Concern for descriptions of the ocean environment, especially with respect to wave, current and wind, in deep and shallow waters, and ice, as a basis for the determination of environmental loads for structural design. Attention shall be given to statistical description of these and other related phenomena relevant to the safe design and operation of ships and offshore structures. The committee is encouraged to cooperate with the corresponding ITTC committee.
Introduction and Metocean Forcing
Environment Committee of ISSC, by its Mandate, deals with the Metocean environments. “In offshore and coastal engineering, metocean refers to the syllabic abbreviation of meteorology and (physical) oceanography” (Wikipedia). Metocean research covers dynamics of the oceaninterface environments: the air-sea surface, atmospheric boundary layer, upper ocean, the sea bed within the wavelength proximity (~100 m for wind-generated waves), and coastal areas. Metocean disciplines broadly comprise maritime engineering, marine meteorology, wave forecast, operational oceanography, oceanic climate, sediment transport, coastal morphology, and specialised technological disciplines for in-situ and remote sensing observations. Metocean applications incorporate offshore, coastal and Arctic engineering; navigation, shipping and naval architecture; marine search and rescue; environmental instrumentation, among others. Often, both for design and operational purposes the ISSC community is interested in Metocean Extremes which include extreme conditions (such as extreme tropical or extra-tropical cyclones), extreme events (such as rogue waves) and extreme environments (such as Marginal Ice Zone, MIZ). Certain Metocean conditions appear extreme, depending on applications (e.g. swell seas are benign for recreational sailing, but can be dangerous for dredging operations and are extreme for vessels transporting liquids).
This report builds on the work of the previous Technical Committees in charge of Environment.
The goal continues to be to review scientific and technological developments in the Metocean field from the last report, and to provide context of the developments, in order to give a balanced, accurate and up to date picture about the natural environment as well as data and models which can be used to accurately simulate it. The content of this report also reflects the interests and subject areas of the Committee membership, in accordance with the ISSC I.1 mandate. The Committee has continued cooperation with the Environment Committee of ITTC and with ISSC Committee V.6 Ocean Space Utilization.
The Committee consisted of members from academia, research organizations, research laboratories and classification societies. The Committee formally met as a group in person two times before the COVID onset: in Glasgow, Scotland on the 9th of June 2019, before the 38th International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2019) and in Melbourne, Australia on the 10th of November 2019, following the 15th International Workshop on Wave Hindcasting and Forecasting. It’s also held a number of regular teleconferences: two before the face-to-face meetings and seven after, once international travel was stopped by the pandemic.
Additionally, Committee members met on an ad-hoc basis during their international travels in 2019. With the wide range of subject areas that this report must cover, and the limited space, this Committee report does not purport to be exhaustive; however, the Committee believes that the reader will be presented a fair and balanced view of the subjects covered, and we recommend this report for the consideration of the ISSC 2022 Congress.
The report consists of 11 Sections: two of which include the Introduction and Conclusions, and nine are the main content. The opening Section 1 outlines and defines Metocean Forcings which can affect the offshore design and operations and are the subject of this Review Chapter. The review of publications starts from progress in Analytical Theory in 2018-2021, Section 2. It covers the basic framework of experimental, numerical, remote sensing and all the other methods and approaches in Metocean science and engineering. Numerical Modelling (Section 3) is one of the most rapidly developing research and application environments over the past two decades, it allows us to extend the theory when analytical solutions are not possible, and to complement (or even replace) some of the experimental approaches of the past. Computer simulations will always need verification, validation and calibration of their outcomes through experiments and observations, particularly in engineering applications and offshore Metocean science. Therefore, Section 4 (Measurements and Observations) is the largest in the Chapter. Section 5 is effectively a modern extension of the measurement section – it is dedicated to Remote Sensing. Over the last four decades, the remote sensing has both become a powerful instrumental tool for field observations and remains an active area of engineering research in its own right as we see through growing developments of new capabilities in this space.
While the first five chapters are broadly dedicated to direct outcomes of Metocean research, the rest of the chapters focus more on analysis and indirect outputs. With mounting amounts of collected data: numerical, experimental, remote sensing, - Section 6 discusses advances in Data Analysis, and Section 7 in Statistics, its Theory and Analysis. Section 8, on Wave- Coupled Phenomena, reflects one of the most rapidly developing areas in Metocean science, particularly important in our era of numerical modelling. It accommodates various topics of interactions between small-scale phenomena (waves) and large-scale processes in the air-sea environments: wave breaking, wave-current and wave-ice interactions, wave influences in the Atmospheric Boundary Layer (ABL) and in the upper ocean, and complex wave-coupled modelling in the full combined air-sea-ice-wave system. Most essential for offshore engineering, is modelling and understanding of Extreme Events and Conditions, which are the subject of Section 9. Last, but not the least, Section 10 discusses Wind-Wave Climate which is connected to the global climate change. This connection is threaded throughout other sections of the chapter and is of utmost significance in offshore Metocean design and planning.