干旱区生态环境知识资源中心

Research on the wind environment provides an important reference for tackling desertification and related environmental issues in desert regions. This article examines spatial and temporal variation of the near-surface wind environment in the dune fields of northern China, using data from 40 meteorological stations inside and around the dune fields. Wind speed series were first subjected to homogenization, with monthly mean wind speed of the highly correlated neighbour stations as reference series. We found that the homogenized wind speed trends were approximately in accordance with the raw wind speed trends. The wind environment showed spatial and temporal differences, but wind speed has generally decreased both annually and seasonally since 1960, with an average trend of -0.193ms(-1) decade(-1). Mean wind speed (1960-2014) and maximum wind speed (1975-2014) decreased significantly, with distinct seasonal differences. The decreasing trend depended strongly on a decreased wind of speeds >5 ms(-1) and its frequency. Overall, 48.7-80.8% of the decrease resulted from decreases in the maximum wind speed. Thus, decreases in the maximum wind speed were the dominant change in the study area. We also found that two thirds of the decrease in the drift potential primarily resulted from decreases in three prevailing wind groups (northwest, west, and south winds). This resulted from changes in the East Asian monsoon and westerly circulation. Mean air and ground surface temperatures (1960-2014) increased significantly and were significantly negatively correlated with mean wind speed, whereas sunshine duration (1960-2014) decreased significantly and was significantly positively correlated with mean wind speed. Both correlations reveal that an increasing of atmospheric dust may be responsible for the weakened wind environment. However, China’s widespread sand-control and ecological construction projects have increased ground roughness.