Abstract: In this paper, the climatic factor index of wind erosion, climate trend rate, Pettitt sharp change point detection and Morlet wavelet transform were used to analyze the spatial distribution, spatiotemporal variation, sharp change and periodicity of wind speed as well as their effects on climatic factor index of wind erosion based on the data from 30 meteorological stations in the wind erosion and windwater erosion regions in the Loess Plateau during the period from 1961 to 2010. The results are as follows: ① The multi-year average wind speed was 2.2 m•s-¹, and it was relatively high in most regions in Inner Mongolia and Ningxia Hui autonomous regions, but low in north Shaanxi Province, northwest Shanxi Province, east Gansu Province and some areas in Qinghai Province. Wind speed was the highest in spring, and then in summer, autumn and winter, it was holistically in a decrease trend in recent 50 years, lowest in the 1970s but highest in the 2000s; ② A sharp change of wind speed occurred at 83% stations, the holistic sharp change in the study area occurred in 1982, and the seasonal sharp change was similar to the annual one; ③ Three times of alternant change of wind speed occurred in recent 50 years, the wind speed was high during the periods of 1961—1977 and 1995—2010 but low during the period of 1977—1995, seasonal change of wind speed was similar, and the wind speed would be still low in near future; ④ The spatial distribution and spatiotemporal change trend of climatic factor index of average annual wind erosion was similar to the change of wind speed; ⑤ The climatic factor index of wind erosion was correlated negatively with relative humidity and precipitation, thus the increase of precipitation or relative humidity could restrain wind erosion; there were positive correlations among the climatic factor index of wind erosion and the potential evaporation, drought index and wind speed. The increase of wind speed, drought index, temperature and evaporation could promote wind erosion.

Key words: wind speep, relative humidity, precipitation, wind erosivity, spatiotemporal change, the Loess Plateau