Environmental factors causing the formation of sand-accumulation belt along the oasis fringe in Minqin
Received date: 2019-01-19
Revised date: 2019-06-02
Online published: 2019-11-17
After 60 years of desert control effort in Hexi region of Gansu Province, China, a sand-accumulation belt are formed along the oasis fringe. The sand-accumulation belt is 4.8-18.6 m high and 30.4-461.4 m wide along the fringe of Minqin Oasis. Why the belt is higher in some area while relatively short in another area; or wider in some area while narrow in another area? To find the answers, we investigated the sand-accumulation belt along the fringe of Minqin Oasis, and made the analysis using the correlation analysis method and SPSS software. The results show as follows: (1) According to its formation ways, the sand-accumulation belt along the fringe of Minqin Oasis can be divided into 3 types as natural shrub belt, arbor forest belt and artificial sand-fixation forest belt. The belt formed by natural shrubs is relatively tall, whereas the belt formed by arbor forest trees at the edge of farmland is relatively narrow. (2) The angle between the sand-accumulation belt and the prevailing wind is the main environmental factor controlling the height of sand-accumulation belt. The smaller the angle is, the lower the belt is. When the upper wind is aligned with the wind-drift sand mouth, the smaller the angle is, the narrower the belt is. (3) Result of canonical correlation analysis is better than that of single correlation analysis. The morphological of sand-accumulation belt are mainly determined by its width, aspect ratio and sectional shape. The main environmental factors effecting the morphological characteristics of sand-accumulation belt are whether there is wind-drift sand mouth in the upper wind direction as well as the distance from sand source. If there is no sand mouth in its upwind direction, the sand accumulation belt will be wider and the sectional area be bigger; if the distance between the sand-accumulation belt and the upwind sand source is small, the sand-accumulation belt will be higher.