Temporal and spatial variability of the open coast wave climate of Victoria, Australia

2020 ◽  
Vol 71 (3) ◽  
pp. 394 ◽  
Author(s):  
S. L. McSweeney
Keyword(s):  
Wave Height ◽  
East Coast ◽  
Southern Oscillation ◽  
Southern Annular Mode ◽  
Wave Climate ◽  
Strong Positive Correlation ◽  
Wave Direction ◽  
The West ◽  
Open Coast ◽  
Wave Conditions

The open coast of Victoria, Australia, is one of the highest wave energy coastlines globally. Despite this, a lack of permanently deployed wave buoys has limited prior analysis of wave conditions. In this study, the wave climate of Victoria was analysed using 31 years of directional data hindcast from the National Oceanic and Atmospheric Administration’s WaveWatch-III model (Climate Forecast System Reanalysis hindcasts). An eastward decrease in wave height and period occurs from Portland to Wilson’s Promontory. This trend then reverses on the east coast. Across the west and central coasts, wave direction is dominated by south-west swells as influenced by strong westerly winds and mid-latitude low-pressure systems. On the east coast, wave direction becomes more variable, with added southerly, south-east and easterly components. The Southern Annular Mode influences wave climate variability on the west coast and is negatively correlated with storm frequency and wave direction. On the east coast, the El Niño–Southern Oscillation showed a strong positive correlation with wave height and a negative correlation with direction. This work provides a benchmark to compare to future changes. It will inform a higher-resolution analysis of the spatial correlation of wave conditions with climate processes to predict shoreline response.

scholarly journals Present Wave Climate in the Bay of Biscay: Spatiotemporal Variability and Trends from 1958 to 2001

2012 ◽  
Vol 25 (6) ◽  
pp. 2020-2039 ◽  
Author(s):  
Elodie Charles ◽  
Déborah Idier ◽  
Jérôme Thiébot ◽  
Gonéri Le Cozannet ◽  
Rodrigo Pedreros ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Wave Height ◽  
Wave Climate ◽  
Coastal Hazards ◽  
Spatiotemporal Variability ◽  
Bay Of Biscay ◽  
Wave Direction ◽  
Extreme Wave ◽  
Wave Fields ◽  
Wave Conditions

Abstract Climate change impacts on wave conditions can increase the risk of offshore and coastal hazards. The present paper investigates wave climate multidecadal trends and interannual variability in the Bay of Biscay during the past decades (1958–2001). Wave fields are computed with a wave modeling system based on the WAVEWATCH III code and forced by 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) wind fields. It provides both an extended spatiotemporal domain and a refined spatial resolution over the Bay of Biscay. The validation of the wave model is based on 11 buoys, allowing for the use of computed wave fields in the analysis of mean and extreme wave height trends and variability. Wave height, period, and direction are examined for a large array of wave conditions (by seasons, high percentiles of wave heights, different periods). Several trends for recent periods are identified, notably an increase of summer significant wave height, a southerly shift of autumn extreme wave direction, and a northerly shift of spring extreme wave direction. Wave fields exhibit high interannual variability, with a normalized standard deviation of seasonal wave height greater than 15% in wintertime. The relationship with Northern Hemisphere teleconnection patterns is investigated at regional scale, especially along the coast. It highlights a strong correlation between local wave conditions and the North Atlantic Oscillation and the east Atlantic pattern indices. This relationship is further investigated at the local scale with a new method based on bivariate diagrams, allowing the identification of the type of waves (swell, storm, intermediate waves) impacted. These results are discussed in terms of comparison with previous studies and coastal risk implications.

scholarly journals Pemanfaatan Data Angin Untuk Karakteristik Gelombang Laut Di Perairan Natuna Berdasarkan Data Angin tahun 2009 - 2018

2019 ◽  
Vol 8 (2) ◽  
pp. 55
Author(s):  
Ary Afriady ◽  
Tasdik Mustika Alam ◽  
Mochamad Furqon Mustika Azis Ismail
Keyword(s):  
Wave Height ◽  
Wave Period ◽  
Wind Data ◽  
Wave Direction ◽  
The West ◽  
Maximum Wave Height ◽  
Transition Season ◽  
Forecasting Analysis ◽  
Environmental Prediction ◽  
Wave Forecasting

Analisis data angin dilakukan untuk meramalkan dan menentukan karakteristik gelombang laut di perairan Pulau Natuna. Data angin yang digunakan dalam penelitian ini berasal dari National Centers for Environmental Prediction (NCEP) selama 10 tahun dari tahun 2009 sampai dengan tahun 2018. Metoda yang digunakan untuk estimasi tinggi, periode dan arah gelombang laut yang dibangkitkan oleh angin adalah metode Svedrup, Munk dan Bretschneider (SMB). Hasil perhitungan peramalan karakteristik gelombang diperoleh bahwa pembentukan gelombang didominasi oleh arah yang berasal dari timur laut dan terjadi pada musim barat dan musim peralihan 1. Adapun pada musim timur dan peralihan, arah dominan gelombang masing-masing berasal dari selatan dan barat daya. Tinggi gelombang maksimum 1,0-1,4 m sering terjadi pada musim musim timur, adapun tinggi gelombang minimum 0,2-0,6 m dominan terjadi pada musim musim peralihan. Periode gelombang dominan ditemukan pada kisaran 7-9 detik yang terjadi pada tiap musim.  The analysis of wind data has been done to forecast and determine the characteristic of the ocean wave in Natuna Island waters. The wind data in this study came from the National Centers for Environmental Prediction (NCEP) for a period of 10 years from 2009 to 2018. The method to estimate wave height, wave period, and wave direction generated by wind is Sverdrup, Munk dan Bretschneider (SMB) system. The results of wave forecasting analysis show that the formation of the wave is mainly originated from the northeast which occurs during the west and first transition season. As for the east and second transition season, the origin of wave formation coming from the south and southwest, respectively. The maximum wave height of 1.0-1.4 m frequently occurs during the east monsoon, while the minimum wave height. The dominant wave period is found in the range of 7-9 seconds, which occurs in every season. 

scholarly journals Climate-induced variability in South Atlantic wave direction over the past three millennia

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
A. P. Silva ◽  
A. H. F. Klein ◽  
A. F. H. Fetter-Filho ◽  
C. J. Hein ◽  
F. J. Méndez ◽  
...  
Keyword(s):  
Global Climate ◽  
Southern Annular Mode ◽  
Wave Climate ◽  
Wave Generation ◽  
South Atlantic ◽  
Wave Direction ◽  
Global Climate Changes ◽  
Ocean Wave Climate ◽  
Forcing Mechanisms

Abstract Through alteration of wave-generating atmospheric systems, global climate changes play a fundamental role in regional wave climate. However, long-term wave-climate cycles and their associated forcing mechanisms remain poorly constrained, in part due to a relative dearth of highly resolved archives. Here we use the morphology of former shorelines preserved in beach-foredune ridges (BFR) within a protected embayment to reconstruct changes in predominant wave directions in the Subtropical South Atlantic during the last ~ 3000 years. These analyses reveal multi-centennial cycles of oscillation in predominant wave direction in accordance with stronger (weaker) South Atlantic mid- to high-latitudes mean sea-level pressure gradient and zonal westerly winds, favouring wave generation zones in higher (lower) latitudes and consequent southerly (easterly) wave components. We identify the Southern Annular Mode as the primary climate driver responsible for these changes. Long-term variations in interhemispheric surface temperature anomalies coexist with oscillations in wave direction, which indicates the influence of temperature-driven atmospheric teleconnections on wave-generation cycles. These results provide a novel geomorphic proxy for paleoenvironmental reconstructions and present new insights into the role of global multi-decadal to multi-centennial climate variability in controlling coastal-ocean wave climate.

scholarly journals THE DYNAMICS OF A COAST WITH A GROYNE SYSTEM

1970 ◽  
Vol 1 (12) ◽  
pp. 64 ◽  
Author(s):  
W.T. Bakker ◽  
E.H.J. Klein Breteler ◽  
A. Roos
Keyword(s):  
Theoretical Model ◽  
Computer Program ◽  
Wave Height ◽  
Mathematical Theory ◽  
Coastal Engineering ◽  
Wave Direction ◽  
Line Theory ◽  
Wave Conditions ◽  
Made In

This paper is a continuation of the paper with the same name, presented on the Xlth Conference on Coastal Engineering by the first author [1] , in which a mathematical theory was given about the behaviour of a coast after the construction of a groyne system. Now this paper extends the former paper theoretically and practically. 1. Theoretically a computer program has been made in which the influence of diffraction behind the groyne has been taken into account. 2. Practically the coastal constants used in the theoretical model of the coast will be expressed in terms of wave height and wave direction, based on the theory of SVASEK [2] . Results are given of computations with a coastal model in which the coast is schematized to one line (one-line theory) and a model in which the coast is schematized to a beach line and on mshorelme (two-line theory). The influence of changing wave conditions is investigated.

scholarly journals Interannual Response of Reef Islands to Climate-Driven Variations in Water Level and Wave Climate

2020 ◽  
Vol 12 (24) ◽  
pp. 4089
Author(s):  
Michael V. W. Cuttler ◽  
Kilian Vos ◽  
Paul Branson ◽  
Jeff E. Hansen ◽  
Michael O’Leary ◽  
...  
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Southern Oscillation ◽  
Wave Climate ◽  
Water Levels ◽  
Short Term ◽  
Island Evolution ◽  
Reef Islands ◽  
Wave Conditions

Coral reef islands are among the most vulnerable landforms to climate change. However, our understanding of their morphodynamics at intermediate (seasonal to interannual) timescales remains poor, limiting our ability to forecast how they will evolve in the future. Here, we applied a semi-automated shoreline detection technique (CoastSat.islands) to 20 years of publicly available satellite imagery to investigate the evolution of a group of reef islands located in the eastern Indian Ocean. At interannual timescales, island changes were characterized by the cyclical re-organization of island shorelines in response to the variability in water levels and wave conditions. Interannual variability in forcing parameters was driven by El Niño Southern Oscillation (ENSO) cycles, causing prolonged changes to water levels and wave conditions that established new equilibrium island morphologies. Our results present a new opportunity to measure intermediate temporal scale changes in island morphology that can complement existing short-term (weekly to seasonal) and long-term (decadal) understanding of reef island evolution.

scholarly journals Large-Scale Influences on the Evolution of Winter Subtropical Maritime Cyclones Affecting Australia’s East Coast

2013 ◽  
Vol 141 (7) ◽  
pp. 2416-2431 ◽  
Author(s):  
Stuart A. Browning ◽  
Ian D. Goodwin
Keyword(s):  
Indian Ocean ◽  
Large Scale ◽  
East Coast ◽  
Southern Oscillation ◽  
Southern Annular Mode ◽  
Winter Period ◽  
Evolutionary Trajectory ◽  
Late Autumn ◽  
Tasman Sea ◽  
Eastern Seaboard

Abstract Subtropical maritime low pressure systems frequently impact Australia’s eastern seaboard. Closed circulation lows in the Tasman Sea region are termed East Coast Cyclones (ECC); they can evolve in a range of climatic environments and have proven most destructive during the late autumn–winter period. Using criteria based on pressure gradients, inferred wind field, and duration, an objectively determined database of ECC occurrences is established to explore large-scale influences on ECC evolution. Subclassification based on evolutionary trajectory reveals two dominant storm types during late autumn–winter: easterly trough lows (ETL) and southern secondary lows (SSL). Synoptic composites are used to investigate the climatological evolution of each storm type. ETL cyclogenesis occurs along the eastern seaboard at the confluence of warm moist subtropical easterlies and cool air over the continent that is advected from higher latitudes. SSL develop when a cold extratropical cyclone moves equatorward and interacts with warm moist conditions in the Tasman Sea. At seasonal time scales, a complex interplay of tropical and extratropical influences contributes to high-frequency storm seasons. ETL are more frequent during neutral or positive phases of the El Niño–Southern Oscillation, cool sea surface temperature anomalies (SSTAs) in the tropical Indian Ocean, and neutral to positive southern annular mode phases. SSL are more frequent during years with warm SSTAs in the eastern Indian Ocean, warm SSTAs in the western Pacific, and high-latitude blocking.

scholarly journals How Oceanic Oscillation Drives Soil Moisture Variations over Mainland Australia: An Analysis of 32 Years of Satellite Observations*

2013 ◽  
Vol 26 (24) ◽  
pp. 10159-10173 ◽  
Author(s):  
Bernhard Bauer-Marschallinger ◽  
Wouter A. Dorigo ◽  
Wolfgang Wagner ◽  
Albert I. J. M. van Dijk
Keyword(s):  
Soil Moisture ◽  
Southern Oscillation ◽  
Southern Annular Mode ◽  
Total Variance ◽  
The West ◽  
Climate Modes ◽  
North East ◽  
The North ◽  
Strongly Connected ◽  
Droughts And Floods

Abstract Australia is frequently subject to droughts and floods. Its hydrology is strongly connected to oceanic and atmospheric oscillations (climate modes) such as the El Niño–Southern Oscillation (ENSO), Indian Ocean dipole (IOD), and southern annular mode (SAM). A global 32-yr dataset of remotely sensed surface soil moisture (SSM) was used to examine hydrological variations in mainland Australia for the period 1978–2010. Complex empirical orthogonal function (CEOF) analysis was applied to extract independent signals and to investigate their relationships to climate modes. The annual cycle signal represented 46.3% of the total variance and a low but highly significant connection with SAM was found. Two multiannual signals with a lesser share in total variance (6.3% and 4.2%) were identified. The first one had an unstable period of 2–5 yr and reflected an east–west pattern that can be associated with ENSO and SAM but not with IOD. The second one, a 1- to 5-yr oscillation, formed a dipole pattern between the west and north and can be linked to ENSO and IOD. As expected, relationships with ENSO were found throughout the year and are especially strong during southern spring and summer in the east and north. Somewhat unexpectedly, SAM impacts strongest in the north and east during summer and is proposed as the key driver of the annual SSM signal. The IOD explains SSM variations in the north, east, and southeast during spring and also in the west during winter.

scholarly journals MORPHOLOGY AND DYNAMICS OF CRESCENTIC BAR SYSTEMS

1982 ◽  
Vol 1 (18) ◽  
pp. 59
Author(s):  
V. Goldsmith ◽  
D. Bowman ◽  
K. Kiley ◽  
B. Burdick ◽  
Y. Mart ◽  
...  
Keyword(s):  
Wave Height ◽  
Wave Energy ◽  
Field Studies ◽  
Wave Climate ◽  
Phase Correlation ◽  
Mature Stage ◽  
Wave Direction ◽  
Significant Wave ◽  
Wave Measurements ◽  
Wave Heights

Aerial photograph and field studies in the southeastern Mediterranean, involving bathymetric mapping, and concurrent and antecedent wave measurements, have been used to delineate the sequential development of crescentic bars and associated dynamics. The bar sequence includes multiple parallel or wavy bars, ridge and runnels, oblique/transverse bars, single crescentic and double crescentic bars, and occurs during a calming down of wave activity from 2.5 to 0.5 m waves. The concomitant wave data, including wave directions, energy spectrum, significant wave height, and length of the calm period, showed strong correlation with the bar stages. An increase in total bar occurrence during summer is related to a major wave energy decrease in the spring, when significant wave heights (H ) < 1 m sharply increase to 70-85% in April-May. Inner single crescentic and initial double-crescentic bars are largely restricted to the calmest wave months of May/April to October/November, which reflects their sensitivity to wave energy. The aseasonal occurrence is best shown by the mature double crescentic type, which apparently is the final stage in the crescentic bar development sequence. Two bar developmental sequences were delineated: one shore-normal and the other initially oblique, but gradually rotating to shore-normal in the mature stage. Out of phase relationships between inner and outer bar systems resulted from the lag in response of the outer bars behind changes in wave direction. Among the inner crescentic bars and shore rhythms, phase-correlation was the rule. Crescentic bars are well developed on this coast because of the dissipative conditions and the distinct wave climate. High waves in the winter remove the existing bars, and extended calms allow the full development of the crescentic bar sequence. Similar bar types occur on different coasts in different sequences and in different proportions of time. Thus, it is suggested that these differences are attributable to global differences in the occurrences of threshold wave height conditions .

scholarly journals CLIMATE VARIABILITY INDUCED SHIFTS OF THE WAVE CLIMATE IN MEXICO

2020 ◽  
pp. 21
Author(s):  
Rodolfo Silva ◽  
Itxaso Oderiz ◽  
Thomas Mortlock ◽  
Ismael Marino-Tapia
Keyword(s):  
Sediment Transport ◽  
Southern Oscillation ◽  
Wave Climate ◽  
Global Scale ◽  
Wave Direction ◽  
Erosion Risk ◽  
Primary Driver ◽  
Important Challenge ◽  
Offshore Wave

Inter-annual variability of wave climates is important for coastal risk assessment because these fluctuations can increase or decrease seasonal erosion risk (Wahl and Plant 2015). Understanding how long-term variability affects the seasonality of sediment transport is an important challenge in risk assessments (Toimil et al. 2020). There have been many attempts to quantify long-term variability in offshore wave climate, as this is the primary driver of coastal processes on sandy coasts. However, there is very little work on how the long-term variability of wave climate influences sediment transport. One of the most important drivers of sediment transport is the mean wave direction of incoming waves (Barnard et al. 2015; Hemer, Church, and Hunter 2010; Morim et al. 2019), although it is still not fully understood. An important contribution in this regard is the work of (Barnard et al. 2015), who found that El Nio Southern Oscillation (ENSO) dominates coastal vulnerability in the Pacific Ocean. On the other hand, several works at global scale (Godoi and Torres Junior 2020; Reguero, Losada, and Mendez 2019; Stopa and Cheung 2014) have found that ENSO is the climatic driver that most affects the interannual variability of the wave climate. However, understanding how ENSO impacts wave direction is still lacking.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/_M5Mxm7PnQg

The Concept of the Optimum Alignment of Discharge Pipelines Due to the Minimization of the Wave Forces

1992 ◽  
Vol 25 (9) ◽  
pp. 211-216
Author(s):  
A. Akyarli ◽  
Y. Arisoy
Keyword(s):  
Wave Height ◽  
Wave Force ◽  
Wave Forces ◽  
Wave Direction ◽  
Incoming Wave ◽  
Pipeline Route ◽  
Optimum Alignment ◽  
The Cost ◽  
Resultant Wave

As the wave forces are the function of the wave height, period and the angle between the incoming wave direction and the axis of the discharge pipeline, the resultant wave force is directly related to the alignment of the pipeline. In this paper, a method is explained to determine an optimum pipeline route for which the resultant wave force becomes minimum and hence, the cost of the constructive measures may decrease. Also, the application of this method is submitted through a case study.

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