Campbell Plateau Meander Analysis

This repository provides supporting figures and analyses for the paper:

“Characteristics and Trends of the Campbell Plateau Meander in the Southern Ocean: 1993–2020”, Journal of Geophysical Research: Oceans
by Xinlong Liu, Amelie Meyer, and Christopher C. Chapman

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Supporting Figures for Meander Analysis

1. Meander Trends Analysis

This section presents the statistical analysis of the meander’s characteristics—latitude position, width, and geostrophic current speed—using both raw monthly time series and smoothed rolling-year means. It includes:

• Rolling-year mean trends – long-term changes in meander position, width, and speed.
• Sample autocorrelation functions – assessment of temporal persistence in the monthly records.
• Confidence interval testing – uncertainty analysis of autocorrelation functions at the 95% confidence level.

2. Tests in Meander Position Identification

This section documents the statistical tests used to evaluate and revise the identification of the meander’s position. It includes:

• Trajectory ‘jump’ tests – identification and handling of discontinuities in the meander’s monthly position.
• Sum-period value tests – quality checks on the temporal consistency of the meander detection.

Analysis Notebooks and Scripts

Below are the included Jupyter notebooks and MATLAB functions, with their descriptions. These files provide reproducible workflows and visualisations underpinning the results of the study.

1. Jupyter Notebooks

• 01-Campbell-Plateau-Argo-Meander-Analysis.ipynb

  • Analysis of Argo float hydrographic data in the Campbell Plateau region to assess subsurface structure and variability of the meander.

• 02-EKE-Analysis-Campbell-Plateau-Geos-1993-2020.ipynb

  • Investigation of eddy kinetic energy (EKE) trends and variability across the Campbell Plateau using geostrophic velocity fields from satellite altimetry.

• 03-SPG-Gyre-Index-Trend-Analysis-1993-2020.ipynb

  • Evaluation of Subpolar Gyre (SPG) index variability and its long-term trends to provide broader context for meander dynamics.

• 12-Campbell-Plateau-Winds-JRA55-1958-2021-Monthly-Means-Trends-1993-2020.ipynb

  • Analysis of surface winds from the JRA-55 reanalysis to examine atmospheric forcing over the Campbell Plateau, including climatologies and trend assessment.

2. MATLAB Functions

• 04-Plot-ADT-and-ADT-Gradient-Maps.m

  • Generates maps of Absolute Dynamic Topography (ADT) and its gradients to visualise frontal structures in the meander region.

• 05-Plot-Masked-Meander-ADT-Abs-VS-Rel-Thresholds.m

  • Compares absolute and relative ADT thresholding approaches for masking meander features and highlights methodological sensitivity.

• 06-Plot-Meander-Probability-Rolling-Mean-And-Peak-Positions.m

  • Computes and visualises rolling-mean meander probabilities and the positions of their statistical peaks over time.

• 07-Plot-Rolling-Mean-SLA-Meander-And-Trough-Positions.m

  • Produces plots of rolling-mean sea-level anomaly (SLA) meander positions and trough locations to capture temporal variability.

• 08-Plot-Meander-Monthly-Trajectory-Frequency.m

  • Generates frequency plots of monthly meander trajectories to assess spatial persistence and variability.

• 09-Plot-Monthly-Meander-Positions-With-Frequency-Analysis.m

  • Combines monthly meander positions with frequency-based analysis to highlight dominant pathways and shifts.

• 10-Plot-Meander-Frequency-Maps-and-Transects.m

  • Creates spatial maps and transects of meander occurrence frequency across the Campbell Plateau.

• 11-Export-Month-Mean-Meander-Occurrence-From-SLA-Altimetry.m

  • Exports monthly mean meander occurrence values derived from SLA altimetry datasets for further statistical and comparative analyses.