Airflow Field Around Hippophae rhamnoides in Alpine Semi-Arid Desert

文献类型： 外文期刊

第一作者： Tian, Lihui

作者： Tian, Lihui;Zhang, Dengshan;Wu, Wangyang;Yu, Yang

作者机构：

关键词： alpine semi-arid desert; Hippophae rhamnoides; wind flow; airflow decreases rate; effective protection length

期刊名称：LAND （ 影响因子：3.9； 五年影响因子：4.0 ）

ISSN：

年卷期： 2020 年 9 卷 5 期

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收录情况： SCI

摘要： The research on wind regimes and the wind protection mechanism of sand-fixing plants has mainly relied on wind tunnel experiments; few observations have been made in the field. At the same time, airflow around individual standing vegetation elements and communities is relatively lacking in alpine semi-arid deserts. Therefore, this paper selected 10-year-oldHippophae rhamnoides(sea buckthorn) on sandy land on the eastern shore of Qinghai Lake as the study object. Based on spatial and temporal changes of wind regime in the afforestation forest, a structural simulation of airflow near the plant and at different layers above the ground, and the annual changes in wind protection, we studied the wind protection mechanisms ofH. rhamnoidesas single elements or communities. The results were as follows: the effective protection length of the sublayer ofH. rhamnoideswas 1.0 to 1.8 m. The higher the layer, the smaller the decrease in wind velocity behind elements, and the smaller the effective protection length. Wind velocity downwind ofH. rhamnoidesincreased, with height increasing where the airflow decreases rate (R) decreased in the sublayer, and increasing in the middle layer as plant height increased. Meanwhile, the airflow decreases rate (R) was negative in the upper layer because it decreased as the plant height increased. The airflow movement between elements had various directions because the upper layer was prone to fluctuations due to the swinging of the crown and branches, and turbulence was seen at the sublayers owing to the mechanical resistance of the elements. When the wind speed at the standard point was 8.5 m/s and the wind direction was east (E), the increase of airflow velocity at the side and center in the upper layer was more significant, and there was a strong wind zone in the azimuth of NW-N-NE-E-SE, while the S-SW-W azimuth zone was weaker. The sand-fixing shrubH. rhamnoideshad a significant windproof function, and the 1.5 m square interval density ofH. rhamnoideswas suitable for alpine desert control projects.

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