Jorge Perez joins MetOcean Solutions

We are very pleased to welcome Dr Jorge Perez to MetOcean Solutions. Jorge is a physical oceanographer and will be working in our science team in Raglan. In his role, he will work on improving wave hindcasting and forecasting capabilities at Metocean Solutions.

 
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Following an MSc in Coastal and Port Engineering, Jorge completed a PhD in Physical Oceanography at the University of Cantabria, Spain. His research has focused on wave climate, including a wide range of temporal and spatial scales.

With almost 10 years of experience in wave dynamics, Jorge has participated in a broad variety of projects, developing innovative solutions for statistical downscaling methods, wave tracking algorithms, and climate change projections. In his last research position he managed wave climate databases and generated wave historical data.

“Metocean Solutions makes top quality data easily accessible, removing the gap between advancements of research and final users,” says Jorge. “I am happy to join the team and participate in this exciting development”.

Tracking a lost sailing yacht

At the end of October, MetOcean Solutions helped an insurance company find a missing yacht that had been drifting for weeks in the Atlantic Ocean.

Pantaenius, the global yacht insurance company, were trying to help find a yacht abandoned during the Mini Transat 6.50 race. This solo race across the Atlantic Ocean, held every two years, sees sailors brave the roughly 4000 miles from France to the Caribbean only stopping in the Canary Islands on the way.

 
Jolly Rogers adrift in the Atlantic.

Jolly Rogers adrift in the Atlantic.

 

The yacht was Jolly Rogers, a MINI 6.50 (a 6.5 m high-performance sailing vessel), which had been abandoned on 5 October off Spain’s Cape Finisterre when persistent technical issues caused the sailor Luca Sabiu to set off his distress beacon. Luca was airlifted out by helicopter by the Spanish navy, leaving Jolly Rogers adrift.

The yacht was considered lost at sea until a sighting on Friday 20 October provided a position when preparations were made to start a salvage operation. The weather was closing in, however, with forecasts promising strong winds and wave heights in excess of 6 m. Worried that the boat would have drifted too far to be found by the time the weather settled down, Olivier de Roffignac from Pantaenius contacted MetOcean Solutions for advice on where the boat would drift to over two to three days of high winds and heavy seas.

“Searching for a 6 m sailboat in the Atlantic Ocean is a bit like looking for a needle in a haystack,” explains MetOcean Solutions’ oceanographer Simon Weppe, based in France.  “Salvage operations are costly, and Pantaenius wanted guidance on the likely drift track of the boat so that they could narrow down the search radius when the weather was calm enough to initiate the search.”

“To help Pantaenius we modelled the predicted drift of the vessel, continuously updating our predictions as new forecast cycles became available. To account for the uncertainties in the drifting behaviour of the boat, we ran simulations affording different importance to windage (wind-related drifting).

“The global models differ somewhat, and so to get the best results we used several different forecast datasets for winds and currents: the European Centre for Medium-Range Weather Forecasts (ECMWF) winds and MERCATOR currents*, and the US National Oceanic and Atmospheric Administration (NOAA) Global Forecasting System (GFS) winds and Real-Time Ocean Forecast System (RTOFS) currents.

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Jolly Rogers was found only a couple of miles from the predicted location when using ECMWF winds and MERCATOR currents.

Jolly Rogers was found only a couple of miles from the predicted location when using ECMWF winds and MERCATOR currents.

“We found a large variability in the predicted tracks depending on which current data we used. In this location, MERCATOR currents and the ECMWF winds yielded the best predictions. The salvage operation was launched on Monday 23 October, and the yacht was found 2-3 miles from the location we predicted, which is very encouraging given the many uncertainties.

“In this case, getting the current-related component of the drift was important because the yacht had sails and rigging dragging in the water, which would have acted as a sea anchor. In that region of the world, the MERCATOR currents are obviously more accurate than the RTOFS ones”.

The case highlights the importance of using several data sources and drifting model setups for situations where there is limited data on the drifting characteristics of the object lost.

Our team of experienced modellers is able  to quickly simulate the drifting trajectory of anything lost at sea - including vessels, personnel, and oil spills. By using different global datasets we can model a suite of possible trajectories, and compare the outputs, providing the best possible guidance for our clients.

“In the past, we have assisted clients by modelling the trajectory of oil spills, the spread of invasive species, and the dispersal of rubbish in the ocean. It is great that we could assist Pantaenius find the yacht.”

For more information about how we can assist with trajectory modelling, contact us at enquiries@metocean.co.nz.

* All MERCATOR current datasets (and more) can be accessed freely via The Copernicus Marine Environment Monitoring Service. The Copernicus Marine Environment Monitoring Service provides Full, Free and Open Access to Data & Information related to the Global Ocean and the Marine Environment.

Modelling the effects of dredge spoil disposal

As port weather experts, MetOcean Solutions regularly provides modelling support for port dredging operations. 

“The disposal of dredge spoil requires careful consideration,” explains Oceanographer Simon Weppe. “Over time, disposed sediments will be redistributed by currents and waves. When selecting offshore disposal sites, ports have to consider the hydrodynamic processes of the area and evaluate the longer-term changes to the shape of the seabed (morphological changes). Understanding the general morphological behaviour of the region is essential if we are to reduce the potential for sediment recirculation in the channel and port.

“Through our work with numerous ports, we’ve developed a process for modelling the effects of dredge spoil disposal. The changes to the shape of a disposal mound are governed by long-term hydrodynamic patterns slowly transporting sediments, and by extreme events such as storms, which can drastically change the shape of the seabed over short timescales. We use a coupled wave, current, and morphological model system, Delft3D, to understand the processes governing sediment transport in the area, and to identify key transport pathways. This gives us information to help predict the expected long-term morphological changes, as well as those arising from extreme events.”
 

Morphological changes predicted at the end of an accelerated 1-year simulation. A positive magnitude indicates sedimentation. The black polygons show the proposed disposal grounds and channel.

Morphological changes predicted at the end of an accelerated 1-year simulation. A positive magnitude indicates sedimentation. The black polygons show the proposed disposal grounds and channel.

The Delft3D modelling system is placed within broader regional wave and 3D hydrodynamic models of the area. 

For waves, a 10-year historical data set (hindcast) is prepared using the Simulating WAves Nearshore (SWAN) model, carefully downscaled from a New Zealand-wide model to the high-resolution location domain. 

For currents, the Regional Ocean Modelling System (ROMS) is used to create a 10-year hydrodynamic hindcast using a three-step nesting approach, transferring the energy from a New Zealand-scale domain to a high-resolution local domain. 

The Delft3D model is used to simulate coupled wave, current and sediment transport. The modelling system uses boundary conditions from the regional wave (SWAN) and hydrodynamic (ROMS) models.

“Sediment transport depends on the particle size,” continues Simon. “To accurately predict the dispersal of sediments from the disposal site, we need reliable sediment grain size information. The settlement of larger particles, such as sandy sediments, is governed by gravitational forces, whereas for very fine sediments like silts and clays, inter-particle forces caused by ionic charges become significant. 

“When applying process-based models to predict morphological evolution, the main challenge is that the morphology of coastal systems develops over time scales several orders of magnitude larger than the time scale of the hydrodynamic fluctuations responsible for sediment transport, i.e. hours to days versus years to decades, and more. This means that a model system that can predict the time series of instantaneous hydrodynamics and sediment transport will require an unfeasibly long period to compute a multi-year real-time simulation. 

“To overcome this, we use the Morphological Acceleration Factor (MORFAC) method. MORFAC combines the reduction of the input forcing with the use of morphological factors. This means that we reduce the ambient wave and hydrodynamic forcings to a set of representative conditions that reproduce the same morphological evolution as the real-time forcing would. We do this by combining representative wave events with representative tides and current patterns for the site. 

Morphological Acceleration Factors (MORFACs) are used to represent the long-term effects of tides and waves on the seabed morphology within morphological models. Adapted from Ranasinghe et al. (2011).

Morphological Acceleration Factors (MORFACs) are used to represent the long-term effects of tides and waves on the seabed morphology within morphological models. Adapted from Ranasinghe et al. (2011).

“To account for long-term sediment movement as well as that resulting from storms, we generate two types of results: annual morphological simulations and historical storm simulations. The annual simulations provide information on the net sediment dispersion around the disposal mound each year. The real historical storm simulations model the detailed wave, circulation and sediment transport patterns that develop during energetic events, which normally cause the most significant morphological changes.

“Our modelling provides a best estimate of sediment dispersal from the disposal site over time, taking into consideration both day-to-day currents and waves and storm conditions which move large amounts of sediment in one go. The actual sediment transport may differ slightly depending on the timing of storms, but the overall pattern of sediment movement will remain valid. 

“Regulators use the information to determine the potential effects of the dredge disposal on local hydrodynamic processes, and to ensure there is minimal impact on sites of particular ecological or amenity value. Knowing where sediments will end up helps the mitigation, monitoring and management of dredging operations.”

For more information on dredge disposal modelling, contact us at enquiries@metocean.co.nz.
 

Mean wave, current velocity and sediment transport fields for a disposal site for Lyttelton Port off the Canterbury coast in New Zealand. The black polygons show the proposed disposal grounds and channel.

Mean wave, current velocity and sediment transport fields for a disposal site for Lyttelton Port off the Canterbury coast in New Zealand. The black polygons show the proposed disposal grounds and channel.

Drifting wave buoy caught in Southern Ocean eddy

The drifting Southern Ocean Wave Buoy is going round in circles deep in the Southern Ocean, temporarily slowing down its steady passage east across the southern margin of the Pacific. 

The buoy is caught in an eddy, a circular movement of water created when a bend in a surface ocean current pinches off to make a loop, which separates from the main current. 

The buoy, which has been drifting with the ocean currents since it left its moored location on 28 July, was deployed south of Campbell Island in February 2017. Part of a collaborative research project involving the Defence Technology Agency and MetOcean Solutions, the buoy has been transmitting wave spectra data via a satellite link, providing vital information which will help the New Zealand Defence Force to design patrol ships suited to the rough seas of the Southern Ocean. 

In the two and a half months since its escape, the buoy has drifted some 450 nautical miles east-northeast. In late September, the buoy passed within 20 nautical miles of the remote uninhabited Antipodes Island group.

Senior Oceanographer Dr Peter McComb is happy that data is still being transmitted. "The buoy is solar powered, and we were expecting the batteries to run out during the subantarctic winter. However, it is still happily sending wave spectra data from its path drifting slowly eastwards along the southern margin of the Pacific Ocean. So far, it has encountered moderately rough seas, with significant wave heights of up to 9 m and maximum wave heights of 15 m. 

"The prevailing winds and ocean currents in this region are towards the east, however, the buoy track meanders significantly as the drift is influenced by ocean eddies within the Antarctic Circumpolar Current. The average drift speed is about 1 km per hour, but the net eastward drift is about half that. The buoy has been trapped in an eddy for the last three weeks, resulting in almost no net drift. The eddy is unlikely to last long, and the buoy will soon be released and continue drifting east. From now on, there are very few islands in the way - if it continues due east at the current speed, it will get to the west coast of South America in about a year and a half. However, a strong southerly blow in the next few weeks could push it north toward the Chatham Islands, and if that happens we might launch a recovery mission.”  

In May 2017 the buoy made headlines when it measured a monster 19.4 m wave from the moored location near Campbell Island. 
 

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Meet us at the GODAE Ocean View Summer School

Prof Moninya Roughan sharing her ocean observation expertise.

Prof Moninya Roughan sharing her ocean observation expertise.

This week, Prof Roughan is teaching at the GODAE Ocean View Summer School in Mallorca, Spain. GODAE is the Global Ocean Data Assimilation Experiment, an international initiative started in 1997 aiming to establish infrastructure for global operational oceanography. Prof Roughan is part of a team of world-leading oceanographers brought together in the summer school to teach the next generation of leading oceanographers, some 70 students from around the world. 

Prof Roughan is giving two lectures on ocean observing, covering global and coastal in situ observations. 

New Zealand aims to be a GODAE contributor within 1-2 years with the operational development of the Moana Project modelling hindcast / forecast suite, which will be greatly facilitated by MetOcean Solutions' new role as New Zealand's operational oceanography provider. Operational oceanography is an integrated approach using a variety of methods (including satellite observations, in situ monitoring, and modelling), science-based and user-driven to describe and forecast the ocean to support societal needs.

The participants of the GODAE Ocean View Summer School. 

The participants of the GODAE Ocean View Summer School. 

MetOcean Solutions and MetService join forces

 
Today the Meteorological Service of New Zealand (MetService) acquired the final 51% of shares in MetOcean Solutions to become 100% owner. The acquisition is the result of more than four years of collaboration and planning, notes Managing Director Dr Peter McComb. ”This is the start of an exciting new phase for ocean science in New Zealand and the South Pacific,” he says. “For the first time, our country will have a cohesive national operational oceanographic capability. New Zealand is custodian of the 4th largest marine estate on the planet and that comes with a broad responsibility. The MetOcean Solutions science team has been building the expertise and resources to meet that need for the last 10 years, and now we are delighted the investment by MetService will allow the country and indeed the wider South Pacific region to realise those benefits. This means improved forecasting of waves, coastal currents, ocean temperature, storm surge and hazardous situations. Also, a rapid and reliable marine response capability in disaster situations like the MV Rena grounding will now be possible.”
 
CEO of MetService, Peter Lennox adds, ”The benefits go beyond national marine safety improvements; we see a future where exceptional weather services developed for our geography are exported to the world. The technologies developed by MetOcean Solutions are already well respected in overseas markets and with full partnership, the two organisations can more effectively leverage each other's strengths and bring the unique value of our Powerful Weather Intelligence to commercial opportunities worldwide.”    
 
MetOcean Solutions will continue to operate as a separate trading entity, maintaining the strong R&D pedigree of the past decade and adhering to its core principles of scientific integrity and technical elegance along with the ethos of ‘collaboration for success’.

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Modelling support for port modifications

Over recent years, MetOcean Solutions has modelled the effects of dredging for ports all over New Zealand and Australia. 

Using models we can estimate the percentage of time suspended solid concentration thresholds (here 10 mg/L) are exceeded during dredge spoil disposal operations. Inner and outer dashed circles radius: 500 and 1000 m, respectively. 

Using models we can estimate the percentage of time suspended solid concentration thresholds (here 10 mg/L) are exceeded during dredge spoil disposal operations. Inner and outer dashed circles radius: 500 and 1000 m, respectively. 

“Port modifications and maintenance often involve dredging,” explains Project Director Dr Brett Beamsley. “This can include deepening channels or berth pockets, or maintaining existing depths.” 

“Over the years, we have developed modelling processes to support ports and regulators evaluate the impacts from, and manage, port dredging in the best possible manner.” 

Dredging can have complex effects. It causes sediment release and temporarily increased levels of suspended solids. Dredge spoil disposal changes the shape of the seabed at the disposal site, and deepening channels can alter the waves and tidal flows in nearby areas, potentially affecting structures such as wharves and jetties, as well as processes like shoreline erosion. 

Source of a dredge plume for a Trailing Suction Hopper Dredger. 1. Drag head; 2. Overflow; 3. Prop wash. After Becker et al. (2015).  

Source of a dredge plume for a Trailing Suction Hopper Dredger. 1. Drag head; 2. Overflow; 3. Prop wash. After Becker et al. (2015).
 

The dispersal of sediments occurring during dredge disposal can be modelled.

The dispersal of sediments occurring during dredge disposal can be modelled.

Suspended solids can be harmful to marine life. To minimise adverse effects, managers need to know the extent and duration of suspended sediment plumes, and what levels of suspended solids to expect within the plumes. Because the plumes move with the water, hydrodynamic models can be used to predict their extent and duration.

Managers also need to know the effects of discharging sediment at offshore disposal sites. They need to ensure that dredge spoil is disposed at suitable sites, where potential changes to the seabed shape will not cause adverse effects on flow, tidal flushing and local wave climate, and that disposed sediments will not be carried to nearby areas of environmental or amenity importance.

MetOcean Solutions employs a multi-disciplinary team of scientists with a wide range of expertise in port studies and is therefore well placed to provide scientific advice to ports. Two of the company’s founding directors did PhD research on the wave and sediment dynamics at New Zealand ports.

“We use a variety of techniques to get the modelling spot on,” continues Dr Beamsley. “As a starting point, we collate all information we can find for the site, including any wave or current measurements. Additional field data is often collected to ensure that important flow dynamics are captured.” 

“Once we have enough data, we set up a series of models. First, we develop regional and local-scale wave and hydrodynamic models which capture important processes responsible for sediment entrainment and transport. We nest these into larger-scale wave and hydrodynamic models to ensure atmospheric forcing and river discharges are taken into account where necessary. We calibrate and validate the models against all available measured data.

“Once we’re satisfied our models are performing well, we generate a historical data set for the location, detailing wind, waves and currents for multiple years. This historical data set is used to define the wave and hydrodynamic climate of the site and is used as input into all subsequent studies.

“We simulate dredging plumes using models that track sediment particles as they disperse from the site of dredging. Dredging typically releases sediments near the seabed and just below the water surface. Following an initial near-field phase, dredge plumes move with current flows. Over time, the particulates settle out, with larger grain sizes settling faster and finer sediments being transported further, although flocculation needs to be considered. Through modelling the evolution of the plume over time, our oceanographers simulate the particulates as they settle on the seabed, and trace the levels of suspended solids that remain in the water column. 

Example of plume modelling, showing average near-seabed suspended solid concentrations (SSC) for Lyttelton Harbour, New Zealand.

Example of plume modelling, showing average near-seabed suspended solid concentrations (SSC) for Lyttelton Harbour, New Zealand.

“The dispersal of dredge spoil disposal is investigated using high-resolution morphological models, which account for the surficial sediment grain size within the disposal ground. Using these morphological model we simulate the development of the disposal ground over multiple years to decades, modelling how existing flow patterns will affect the disposal mound and how the mound will affect circulation. As part of this, we determine the likely length of time that discharged sediment resides at the offshore disposal ground and highlight sediment transport pathways, determining where the disposed sediments are likely to ultimately end up.”

After five years the disposed sediments at this site have dispersed. The figure shows the cumulative morphological changes after each year over a 5-year morphological simulation of the disposal of 18 million m3 sediment onto a 12.5 km2 disposal ground. Initial bathymetric contours are shown in black. A positive magnitude (yellow and red colours) indicates sedimentation.

After five years the disposed sediments at this site have dispersed. The figure shows the cumulative morphological changes after each year over a 5-year morphological simulation of the disposal of 18 million m3 sediment onto a 12.5 km2 disposal ground. Initial bathymetric contours are shown in black. A positive magnitude (yellow and red colours) indicates sedimentation.

For a discussion about how MetOcean Solutions can help you predict and manage the effects of your dredging operations, contact us at enquiries@metocean.co.nz.

Smart Ideas funding for MetOcean Solutions

MetOcean Solutions has received research funding for a project applying innovative technology to weather forecasting. The research, entitled ‘Machine learning for convective weather analysis and forecasting’, was funded in the Ministry of Business, Innovation and Employment (MBIE) 2017 Endeavour Round.

Led by MetOcean Solutions, the project is a collaboration with the Knowledge, Engineering & Discovery Research Institute (KEDRI) of Auckland University of Technology, and the New Zealand MetService.

“We are very pleased to receive funding for this exciting project,” states project lead Dr David Johnson.

The research will use machine learning to predict convective weather events. Convective weather produces heavy rain, lightning and strong winds, significantly impacting the safety, efficiency and well-being of New Zealanders, and recent severe events have caused loss of life and extensive damage to property.

“Convective weather is localised in time and space and can develop quite quickly and sometimes without much warning,” continues Dr Johnson. “These events are always associated with cloud masses - like big thunderstorm clouds - which can be seen from Earth-observing satellites. Currently, human forecasters detect these events by looking at satellite imagery, numerical model guidance, and rain radar. Trained forecasters are good at doing this, but humans cannot look everywhere all the time. Recent advances in machine learning mean that computers are now exceptionally good at identifying and labelling features in images. Our research will train a machine-learning algorithm to analyse satellite imagery, possibly combined with other inputs such as numerical model guidance or rain radar, and predict where and when heavy rain, lightning or wind squalls might occur. As this is a machine process it can potentially be fully automated and then used to send alerts on a phone app.

“There is a good chance that the algorithm will be better than a human at consistently making the correct predictions, which means that all New Zealanders will benefit from better weather forecasts. An automated forecasting system also allows for greater customisation and localisation for individual needs. If successful, the research could lead to apps that makes it possible for you to request a phone alert if heavy rain is likely at your location - your phone already knows where you are - allowing you to take in your washing, seek shelter or postpone your drive home. Many industries are weather-dependent, and accurate local forecasts of strong winds or heavy rainfall will help anyone working or organising events outdoors, including the forestry, fisheries, construction and transport industries, all of whom have different weather thresholds to ensure safety and efficiency. Human forecasters could never manage to serve all the myriad of end-user needs at different locations and times.

“The key to success is the collaboration with KEDRI, who are world-leading machine learning experts, and MetService who carry out day-to-day severe weather forecasts for New Zealand. MetOcean Solutions brings our track-record of applying state of the art science and technology to provide end-user tools and services.”

MBIE's 2017 Endeavour Round funded 68 new scientific research projects from 408 applications.

Click here for the MBIE press release on the funding.

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Hauraki Gulf current hindcast now available

MetOcean Solutions recently completed a 26-year hindcast detailing currents and water elevation of the Hauraki Gulf. The hindcast was created using a 2-dimensional Regional Ocean Modeling System (ROMS) model run at 250 m resolution, delivering detailed depth-averaged currents and water elevation data from 1989 to 2016.

Oceanographer Phellipe Couto carried out the modelling. He explains: “The model resolves barotropic tides - the depth-averaged velocity component of the tide - as well as water levels. The Hauraki Gulf is subject to storm surges, which are driven by wind setup and atmospheric pressure. Low-pressure systems sweeping across New Zealand result in surge, which can act to amplify the tides, causing very low or high water levels."

Snapshots of modelled atmospheric and oceanic fields during a meteorological event. Upper panels show mean sea level pressure contours and non-tidal sea surface elevation provided by the New Zealand-wide grid. The animation at the bottom illustrates the depth-averaged current flow field inside the Hauraki Gulf reproduced in the high-resolution grid.

“To accurately resolve the tides and water levels inside the Gulf, we had to get the forcings right. We used high-resolution tidal constituents at the boundaries combined to fine resolution bathymetry constructed from available data, including data from nautical charts and independent surveys. We also ran a New Zealand-scale ROMS model at 5 km resolution to provide boundary conditions, allowing us to properly downscale energy and associated sea surface perturbations from the larger scales into the 250 m grid of the Hauraki Gulf model. For atmospheric forcing, we used the Hau-Moana data set - the 12 km resolution atmospheric hindcast for the New Zealand-wide domain, and the 4 km resolution Hauraki Gulf data for our higher resolution grid.”

The hindcast data was validated against water elevation data from a tide gauge at Tiritiri Matangi Island.  

“The validation shows good agreement between modelled and measured water elevation levels,” continues Phellipe. “The hindcast provides a robust baseline tide and water elevation data set for the area, outlining the prevailing conditions for use by people who operate within or manage the Gulf. The data can also be used as boundary conditions for higher resolution modelling of local areas within the Gulf, e.g. for the hydrodynamic modelling of estuaries or embayments. This study forms the foundation for developing a full 3-dimensional hydrodynamic model which will help with the management of water quality, and gain insight into transport (e.g. of larvae or sediments), dispersion, and flushing timescales in the Hauraki Gulf.”

For further information about the Hauraki Gulf ROMS hindcast, please contact enquiries@metocean.co.nz.     

Moana Project releases Hau-Moana: NZ atmospheric downscaling data

The first output from the Moana Project is available. The project team is pleased to release the Hau-Moana data set, the New Zealand atmospheric downscaling.

Project Leader Associate Professor Moninya Roughan is excited. “We are happy to have the first data product available already. The MetOcean Solutions team has been working hard to finish this first step of the Moana Project, paving the way for the work packages to come.”
 

Top panels show low-resolution atmospheric products available globally from CFSR. The lower panels show the benefit of increasing the resolution in an NZ specific context around regions of complex topography such as the Cook Strait. Higher resolution modelling increases the accuracy of the data.  

Top panels show low-resolution atmospheric products available globally from CFSR. The lower panels show the benefit of increasing the resolution in an NZ specific context around regions of complex topography such as the Cook Strait. Higher resolution modelling increases the accuracy of the data.
 

Oceanographer Rosa Trancoso presented the project at the 2017 NZ Physical Oceanography Workshop in Wellington in mid-August. “Hau-Moana came about because we needed more accurate wind fields to improve our ocean modelling,” she explains. “The global Climate Forecast System Reanalysis (CFSR) made public by the National Center of Environmental Prediction, is used globally, however it does not provide accurate wind fields for nearshore areas, particularly around NZ. For accurate ocean modelling, atmospheric forcing needs to account for coastal topographic effects, shoreline complexity, and ocean surface temperatures. New Zealand is subject to rapidly moving weather systems, and complex topography, which means that we require atmospheric forcing data at good spatial and temporal resolution.

For the downscaling, the team used 0.312 degrees for sea surface temperature (SST) and surface fields such as pressure, humidity, temperature, etc. The modelling was done using 12-hour independent runs, discarding the first five hours to allow for model spin-up. 

The outputs were validated against data from 33 coastal sites around New Zealand and two offshore sites.

The model was validated using weather data from 33 coastal and two offshore observation sites.

The model was validated using weather data from 33 coastal and two offshore observation sites.

“Overall, the validation shows the model to perform well,” adds Rosa. “This means that we now have a better atmospheric data set for New Zealand than we’ve ever had in the past. Hau-Moana version 1.0 is a first step towards a high-quality, high-resolution, long-term reference data set, which can be improved in the future. The dataset covers the period from 1979 to 2015, and we’re currently working on a comprehensive validation and a descriptive paper for publication in a scientific journal.”

NIWA Ocean Modeller Dr Mark Hadfield says that the Hau-Moana high-resolution wind field is a key component in improving modelled circulation in the Cook Strait.

The Hau-Moana data set is freely available upon request - contact us at info@moanaproject.org if you would like to access it. 

For more information about the Moana Project, visit the website: www.moanaproject.org

Higher-resolution atmospheric modelling improves modelling of waves and currents. Left-hand images show the CFSR and WRF model outputs for mean wind speed (m/s) (top) and mean significant wave height (m) (bottom); right-hand images show the difference between the two, with negative values in blue and positive values in red.

Higher-resolution atmospheric modelling improves modelling of waves and currents. Left-hand images show the CFSR and WRF model outputs for mean wind speed (m/s) (top) and mean significant wave height (m) (bottom); right-hand images show the difference between the two, with negative values in blue and positive values in red.

Modelling the dispersal and settlement of drill cuttings

Drilling operations at sea produce a mix of fine rock fragments that need to be discharged into the ocean. While inert, these fragments (known as drill cuttings) can have sediments, contaminants and drilling fluids adhering to them. To help regulators and marine managers assess the potential impact of drilling operations, MetOcean Solutions is regularly engaged to model the dispersal and settlement of drill cuttings in the marine environment at locations all over the world. 

“Drill cuttings settle on the seabed, where they can cause adverse environmental impacts,” explains Oceanographer Remy Zyngfogel. “The oceanic discharge of drill cuttings occurs over specific time periods, but their dispersal and deposition are driven by random variables such as currents and turbulence.” 

“To determine where the drill cuttings end up on the seabed, we use a variety of methods and leverage the expertise of our multidisciplinary science team. This includes modelling the hydrodynamics of the region and simulating the trajectory and the settling of the drill cuttings to the seabed. Regulators and marine managers require good knowledge of the likely footprint of  deposition and how thick the deposits will be at increasing distances from the drill site.”

Project Director Dr Brett Beamsley oversees the hydrodynamic modelling. “We use different models to produce the historical datasets needed for the studies,” advises Brett. “Oceanic and coastal currents vary according to synoptic and seasonal winds, tides and density differences. To account for this variability, and to provide robust statistical estimates of dispersal and deposition, we use historical data to recreate the actual oceanographic conditions, typically hour-by-hour for a 10-year period. We recreate these currents using the most appropriate model. For offshore studies, we use the Regional Ocean Modeling System (ROMS), whereas for smaller-scale studies at inshore sites SCHISM or Delft3D are used.” 
 

An example of 7-day mean surface current circulation and Sea Surface Temperature (°C) for the south-eastern region of Brazil.

An example of 7-day mean surface current circulation and Sea Surface Temperature (°C) for the south-eastern region of Brazil.

Remy uses the historical current dataset to determine the dispersal of drill cuttings. “Once we have the historical currents, we use a particle tracking model to trace the dispersal and deposition of drill cuttings for simulated discharges at different times of the year,” he explains. “Ocean currents vary with factors like seasonal winds and riverine discharges, so the depositional footprint will differ depending on which time of year the drilling is done. The size of fragments discharged into the sea depends on the rock type and the drill bit design. From an estimate of particle size, we can determine settling velocities - the finest fractions of the drill cuttings settle through the water column very slowly and become widely dispersed, whereas larger particles settle quickly and much closer to the discharge location.”

Example deposition thickness for drill cuttings discharged from a marine location. The spatial distributions of deposition thickness are color-coded with values in mm on each contour line in four zoom views: 100x100 km (top left), 10x10 km (top right), 1x1 km (bottom left) and 100x100 m (bottom right). The release site is indicated as a black cross. 

Example deposition thickness for drill cuttings discharged from a marine location. The spatial distributions of deposition thickness are color-coded with values in mm on each contour line in four zoom views: 100x100 km (top left), 10x10 km (top right), 1x1 km (bottom left) and 100x100 m (bottom right). The release site is indicated as a black cross. 

“The modelling represents what is likely to happen statistically, over long time periods. Naturally, for any given discharge, the drill cuttings will disperse according to the flow conditions at the time. For example, if discharge occurs during high current flows, the drill cuttings will be transported further, and the deposition will be more spread out. If current velocities are low at the time of discharge, the cuttings will accumulate closer to the discharge point.” 

Where pre- and post-drilling sediment samples have been taken, it is possible to verify the dispersal modelling. 

“We often use barium as a tracer,” explains Remy.  “Drill cuttings contain elevated concentrations of barium from the drilling fluids. This makes barium an ideal tracer of discharged cuttings. Seabed samples taken before and after drilling can be used to determine the change in barium concentration and thereby verify the modelled deposition of the cuttings.“

“The modelling provides a statistical representation of possible outcomes, taking into account the natural variety of current flow conditions. The modelled results typically show good agreement with observed barium levels, which means that operators and regulators can confidently use the modelling to determine the extent of potential adverse effects. This information is used both when applying for permits and post-permit, in the design of environmental monitoring programmes.” 

Contact us if you would like to discuss modelling the discharge of drill cuttings or historical current data for your drilling location.

Forecasting non-tidal water level in Port Phillip Bay, Australia

When Viva Energy Australia asked MetOcean Solutions to model water levels and storm surges in Port Phillip Bay (Victoria, Australia), we jumped at the challenge. With its large surface area, shallow depth and restricted entrance, resolving the hydrodynamics of Melbourne’s main coastal inlet required careful thought.

“Viva Energy is focussed on maintaining safe under keel clearance required for ships entering Port Phillip Bay,” explains Senior Oceanographer Dr Rafael Soutelino, the project leader. “The DUKC® system recently commissioned by the Victorian Regional Channels Authority is already delivering Viva Energy thousands of tons of extra cargo on every shipment, however, improved forecasting of non-tidal water levels has the potential to further increase safe vessel draughts and increase operational planning windows. Port Phillip Bay is a complex location subject to a variety of different forcings, and discerning the interaction between all the different influences on water level was crucial if we were to make accurate forecasts for their operations.

“The main issue for Viva Energy is negative storm surge when water depth is reduced due to the complex interplay between the meteorological and hydrodynamic processes. There are particular shallow patches and sand banks along the shipping channel, which can get too shallow for larger vessels to pass. Viva Energy required us to set up a robust forecast model for the Bay, generating alerts when water depths were likely to dip below safe levels. The detailed water level forecasts we produce will also be combined with recent observations and used in the DUKC® to provide improved planning advice to all port users.”

To generate accurate forecasts, the modelling had to include a variety of forcings, including the inverse barometric effect on water levels, the important phase lag effects caused by the constrained embayment, and the local and regional meteorological effects due to wind. The model also had to capture the behaviour of the progressive coastal-trapped waves that propagate eastwards across Australia’s extensive southern coastline.

“We used the Regional Ocean Modeling System (ROMS) for this work,” continues Rafael. “To translate the wide forcing into the local area of the Bay, we downscaled from a 5 km resolution parent domain covering most of the Australian South coast to a local 300 m resolution domain covering Port Phillip Bay. The model is forced by the ECMWF forecast winds, and has an external boundary condition prescribed by the Mercator solution.”  

The ROMS 2D model grid setup. The upper panel shows the parent 5 km domain. The lower panel shows three different zoom levels of the child nest bottom topography, grid nodes and connectivity between parent and child models.

The ROMS 2D model grid setup. The upper panel shows the parent 5 km domain. The lower panel shows three different zoom levels of the child nest bottom topography, grid nodes and connectivity between parent and child models.

Viva Energy provided a host of water level data for the model validation.

“Previous studies have shown that storm surges generated in the southwest of the Australian coast propagate eastwards toward Port Phillip Bay as coastal-trapped waves. On many occasions, that travelling patch of high water level is consistently re-intensified by the storm which is also propagating eastwards, providing the perfect set of ingredients for storm surge build up.”

A significant extra-tropical storm event in June 2014 caused a strong and extensive storm surge while propagating from west to east off the south coast of Australia. Water elevations relative to mean sea level are shown in red/blue shades and mean sea level pressure (HPa) in black contours.

A significant extra-tropical storm event in June 2014 caused a strong and extensive storm surge while propagating from west to east off the south coast of Australia. Water elevations relative to mean sea level are shown in red/blue shades and mean sea level pressure (HPa) in black contours.

The final model reproduced water level variations inside Port Phillip Bay very well, and MetOcean Solutions now runs an operational forecast for the location to help Viva Energy and the Port of Geelong safely manage shipping operations.

This work was carried out in collaboration with our science partners at MetraWeather and OMC International.

Southern Ocean wave buoy heading for Chile!

On Friday 28 July, New Zealand’s Southern Ocean Wave Buoy started drifting eastward with the ocean currents.  
 
"We're not exactly sure what happened," advises oceanographer Dr Peter McComb. "However it’s likely the compliant bungy section of the mooring failed under the extreme wave conditions down there. Since February 2017, the maximum wave heights have exceeded 10 m for 26% of the time, and there are very few places on our planet that energetic. At the start of the project there were many uncertainties. Would there be enough solar power to keep it alive during the deep south winter? Would the mooring survive the constant stresses and ride out the ferocious storms? Ultimately, we are very pleased to have succeeded in our goal of making almost 6 months of very detailed spectral measurements at this location in the sub-Antarctic.”

The HMNZS OTAGO deployed the buoy in February 2017 for a collaborative research project between the Defence Technology Agency and MetOcean Solutions. From the chilly waters just south of Campbell Island, the buoy has been sending back vital wave spectral data via a satellite link. These data will now be used by the New Zealand Defence Force to design the next class of patrol ships suited to the harsh Southern Ocean climate. MetOcean Solutions have a research project to develop a global wave model with improved performance in the Southern Hemisphere, and will use the data to verify the next generation of model physics. The wave data will also be made freely available to the international research community. The Southern Ocean is known to play an important role in the climate system - cycling heat, carbon, and nutrients. Waves modulate the air-sea fluxes and the swells generated in this region have far-reaching effects, contributing significantly to the wave climate in all the major ocean basins. 

Drift track and significant wave heights measured over the last 14 days.

Drift track and significant wave heights measured over the last 14 days.

Another positive outcome is the realisation that our research project is not over yet - the buoy continues to measure wave spectra and send its data via the satellite link as long as there is sufficient solar power.  

“Now we have a new and unique opportunity to make ongoing Southern Ocean wave measurements at the very extremity of the planets’ largest ocean – the Pacific. It’s highly valuable data for oceanographers," says Peter. “Conceivably, it might take over a year to reach Chile, which would make a fantastic and very significant dataset. Let’s hope there is enough sunlight to keep powering the system during this journey.”   

MetOcean Solutions plans to deploy another wave buoy at the Campbell Island site in February 2018, with the goal of establishing a long term sub-Antarctic wave monitoring station.

“The international ocean research community recognises the value of detailed wave spectra collected at this remote location,” notes Peter, “and Campbell Island is the perfect site to make baseline measurements for climate change studies as well improving our fundamental understanding of wave physics at a planetary scale. New Zealand can make a very practical contribution to global oceanography by making high quality, real-time measurements from this site. As a nation, we are very fortunate to have some Deep South real estate with a great harbour. It’s got a lot of potential for meaningful, long term research.” 

The buoy was deployed in February 2017.

The buoy was deployed in February 2017.

A real-time data solution supports drilling operations in Wellington Harbour

Griffiths McMillan JV (GMJV) is tasked by Wellington Water and the Greater Wellington Regional Council with drilling for a new water source for Wellington City, with the goal of providing an alternative supply in the event of a severe earthquake. GMJV approached Heron Construction Company to supply the jackup barge and support tug for the project. The target aquifer, however, lies beneath Wellington Harbour - just north of the Miramar Peninsula. A marine drilling rig is required for the operations, which means that operations are very sensitive to the wave conditions.

A marine drilling rig.

A marine drilling rig.

MetOcean Solutions has been supporting Heron Construction in their specialist marine activities with high resolution forecasting for the last decade. Managing director Greg Kroef says, “We rely on the forecast guidance from MetOcean Solutions wherever we are working in Australia and New Zealand. So, when the need arose in Wellington, we approached them for the best possible weather forecasting system for this site.”

The drilling job in the harbour requires very accurate predictions of wave height. However, the oceanographic conditions in Wellington Harbour present significant challenges for forecasting, with ocean swells entering from the south along with local seas generated by the infamous capital city winds.
 
Oceanographer Dr Peter McComb and his science team extensively studied the harbour dynamics for the recent harbour deepening project. “The drilling location is affected by both the southerly ocean swells and the short local wind seas,” explains Peter. “Our forecasting model has to deal with multiple and sometimes simultaneous sources of wave energy, plus discern how those waves refract and transform due to the shape of the seabed and the harbour tidal hydrodynamics.”

The wave buoy, framed by Wellington City

The wave buoy, framed by Wellington City

The operational SWAN wave model for Wellington Harbour has a spatial resolution of 80 m, and is one of nearly 200 forecasting domains that MetOcean Solutions run four times per day for various parts of the planet. This high-resolution model is coupled with the tidal hydrodynamics to capture the effects of the ebb and flood flows through the entrance on the waves, and it has spectral boundaries prescribed by a 3-stage nest into our global WAVE WATCH III wave forecast model. The model system produces the hour-by-hour wave conditions for the coming 7 days.  

Forecast model result from MetOceanView showing the 13 July 2017 southerly storm waves penetrating Wellington Harbour. The X denotes the wave buoy location.

Forecast model result from MetOceanView showing the 13 July 2017 southerly storm waves penetrating Wellington Harbour. The X denotes the wave buoy location.

“However, just having a wave forecast model is sometimes not enough to ensure safe operations - especially in Wellington which is notorious for rapid changes in weather conditions,” continues Dr McComb. “So we decided to deploy one of our directional wave buoys near the drilling site to provide real-time monitoring of the wave conditions along with instant verification of the forecast accuracy.”

The wave buoy sends data ashore every hour so everyone involved can monitor the sea conditions in real time. See for yourself at:  http://wavebuoy.metocean.co.nz/wellington 

“When ingested into the MetOceanView forecasting system, we co-plot the measured and the forecast wave heights. This is the most honest representation of forecast accuracy, and allows users to gain confidence in the timing and the magnitude of the wave predictions. The recent storm from 13 July was a very energetic event, but we captured it perfectly from 3-4 days ahead.”   

The real-time wave buoy data shows the waves resulting from the storm in mid-July.

The real-time wave buoy data shows the waves resulting from the storm in mid-July.

Accurate wave forecast – the significant wave heights measured by the buoy were very close to those forecasted for the storm in mid-July.

Accurate wave forecast – the significant wave heights measured by the buoy were very close to those forecasted for the storm in mid-July.

MetOceanView ingests observations from over 10,000 sites every day, including 252 locations around New Zealand. 

For queries about ingesting site-specific data, contact enquiries@metocean.co.nz.

Dr Aitana Forcén-Vázquez joins MetOceanView support team

This week we welcome Aitana Forcén-Vázquez, our new Technical Support Liaison.

Originally from Spain, Aitana has a PhD in physical oceanography from Victoria University, and recently completed Postdoctoral research in Southern Ocean dynamics at NIWA in Wellington. In her new role, Aitana will be providing technical support to our marine forecast clients throughout New Zealand and worldwide.

"I am looking forward to engaging with the MetOceanView users," says Aitana. "Having spent substantial time in and on the ocean, I understand the challenges that weather poses for ocean-based industries. I’m really excited to be part of a team providing scientifically robust data in meaningful ways.”  

Aitana is based in our Raglan Office. 

SurfZoneView part of KiwiNet Awards

MetOcean Solutions is proud to be part of the KiwiNet Research Commercialisation Awards. Last week, we attended awards night, where shortlisted New Zealand innovators shared how they are bringing their ground-breaking research to market.

The Kiwi Innovation Network (KiwiNet) is New Zealand’s network of public research organisations, working together to transform scientific discoveries into marketable products and services. MetOcean Solutions and the Defence Technology Agency were nominated for SurfZoneView, a software tool which helps safely plan nearshore operations such as landing vessels, personnel or supplies.

Sally Garrett from the Defence Technology Agency with David Johnson.

Sally Garrett from the Defence Technology Agency with David Johnson.

"We are very honoured to be part of the event," states Technical Director Dr David Johnson. "It is fantastic to see the real-word ingenuity and problem-solving displayed by participants, and the great examples of partnerships between research and industry, We value our collaboration with the Defence Technology Agency, and are proud to have worked with them to come up with solutions to make the New Zealand Defence Force safer." 

View the award video below, visit our SurfZoneView webpage or read the SurfZoneView pdf.

Meet us at the NZ Marine Sciences Society Conference

MetOcean Solutions will be at the New Zealand Marine Sciences Society annual conference in Christchurch this week.

The conference, which is held 4-6 July at the University of Canterbury, has as its theme 'Mahi Ngatahi: Working together for better management into the future'. 

At the conference, Dr Brett Beamsley will present estuary modelling done for Otago Regional Council, and Dr Peter McComb will present the multi-agency Moana Project

For more information, visit the conference website: https://www.nzmss2017.org/

Storm watch helps safe management

Forecasts of wind and wave conditions are vital for effective and safe management of near- and offshore operations. MetOcean Solutions has developed a warning system based on ensemble forecasting, which allows us to provide warning of upcoming severe wind and wave conditions for up to 7-day horizons, thereby helping operators plan for safe and efficient management.

Accurate high-resolution forecasts of wave conditions at local scales can be done using nested or grid-refining models such as SWAN (Simulating WAves Nearshore). Such forecasts capture local wave transformation and dissipation, and can be done at a reasonable computational cost. However, at horizons beyond 2-3 days a forecast inevitably suffers from the onset of chaotic uncertainty that is a physical characteristic of the atmosphere-ocean system. 

Ensemble forecasting is a method that quantifies this uncertainty in longer-range forecasts, providing probabilistic guidance for management decisions. MetOcean Solutions can customise a forecast warning system for any offshore or nearshore location based on the 7-day forecast wind speed, significant wave height (Hs) and maximum individual wave height (Hmax). The method used to estimate extreme Hmax accounts for the long-term uncertainty of the severity of the environment and the short-term uncertainty of the severity of the maximum wave of a given sea state, complying with the International Organization for Standardization (ISO standards).

Example of Storm Watch programme. T indicates present time.

Example of Storm Watch programme. T indicates present time.

We use such ensemble forecasts to provide the best possible site-specific warning to clients of upcoming severe conditions, using pre-set thresholds to define the level of alert. 

Up to 60 wind and wave ensemble forecasts can be used to support a storm watch programme.  

An example of email alert is illustrated below. All components of the email can be customised upon request.
 

Example of Storm Watch alert email. 

Example of Storm Watch alert email. 

Storm watch guidance. Orange shading indicates when the alerting thresholds are exceeded. Wsp: windspeed. Hmax: maximum wave height. Hs: significant wave height. 90 PCTL: 90th percentile. 

Storm watch guidance. Orange shading indicates when the alerting thresholds are exceeded. Wsp: windspeed. Hmax: maximum wave height. Hs: significant wave height. 90 PCTL: 90th percentile. 

Wave height warnings. Red shaded area represents the incoming wave direction for which thresholds are exceeded.

Wave height warnings. Red shaded area represents the incoming wave direction for which thresholds are exceeded.

MetOcean Solutions can set up a storm watch programme for any location. For more information, or to discuss your site, contact us at enquiries@metocean.co.nz.

Meet us at Coasts & Ports 2017

Later this week, MetOcean Solutions will be at the 2017 Coasts & Ports Conference in Cairns, Australia. 

Project Director Dr Brett Beamsley and MetOcean Solutions' Australian representative Dr Alexis Berthot will both attend the conference. Brett will be presenting recent research on dredging plume dispersion.  

Running from 21 to 23 June, the Coasts & Ports Conference is the pre-eminent forum in the Australasian region for professionals to meet and discuss multi-disciplinary issues related to coasts and ports. This year the conference theme is 'Working with Nature', reflecting the need to design and operate projects from a perspective that places the natural environment at the forefront.

Geraldton Port - improving long wave predictions with real-time wave buoy data

“MetOcean Solutions has worked exceptionally hard to assist the Port of Geraldton with its surge problem. The product they now deliver is heavily relied on when scheduling shipping. The efficiencies gained in reduced labour costs to port users are significant, but is the contribution to safety that represents the greatest gain. In 2005 there were 242 parted ships lines at Geraldton. Following the developments in forecasting Long Wave effects at Geraldton, last year there were only 30 parted ships lines. This was the lowest number of parted lines since records have been kept. MetOcean Solutions is keeping Geraldton Port efficient, and port workers safe.”
Captain Ross Halsall, Acting Harbour Master, Port of Geraldton.

Observational wave data can help ports manage the onset of long wave events. In recent work for Geraldton Port (Australia), we improved our harbour long wave forecasts by integrating wave buoy data from two upstream locations into the short-range predictions.

Long (or infragravity) waves are created when swell waves interact with the coast and result in water level oscillations with periods much longer than the original swell waves. Long wave periods of 60-120 seconds are typical, and these are very problematic because their wavelength is similar to the size of ships. When such waves enter a harbour the moored vessels are energised, causing dangerous surging which can break lines and put personnel in danger. As a result, ports often have to close when long wave heights exceed a safe threshold.
 
Accurate forecasts of long wave height can help ports increase safety, reduce unwarranted closures and effectively plan for reopening. For the past 11 years, MetOcean Solutions has provided a specialist long wave forecasting service that ports and harbours throughout New Zealand and Australia have come to rely upon.   
 

Numerical simulation showing that the sea-swell climate in the vicinity of the Port of Geraldton is extremely complex, mainly due to the reef near the Port entrance.

Numerical simulation showing that the sea-swell climate in the vicinity of the Port of Geraldton is extremely complex, mainly due to the reef near the Port entrance.

“Our scientific research over many years provides the basis for a robust prediction system,” explains Senior Oceanographer Dr Severin Thiebaut. “We use a semi-empirical technique to establish the relationship between the offshore wave spectra and the long wave height at each berth in a port. It's a method that we have tested at more than 30 locations worldwide”. 
 
The forecast wave spectra is derived from the suite of global and regional numerical models run by MetOcean Solutions. Geraldton Port have been using these predictions to guide the harbour operations since 2007. Predictions have proved very reliable, but sometimes the arrival of a swell front may differ from the forecast by a few hours as the exact timing is difficult to resolve perfectly with a spectral wave model. To supplement the long wave forecasts, we developed a new technique using real-time wave buoy data to improve the short term predictions and better detect occasions with a sharp rise in long wave energy inside the harbour. 
 
‘“The goal is to ensure that our port clients are never surprised by weather events,” says Dr Thiebaut.  

The Department of Transport maintains wave buoys at Rottnest Island and at Jurien Bay, some 370 km and 170 km to the south of Geraldton, respectively. The live data from these buoys, updated at 30 minute intervals, are used to track the progression of swell up the west coast of Australia and provide harbour long wave predictions some 5-6 hours ahead.

Data from wave buoys at Rottnest Island and Jurien Bay help improve long wave predictions for Geraldton Port.

Data from wave buoys at Rottnest Island and Jurien Bay help improve long wave predictions for Geraldton Port.

“Using the live buoy data provides additional confidence to the standard forecasts. In particular, it allows us to accurately capture any rapidly rising long wave events. It also gives the port operators a better idea of when wave heights will decrease to safe working levels. Geraldton Port accesses the forecast information through the web-based MetOceanView platform and through their local environmental monitoring software. On the same plot we show the measured long waves at the berth along with the values that are forecast by our standard system plus those predicted by the buoys.” 
 

Comparison between measured and predicted significant long wave heights (Hslpw) in the Port of Geraldton in 2012 based on Jurien Bay real-time wave buoy data.

Comparison between measured and predicted significant long wave heights (Hslpw) in the Port of Geraldton in 2012 based on Jurien Bay real-time wave buoy data.

Contact us for a discussion of what we can do to help your port. Call +64 6 758 5035, email enquiries@metocean.co.nz or visit www.metoceanview.com.