Rapid-response observations on barrier islands along Cape Fear, North Carolina, during Hurricane Isaias

Shore & Beach ◽  
2021 ◽  
pp. 86-96
Author(s):  
Ryan Mieras ◽  
Christopher O'Connor ◽  
Joseph Long
Keyword(s):  
North Carolina ◽  
Storm Surge ◽  
Low Cost ◽  
Pressure Sensors ◽  
Wave Climate ◽  
Wave Direction ◽  
Wave Runup ◽  
Wind Speeds ◽  
The North ◽  
Cape Fear

Hurricane Isaias struck the Cape Fear Region of North Carolina around 23:00 EDT on 3 August 2020, making landfall at Ocean Isle Beach as a Category 1 storm with peak wind speeds of 80 mph. An array of nearshore Sofar Spotter wave buoys captured the wave field at two beaches off the coasts of Bald Head Island (south-facing and east-facing beaches) and Masonboro Island. Local variations in significant wave height and peak wave direction were observed along the Lower Cape Fear Region, due to large shoal features impacting the regional wave climate. A cross-shore transect of five pressure sensors was installed at the north end of Masonboro Island 2.5 days prior to landfall to measure storm surge, wave runup, and variation of gravity/ infragravity wave energy across the barrier island. The three fast-sampling wave gauges along the backshore became buried before Hurricane Isaias peak storm surge, and the two gauges on and behind the dune were never inundated. A low-cost (< $250) Storm Surge Observation Camera (SSOC) prototype captured storm surge and coastal erosion at Kure Beach, in conjunction with pre- and post-storm RTK GPS beach profile surveys. Kure Beach experienced more than 1.0 m of vertical erosion of the berm, while Masonboro Island experienced around 0.1 m of accretion across the backshore, despite nearly identical wave and wind forcing conditions at the two beaches separated by ~20 km. Pre-storm berm height and width (higher and wider at Kure Beach), as well as foreshore slope (steeper, 1:9, at Kure Beach), are likely factors influencing significant erosion at Kure Beach, while slight accretion was observed at Masonboro Island.

scholarly journals Joint Modelling of Wave Energy Flux and Wave Direction

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 460
Author(s):  
Takvor H. Soukissian ◽  
Flora E. Karathanasi
Keyword(s):  
Energy Flux ◽  
Wave Energy ◽  
Goodness Of Fit ◽  
North Atlantic Ocean ◽  
Wave Climate ◽  
Western Mediterranean ◽  
Wave Direction ◽  
Bivariate Model ◽  
The North ◽  
Wave Energy Flux

In the context of wave resource assessment, the description of wave climate is usually confined to significant wave height and energy period. However, the accurate joint description of both linear and directional wave energy characteristics is essential for the proper and detailed optimization of wave energy converters. In this work, the joint probabilistic description of wave energy flux and wave direction is performed and evaluated. Parametric univariate models are implemented for the description of wave energy flux and wave direction. For wave energy flux, conventional, and mixture distributions are examined while for wave direction proven and efficient finite mixtures of von Mises distributions are used. The bivariate modelling is based on the implementation of the Johnson–Wehrly model. The examined models are applied on long-term measured wave data at three offshore locations in Greece and hindcast numerical wave model data at three locations in the western Mediterranean, the North Sea, and the North Atlantic Ocean. A global criterion that combines five individual goodness-of-fit criteria into a single expression is used to evaluate the performance of bivariate models. From the optimum bivariate model, the expected wave energy flux as function of wave direction and the distribution of wave energy flux for the mean and most probable wave directions are also obtained.

scholarly journals Numerical Investigation of Hydrodynamics and Cohesive Sediment Transport in Cua Lo and Cua Hoi Estuaries, Vietnam

2021 ◽  
Vol 9 (11) ◽  
pp. 1258
Author(s):  
Viet Thanh Nguyen ◽  
Minh Tuan Vu ◽  
Chi Zhang
Keyword(s):  
Sediment Transport ◽  
Great Influence ◽  
Wave Model ◽  
Sediment Concentration ◽  
Wave Climate ◽  
Cohesive Sediment ◽  
Wave Direction ◽  
The South ◽  
The North ◽  
Cohesive Sediment Transport

Two-dimensional models of large spatial domain including Cua Lo and Cua Hoi estuaries in Nghe An province, Vietnam, were established, calibrated, and verified with the observed data of tidal level, wave height, wave period, wave direction, and suspended sediment concentration. The model was then applied to investigate the hydrodynamics, cohesive sediment transport, and the morphodynamics feedbacks between two estuaries. Results reveal opposite patterns of nearshore currents affected by monsoons, which flow from the north to the south during the northeast (NE) monsoon and from the south to the north during the southeast (SE) monsoon. The spectral wave model results indicate that wave climate is the main control of the sediment transport in the study area. In the NE monsoon, sediment from Cua Lo port transported to the south generates the sand bar in the northern bank of the Cua Hoi estuary, while sediment from Cua Hoi cannot be carried to the Cua Lo estuary due to the presence of Hon Ngu Island and Lan Chau headland. As a result, the longshore sediment transport from the Cua Hoi estuary to the Cua Lo estuary is reduced and interrupted. The growth and degradation of the sand bars at the Cua Hoi estuary have a great influence on the stability of the navigation channel to Ben Thuy port as well as flood drainage of Lam River.

scholarly journals Evaluation of a Wind-Wave System for Ensemble Tropical Cyclone Wave Forecasting. Part II: Waves

2013 ◽  
Vol 28 (2) ◽  
pp. 316-330 ◽  
Author(s):  
Steven M. Lazarus ◽  
Samuel T. Wilson ◽  
Michael E. Splitt ◽  
Gary A. Zarillo
Keyword(s):  
Tropical Cyclone ◽  
Wind Wave ◽  
Wave Model ◽  
Wave System ◽  
Wave Direction ◽  
Wind Speeds ◽  
The North ◽  
Wave Forecast ◽  
Wind Events ◽  
The Right

Abstract A wind-wave forecast system, designed with the intention of generating unbiased ensemble wave forecasts for extreme wind events, is assessed. Wave hindcasts for 12 tropical cyclones (TCs) are forced using a wind analysis produced from a combination of the North American Regional Reanalysis (NARR) and a parametric wind model. The default drag parameterization is replaced by one that is more in line with recent studies where a cap at weak-to-moderate wind speeds is applied. Quadrant-based significant wave height (Hs) statistics are composited in a storm-relative reference frame and stratified by the radius of maximum wind, storm speed, and storm intensity. Improvements in Hs are gleaned from both downscaling the NARR winds and tuning the wave model. However, the paradigm whereby the drag coefficient depends solely on the wind speed is limiting. Results indicate that Hs is biased low in the right quadrants (for all statistical subcategories). Conversely, Hs is high biased in the left-rear quadrant even though the analysis wind field is underforecast there. At radii less than 100 nautical miles, the model peak wave direction is offset from the observed, with the model (buoy) peak more in line with (to the left of) the direction of the tropical cyclone motion. As a result, the predominant storm-relative wind direction, which is northwesterly in the left-rear quadrant, opposes that of the buoy peak wave direction, while the model peak is more crosswise with respect to the wind. This will likely reduce the magnitude of the wind stress in the model.

scholarly journals A new roughness parameterization accounting for wind-wave (mis)alignment

2018 ◽  
Author(s):  
Sara Porchetta ◽  
Orkun Temel ◽  
Domingo Muñoz-Esparza ◽  
Joachim Reuder ◽  
Jaak Monbaliu ◽  
...  
Keyword(s):  
Wind Wave ◽  
Climate Modeling ◽  
Numerical Models ◽  
Offshore Wind ◽  
Wave Direction ◽  
Data Set ◽  
Wind Speeds ◽  
The North ◽  
Effective Roughness ◽  
The North Sea

Abstract. Two-way feedback occurs between offshore wind and waves. However, the influence of the waves on the wind profile remains remains understudied, in particular the momentum transfer between the sea surface and the atmosphere. Previous studies showed that for swell waves it is possible to have increasing wind speeds in case of aligned wind-wave directions. However, the opposite is valid for opposed wind-wave directions, where a decrease in wind velocity is observed. Up to now, this behavior has not been included in most numerical models due to the lack of an appropriate parameterization of the resulting effective roughness length. Using an extensive data set of offshore measurements in the North Sea and the Atlantic Ocean, we show that the wave roughness affecting the wind is indeed dependent on the alignment between the wind and wave direction. Moreover, we propose a new roughness parameterization taking into account the dependence on alignment, consisting of an enhanced roughness for increasing misalignment. Using this new roughness parameterization in numerical models will facilitate a better representation of offshore wind, which is relevant to many applications including offshore wind energy and climate modeling.

Short-term beach rotation, wave climate and the North Atlantic Oscillation (NAO)

2011 ◽  
Vol 35 (3) ◽  
pp. 333-352 ◽  
Author(s):  
T. Thomas ◽  
M.R. Phillips ◽  
A.T. Williams ◽  
R.E. Jenkins
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Wave Climate ◽  
Wave Direction ◽  
Short Term ◽  
The North ◽  
The North Atlantic ◽  
Beach Rotation ◽  
Offshore Wave ◽  
The North Atlantic Oscillation

Beach profile surveys, offshore wave climate and variations in atmospheric conditions have been utilized to assess a short-term beach rotation phenomenon in a headland embayment Tenby, West Wales. Beach rotation, expressed by subaerial volumetric change, was shown by a negative phase relationship between beach extremities (r = —0.67), while cross-correlation at a one-month timelag increased statistical significance (r = 0.84). Due to beach aspect, gale wave heights decreased as wave direction rotated to the south (R2 = 0.4) and west (R 2 = 0.65), while offshore wave direction influenced change at the southern and northern extremities (R2 = 0.52 and 0.34, respectively). Shelter from offshore islands and Giltar Headland contributes via wave diffraction to accretive, erosive and rotational patterns, and these are sensitive to variations around the predominant wave direction (229°). A southerly shift induces north/south sediment movement, as waves diffract around the offshore islands, while a westerly change results in south/north sediment movement (i.e. beach rotation), as diffracted wave domination transfers to the headland. A general gale wave height reduction occurred when the North Atlantic Oscillation (NAO) was weak or in a transitional phase between positive or negative phases (R2 = 0.69 and R2 = 0.72, respectively). Morphological change was also attuned to atmospheric variation where a reversal in beach rotation was influenced by variations in positive and negative NAO/volume correlations and longshore profile location (R2 = 0.54 and 0.69, respectively). The results of this study have wider implications for coastal management; it is suggested that models developed in similar systems elsewhere will form the basis of human intervention or no active intervention strategies.

scholarly journals Improving Local Non-Communicable Disease Surveillance within a Changing Data Environment

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Allison Young ◽  
Mike D. Fliss ◽  
Amy Ising
Keyword(s):  
North Carolina ◽  
Disease Surveillance ◽  
Situational Awareness ◽  
Communicable Disease ◽  
Low Cost ◽  
Health Indicators ◽  
Noncommunicable Disease ◽  
Local Health ◽  
The North ◽  
Trend Data

This project aims to fill a growing county-level health data gap, increase noncommunicable disease surveillance capacity within North Carolina local health departments (LHDs), and improve situational awareness through the development of a low-cost, Excel-based surveillance tool. This prototype utilizes emergency room data collected by the North Carolina Disease Event Tracking and Epidemiologic Collection Tool (NC DETECT), a state-wide surveillance system, in order to visualize, monitor, and compare local health indicators. An Excel template is in development that will allow (NC DETECT) 166 registered LHD users to select common health indicators, pull annual trend data, and visualize them through meaningful reports.

scholarly journals WAVE RUN-UP CAUSED BY NATURAL STORM SURGE WAVES

1982 ◽  
Vol 1 (18) ◽  
pp. 49
Author(s):  
Joachim Grune
Keyword(s):  
Storm Surge ◽  
German Bight ◽  
Field Measurements ◽  
Wave Climate ◽  
Wave Runup ◽  
Sea State ◽  
Run Up

This paper describes results of field measurements on wave run-up caused by storm surge waves. The measurements have been done with newly developed run-up probes at two locations at the German Bight with different dyke profiles. It was found from the results that the wave runup, measured under real sea state conditions, have greater values than predicted by commonly used formulae. Furthermore the wave climate and the breaker type seem to have an influence on the magnitudes of wave run-up.

scholarly journals A Quantitative Evaluation of the Nighttime Visual Sign Inspection Method

2010 ◽  
Author(s):  
William J. Rasdorf ◽  
Joseph E. Hummer ◽  
Stehanie C. Vereen ◽  
Hubo Cai
Keyword(s):  
North Carolina ◽  
Visual Inspection ◽  
Low Cost ◽  
Inspection Method ◽  
North Carolina State University ◽  
The North ◽  
Replacement Procedure ◽  
Program Costs ◽  
The Cost ◽  
Visual Sign

A research project to determine the appropriate sign inspection and replacement procedure was conducted at North Carolina State University and sponsored by the North Carolina DOT. The purpose was to determine the optimum strategy for sign inspection and replacement under different conditions to respond to the pending retroreflectivity requirements. This paper reports on a spreadsheet tool developed to quantitatively evaluate the effectiveness of different sign inspection and replacement scenarios. The spreadsheet was designed for yellow and red engineer-grade sign sheetings, and takes into account sign vandalism and knock-downs as well as normal sign aging. The spreadsheet provides estimates of the number of signs in place that would not meet the minimum retroreflectivity standard and the cost of the sign inspection and replacement program. The results from a number of trials of the spreadsheet show that agencies that generally conform to the key assumptions made to build the spreadsheet should consider replacing all signs every seven years, as that insures that no aged signs are in place at a relatively low cost. If total replacement is not possible, an inspection program using retroreflectometers every three years appears very competitive in its effectiveness with a program using typical visual inspection rates each year. The retroreflectometers appear to allow fewer deficient signs, while the typical visual inspection program costs are lower for a given vandalism rate. More conservative visual sign replacement rates do not appear to offer distinct advantages, because typical replacement rates with visual inspections every two or three years allow relatively high numbers of deficient signs to remain on the roads.

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