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Nonlinear stratospheric variability: multifractal de-trended fluctuation analysis and singularity spectra
Gualtiero Badin1, Daniela I V Domeisen2
1Institute of Oceanography , University of Hamburg , Bundesstrasse 53, 20146 Hamburg, Germany.
Proceedings. Mathematical, Physical, and Engineering Sciences
|August 6, 2016
Summary
Stratospheric variability exhibits complex scaling behaviors across different time scales. Multifractal de-trended fluctuation analysis reveals distinct patterns in the Northern and Southern Hemispheres, with models partially capturing these dynamics.
Area of Science:
- Atmospheric Science
- Geophysics
- Complex Systems Analysis
Background:
- The stratosphere, a critical atmospheric layer, exhibits turbulent characteristics with temporal fluctuations.
- Traditional analysis often fails to capture the intermittent behavior and diverse time-scale correlations present in stratospheric variability.
Purpose of the Study:
- To investigate the distinct scaling laws governing long-term stratospheric variability.
- To analyze and compare stratospheric variability using multiple re-analysis products and numerical models.
- To isolate the influence of topographic forcing, seasonal cycles, and the absence of climate teleconnections on stratospheric dynamics.
Main Methods:
- Application of multifractal de-trended fluctuation analysis (MF-DFA) to study scaling properties.
- Comparison of four atmospheric re-analysis datasets.
- Analysis of an idealized numerical model with variations in forcing (topography, seasonality, teleconnections).
Main Results:
- A transition in scaling exponents was observed in the Northern Hemisphere (NH) around 1-year time scales, shifting from multifractal to monofractal behavior.
- Southern Hemisphere (SH) variability also displayed a transition at annual scales, with a narrower dynamical range of multifractality compared to the NH.
- Numerical models successfully reproduced low-frequency variability but struggled to fully capture shorter-term stratospheric fluctuations.
Conclusions:
- Stratospheric variability is characterized by multifractality at shorter time scales and monofractality at longer scales, with hemispheric differences.
- The study highlights the complexity of stratospheric dynamics and the challenges in fully replicating observed variability with current numerical models.
- MF-DFA is a valuable tool for characterizing the complex scaling behavior of atmospheric systems like the stratosphere.
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