In 1989, a technical appraisal of the MIROS Directional Wave and Surface Current Radar was completed for a joint industry project involving BP International, Shell UK Exploration and Production, and the UK Department of Energy The study involved contributions from three scientists working in the fields of wave measurements (M J Tucker), statistics (R G Tickell) and kinematics (J R Chaplin) The findings and recommendations of this study have now been incorporated into a new generation of Wave Radar, and this paper describes the rationale for the changes, and how they have been implemented, and presents data obtained from the Esso Odin Field using the new version of the Wave Radar where it has been trialed The data shows that the new implementation of the design, in an equivalent configuration, has been validated against the previous design, while providing increased flexibility in configuration, and enabling all the major recommendations of the joint industry project to be realized
The MIROS Directional Wave and Surface Current Radar has been developed over a number of years, starting with the trial of the development prototype at Lindesnes in 1983 (Gronlie et al, 1984) Since then, over ten systems have been delivered for applications In the North Sea
Of course, any new measurement technique has to be validated against established methods, both to confirm its calibration, and to maintain continuity between long term data sets from different sensors In the winter of 1985186, an early MIROS Wave Radar participated In the WADIC directional wave sensor field intercomparison (Allender et al, 1989) Over the winter of 1986187, a MIROS Wave Radar was evaluated by Shell UK Expro on the North Cormorant platform (Dacunha and Angevaare, 1988)
Since that time, a number of improvements have been made and evaluated on the Esso Odin platform, including
fixed multiple antenna instead of servo controlled rotating antenna
dual footprint to remove directional ambiguity
updated spectra every 15 minutes (for operational users)
In 1989, a technical appraisal of the MIROS Wave Radar was completed (Archer, 1989) for a joint industry project involving BP International, Shell UK Exploration and Production, and the UK Department of Energy The study involved contributions from three specialists working in the fields of wave measurements (M J Tucker), statistics (R G Tickell) and kinematics (J R Chaplin)
Since then, the findings and recommendations of this study have been incorporated in a new generation of Wave Radar, and this paper will describe the rationale for the changes, and will describe how they have been implemented Finally, data obtained from the Esso Odin Field using the new version of the Wave Radar will be presented
The principles of operation of the new Wave Radar remain unaltered from the original design (Gronlie et al, 1984) A microwave pulse is transmitted from an antenna at an elevation of about 50 m above the sea surface, and is reflected from the illuminated area ("footprint") on the sea surface which is defined by the receiver range gate and pulse length and antenna horizontal beam pattern
