Argo Profiling Floats

The Argo oceanographic radiosonde is a revolutionary concept that enhances the real time capability for the measurement of temperature and salinity through the upper 2,000 m in the ice free global Ocean. The exclusion of the high latitudes was due to the inability of early floats to sample under sea-ice. However, technological advances in float design in recent years now give us this capability. Advancements have come through re-design of hardware (i.e. armoured ice floats with ice-hardened...

Dispersion Relation

Substitution of the solutions for < p(x, z, t) and n(x, t) into the Bernoulli equation (Eq. 8.11) will give the following relationship between wave frequency and wavenumber This is the dispersion relation (so-called for reasons which will become apparent later). A number of useful properties of the motion can now be derived. We will firstly examine the differences between waves in deep water and waves in shallow water. Waves in deep water are defined to be those for which the depth of the...

Forecast Methods Their Strengths and Weaknesses 2431 Climatology

Until the recent advent of operational oceanography, navies have had to rely on climatologies or point observations to make operational decisions (Jacobs et al. 2009). Climatologies can be useful for planning purposes, but they are of limited use where oceanic variability is high. In the extreme case of a bimodal system, climatology shows the mean of the two modes, which may be a physical situation that never arises in reality (e.g. south or north of a front, inside or outside an eddy). Figure...

Quality Control Decision Making Algorithms

The quality control outcomes of the various external data checks described previously are combined in a decision-making algorithm. The outcome of the decision-making algorithm is the overall indication of observation quality, which is used to select data for the assimilation. The decision-making algorithm is applied to each observed reporting level and, in the case of profile (and glider) observations, to the entire profile in the shape comparison test. Thus, for profile observations there are...

Amphibious Warfare

Amphibious operations can be very sensitive to weather and oceanographic conditions. The offloading of troops and equipment from specialist amphibious shipping to a beachhead involves transfers from ships to landing craft, and from landing craft to the beach itself. Most navies possess a range of relatively small watercraft for use during amphibious operations. Such activities are sensitive to sea state, swell and surf conditions, tidal streams, longshore currents and rips, which must all be...

An Overview of Recent Developments for Computationally Efficient Applications in Operational Oceanography

Abstract Ensemble-based methods have become very popular for data assimilation in numerical models of oceanic or atmospheric flows. Unlike the deterministic Extended Kalman Filter which explicitly describes the evolution of the best estimate of the system state and the associated error covariance, ensemble filters rely on the stochastic integration of an ensemble of model trajectories that are intermittently updated according to data, using the forecast error covariance represented by the...

Salinity Gradients

Seawater is approximately 200 times more saline than fresh river water, derived from rain, snowmelt or groundwater and is delivered to the coast by major rivers. Global salinity differences arise from submarine and surface current movements (Fig. 26.6). The relatively high level of salinity in seawater thus establishes a pressure potential with sweet river water, which can be used to generate electricity or derive fresh (drinking) water from the seawater. This 'osmotic' pressure differential...

Ship and Buoy Sea Surface Temperature

Volunteer observing ship (VOS) temperatures have very different error characteristics depending on the measurement method. Hull contact sensor measurements of temperature appear to be the most accurate followed by engine room intake and buckets. However, all ship-based measurement systems are prone to error since the on-board instruments are rarely calibrated. In general, ship-based SST measurements are noisy and observations from engine-room-intake instruments tend to be warm biased, while...

Basin Scale Observing System IndOOS

Of the three major oceans Pacific, Atlantic, and Indian the Indian Ocean has is the only one that is not open to the northern subtropical regions. This is a consequence of the presence of the Asian landmass restricting the Indian Ocean to south of about 25 N and hence it cannot transport heat gained in the tropics to the higher northern latitudes, as the Pacific and Atlantic oceans do, mainly via their western boundary currents. Furthermore, the Indian Ocean is the only ocean with a...

Ocean Data Quality Control

Abstract Automated ocean data quality procedures are presented. The procedures are logically grouped into four stages of processing, which when taken together form a complete sensor-to-prediction quality control system. The main features of the different ocean observing systems assimilated by GODAE are presented along with sources and types of errors that can occur in the data. Specific quality control procedures are described that test for these errors as well as more general procedures that...

Ocean Modelling

The science about turbulent closure schemes is now fairly mature, but there may still be surprises associated with subtle aspects of vertical mixing in the deep ocean that may have important consequences on long time scales. Vertical mixing is also critically important for biogeochemical cycles, because it controls the return of nutrients to the surface euphotic zone, and therefore the magnitude of primary production. Another area where there still is room for improvement concerns the exchanges...

Impacts on Marine Biota

The effects of arrays of ocean energy converters on marine mammals, elasmo-branchs (i.e., sharks) and other marine fauna are likely to be principally habitat modification, collision risk, noise and electromagnetic fields. As noted above, placement of artificial structures on the seabed will modify local current patterns and cause scouring or sediment deposition. However, these effects are likely to be limited with respect to tidal or ocean current devices. In the case of tidal current devices,...

First Installation Site Garden Island WA

The first full scale CETO devices will be deployed in an area near Garden Island off the coast of Western Australia as in Fig. 27.3. This is ultimately the planned site for a 5 MW wave farm comprising multiple CETO units that is expected to be one of the first (if not the first) commercial scale wave farm in the southern hemisphere. Grid connected power is expected to be available by 2012. The site is located in the Sepia Depression, an area of 20-25 m water depth between Five Fathom Bank and...

Ships of Opportunity

The primary objective of the Ship-of-Opportunity Programme (SOOP) is to fulfill the XBT upper ocean data requirements established by the international scientific and operational communities, which can be met at present by measurements from ships of opportunity. The annual assessment of transect sampling is undertaken by the Joint WMO-IOC Technical Commission for Oceanography and Marine Meteorology (JCOMMOPS) on behalf of the Ship Of Opportunity Programme Implementation Panel (SOOPIP). Data...

The Challenges for the Next Decade

Most national forecasting centres have or are now transitioning towards operational or pre-operational status. Ocean forecasting systems are also evolving to satisfy new requirements just mentioned and must benefit from scientific advances in ocean modelling and data assimilation. International collaboration and coordination of both operational and research activities related to ocean analysis and forecasting must continue during this sustained operational phase. The challenges and expectations...

Classification of Ocean Energy Conversion Technologies

There are a number of classification schemes for ocean energy conversion technologies. A primary classification can be made based upon the basic energy resource being harnessed 1. Potential and kinetic energy in waves and currents 2. Chemical potential of seawater (salinity gradients) 3. Heat potential of seawater (ocean heat and geothermal heat) 4. Biological potential of seawater 26.4.1.1 Wave, Tidal and Ocean Current Technologies These technologies effectively utilize the potential energy...

Acoustic Tomography

The ocean is largely transparent to sound, but opaque to electromagnetic radiation. Underwater sound is therefore a powerful tool for remote sensing of the ocean interior. This technique is used in Ocean Acoustic Tomography. It is used to measure temperatures and currents over large regions of the ocean (Munk et al. 1995). On ocean basin scales, this technique is also known as acoustic thermometry. The technique relies on precisely measuring the time it takes sound signals to travel between two...

OC2m2

Fig. 19.11 Sensitivity of J to surface temperature at different times during the 3-day period. Top row. Southward down-welling winds. Bottom row. Northward upwelling winds. Panel at right shows sensitivity at day 0 (upwelling case) on a vertical section. (See the text for discussion) dynamical processes that were not incorporated in the model physics employed here that are worthy of incorporation in future model-based studies. In the NYB, sea-land-breeze system (SLBS) activity can be pronounced...

Location Speed Test

A location (speed) test is used to determine if the reported position of an observation is consistent with prior positions from the same platform. The test is necessarily restricted to data types that report unique call signs, such as Argo floats, surface ships, aircraft, and fixed and drifting buoys. Observations failing the location speed test are typically scheduled for manual intervention. No automated method exists at the present time to correct erroneous reported positions. The speed test...

General Environmental Effects

The key effect will be occupation of sea space, particularly for 'arrays' or 'farms' of devices, a problem potentially exacerbated by regulatory requirements for exclusion zones to prevent other activities, e.g., fishing, particularly trawling, in the same area. Ocean energy projects will compete for access to sea space with pre-existing or pre-assigned uses, such as fishing quota zones, marine reserves and areas reserved for military use and shipping lanes. Hard structures, such as converter...

Tides

Periodic movements which are directly related in amplitude and phase to some periodic geophysical force are defined a tides and astronomic tides are the most widely recognised phenomena affecting water levels (Pugh 1987). These tides are the harmonic fluctuations of water level developed through the gravitational attraction from astronomic bodies (mainly the sun and moon). In majority of the world's coastlines there are two tidal cycles per day (i.e. two high and low waters per day and these...

Spill Forecast Bulletin for Montara Incident Issued Midday 29October2009for the Australian Maritime Safety Authority

Over flight and satellite observations collected from the 24th-28th October 2009 have been used to update oil, oil patches and wax positions within the AMSA OIL-MAP Oil Spill Trajectory Model (OSTM). The recent satellite observations indicated that the slick was patches of oil wax lying east and southeast of Montara extending to the south as patches (refer to Fig. 25.5). The winds have remained favourable over recent days which has seen the edge of the slick move parallel to the coast...

Seiches

A free oscillation in an enclosed or semi-enclosed body of water, similar to the oscillation of a pendulum where the oscillation continues after the initial force has stopped, is defined as a seiche (Miles 1974). Several factors cause the initial displacement of water from a level surface, and the restoring force is gravity, which tends to maintain a level surface. Once formed, the oscillations are characteristic only of the system's geometry (length and depth) and may persist for many cycles...

Air Sea Fluxes of Heat Freshwater and Momentum

Abstract An overview of the air-sea fluxes of heat, freshwater and momentum is presented with the emphasis being on methods used to determine these fluxes and the role they play within the wider climate system. The equations used to determine the various heat flux components and the wind stress (which is equivalent to the momentum flux) are described in detail, together with the main spatial characteristics of the resulting global fields. This is followed by an overview of currently available...

Elements of Observing System 321 Tide Gauges

The measurement of changes in sea level to understand the mechanisms responsible for phenomena such as the tides and the catastrophic floods due to storms and tsunami was performed by the observers of the Ocean from ancient times. It is now realized that sea level changes are important on all timescales from seconds (due to wind waves) through to millions of years (due to the movement of continents). The devices employed to make sea level changes (relative to the level of the land where the...

Xa Xb aXX Vyy Xb136

In spite of its simplicity, this example shows some of the key features of advanced linear data assimilation methods. First, note that the optimal estimate in Eq. (13.6) is a linear combination of the background xb and the residual y - xb. The term Sxa a2x(a2x + o2y)- y - xb) (13.8) is called the analysis increment. Note the limits ox 0 (perfect background) and y 0 (perfect data), which yield xa xb and xa y, respectively. Furthermore, the estimated variance of the optimum (13.7) is less than...

Preliminary Data Sensibility Checks

Several preliminary data sensibility error checks are performed prior to the quality control of the observed values. Observations failing any one of these preliminary data checks are considered to have gross errors and are discarded or flagged for rejection. In some cases the preliminary data checks are performed by the data provider and the observations are simply not distributed. The preliminary data checks and logic for accepting rejecting observations at this stage of the quality control...

Isopycnic and Hybrid Ocean Modeling in the Context of GODAE

Abstract An ocean forecasting system has three essential components (observations, data assimilation, numerical model). Observational data, via data assimilation, form the basis of an accurate model forecast the quality of the ocean forecast will depend primarily on the ability of the ocean numerical model to faithfully represent the ocean physics and dynamics. Even the use of an infinite amount of data to constrain the initial conditions will not necessarily improve the forecast against...

Ty pCDUyU2 Uy12

Where ux and uy are the zonal and meridional components of the wind speed respectively, and CD is the drag coefficient which depends upon the height of the wind measurement and the atmospheric stability as well as wave characteristics (e.g. Smith 1988 Taylor and Yelland 2001). Climatological analyses of the wind stress using these formulae with ship meteorological reports have been carried out in a number of studies (e.g. Hellerman and Rosenstein 1983 Harrison 1989 Josey et al. 2002). More...

Seasonal and Decadal Prediction

Oscar Alves, Debra Hudson, Magdalena Balmaseda and Li Shi Abstract Dynamical seasonal prediction has grown rapidly over the last decade or so. At present, a number of operational centres issue routine seasonal forecasts produced with coupled ocean-atmosphere models. These require real-time knowledge of the state of the global ocean since the potential for climate predictability at seasonal time scales resides mostly in information provided by the ocean initial conditions, in particular the...

References

Alcocer SM, Hiriart G (2008) An applied research program on water desalination with renewable energies. Am J Environ Sci 4(3) 190-197 Alves O, Hudson D, Balmaseda M, Shi L (2010) Seasonal and decadal prediction. In Schiller A, Brassington GB (eds) Operational oceanography in the 21st century. Springer, Dordrecht Brehany JJ (1983) Economic and systems assessment of the concept of nearshore kelp farming for methane production. Parsons Co. and Gas Research Institute, Technical Report PB-82-222158...

Integrating Coastal Models and Observations for Studies of Ocean Dynamics Observing Systems and Forecasting

Zhang, Bronwyn E. Cahill and Robert C. Chant Abstract In coastal oceanography, simulation models are used to a variety of ends. Idealized studies may address particular dynamical processes or features of coastline and bathymetry reproducing the circulation in a geographical region can compliment studies of ecosystems and geomorphology and models may be employed to simulate observing systems and to forecast oceanic conditions for practical operational needs....

Case Study 1Pacific Adventurer

In the early hours of the morning on the 11th of March 2009 the Pacific Adventurer encountered severe weather conditions (as a result of nearby Tropical Cyclone Hamish) whilst on route from Newcastle to Indonesia. As a result of the severe weather conditions, 31 shipping containers (containing a total of approximately 600 tonnes of ammonium nitrate) were lost overboard. Several of the containers ruptured the ship's fuel tanks, which resulted in the loss of 270 tonnes of heavy fuel oil to the...

Tides and Internal Waves on the Continental Shelf

Abstract We review recent laboratory experiments, field observations and numerical modeling of internal waves produced by tidal motions, with specific focus on the Australian North West Shelf. Distinct regimes are observed depending upon both the characteristics of the ambient density stratification, the topography, and the intensity of the tidal forcing. The character of the near boundary flow in the region where waves are generated is very important in determining the internal wave response....

Evaluating the Large Scale Mean and Variability

It is important to check that the average properties of the ocean forecasting systems are providing a good representation of the ocean climate. This is usually done by comparing multi-annual averages to climatologies generated from observational data-sets. One example of this is a comparison between a mean dynamic topography (MDT, such as that of Rio et al. 2005 or Maximenko and Niiler 2005), with the model's average sea surface height field. This provides a useful guide as to the ability of...

Trends and Growth in Ocean Energy

The year 2008 was an important one for ocean energy. The world's first 'pre-commercial tidal demonstrator', the Marine Current Turbines' SeaGen tidal generator, began to feed electricity into the Northern Ireland Grid (Fig. 26.11a). Shortly afterwards, the world's first wave farm array (of three Pelamis devices) became operational at Agu adoura in northern Portugal (Fig. 26.11b). Fig. 26.11 Recent marine energy deployments. a MCT's SeaGen pre-commercial tidal demonstrator (Source and b Pelamis...

Drifting Buoys

For several years, oceanographers and meteorologists have deployed satellite-tracked drifting buoys in support of their research and operational programmes. These two bodies of users have, however, sought different capabilities from their drifters the oceanographers have mainly looked for designs which accurately follow water parcels at a given depth, whereas the meteorologists have equipped their drifters with air-pressure sensors to collect real-time observations for weather forecasting....

Forms of Ocean Energy

For the purposes of this paper, ocean energy resources are defined as those energy resources, which use seawater as either the motive power or for its chemical or heat potential. There are at least six principal forms of ocean energy, which could be harnessed to produce electricity or other products. These forms are a. Ocean Thermal Energy Conversion (OTEC) Some authors consider offshore wind energy as a form of ocean energy but it is derived from the movement of winds, rather than the kinetic...

Scientific Objectives of Godae Ocean View

The GODAE OceanView Science Team (GOVST) was established in 2008, with the mission to define, monitor, and promote actions aimed at coordinating and integrating research associated with multi-scale and multidisciplinary ocean analysis and forecasting systems, thus enhancing the value of GODAE OceanView outputs for research and applications. Over the next decade, the science team will provide international coordination and leadership in The consolidation and improvement of global and regional...

Voluntary Observing Ships

The Voluntary Observing Ships (VOS) scheme is an international programme comprising member countries of the WMO IOC that recruit ships to take, record and transmit marine meteorological observations whilst at sea. The VOS Scheme is a core observing programme of the Ship Observations Team (SOT) in the Observations Programme Area of JCOMM. There are three types of ships in the VOS Scheme such as selected ships, supplementary ships and auxiliary ships. A selected ship is equipped with sufficient...

HF Radar

Real-time surface current information is a valuable supplement to understanding coastal air-sea interaction and dynamical processes at the coastal scales. Coastal surface current information may be correlated to winds and tidal currents among other physical phenomena. High-frequency (HF) radars have been used for measuring surface current fields and ocean-wave spectra. The physics behind HF radar is based on backscattering from a moving rough sea surface. The Radar transmits electromagnetic...

Impacts of the Ocean on Operations 2421 Anti Submarine Warfare ASW

The need for specialist oceanographic expertise first came to be recognised by the RAN in the mid 1950s, when the Fairey Gannet Anti-Submarine Warfare (ASW) aircraft was first operated from the aircraft carrier HMAS MELBOURNE. Meteorological officers onboard MELBOURNE provided tactical oceanographic advice to the Gannet squadrons, using bathythermographic observations of the ocean as the basis for sonar performance predictions. This advice was used by the Gannet crews to determine the optimum...

Ocean Observing Systems

A wide variety of observation data types are used in GODAE assimilation systems. The data include both in situ and remotely sensed measurements from space. As will be discussed, each observing system has its own unique data issues and Fig. 4.1 Chart showing flow of ocean observations through the different stages of ocean data quality control in the U.S. Navy global HYCOM system. Stage 1 sensibility error checks are performed on the raw data stage 2 external data checks are performed in the...

Case Study 3MSC Lugano Stranding

The MSC Lugano is a 240 m container ship which was en route from Adelaide in South Australia to Fremantle in Western Australia. On the 31st of March 2008 it was disabled by an engine room fire and as a result, was in jeopardy of grounding off Esperance, Western Australia. Three tugs from nearby Esperance were called in to provide assistance, whilst another larger and better equipped tug was en route from Fremantle. The tugs took Table 25.2 Metocean forecast products used during the Montara well...

Moorings

Moorings are capable of measuring some of the key variables needed to describe, understand and predict large-scale ocean dynamics and ocean-atmosphere interactions. Marine meteorological variables include those needed to characterize fluxes of momentum, heat and fresh water across the air-sea interface, namely, surface winds, SST, air temperature, relative humidity, downward short and long-wave radiation, barometric pressure and precipitation. Physical oceanographic variables include...

Surface Waves

Abstract In this chapter, we first present the governing equations for linear wave theory. This provides a simple but yet powerful description of the wind-driven waves on the ocean surface. A number of important concepts are derived, including the dispersion relation. From the dispersion relation we examine some differences between waves in deep water and waves in shallow water and in particular we demonstrate that deep water waves are dispersive, while shallow water waves are non-dispersive....

Dynamical Evaluation of Ocean Models Using the Gulf Stream as an Example

Joseph Metzger, James G. Richman, Eric P. Chassignet, Yann Drillet, Matthew W. Hecht, Olivier Le Galloudec, Jay F. Shriver, Xiaobiao Xu and Luis Zamudio Abstract The Gulf Stream is the focus of an effort aimed at dynamical understanding and evaluation of current systems simulated by eddy-resolving Ocean General Circulation Models (OGCMs), including examples with and without data assimilation and results from four OGCMs (HYCOM, MICOM, NEMO, and POP), the first two...

Summary and Conclusions

Over the past 40 years, numerical modelling has developed rapidly in scope (from hydrodynamics to ecology) and resolution (from one-dimensional, 102 elements to three-dimensional, 108 elements) exploiting the contemporaneous development of computing power. Although we have made significant progress with the implementation of the global ocean observing system, concurrent development in observational capabilities has not been achieved yet in areas demanding high spatial resolution such as coastal...

Brief History of Oceanography

The focus of this article and this book is on the two branches of oceanography that Physical oceanography, or marine physics, that studies the ocean's physical attributes including temperature-salinity structure, mixing, waves, internal waves, surface tides, internal tides, and currents, acoustical and optical oceanography and, to some extent, biogeochemical oceanography which involves the scientific study of the chemical, physical, geological, and biological processes and reactions that govern...

Repeat Hydrography and Carbon Inventory

Despite numerous technological advances over the last several decades, ship-based hydrography using research vessel remains the only method for obtaining high-quality, high spatial and vertical resolution measurements of a suite of physical, chemical, and biological parameters over the full water column (Hood et al. 2009). It is worth mentioning here that VOS and SOOP collect data while cruising, whereas research vessel stops at different locations and collect surface and subsurface data upto...

Movemricomwnp

COM-WNP (Multivariate Ocean Variational Estimation system Meteorological Research Institute Community Ocean Model western North Pacific version) uses MRI.COM as ocean model. The layer thickness near the surface follows surface topography in this z-coordinate model (Hasumi 2006). For the nonlinear momentum advection, the generalized entropy-preserving scheme (Ara-kawa 1972) is used, which is based on the concept of diagonally upward downward mass momentum fluxes along the sloping...

Ocean Forecasting Systems Product Evaluation and Skill

Abstract The evaluation of output from ocean forecasting systems is important in order to inform users how much confidence can be placed in the products, and helps identify areas for improvement in the systems. An overview of the statistical methods which can be used to perform the evaluation is provided. Examples of some commonly used methods from various GODAE systems are given, including evaluation of large-scale model performance, the use of output from data assimilation systems, the use of...

Relocatable Ocean Atmosphere Model ROAM

The Relocatable Ocean Atmosphere Model (ROAM) is used by the RAN to generate high resolution oceanic and atmospheric forecasts over limited domains of interest to the Australian Defence Force (ADF). ROAM is designed to be set up by non-expert users, with minimal input, anywhere in the Australian region (Herzfeld 2009), and is used routinely by RAN forecasters. The ROAM ocean model is initialised and forced by data from OceanMAPS, and is typically implemented at resolutions of 1-2 km. Figure...

Interp k e [1 K

The cell average values are then recovered as, The exact integrals of the discrete integral variable are advantageous when Ax is chosen to be an integer multiple of AX i.e., Ax nAX such that a subset of k are equivalent to This formulation has been expressed for a uniform grid in Cartesian coordinates but this method is readily extended to non-uniform grids and other orthogonal curvilinear coordinate systems. It is also noteworthy that a centre point value is a second-order accurate estimate of...

Marine Biogeochemical Modelling and Data Assimilation

Abstract The inclusion of biogeochemistry into the Global Ocean Data Assimilation Experiment systems represents an exciting opportunity that involves significant challenges. To help articulate these challenges we review marine biogeochemical modeling and the existing applications of biogeochemical data assimilation. The challenges of biogeochemical data assimilation stem from the large model errors associated with biogeochemical models, the computational demands of the global data assimilation...

Forecast Skill

As mentioned in Sect. 20.2, ENSO is the most predictable large-scale phenomenon on seasonal to interannual timescales, and is the major source of predictability. Successful predictions with a coupled seasonal forecast model are, therefore, often related to a model's ability to reproduce the slow coupled dynamics of ENSO and accurately forecast its amplitude, spatial pattern and detailed temporal evolution Wang et al. 2008a . The skill of forecasting ENSO varies depending on the season, as well...

Eddying vs Laminar Ocean Circulation Models and Their Applications

Bernard Barnier, Thierry Penduff and Clothilde Langlais Abstract Mesoscale eddies are ubiquitous and very energetic features of the ocean circulation. They are represented in the high resolution models used for ocean forecasting, but not yet in today's laminar, coarse-resolution ocean components of models of the climate system. However, advances in high performance computing are likely to change this in a near future, as the next decade should see the use of eddying models to become more and...