offshore Offshore may refer to: Science and technology * Offshore (hydrocarbons) * Offshore construction, construction out at sea * Offshore drilling, discovery and development of oil and gas resources which lie underwater through drilling a well * Off ...

and coastal engineering, metocean refers to the

syllabic abbreviation An abbreviation (from Latin ''brevis'', meaning ''short'') is a shortened form of a word or phrase, by any method. It may consist of a group of letters or words taken from the full version of the word or phrase; for example, the word ''abbrevia ...

of meteorology and (physical) oceanography.

Metocean study

In various stages of an offshore or coastal engineering project a metocean study will be undertaken. This, in order to estimate the environmental conditions of direct influence on the choices to be made during the project phase at hand, and to arrive at an effective and efficient solution for the problems/goals stated. In later phases of a project, more detailed and thorough metocean studies may be needed, depending on whether there is an expected additional gain with respect to the successful and efficient completion of the project.

Metocean conditions

Metocean conditions refer to the combined wind, wave and climate (etc.) conditions as found on a certain location. They are most often presented as statistics, including

seasonal variation In time series data, seasonality is the presence of variations that occur at specific regular intervals less than a year, such as weekly, monthly, or quarterly. Seasonality may be caused by various factors, such as weather, vacation, and holidays a ...

s, scatter tables, wind roses and probability of exceedance. The metocean conditions may include, depending on the project and its location, statistics on: ;Meteorology: * wind speed, direction, gustiness, wind rose and wind spectrum * air temperature * humidity * occurrence and strength of typhoons, hurricanes and (other)

cyclone In meteorology, a cyclone () is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an anti ...

;Physical oceanography * water level fluctuations ** historical, expected and seasonal sea level changes **

storm surge A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the n ...

s ** tides ** tsunamis ** seiches **

wind wave In fluid dynamics, a wind wave, water wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result from the wind blowing over the water surface. The contact distance in the direction of t ...

s – wind seas and swells – characterised by statistics like: significant wave heights and periods, propagation directions and (directional) spectra * bathymetry *

salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

, temperature and other constituents * stratification, density-driven currents and internal waves * ice occurrence, extent, thickness, strength and seabed gouging

Metocean data

The metocean conditions are preferably based on metocean data, which can come from measuring instruments deployed in or near the project area, global (re-analysis) models and remote sensing (often by satellites). For estimating probabilities of exceedance – for relevant physical quantities – data of extreme events during more than one year is needed. By use of validated numerical models, the availability of metocean data can be extended. For instance, consider the case of a coastal location where no wave measurements are available. If there is long-term wave data available in a nearby offshore location (e.g. from satellites), a wind wave model can be employed to transform the offshore wave statistics to the nearshore location (provided the bathymetry is known). Often, long-term local measurements of wave conditions due to extreme events (e.g. hurricanes) are missing. By using estimates for the wind fields during past extreme events, the corresponding wave conditions can be computed through

wave hindcast In fluid dynamics, wind wave modeling describes the effort to depict the sea state and predict the evolution of the energy of wind waves using numerical techniques. These simulations consider atmospheric wind forcing, nonlinear wave interactio ...

Notes

References

* {{ref end Offshore engineering Coastal engineering Physical oceanography Climate and weather statistics