Resolution of higher-order stochastic structure in drifter data

Determine whether the higher-order Markov-2 stochastic model for drifter motion, which represents autocorrelated particle accelerations through velocity and acceleration decay timescales, can be reliably resolved from available drifter observations across different oceanic regions.

Background

The paper reviews a hierarchy of stochastic differential equation models for Lagrangian particle motion. The Markov-2 model extends the Markov-1 model by introducing an acceleration process with its own decay timescale, allowing it to represent more complex geophysical fluid structure and autocorrelation in particle accelerations.

The additional acceleration timescale may not be estimable with equal reliability throughout the ocean. The cited analysis of Global Drifter Program data found that the acceleration timescale is better resolved along major currents such as the Gulf Stream, but less well resolved away from such currents. The paper therefore leaves open whether the Markov-2 structure is practically identifiable from drifter observations in general.

References

The Markov-2 model captures more complex geophysical fluid structure than the Markov-0 and Markov-1 models, but a practical question is whether such structure can realistically be resolved from drifter data.

— Statistical Oceanography of Profiling Floats and Surface Drifters  (2610.09668 - Kuusela et al., 7 Oct 2026) in Section 4.1, subsection “Stochastic process representations of drifter motion”