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.
Key Points
Scale‐dependent triplet statistics are computed from two launches of ∼90 surface drifter triads with initial 100 m and 500 m sides
Unlike AVISO‐based trajectories, drifter triangles reach highly elongated configurations on short (12 h‐2 day) timescales
Magnitudes of triplet‐derived strain rate and divergence are scale dependent and comparable and exceed the local Coriolis parameter
