Submesoscale evolution of surface drifter triads in the Gulf of Mexico

Abstract

Triangle shape metrics are analyzed to quantify the evolution of submesoscale (100–500 m initial separation) surface drifter triplets released in the northern Gulf of Mexico. The observations are compared to synthetic drifters advected by geostrophic velocity fields derived from satellite altimetry. Observed submesoscale triads evolve rapidly, reaching highly elongated configurations on timescales of 6 h to 2 days, in contrast to 6 days or longer for altimetry‐derived synthetic data. Estimates of horizontal divergence and strain rate from the drifter triplets indicate the relative importance of divergence in the evolution of triangle shape. Horizontal divergence is scale dependent, on the order of the local Coriolis parameter, and 2 to 3 times larger for initial 100 m scales compared to initial 500 m scales.

Diurnal Cycling of Submesoscale Dynamics: Lagrangian Implications in Drifter Observations and Model Simulations of the Northern Gulf of Mexico

“…We then calculate the dynamical quantities of interest using the least squares method introduced by Molinari and Kirwan (1975) and Okubo and Ebbesmeyer (1976), as done for the LASER drifters. The precision at which this method allows for reconstructing dynamical quantities depends on the error in the available data and even more on the triplet configuration (Berta et al 2016;Ohlmann et al 2017). In the LASER case the position error associated with the GPS precision is on the order of 7 m, while in the modeled case, a small-but not zero-error is introduced because the Eulerian data are saved as hourly averages (Keating et al 2011) and is further amplified by the LTRANS interpolation.…”

Clustering of Floating Tracer Due to Mesoscale Vortex and Submesoscale Fields

“…Ocean circulation at the scales smaller than the mesoscale is dominated by the broad range of submesoscale processes, which have been intensively studied (Berti et al, , ; Haza et al, ; Huntley et al, ; Jacobs et al, ; McWilliams, ; Ohlmann et al, ; Schroeder et al, ; Zhong & Bracco, ). Interactions between submesoscale and mesoscale motions are essential in the formation and breakdown of coherent mesoscale vortices, but the theoretical understanding is hindered by overwhelming computational costs due to the spatial resolution requirements (Dauhajre et al, ).…”

Linking sardine recruitment in coastal areas to ocean currents using surface drifters and HF radar: a case study in the Gulf of Manfredonia, Adriatic Sea

“…In addition to fishing pressure, environmental conditions (e.g., temperature, salinity, and ocean currents) also influence the stock variability of short-lived pelagic species by impacting the survival of early life history stages (ELHSs) and therefore recruitment strength (Peterson and Wroblewski, 1984;Bradford, 1992;Bakun, 1996;Regner, 1996;Coombs et al, 2003;Santojanni et al, 2006;Garrido et al, 2017). In general, oceanographic processes, and their modulation by high-and low-frequency variability, are fundamental in driving dispersal and retention of ELHSs and can affect the spawning habitat and behavior of adults, as well as the survival of eggs and larvae, largely contributing to recruitment variability (Lasker, 1981;Boehlert and Mundy, 1994;Govoni and Pietrafesa, 1994;Sabatés and Olivar, 1996;Hare et al, 2002;Sanchez-Velasco et al, 2002;Santos et al, 2004Santos et al, , 2018. In particular, ocean currents and their spatiotemporal variability can impact sardine recruitment during the dispersal stage, when eggs and developing larvae can be treated, at least to some degree, as passive (Largier, 2003).…”