Instruction:
a. If cp is a peak wave period and theta is not provided, this is identical to the original COARE3.5 wave based formulations (Edson et al. 2013).
b. If cp is a peak period but theta is provided, then it will use the revised COARE3.5 wave based formulation #1 (Sauvage et al. 2023), which accounts for the wind wave misalignment.
new roughness formulation: zo_new=sigH.Ad_new.(usr./cp).^Bd_new;
where new coefficients are used, notably based on findings from Porchetta et al. 2019:
Ad_new=0.091.*cos(0.45.*theta);
Bd_new=2.*cos(-0.32.*theta);
with theta (θ) in radians, the angle between the wind direction and the wave direction which varies between 0 and π.
i.e., if θ = 0, wind and waves are perfectly aligned, whereas θ = π means wind and waves are opposed.
c. If cp is a mean period but theta is not provided, it will use the revised COARE3.5 wave based formulation #2 (Sauvage et al. 2023) which uses the mean wave age.
new roughness formulation: zo_new=sigH.Ad_new.(usr./cp).^Bd_new;
Ad_new=0.39
Bd_new=2.6
These coefficients have been tuned using the COARE3.5 set of observations.
The mean wave age used as input here uses the mean period, Tm. Tm is based on the zero-crossing period, as it is the one used to describe the mean period in the observation.
d. If cp is a mean period, and theta is provided, this will abort. In the current implementation, our study shows that it results in overfitting.
Citation: Sauvage, C., Seo, H., Clayson, C. A., & Edson, J. B. (2023). Improving wave-based air-sea momentum flux parameterization in mixed seas. Journal of Geophysical Research: Oceans, 128, e2022JC019277. https://doi.org/10.1029/2022JC019277
Contact: César Sauvage at csauvage@whoi.edu
Website: https://cesarsauvage.github.io/
GitHub: https://github.com/cesarsauvage
References:
Porchetta, S., Temel, O., Muñoz-Esparza, D., Reuder, J., Monbaliu, J., van Beeck, J., and van Lipzig, N.: A new roughness length parameterization accounting for wind–wave (mis)alignment, Atmos. Chem. Phys., 19, 6681–6700, https://doi.org/10.5194/acp-19-6681-2019, 2019.
Edson, J. B., Jampana, V., Weller, R. A., Bigorre, S. P., Plueddemann, A. J., Fairall, C. W., Miller, S. D., Mahrt, L., Vickers, D., & Hersbach, H. (2013). On the Exchange of Momentum over the Open Ocean. Journal of Physical Oceanography, 43(8), 1589-1610. https://doi.org/10.1175/JPO-D-12-0173.1