scholarly journals Description of a coastal impact event in Basque Country: the 9 February 2016 case

2018 ◽  
Vol 15 ◽  
pp. 137-143
Author(s):  
Santiago Gaztelumendi ◽  
Joseba Egaña ◽  
Pedro Liria ◽  
José A. Aranda
Keyword(s):  
Basque Country ◽  
High Tide ◽  
Warning System ◽  
Impact Event ◽  
Wave Impact ◽  
Peak Period ◽  
Wave Characteristics ◽  
Westerly Winds ◽  
Points Of View ◽  
Basque Coast

Abstract. In this work we analysed a case from 9 February 2016 from two points of view, the meteorological–ocean characteristics of the event and the damage produced during the episode in the Basque coastal area. On 7 and 8 February 2016 an intense zonal circulation was established in the Atlantic, with very strong westerly winds (over 100 km h−1) and high fetch (more than 2000 km). As a consequence a strong swell (over 7 m) arrived on the Basque coast affecting littoral areas. The wave characteristics are particularly energetic during the morning of the 9 February, which had a significant wave of 9.5 m and a peak period of 20 s in deep water (Donostia buoy). The arrival of these energetic waves coincides with high tide during spring when the sea level reaches 4.69 m in the Port of Bilbao. Overtopping indexes exceeded red-level thresholds established within the Euskalmet coastal warning system and the wave impact resulted in relevant damage (more than EUR 3 million) in different littoral areas. This event is the first red-level case since the new Euskalmet warning procedure became operational at the beginning of 2015.

scholarly journals An early warning system for wave-driven coastal flooding at Imperial Beach, CA

2021 ◽  
Author(s):  
Mark A. Merrifield ◽  
Mele Johnson ◽  
R. T. Guza ◽  
Julia W. Fiedler ◽  
Adam P. Young ◽  
...  
Keyword(s):  
Water Level ◽  
Sea Level ◽  
Incident Wave ◽  
High Tide ◽  
Warning System ◽  
Model Errors ◽  
Wave Runup ◽  
Peak Period ◽  
Beach Morphology ◽  
Wave Forecast

AbstractWaves overtop berms and seawalls along the shoreline of Imperial Beach (IB), CA when energetic winter swell and high tide coincide. These intermittent, few-hour long events flood low-lying areas and pose a growing inundation risk as sea levels rise. To support city flood response and management, an IB flood warning system was developed. Total water level (TWL) forecasts combine predictions of tides and sea-level anomalies with wave runup estimates based on incident wave forecasts and the nonlinear wave model SWASH. In contrast to widely used empirical runup formulas that rely on significant wave height and peak period, and use only a foreshore slope for bathymetry, the SWASH model incorporates spectral incident wave forcing and uses the cross-shore depth profile. TWL forecasts using a SWASH emulator demonstrate skill several days in advance. Observations set TWL thresholds for minor and moderate flooding. The specific wave and water level conditions that lead to flooding, and key contributors to TWL uncertainty, are identified. TWL forecast skill is reduced by errors in the incident wave forecast and the one-dimensional runup model, and lack of information of variable beach morphology (e.g., protective sand berms can erode during storms). Model errors are largest for the most extreme events. Without mitigation, projected sea-level rise will substantially increase the duration and severity of street flooding. Application of the warning system approach to other locations requires incident wave hindcasts and forecasts, numerical simulation of the runup associated with local storms and beach morphology, and model calibration with flood observations.

scholarly journals The new Euskalmet coastal–maritime warning system

2016 ◽  
Vol 13 ◽  
pp. 91-96 ◽  
Author(s):  
Santiago Gaztelumendi ◽  
Joseba Egaña ◽  
Pedro Liria ◽  
Manuel Gonzalez ◽  
José Antonio Aranda ◽  
...  
Keyword(s):  
Basque Country ◽  
Warning System ◽  
Sea State ◽  
Risk Warning ◽  
Coastal Impacts ◽  
Impact Risk ◽  
Clear Differentiation ◽  
Coastal Risk ◽  
Flooding Events ◽  
Basque Coast

Abstract. This work presents the main characteristics of the Basque Meteorology Agency (Euskalmet) maritime–coastal risk warning system, with special emphasis on the latest updates, including a clear differentiation on specific warning messages addressing sea conditions for navigation purposes in the first 2 nautical miles, and expected coastal impacts. Some details of the warning bulletin for maritime and coastal risk situations are also presented, together with other communication products and strategies used in coastal and maritime severe episodes at the Basque coast. Today, three different aspects are included in the coastal–maritime risk warning system in Basque Country, related to the main potential severe events that affecting coastal activities. – "Galerna" risk relates to a sudden wind reversal that can severely affect coastal navigation and recreational activities. – "Navigation" risk relates to severe sea state conditions for 0–2 miles, affecting different navigation activities. – "Coastal impact" risk relates to adverse wave characteristics and tidal surges that induce flooding events and different impacts in littoral areas.

Distribution of Wave Impact Forces From Breaking and Non-Breaking Waves

2009 ◽  
Author(s):  
Anne M. Fullerton ◽  
Thomas C. Fu ◽  
Edward S. Ammeen
Keyword(s):  
Free Surface ◽  
Wave Height ◽  
Breaking Waves ◽  
Qualitative Assessment ◽  
Total Force ◽  
Impact Loads ◽  
Wave Impact ◽  
Data Set ◽  
Wave Characteristics ◽  
Wide Range

Impact loads from waves on vessels and coastal structures are highly complex and may involve wave breaking, making these changes difficult to estimate numerically or empirically. Results from previous experiments have shown a wide range of forces and pressures measured from breaking and non-breaking waves, with no clear trend between wave characteristics and the localized forces and pressures that they generate. In 2008, a canonical breaking wave impact data set was obtained at the Naval Surface Warfare Center, Carderock Division, by measuring the distribution of impact pressures of incident non-breaking and breaking waves on one face of a cube. The effects of wave height, wavelength, face orientation, face angle, and submergence depth were investigated. A limited number of runs were made at low forward speeds, ranging from about 0.5 to 2 knots (0.26 to 1.03 m/s). The measurement cube was outfitted with a removable instrumented plate measuring 1 ft2 (0.09 m2), and the wave heights tested ranged from 8–14 inches (20.3 to 35.6 cm). The instrumented plate had 9 slam panels of varying sizes made from polyvinyl chloride (PVC) and 11 pressure gages; this data was collected at 5 kHz to capture the dynamic response of the gages and panels and fully resolve the shapes of the impacts. A Kistler gage was used to measure the total force averaged over the cube face. A bottom mounted acoustic Doppler current profiler (ADCP) was used to obtain measurements of velocity through the water column to provide incoming velocity boundary conditions. A Light Detecting and Ranging (LiDAR) system was also used above the basin to obtain a surface mapping of the free surface over a distance of approximately 15 feet (4.6 m). Additional point measurements of the free surface were made using acoustic distance sensors. Standard and high-speed video cameras were used to capture a qualitative assessment of the impacts. Impact loads on the plate tend to increase with wave height, as well as with plate inclination toward incoming waves. Further trends of the pressures and forces with wave characteristics, cube orientation, draft and face angle are investigated and presented in this paper, and are also compared with previous test results.

scholarly journals XI.—An Account of the Great Finner Whale (Balænoptera Sibbaldii) stranded at Longniddry Part I. The Soft Parts.

1870 ◽  
Vol 26 (1) ◽  
pp. 197-251 ◽  
Author(s):  
Wm Turner
Keyword(s):  
High Tide ◽  
Daily Newspapers ◽  
Points Of View ◽  
Fin Whales ◽  
Firth Of Forth

On the 3d November 1869, a huge Finner whale was stranded on the beach at Gosford Bay, Longniddry, Firth of Forth.Most of the large Fin whales which have been examined by British and Continental anatomists have been found floating dead on the surface of the sea, and have then been towed ashore by their captors. But, from the account which was given in the Edinburgh daily newspapers, it would appear that, for some days previously, this animal had been recognised by the fishermen, swimming to and fro in the Firth. On the morning of the 3d it was seen from the shore, blowing with great violence from its nostrils, flapping its huge tail, and obviously struggling to disengage itself from the rocks and shoals, amidst which an unusually high tide had permitted it to wander. Shots were fired at it, and, from the wounds produced, blood poured forth which tinged the surrounding waves. As the tide receded, the animal was fairly stranded; and, after some vigorous but ineffectual attempts to disengage itself from its position, it slowly died. The animal lay some yards above low-water mark, so that for several hours each day it could be examined, and photographs taken from various points of view.

scholarly journals FIELD MEASUREMENTS OF BEDFORMS IN A RIP CHANNEL ON A MACRO-TIDAL BEACH

2012 ◽  
Vol 1 (33) ◽  
pp. 93
Author(s):  
Antony Thorpe ◽  
Jon Miles ◽  
Gerd Masselink ◽  
Paul Russell ◽  
Tim Scott ◽  
...  
Keyword(s):  
Sandy Beach ◽  
High Tide ◽  
Field Measurements ◽  
Rip Current ◽  
Peak Period ◽  
Migration Rates ◽  
Sand Ripple ◽  
Current Maximum ◽  
Offshore Flow ◽  
And Migration

A Sand Ripple Profiler (SRP) was deployed in a rip channel on a dissipative sandy beach to measure bedform height (∆), length (λ) and migration rate (Mr¬) throughout a macro-tidal cycle with an offshore significant wave height of 0.7 m and peak period of 10 s. At lower tidal elevations in the strong offshore flow of the rip current (maximum = 0.4 m/s) bedforms (∆ = 0.15 m, λ = 3 m) were found to migrate offshore (Mr = 0.21 m/hr). Outside of active rip current conditions (water depth (h) = >~2.5 m) bedforms were found to be of smaller scale (∆ = 0.09 – 0.12 m, λ = 1 – 1.2 m) migrating onshore at a rate of 0.35 m/hr at mid tide (h = 3.3 m) and 0.03 m/hr at high tide (h = 6.3 m). Onshore migration rates were found to increase with increased wave skewness and velocity variance.

scholarly journals CHARACTERISTICS OF BREAKING WAVES AND ANALYSIS OF SEDIMENT TRANSPORT IN TELUK KENDARI

2018 ◽  
Vol 9 (2) ◽  
pp. 585-596
Author(s):  
Koko Ondara ◽  
Semeidi Husrin
Keyword(s):  
Sediment Transport ◽  
Wind Direction ◽  
High Tide ◽  
Distribution Patterns ◽  
Breaking Waves ◽  
Hydrodynamic Conditions ◽  
Wave Characteristics ◽  
Bay Area ◽  
Tidal Data ◽  
Wave Hindcasting

One of the problems that often occured in the bay area is a sedimentation process that occurred continuously, causing silting. The movement of sediment material in the process of sedimentation is influenced by the movement of the water flow like the tides, winds, currents and waves. The aim of this study was to determine the characteristics of the hydrodynamic conditions, particularly the distribution pattern and the capacity of the sediments in the Kendari Bay with oceanographic modeling approach. Bathymetry data measured at the site of the research conducted in August 2015. The analysis of distribution patterns of sedimentation, sedimentation capacity, wave hindcasting, wind data and tidal data using software, hindcasting results indicate the dominant wind direction coming from the east. Type tides in Kendari Bay is a mixed mainly semiurdunal tides. The concentration of suspended sediment at low tide is greater than at high tide.  Keywords: sediment transport, wave characteristics, Kendari Bay, hydro - dynamics, mike21

scholarly journals Defining and Predicting Heat Waves in Bangladesh

2017 ◽  
Vol 56 (10) ◽  
pp. 2653-2670 ◽  
Author(s):  
Hannah Nissan ◽  
Katrin Burkart ◽  
Erin Coughlan de Perez ◽  
Maarten Van Aalst ◽  
Simon Mason
Keyword(s):  
Soil Moisture ◽  
Heat Wave ◽  
Heat Waves ◽  
Warning System ◽  
Circulation Pattern ◽  
Westerly Winds ◽  
Additive Regression Model ◽  
Additive Regression ◽  
Definition Of ◽  
Moisture Conditions

AbstractThis paper proposes a heat-wave definition for Bangladesh that could be used to trigger preparedness measures in a heat early warning system (HEWS) and explores the climate mechanisms associated with heat waves. A HEWS requires a definition of heat waves that is both related to human health outcomes and forecastable. No such definition has been developed for Bangladesh. Using a generalized additive regression model, a heat-wave definition is proposed that requires elevated minimum and maximum daily temperatures over the 95th percentile for 3 consecutive days, confirming the importance of nighttime conditions for health impacts. By this definition, death rates increase by about 20% during heat waves; this result can be used as an argument for public-health interventions to prevent heat-related deaths. Furthermore, predictability of these heat waves exists from weather to seasonal time scales, offering opportunities for a range of preparedness measures. Heat waves are associated with an absence of normal premonsoonal rainfall brought about by anomalously strong low-level westerly winds and weak southerlies, detectable up to approximately 10 days in advance. This circulation pattern occurs over a background of drier-than-normal conditions, with below-average soil moisture and precipitation throughout the heat-wave season from April to June. Low soil moisture increases the odds of heat-wave occurrence for 10–30 days, indicating that subseasonal forecasts of heat-wave risk may be possible by monitoring soil-moisture conditions.

scholarly journals An overview of a regional meteorology warning system

2012 ◽  
Vol 8 (1) ◽  
pp. 157-166 ◽  
Author(s):  
S. Gaztelumendi ◽  
J. Egaña ◽  
K. Otxoa-de-Alda ◽  
R. Hernandez ◽  
J. Aranda ◽  
...  
Keyword(s):  
Basque Country ◽  
Warning System ◽  
Weather Event ◽  
Event Definition

Abstract. In this work we present a regional meteorology warning system, particularly the operational weather warning system used by the Basque Meteorology Agency (Euskalmet) for Basque Country. System considers different meteorological phenomena capable of generate warnings, and is based on combined thresholds criteria depending on particular weather event and area of territory where is applied. In this work we describe the most significant aspects related with the warning event definition and the warning bulletin. Conclusions from comparison with the former system (prior to 2009) and feedback from different users are presented.

Vertical Wave Impact Loading on a Fixed Platform Deck

2015 ◽  
Author(s):  
Jule Scharnke ◽  
Janou Hennig
Keyword(s):  
Impact Loading ◽  
Maximum Load ◽  
Primary Objective ◽  
Model Tests ◽  
Test Results ◽  
Wave Impact ◽  
Sea State ◽  
Peak Period ◽  
Significant Difference ◽  
Crest Length

The TLP model tests in CresT [1] showed that there is a significant difference in the maximum load events due to long-crested and short-crested waves of same peak period and significant wave height. This decrease in load amplitudes for increasing spreading was not dominated by the reduction in crest heights, but related to a change in wave excitation. In ShorT-CresT wave-in-deck model tests were carried out with the focus on the physics of impact loading. The primary objective of the platform tests was to link crest height and wave impact with local and global loading on the deck. The model test results showed that the global vertical loads in short-crested waves can be similar to long-crested events, if the wetted deck area is comparable. In other words, the platform deck loading corresponds to the relative short-crestedness of the sea state: if the crest length is at least as large as the characteristic deck dimension, the loads are significantly larger than for lower crest lengths (step change). In this paper the results of the wave-in-deck model tests are presented and discussed. The analysis of the model tests is focused on a comparison between short-crested and long-crested impacts and a comparison of the measurements to a simplified loading model.

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