scholarly journals FIELD INVESTIGATIONS IN THE TOW STUDY PROGRAMME FOR COASTAL SEDIMENT TRANSPORT IN THE NETHERLANDS

1984 ◽  
Vol 1 (19) ◽  
pp. 123 ◽  
Author(s):  
H. Derks ◽  
M.J.F. Stive
Keyword(s):  
Surf Zone ◽  
Weather Conditions ◽  
Measurement Systems ◽  
Field Investigations ◽  
Study Programme ◽  
Wave Heights ◽  
Coastal Sediment Transport ◽  
Set Up ◽  
Offshore Wave

Field campaigns were conducted in 1981 and 1982/83 on the Dutch coast near Egmond. Measurements were made of surface elevations, water velocities and sediment concentrations in 3 to 8 surf zone locations and 2 to 5 offshore locations simultaneously. A total of 50 measurement series was obtained under a variety of weather conditions, resulting in offshore wave heights of 0.2 to 4.6 m. A description is given of the field set-up, the instruments and measurements, and the collected data. The quality of the various measurement systems and the data produced has been investigated extensively by intercomparison of instruments and devices in the field. The results are reported here.

scholarly journals A Model-Derived Empirical Formulation for Wave Run-Up on Naturally Sloping Beaches

2021 ◽  
Vol 9 (11) ◽  
pp. 1185
Author(s):  
Maarten van Ormondt ◽  
Dano Roelvink ◽  
Ap van Dongeren
Keyword(s):  
Surf Zone ◽  
Sandy Beaches ◽  
Wide Range ◽  
Wave Heights ◽  
Incident Wave Angle ◽  
Wave Angle ◽  
Run Up ◽  
Set Up ◽  
Offshore Wave ◽  
Infragravity Wave

A new set of empirical formulations has been derived to predict wave run-up at naturally sloping sandy beaches. They are obtained by fitting the results of hundreds of XBeach-NH+ model simulations. The simulations are carried out over a wide range of offshore wave conditions (wave heights ranging from 1 to 12 m and periods from 6 to 16 s), and surf zone (Dean parameters aD ranging from 0.05 to 0.30) and beach geometries (slopes ranging from 1:100 to 1:5). The empirical formulations provide estimates of wave set-up, incident and infragravity wave run-up, and total run-up R2%. Reduction coefficients are included to account for the effects of incident wave angle and directional spreading. The formulations have been validated against the Stockdon dataset and show better skill at predicting R2% run-up than the widely used Stockdon relationships. Unlike most existing run-up predictors, the relations presented here include the effect of the surf zone slope, which is shown to be an important parameter for predicting wave run-up. Additionally, this study shows a clear relationship between infragravity run-up and beach slope, unlike most existing predictors.

scholarly journals Wave heights and set-up in a surf zone

1984 ◽  
Vol 8 (4) ◽  
pp. 303-329 ◽  
Author(s):  
I.A. Svendsen
Keyword(s):  
Surf Zone ◽  
Wave Heights ◽  
Set Up

scholarly journals Preharvest calcium sprays were not always needed to improve quality of 'gala' apples in Brazil

2008 ◽  
Vol 30 (4) ◽  
pp. 892-896 ◽  
Author(s):  
Paulo Roberto Ernani ◽  
Jaques Dias ◽  
Cassandro Vidal Talamini do Amarante ◽  
Diorvânia Cardoso Ribeiro ◽  
Douglas Antonio Rogeri
Keyword(s):  
Titratable Acidity ◽  
Weather Conditions ◽  
Soluble Solids ◽  
Average Weight ◽  
Maturity Level ◽  
Physiological Disorder ◽  
Set Up ◽  
Leaf Composition ◽  
Pattern Index

Calcium sprays have normally improved both the quality and the storage life of apples throughout the world because Ca helps to prevent many fruit disorders and that taken up from the soil does not often reach the fruit in adequate amounts. Since the efficacy of Ca sprays varies according to soil, apple cultivar, and weather conditions, this study was carried out from 1998 to 2004, in the Southern of Brazil, in order to assess the effect of Ca sprays on the quality and storability of 'Gala' fruits. The experiment was set up in an orchard planted in 1988, on a density of 1234 trees/ha. Treatments consisted of 0, 4, 8, and 12 annual sprays of 0.5% CaCl2 regularly distributed 30 days after petal fall until one week before harvest. Fruits of the same size and maturity level were annually analyzed at harvest and after five months of conventional cold storage (-1ºC and 90-95% of RH). In five out of six seasons, fruits from all treatments were free of any physiological disorder, and Ca sprays had no effect on leaf composition and on any fruit attribute (soluble solids, titratable acidity, starch pattern index, flesh firmness, and concentrations of N, K, Ca and Mg). In the season of 2000/2001, however, when yield was 18 t ha-1 and fruits had an average weight of 175 g, the incidence of bitter pit plus lenticel blotch pit on stored fruits was 24% in the treatment with no calcium sprays and it decreased up to 2% in that with 12 sprays. Two seasons later, yield was also low (25 t ha-1) and fruits were large (168 g each), but they did not show any physiological disorder regardless of the number of Ca sprays. It seems that the incidence of Ca related disorders in 'Gala' apples grown on limed soils in Brazil with no excess of any nutrient only occurs on seasons with low crop yield, as a result of large fruits and a high leaf/fruit ratio, associated with some unknown environmental conditions.

A composite method for past events characterisation providing insights in past, present and future coastal flood hazards: Joining historical, statistical and modeling approaches

2020 ◽  
Author(s):  
Deborah Idier ◽  
Jeremy Rohmer ◽  
Rodrigo Pedreros ◽  
Sylvestre Le Roy ◽  
Jerome Lambert ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Meteorological Data ◽  
Critical Conditions ◽  
Flood Hazards ◽  
Flood Events ◽  
Coastal Flood ◽  
Set Up ◽  
Offshore Wave

<p>The characterisation of past coastal flood events is crucial for risk prevention. However, it is limited by the partial character of historical information on flood events and the lack or limited quality of past hydro-meteorological data. In addition coastal flood processes are complex, driven by many hydro-meteorological processes, making mechanisms and probability analysis challenging. These issues are tackled by joining historical, statistical and modelling approaches. We focus on a macrotidal site (Gâvres, France) subject to overtopping and investigate the 1900-2010 period. A continuous hydro-meteorological database is built and a damage event database is set up based on archives, newspapers, maps and aerial photographies. Using together historic information, hindcasts and hydrodynamic models, we identified 9 flood events, among which 5 significant flood events (4 with high confidence: 1924, 1978, 2001, 2008; 1 with a lower confidence: 1904). These flood events are driven by the combination of sea-level rise, tide, atmospheric surge, offshore wave conditions and local wind. The critical conditions leading to flood are further analysed, including the effect of coastal defences, showing that the present coastal defences would not have allowed to face the hydro-meteorological conditions of 09/02/1924 for instance, whose bi-variate return periods of exceedance Tr (still water level relative to the mean sea level and significant wave height) is larger than 1000 y. In addition, Tr is expected to significantly decrease with the sea-level rise, reaching values smaller than 1 y, for 8 of the 9 historical events, for a sea-level rise of 0.63 m, which is equal to the median amount of sea-level rise projected by the 5<sup>th</sup> Assessment Report of the IPCC in this region for RCP8.5 in 2100.</p>

Evaluating the Quality of Curing Applications on Concrete Pavements with Ground-Penetrating Radar

2021 ◽  
pp. 036119812199636
Author(s):  
Alireza Joshaghani ◽  
Dan G. Zollinger
Keyword(s):  
Ground Penetrating Radar ◽  
Weather Conditions ◽  
Concrete Pavement ◽  
Concrete Pavements ◽  
Dielectric Measurements ◽  
Field Investigations ◽  
Pavement Construction ◽  
Ground Penetrating ◽  
Curing Compound

The management of concrete pavement curing must take several factors into account, such as the type of curing compound, the rate of the curing application, the uniformity of the curing application, the timing of the application, and the ambient weather conditions. This paper aims to elucidate a new curing application protocol for new concrete pavement construction and introduce a technique to address curing viability. Data for the development of the protocol were obtained from field investigations involving a series of test sections associated with concrete paving projects in: Victoria, TX; Itasca, IL; and Jacksonville, FL. For this undertaking, ground-penetrating radar technology was used to evaluate the efficacy of curing in relation to repeatability and uniformity. Statistical analysis was used to validate the utility of using dielectric measurements to qualify the curing quality. The rate of decrease in the dielectric constant was the critical parameter for evaluating a curing practice. Also, based on the coefficient of variation of data collection, the repeatability of data was acceptable. Finally, as a new method for checking the uniformity of curing applications, percent within limits (PWL) was implemented. Based on the PWL results, the hand-spraying led to a higher degree of non-uniformity in the spraying patterns compared with the spraying machine.

scholarly journals Laser and LIDAR in a System for Visibility Distance Estimation in Fog Conditions

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6322
Author(s):  
Razvan-Catalin Miclea ◽  
Ciprian Dughir ◽  
Florin Alexa ◽  
Florin Sandru ◽  
Ioan Silea
Keyword(s):  
Automotive Industry ◽  
Autonomous Vehicles ◽  
Distance Estimation ◽  
Critical Factor ◽  
Weather Conditions ◽  
Autonomous Driving ◽  
Measurement Systems ◽  
Visibility Distance ◽  
Set Up ◽  
Bad Weather

Visibility is a critical factor for transportation, even if we refer to air, water, or ground transportation. The biggest trend in the automotive industry is autonomous driving, the number of autonomous vehicles will increase exponentially, prompting changes in the industry and user segment. Unfortunately, these vehicles still have some drawbacks and one, always in attention and topical, will be treated in this paper—visibility distance issue in bad weather conditions, particularly in fog. The way and the speed with which vehicles will determine objects, obstacles, pedestrians, or traffic signs, especially in bad visibility, will determine how the vehicle will behave. In this paper, a new experimental set up is featured, for analyzing the effect of the fog when the laser and LIDAR (Light Detection And Ranging) radiation are used in visibility distance estimation on public roads. While using our experimental set up, in the laboratory, the information offered by these measurement systems (laser and LIDAR) are evaluated and compared with results offered by human observers in the same fog conditions. The goal is to validate and unitarily apply the results regarding visibility distance, based on information arrives from different systems that are able to estimate this parameter (in foggy weather conditions). Finally, will be notifying the drivers in case of unexpected situations. It is a combination of stationary and of moving systems. The stationary system will be installed on highways or express roads in areas prone to fog, while the moving systems are, or can be, directly installed on the vehicles (autonomous but also non-autonomous).

scholarly journals WAVE SET-UP IN THE SURF ZONE

1978 ◽  
Vol 1 (16) ◽  
pp. 62
Author(s):  
Uwe A. Hansen
Keyword(s):  
Water Level ◽  
Dynamic Load ◽  
Static Load ◽  
Surf Zone ◽  
Wave Heights ◽  
Level Elevation ◽  
Set Up ◽  
Protective Structures ◽  
The Waves ◽  
Design Water Level

In designing coastal protective structures the knowledge of the static load due to the water level elevation is as important as that of the dynamic load due to the waves. The structure, designed at sandy coasts with well formed surf zones on the beach - these areas are the basis of this examination - has to stand against both, the superposition of the static and dynamic load, which are dependent on each other. Undoubtedly a rise in the design water level (a summation of different influences - see figure 1) will cause an increase in the wave heights and the reverse will happen, when the design water level decreases.

scholarly journals WAVE ATTENUATION AND SET-UP ON A BEACH

1984 ◽  
Vol 1 (19) ◽  
pp. 4 ◽  
Author(s):  
I.A. Svendsen
Keyword(s):  
Surf Zone ◽  
Wave Attenuation ◽  
Outer Region ◽  
Dimensional Model ◽  
Radiation Stress ◽  
Wave Heights ◽  
Actual Flow ◽  
Set Up ◽  
The Waves ◽  
Wave Properties

A theoretical two-dimensional model for wave heights and set-up in a surf zone is described and compared to measurements. The integral wave properties energy flux Ef, and radiation stress Sxx are determined from crude approximations of the actual flow in surf zone waves. Some physical aspects of the outer region are discussed and found to agree with our knowledge of the waves seawards and shorewards of this region.

scholarly journals SHORT WAVE BREAKING EFFECTS ON LOW FREQUENCY WAVES

2011 ◽  
Vol 1 (32) ◽  
pp. 20 ◽  
Author(s):  
Christopher Daly ◽  
Dano Roelvink ◽  
Ap Van Dongeren ◽  
Jaap Van Thiel de Vries ◽  
Robert McCall
Keyword(s):  
Wave Breaking ◽  
Surf Zone ◽  
Low Frequency ◽  
Breaking Waves ◽  
Short Wave ◽  
Frequency Wave ◽  
Wave Heights ◽  
Wave Groupiness ◽  
Set Up ◽  
Low Frequency Waves

The effect of short wave breaking on low frequency waves is investigated using two breaker formulations implemented in a time-dependent numerical model (XBeach): (1) an advective-deterministic approach (ADA) and (2) the probabilistic breaker formulation of Roelvink (1993). Previous research has shown that the ADA breaker model gives different results for the cross-shore pattern of the fraction of breaking waves, which is now shown to affect not only the short wave height but also the short wave groupiness. While RMS short wave heights are comparable to measurements using both breaker models, the ADA breaker model allows higher levels of short wave groupiness into the surf zone. It is shown that this acts as an additional forcing mechanism for low frequency waves in the shoaling and nearshore zone, which, in addition to greater levels of breaking, leads to higher values of wave set-up. These findings are dependent on the complexity of the local bathymetry. For a plane slope, the differences in the low frequency wave heights and set-up predicted by both breaker models are negligible. Where arbitrary breakpoints are present in the field of wave propagation, such as nearshore bars or reefs, the ADA model predicts higher localized set-up, indicative of greater flow over such features. Differences are even more pronounced when the incident wave regime is highly energetic.

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