The Princess and the Pea: The Effect of Small-Scale Bathymetry on Western Boundary Currents: Data from Numerical Simulations
Description
The data here support the publication "The Princess and the Pea: The Effect of Small-Scale Bathymetry on a Double-Gyre System" submitted to the Journal of Physical Oceanography. This investigation explores the impact of small-scale patterns in ocean bathymetry on the dynamics of western boundary currents and associated recirculation gyres. These patterns, commonly referred to as seafloor roughness, are characterized by lateral scales of only a few kilometers and extend vertically by tens or hundreds of meters. Rough topography is ubiquitous in the World Ocean and can profoundly affect flows throughout the water column. At present, comprehensive ocean models cannot accurately represent critical current systems --- including the western boundary currents --- unless rough bathymetry is fully resolved. However, such high-resolution global models require prohibitive computational investments and will not be used for long-term climate simulations in the foreseeable future. To address these limitations, we consider the recently developed “sandpaper” model of roughness, which provides a concise and explicit representation of roughness-induced drag as a function of the abyssal flow speed. The model is applied to the canonical double-gyre system, focusing attention on the mean structure and temporal variability of the western boundary currents. Based on this analysis, we find that the pathway of the separated western boundary current is sensitive to the magnitude of small-scale roughness. The variation in small-scale roughness also affects the statistical properties of coherent vortices formed as a result of instabilities of double-gyre circulation.