Abstract: High-altitude wind energy is an important potential resource in the future. This paper presents a statistical analysis of the wind characteristics in China at different above ground levels below 4000 m, based on the ERA5 wind data from the European Centre for Medium-Range Weather Forecasts and digital elevation data, focusing on the spatiotemporal distributions of wind speeds and the frequencies of typical wind speeds. The results show a complicated spatial pattern of wind speeds over China, i.e., higher wind speeds in the northeastern and plateau regions, and lower wind speeds in the southern and northwestern regions. At low levels such as 100 m, coastal winds are high, while inland winds are low. Seasonal variations in wind feature higher speeds in spring and winter and the lowest in summer. The highest wind speeds occur typically in January and December, while the lowest typically in July and August. Wind power density is generally higher in the northeast, southwest and coastal regions. At low levels, the regions that feature relatively high frequencies of extreme high wind speeds appear in Inner Mongolia and the northeastern provinces; at high levels, they appear in Tibet and Qinghai. This paper also gives the maps and variation patterns of wind resources at different above ground levels, which are helpful for the planning and design of airborne wind power projects.

Key words: wind energy resources, spatiotemporal distribution, reanalysis data, high-altitude wind