Ocean mixing from offshore wind farms: implications for the U.S. Mid-Atlantic Bight cold pool

Offshore wind turbine monopiles extract momentum from ocean currents and generate turbulence that can modify stratification in the coastal ocean. As offshore wind development expands into seasonally stratified regions, these interactions become increasingly important. The U.S. Mid-Atlantic Bight is a strongly stratified shelf in summer with weak tidal currents, active offshore wind development, and a persistent Cold Pool—a bottom layer of cold water beneath a summer thermocline critical for regional fisheries. This study combines regional model output, glider observations, and an analytical model based on the turbulent kinetic energy budget to evaluate the timescales of mixing driven by monopile–flow interaction only. For a current velocity scale of order 0.1 m s-1, corresponding to the most frequently occurring currents at the site, the estimated mixing timescale is on the order of years, far longer than the seasonal overturning timescale (~3 months). Even under cyclone-strength currents (~0.8 m s-¹), full mixing of peak stratification would require ~10 days of sustained forcing, which is rare at the weather-band timescale. Projected monopile array density and weak shelf currents further constrain the area-averaged turbulent energy input relative to bottom friction and storm-driven mixing. Thus, large-scale Cold Pool destratification from offshore wind development appears unlikely in the Mid Atlantic Bight, though localized wake-driven turbulence and associated altered nutrient fluxes may still occur near individual turbines, motivating targeted high-resolution studies.