Open Access

ARTICLE

Non-Stationary Wind Characteristics in Coastal Wind Farms during Typhoons Based on BFAST and Hurst Exponent: A Case Study of Lekima

Liyuan Deng¹, Aodi Fu^2,*, Jing Tan³, Bing Bing⁴, Linzi Wang¹, Haibo Shen¹, Huijun Wu¹
1 Power Dispatching and Control Center of China Southern Power Grid, Guangzhou, China
2 School of Renewable Energy, Hohai University, Changzhou, China
3 School of Management, Shanghai University of Engineering Science, Shanghai, China
4 Meteorological Bureau of Zhaoyuan City, Zhaoyuan, China
* Corresponding Author: Aodi Fu. Email: 250215020001@hhu.edu.cn

Revue Internationale de Géomatique https://doi.org/10.32604/rig.2026.089924

Received 01 August 2026; Accepted 25 August 2026; Published online 31 August 2026

Abstract

The non-stationarity and vertical coupling of the boundary-layer wind field during typhoon passage are key concerns for wind engineering and disaster prevention. Using hourly ERA5 reanalysis data, this study investigates the evolution of the 10 and 100 m wind fields throughout Typhoon Lekima (2019) by combining BFAST breakpoint detection, Hurst exponent analysis, correlation analysis, and segmented linear fitting, together with near-surface temperature, 850 hPa temperature, and mean sea level pressure fields. BFAST detected a structural breakpoint at all 525 grid cells, with breakpoint timing progressing along the storm track (median 26 h at 10 m and 33 h at 100 m) and magnitudes positive in the northeast and negative in the southwest; at the tower, breakpoints at both heights occurred synchronously at 43 h, with a larger jump at 100 m (+2.20 m s⁻¹) than at 10 m (+1.34 m s⁻¹). The two heights remained strongly correlated (domain-mean r = 0.991) with a nearly constant speed ratio of ~1.45 consistent with the logarithmic profile, while wind-direction correlation degraded only within the inner-core region (minimum r = 0.49). The wind-speed Hurst exponent fell from ~1.04 to 0.84 after center passage, whereas the wind-direction exponent rose from 0.88 to 0.91, indicating that turbulent energy injection disrupted wind-speed persistence while wind direction stabilized under the reorganized flow. The pre-to-post transition in non-stationarity is attributed to a shift in boundary-layer forcing from large-scale baroclinic driving to localized thermal perturbations, with the loss of directional coherence in the pressure gradient field weakening the long-range dependence of the wind field.

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Keywords

Typhoon Lekima; boundary layer wind field; BFAST breakpoint detection; Hurst exponent; non-stationarity; vertical correlation

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