Impacts of anemometer changes, site relocations and processing methods on wind speed trends in China

Abstract. In-situ surface wind observation is a critical meteorological data source for various research fields. However, data quality is affected by factors such as surface friction changes, station relocations, and anemometer updates. Previous methods to address discontinuities have been insufficient, and processing methods have not always adhered to World Meteorological Organization (WMO) guidelines. We analyzed data discontinuity caused by anemometer changes and station relocations in China’s daily in-situ near-surface (~10 m) wind speed observations and the impact of the processing methods on wind speed trends. By comparing the wind speed discontinuities with the recorded location changes, we identified 90 stations that showed abnormally increasing wind speeds due to relocation. After removing those stations, we followed a standard quality control method recommended by the World Meteorological Organization to improve the data reliability and applied Thiessen Polygons to calculate the area-weighted average wind speed. The result shows that China's recent reversal of wind speed was reduced by 41 % after removing the problematic stations, with an increasing trend of 0.017 m s⁻¹ year⁻¹ (R² = 0.64, P < 0.05), emphasizing the importance of robust quality control and homogenization protocols in wind trend assessments.