Fractal analysis of deep ocean current speed time series

• Published in: Journal of Atmospheric and Oceanic Technology
• Main Authors: Cabrera Brito, Laura, Rodríguez Rodríguez, Germán, García Weil, Luis, Pacheco Martínez, Mercedes, Pérez-Martell, Esther, Waniek, J. J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: 251007 Oceanografía física; North Atlantic Ocean; Currents; Ocean dynamics; North Atlantic
• Online Access: http://hdl.handle.net/10553/22189; https://doi.org/10.1175/JTECH-D-16-0098.1

Fractal properties of deep ocean current speed time series, measured at a single-point mooring on the Madeira Abyssal Plain at 1000- and 3000-m depth, are explored over the range between one week and 5 years, by using the detrended fluctuation analysis and multifractal detrended fluctuation analysis methodologies. The detrended fluctuation analysis reveals the existence of two subranges with different scaling behaviors. Long-range temporal correlations following a power law are found in the time-scale range between approximately 50 days and 5 years, while a Brownian motion–type behavior is observed for shorter time scales. The multifractal analysis approach underlines a multifractal structure whose intensity decreases with depth. The analysis of the shuffled and surrogate versions of the original time series shows that multifractality is mainly due to long-range correlations, although there is a weak nonlinear contribution at 1000-m depth, which is confirmed by the detrended fluctuation analysis of volatility time series.