scholarly journals THE BEHAVIOUR OF PROTOTYPE BOULDER REVETMENT WALLS

1982 ◽  
Vol 1 (18) ◽  
pp. 115 ◽  
Author(s):  
A.W. Smith ◽  
D.M. Chapman
Keyword(s):  
Tropical Cyclones ◽  
East Coast ◽  
High Energy ◽  
Wave Climate ◽  
Gold Coast ◽  
Third Wave ◽  
Performance Tests ◽  
Storm Activity ◽  
Tasman Sea ◽  
Storm Wave

This paper reports the results of on-site observations of coastal revetment structures under extreme storm conditions on the Gold Coast of Australia. The Gold Coast is located at approximately Lat. 27° S on the East Coast of Australia facing the Tasman sea behind a narrow continental shelf and exposed to a relatively high energy wave climate as depicted in Fig 1. Tropical cyclones generate the highest storm activity on the Gold Coast with Ho values commonly exceeding 10m with the resultant onshore wave i.e. either the second or third wave reformed breaks within the range of 2.5 to 3.5m. Storm wave periods are usually between 8 to 18 seconds. The ocean beach on the Gold Coast, some 30km long has been receding since the early forties and this has resulted in the construction of nearly 20km of revetment walls to "protect" the rear beach. Whilst some walls in particularly erosion-prone areas were constructed in the 1920 decade, most have been constructed since 1967 which represented a particularly high cyclone prone year. Since the latter period the walls have been exposed to three further periods of high cyclone energy attack in 1972, 1974 and 1976. Nearly all revetment walls demonstrated at least some settlement and damage but over the three storm periods at least 0.8km of wall was completely destroyed. Most wall failures were monitored on site and whilst the construction of the walls varied in quality the observational results might well be classified as full scale prototype performance tests.

scholarly journals Large-scale drivers of Australian east coast cyclones since 1851

2016 ◽  
Vol 66 (2) ◽  
pp. 125
Author(s):  
Stuart A. Browning ◽  
Ian D. Goodwin
Keyword(s):  
19Th Century ◽  
Ocean Circulation ◽  
Large Scale ◽  
East Coast ◽  
Early Years ◽  
Winter Period ◽  
Storm Activity ◽  
Data Scarcity ◽  
Tasman Sea ◽  
The 19Th Century

Subtropical maritime low-pressure systems are one of the most complex and destructive storm types to impact Australia’s eastern seaboard. This family of storms, commonly referred to as East Coast Cyclones (ECC), is most active during the late autumn and early winter period when baroclinicity increases in the Tasman Sea region. ECC have proven challenging to forecast at both event and seasonal timescales. Storm activity datasets, objectively determined from reanalyses using cyclone detection algorithms, have improved understanding of the drivers of ECC over the era of satellite data coverage. In this study we attempt to extend these datasets back to 1851 using the Twentieth Century Reanalysis version 2c (20CRv2c). However, uncertainty in the 20CRv2c increases back through time due to observational data scarcity, and individual cyclones counts tend to be underestimated during the 19th century. An alternative approach is explored whereby storm activity is estimated from seasonal atmosphere-ocean circulation patterns. Seasonal ECC frequency over the 1955 to 2014 period is significantly correlated to regional sea-level pressure and sea surface temperature (SST) patterns. These patterns are used to downscale the 20CRv2c during early years when individual events are not well simulated. The stormiest periods since 1851 appear to have been 1870 to the early 1890s, and 1950 to the early 1970s. Total storm activity has been below the long-term average for most winters since 1976. Conditions conducive to frequent ECC events tend to occur during periods of relatively warm SST in the southwest Pacific typical of negative Interdecadal Pacific Oscillation (IPO-ve). Extratropical cyclogenesis is associated with negative Southern Annular Mode (SAM-ve) and blocking in the southern Tasman Sea. Subtropical cyclogenesis is associated with SAM+ve and blocking in the central Tasman Sea. While the downscaling approach shows some skill at estimating seasonal storm activity from the large-scale circulation, it cannot overcome data scarcity based uncertainties in the 19th century when the 20CRv2c is effectively unconstrained throughout most of the southern hemisphere. Storm frequency estimates during the 19th century are difficult to verify and should be interpreted cautiously and with reference to available documentary evidence.

Wave climate of the Sydney region, an energetic and highly variable ocean wave regime

1992 ◽  
Vol 43 (4) ◽  
pp. 765 ◽  
Author(s):  
AD Short ◽  
NL Trenaman
Keyword(s):  
Tropical Cyclones ◽  
East Coast ◽  
Wave Climate ◽  
Ocean Wave ◽  
Climate Extreme ◽  
Extreme Waves ◽  
Wave Regime ◽  
South West ◽  
Wave Heights ◽  
Meteorological Systems

Sydney is located in the south-west Pacific at 34°s and receives waves generated in the southern Coral and Tasman Seas. Waves are generated by five meteorological systems: tropical cyclones, east-coast cyclones, mid-latitude cyclones, zonal anticyclonic highs and local summer seabreezes. An examination of 20 years of Sydney wave data reveals that each source has a characteristic seasonality, location and spectrum, permitting the wave climate to be decomposed accordingly. Although at first glance the annual wave climate is both energetic and highly variable, a distinct seasonality is present, with the months of February-March and June experiencing the largest average monthly wave heights. Although moderate waves dominate the climate, extreme waves (>4 m) and/or low swell may occur in any month.

scholarly journals Numerical Modeling of Storm Surge Induced by May 2009 East Coast Low in Gold Coast, Australia

2011 ◽  
Author(s):  
Aliasghar Golshani ◽  
Will Thurston ◽  
Deborah J. Abbs ◽  
Greg Stuart ◽  
Rodger Tominson
Keyword(s):  
Numerical Modeling ◽  
Storm Surge ◽  
East Coast ◽  
Gold Coast

Twentieth-Century Storm Activity along the U.S. East Coast

2000 ◽  
Vol 13 (10) ◽  
pp. 1748-1761 ◽  
Author(s):  
Keqi Zhang ◽  
Bruce C. Douglas ◽  
Stephen P. Leatherman
Keyword(s):  
Twentieth Century ◽  
East Coast ◽  
Storm Activity ◽  
The U.S

scholarly journals Multiseason Lead Forecast of the North Atlantic Power Dissipation Index (PDI) and Accumulated Cyclone Energy (ACE)

2013 ◽  
Vol 26 (11) ◽  
pp. 3631-3643 ◽  
Author(s):  
Gabriele Villarini ◽  
Gabriel A. Vecchi
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
North Atlantic ◽  
Power Dissipation ◽  
Skill Assessment ◽  
Geophysical Fluid Dynamics Laboratory ◽  
Storm Activity ◽  
The North ◽  
The North Atlantic ◽  
Atlantic Tropical Cyclone

Abstract By considering the intensity, duration, and frequency of tropical cyclones, the power dissipation index (PDI) and accumulated cyclone energy (ACE) are concise metrics routinely used to assess tropical storm activity. This study focuses on the development of a hybrid statistical–dynamical seasonal forecasting system for the North Atlantic Ocean’s PDI and ACE over the period 1982–2011. The statistical model uses only tropical Atlantic and tropical mean sea surface temperatures (SSTs) to describe the variability exhibited by the observational record, reflecting the role of both local and nonlocal effects on the genesis and development of tropical cyclones in the North Atlantic basin. SSTs are predicted using a 10-member ensemble of the Geophysical Fluid Dynamics Laboratory Climate Model, version 2.1 (GFDL CM2.1), an experimental dynamical seasonal-to-interannual prediction system. To assess prediction skill, a set of retrospective predictions is initialized for each month from November to April, over the years 1981–2011. The skill assessment indicates that it is possible to make skillful predictions of ACE and PDI starting from November of the previous year: skillful predictions of the seasonally integrated North Atlantic tropical cyclone activity for the coming season could be made even while the current one is still under way. Probabilistic predictions for the 2012 North Atlantic tropical cyclone season are presented.

scholarly journals Impact of tropical cyclones on modeled extreme wind‐wave climate

2017 ◽  
Vol 44 (3) ◽  
pp. 1393-1401 ◽  
Author(s):  
Ben Timmermans ◽  
Dáithí Stone ◽  
Michael Wehner ◽  
Harinarayan Krishnan
Keyword(s):  
Tropical Cyclones ◽  
Wind Wave ◽  
Wave Climate ◽  
Extreme Wind

scholarly journals The Zadko Telescope: A Southern Hemisphere Telescope for Optical Transient Searches, Multi-Messenger Astronomy and Education

2010 ◽  
Vol 27 (3) ◽  
pp. 331-339 ◽  
Author(s):  
D. M. Coward ◽  
M. Todd ◽  
T. P. Vaalsta ◽  
M. Laas-Bourez ◽  
A. Klotz ◽  
...  
Keyword(s):  
East Coast ◽  
Gamma Ray ◽  
High Energy ◽  
Pilot Program ◽  
Public Outreach ◽  
Southern Latitude ◽  
Optical Transients ◽  
Robotic Telescope ◽  
Optical Transient ◽  
Potential Tool

AbstractThe new 1 m f/4 fast-slew Zadko Telescope was installed in June 2008 about 70 km north of Perth, Western Australia. It is the only metre-class optical facility at this southern latitude between the east coast of Australia and South Africa, and can rapidly image optical transients at a longitude not monitored by other similar facilities. We report on first imaging tests of a pilot program of minor planet searches, and Target of Opportunity observations triggered by the Swift satellite. In 12 months, 6 gamma-ray burst afterglows were detected, with estimated magnitudes; two of them, GRB 090205 (z = 4.65) and GRB 090516 (z = 4.11), are among the most distant optical transients imaged by an Australian telescope. Many asteroids were observed in a systematic 3-month search. In September 2009, an automatic telescope control system was installed, which will be used to link the facility to a global robotic telescope network; future targets will include fast optical transients triggered by high-energy satellites, radio transient detections, and LIGO gravitational wave candidate events. We also outline the importance of the facility as a potential tool for education, training, and public outreach.

scholarly journals COASTAL WAVE MODELING FOR JETTY REHABILITATION AT COOS BAY, OREGON

2018 ◽  
pp. 89
Author(s):  
Lihwa Lin ◽  
Zeki Demirbilek
Keyword(s):  
High Energy ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Wave Modeling ◽  
The Past ◽  
The Pacific ◽  
Coos Bay ◽  
Storm Wave ◽  
Energy Environment ◽  
North And South

Coos Bay Inlet, located on the Pacific coast of southwestern Oregon, is protected by dual jetties constructed in 1928. Because the inlet is exposing to high energy environment, both north and south jetties have deteriorated since the initial construction. Aging, erosion of foundation, lack of effective maintenance, and channel dredging in the past have accelerated the jetty deterioration. To ensure navigation safety, the U.S. Army Corps of Engineers is presently investigating the rehabilitation and redesign of jetties. This paper is focused on numerical storm wave modeling of the existing jetties to provide input forcing information to physical model and redesign of jetties.

scholarly journals FluoroTome 1: An Apparatus for Tomographic Imaging of Radio-Fluorogenic (RFG) Gels

2019 ◽  
Author(s):  
John M. Warman ◽  
Matthijs P. de Haas ◽  
Leonard H. Luthjens ◽  
Tiantian Yao ◽  
Julia Navarro-Campos ◽  
...  
Keyword(s):  
Historical Development ◽  
High Energy ◽  
Performance Tests ◽  
High Energy Radiation ◽  
Tomographic Images ◽  
Laboratory Bench ◽  
Thin Slices ◽  
And Performance ◽  
User Friendly ◽  
3D Movie

Radio-fluorogenic (RFG) gels become permanently fluorescent when exposed to high-energy radiation with the intensity of the emission proportional to the local dose of radiation absorbed. An apparatus is described, FluoroTome 1, that is capable of taking a series of tomographic images (thin slices) of the fluorescence of such an irradiated RFG gel on-site and within minutes of radiation exposure. These images can then be compiled to construct a 3D movie of the dose distribution within the gel. The historical development via a laboratory-bench prototype to a readily transportable, user-friendly apparatus is described. Instrumental details and performance tests are presented.

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