## 1 Introduction  
The Taklimakan Desert, located in the Tarim Basin, is the largest desert in China and the second-largest drifting desert in the world [1]. It has an abundant supply of sand materials from many different sources and comprises many mobile dunes inside [2] and facing a harsh aeolian sand environment. Under the continuous action of sand-moving wind, the Taklimakan Desert presents a trend of southward expansion [3]. Qiemo and Ruoqiang, two counties seated on the southeastern fringe of the Taklimakan Desert, have constructed ecological protection projects [4] based on river systems such as the Qarqan River and the Ruoqiang River, but wind-sand hazards still threaten them. The Hotan-Ruoqiang Railway is the main trunk railway passing through Qiemo and Ruoqiang. The section of the railway running through the two counties is about 261 km in length, of which 58 km is the mobile dune section, 46 km the semi-mobile dune section, and 34 km is the Gobi section. The combined action of rich sand sources and frequent sand-moving winds poses serious threats to the safe service of the railway. In this context, controlling wind-sand hazards is a critical challenge to the construction and maintenance of the railway. Considering that wind is the driving force of wind-sand activities, a systematic study of the characteristics of the local aeolian sand environment is direly needed. Many studies have been conducted on aeolian sand environments in deserts, Gobi areas, and basins [5; 6; 7; 8; 9]. It was found that aeolian sand environments and the intensity of sand drift activities vary across different deserts and different regions of the same desert [10; 11; 12; 13; 14]. There are spatial differences in wind-sand activities. However, the characteristics of the aeolian sand environment in the southeastern fringe of the Taklimakan Desert are rarely systematically explored in the existing studies [15; 16]. Thus, they cannot offer adequate theoretical support to sand control along railways in the study area. There are obvious spatiotemporal differences in the wind regime characteristics of the study area. Sand drift activities are strongest in the spring and weakest in the winter. Sand drift activities decrease in succession from spring to winter. From Ruoqiang to Qiemo, the effect of the northeesterly wind on railways is gradually weakened, whereas that of the northwesterly wind is gradually enhanced. The landforms passed by railways in the study area are largely alluvial and alluvial deposits with a loose surface, providing abundant sand materials for wind-sand hazards along railways. A majority of railways in the southeastern fringe of the Taklimakan Desert are distributed in dune and Gobi sections. Driven by wind, sand materials move along the dominant direction of the sand drift. Both sand drift rate and dune movement distance vary evidently across different mileage sections [17]. With the continuous transport and accumulation of dunes, the possibility of derailment is greatly increased, posing a huge potential safety hazard. In recent years, repeated attempts have been made to prevent and control wind-sand disasters, mainly through setting up obstacles to interfere with airflows, reducing the transport of wind-sand flows, increasing surface roughness, and preventing dunes from moving forward. The efficiency of various wind-sand control measures has been analyzed by numerical simulation [18; 19; 20; 21]. The main forms of sand hazards along railways in the southeastern fringe of the Taklimakan Desert are wind erosion and sand burial. At present, a series of measures proposed according to the \"blocking-fixing\" principle (sand blocking and sand fixing) have been taken along the railway, including upright sand fences, reed checkerboards, shelter forest belts, and natural environments [22; 23; 24]. However, some upright sand fences have toppled under wind-sand action, resulting in weakened sand control effects. As for shelter forest belts, it takes quite a long time to exert their effect fully.