Kelp Forest model development in the Coupled Ocean-Atmosphere-Wave-Sediment-Transport model (COAWST V3.4)

Abstract

Abstract. Kelp forests are essential ecosystems in coastal regions around the world. They have large effects on flow structure, biogeochemical processes, and ecological dynamics. However, studies have yet to simulate these ecosystems in either regional ocean or global climate models. Here we describe and validate a model that simulates kelp forests in the water column for the ocean component of the Coupled Ocean-Atmosphere-Wave-Sediment-Transport model (COAWST V3.3) using a simple yet efficient linear regression approach to simulate kelp canopies. An in-situ dataset of 2-1/2 years, with and without kelp forest coverage around Isla Natividad (Baja CA, MX), allowed model validation for the main tidal constituents. We tested different vegetation drag coefficients and compared simulations with our canopy model against the standard vegetation module in COAWST. Results show that while both models simulate the velocities observed in the in situ dataset reasonably well, our model better represents turbulence kinetic energy through the water column as observed in laboratory experiments. This new kelp model can be helpful in ecology, physics, and biogeochemistry studies.