HMSC Research Seminar, January 26, 2023

Speaker: Kaus Raghukumar, Integral Consulting

Topic: Potential Effects of Large-Scale Floating Offshore Wind Farms on Coastal Upwelling in the California Current System

In California offshore waters, sustained northwesterly winds have been identified as a key energy resource that could contribute substantially to California’s renewable energy goals. However, the development of large-scale offshore wind farms has the potential to reduce the wind stress at the sea surface, which could have implications on wind-driven upwelling, nutrient delivery, and ecosystem dynamics. Using atmospheric and ocean circulation models together with a hypothetical upper boundary buildout scenario of 877 turbines spread across three wind energy areas of interest, wind speed reductions in the lee of the wind energy areas of interest are found to enhance horizontal wind stress shear, leading to reduced upwelling on the inshore side of windfarms and increased upwelling on the offshore side. These changes, when expressed in terms of widely used metrics for upwelling volume transport and nutrient delivery, show that while the net upwelling in a wide coastal band changes relatively little, the spatial structure of upwelling within this coastal region can be shifted outside the bounds of natural variability.