatial variability.

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