Wind speed changes and influencing factors in inland river basin of monsoon marginal zone

Abstract

Scientific understanding of regional wind speed variation characteristics and driving mechanisms is of great practical significance to the management and rational utilization of wind energy resources, ecological protection and governance, and sustainable development of agriculture. Taking the Shiyang River Basin in inland river basin of monsoon marginal zone as the study area, this paper analyzed wind speed changes and influencing factors at different time and space scales. The results showed that, first of all, the annual average wind speed showed a downward trend as a whole in Shiyang River Basin, and the change of spring wind speed and the decreasing frequency of daily max-wind speed above Grade 5 were the main contributors. The turning point of annual average wind speed was consistent with that in spring and autumn (1981) and earlier than that in winter and summer (1982). Secondly, as far as the wind speed change tendency rate is concerned, before the turning point, Yongchang area had the largest decline rate with obvious “2000 m effect”, while after the turning point, Wuwei Basin had the largest rise rate with obvious “basin effect”. Focusing on the downstream desert oasis region, the sand-driving wind speed showed a decreasing trend as a whole, and showed a “cliff-like” decline after 1988. The rising trend of sand-driving wind speed after 2014 will pose greater challenges to ecological governance. Finally, under the background of unbalanced global warming, the wind speed changes in different periods were driven by the circulation system changes. In 1970–1981, the decline of the wind speed was the result of the combined action of Arctic Oscillation and Asia Polar Vortex. However, after 1981, it was affected by North Atlantic Oscillation, Asian Meridional Circulation, Tibet Plateau Circulation, India-Burma Trough, Western Pacific Subtropical High and Northern Hemisphere Subtropical High.