Subinertial Sea Surface Heights Anomalies Estimated Using High Frequency Radar Surface Current Data in the Mississippi Bight

Abstract

To a first order approximation, there is a geostrophic flow in the ocean interior where temporal Rossby, Rossby and Ekman numbers are assumed to be small. The barotropic component of this flow results from the balance between the horizontal components of the Coriolis and pressure gradient forces where pressure gradients result from gradient in sea level (Cushman-Roisin & Beckers, 2012). Typically, the subinertial (defined here as timescales greater than 2-day) sea level gradient in the open ocean can be attributed to changes of currents in accordance with geostrophic balance. However, the dominance of the geostrophic balance becomes less certain on continental shelves (Lentz & Fewings, 2012). This is partly due to the varying bathymetry and stratification, both of which can contribute to the separation or overlap of the surface and bottom boundary layers (Lentz & Fewings, 2012), as well as the prevalence of high frequency (HF) non-linear processes (e.g., surface gravity waves; Woodworth et al., 2019). These changes in ocean dynamics complicates continental shelf processes

Characterizing the weather band variability of the Texas shelf current

“…Adopting the filtering technique described in Nwankwo et al (2023), both the wind and current velocity data were filtered using a 40-h lowpass window. This ensured that the contributions from processes such as tides, sea breeze, and inertial oscillations whose periods are less than 2 days were reduced.…”

Using Lagrangian Filtering to Remove Waves From the Ocean Surface Velocity Field

“…(2020) and Nwankwo et al. (2023) use a low‐pass filter at each physical location to remove waves from their velocity field. The first filtering method that we evaluate in this paper is purely Eulerian and frequency‐based.…”

“…A purely frequency-based method is also sometimes used to remove IGWs from the total velocity field. For example, Qiu et al (2020) and Nwankwo et al (2023) use a low-pass filter at each physical location to remove waves from their velocity field. The first filtering method that we evaluate in this paper is purely Eulerian and frequency-based.…”