Setting a New Standard for Metocean Databases
Authors: De Graaff Reimer , Awda Hisham , Medapureddi Satyanarayana , Majumdar Debasish , Caires Sofia , Peng Zhong , Moerman Emiel 
Published: April 2012

A highly accurate and detailed database of operational and extreme metoceanparameters was recently developed for the offshore waters of Abu Dhabi, U.A.E. The metocean database provides base information for planning of offshoreinstallations and operations, as well as input for design of offshoreplatforms, pipelines, artificial islands or other structures. The developmentof the metocean database was based on the latest available topographic, bathymetric and environmental information and state-of-the-art numericalmodels, statistical data pre- and postprocessing and presentation tools. Recentmarine surveys provided good quality metocean measurements, with which theapplied models and the resulting database contents could be calibrated andvalidated.

Generally, metocean studies of an offshore region include pre-formatted outputof metocean parameters, such as joint-occurrence tables and roses, at a limitednumber of output locations having fixed spacing. Thanks to parallel computingof numerical wave, tide and storm surge models on a high-speed Linux clusterand data storage with high-speed interrogation of NetCDF data files, it waspossible to derive multi-year hindcast time-series and extreme statistics of alarge set of relevant metocean parameters data at any location in a largeoffshore area. With a purpose-built graphical user-interface, the user canperform additional data analysis, for example assessing down-time statistics ata planned offshore loading facility, from the retrieved hindcast time-series. The new database with large, consistent and accurate datasets, will eventually resultin safer and cost-optimal offshore operations and designs. The challenge forthe developer of the database is to safeguard high quality of all dataanalyses, hydrodynamic modelling, data processing and consequently the databasecontents.

This paper describes the state-of-the-art shallow-water wave, water level andcurrent modelling and statistical analyses that are behind the dataset alongwith the calibration and validation of the data. Also the graphical userinterface, developed to retrieve and present data from the database, ispresented.

Introduction

For design, installation and maintenance of offshore structures, reliablemetocean information is required in various formats. These include for instancewind, wave or current climates in the form of joint occurrence tables or roses, tables of individual wave heights, persistence tables, spectral diagrams ortables with extreme value estimates. These metocean information is based onanalyses of hindcast datasets and, in shallow-water cases, on offshore tonearshore wave, tide and surge modelling. Typically, the metocean data arepresented for a number of agreed output locations (typically 5 - 20) andpresented in a metocean report.

Operating a large offshore area, as in the case of an oil company or wind farmoperator, will require huge effort and costs to have metocean data at alllocations within the operating area. In those cases, a metocean database with adedicated user interface will be preferred, as it allows for derivingconsistent sets of metocean data at any location within the database area. Thiswill obviously require some capital investment, but in the end will becomehighly useful and profitable.