TY  - EJOU
AU  - Deng, Liyuan 
AU  - Fu, Aodi 
AU  - Tan, Jing 
AU  - Bing,  
AU  - Wang, Linzi 
AU  - Shen, Haibo 
AU  - Wu, Huijun 

TI  - Non-Stationary Wind Characteristics in Coastal Wind Farms during Typhoons Based on BFAST and Hurst Exponent: A Case Study of Lekima
T2  - Revue Internationale de Géomatique

PY  - 
VL  - 
IS  - 
SN  - 2116-7060

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

DO  - 10.32604/rig.2026.089924