LiDAR Measurements of Wind Shear Exponents and Turbulence Intensity Offshore the Northeast United States

Abstract

This paper presents wind speed shear exponents and turbulence intensity (TI) measurements collected from light imaging, detection, and ranging instruments (LiDARs) measuring wind speeds from 40 m to 200 m above sea level and provides comparisons to industry design guidelines. The high-altitude wind speed data are unique and represent some of the first measurements made offshore in this part of the country, which is actively being developed for offshore wind. The data are used to support the New England Aqua Ventus I Floating Offshore Wind Farm to be located 17 km offshore the Northeast United States. Multiple LiDAR measurements were made using a DeepCLiDAR floating buoy and LiDARs located on a nearby island. The measured wind speed shear exponents are compared against industry standard mesoscale model outputs and offshore design codes including the American Bureau of Shipping, American Petroleum Institute, and Det Norske Veritas-Germanischer Lloyd guides. Significant variation in the vertical wind speed profile occurs throughout the year which is not addressed in design standards. Additionally, TI measurements made from the LiDAR, although not widely accepted in the scientific community, are presented and compared against industry guidelines.