Characteristics of sand-driving wind regime and sediment transport in northeast edge of Ulan Buh Desert

The current researches of near surface sand movement pay more attention to the short period and single direction of the blowing sand structure characteristics, but the results were difficult to combine with the long-term geomorphological processes. The sand drift potential (DP) and sediment transport are two important index to reflect windblown sand activity intensity. In order to prove the characteristic of sand-drift activities of the blown-sand movement in the northeast edge of Ulan Buh Desert, we studied the variations of sand-driving wind regime, drift potential and sediment transport rate in the northeast edge of Ulan Buh Desert, and the dates of the annual wind speed, direction and sediment transport data were collected from the "Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station" during 2013-2017. We analyzed the dates by the methods of field observation, laboratory analysis and calculation. The results showed that: 1) the mean speed, frequency and maximum speed of sand-driving wind in the northeast edge of Ulan Buh Desert were 6.77 m/s, 19.74% and 20.76 m/s, respectively. These indexes were all largest in spring, the value were respectively 7.10 m/s, 24.63% and 18.43 m/s, which was main sandstorm activity period, followed by autumn, and were all smallest in winter, the value were6.53 m/s, 17.61% and 13.60 m/s, respectively. 2) The sand-driving wind direction of four seasons and the whole year were consistent with each other in the northeast edge of Ulan Buh Desert, and the main directions these were the easterly winds (NNE, NE, ENE, E) and the westerly winds (SW, WSW, W, WNW. 3) The yearly sand drift potential and the resultant drift potential(RDP) were respectively 183.38 VU and 73.41 VU, which belongs to an intermediate wind energy environment, and the yearly index of directional wind variability (RDP/DP) was 0.40, which belongs to a intermediate ratio. The yearly resultant drift direction (RDD) was 111.15°, which indicated the southeast by east direction. The sand material of the northeast edge of Ulan Buh Desert move to southeast by east direction. The seasonal variation characteristics and monthly variation characteristics in spring of the sand drift potential and the resultant drift potential, the sand drift potential and the resultant drift potential were largest in May, followed by November, and the smallest in January. 4) The sand transport quantity of the sixteen directions of northeast edge of Ulan Buh Desert was 35.11 kg/m·d, the sediment transport quantity of the WNW direction reached the maximum and the value was 3.21 kg/m·d, and the sediment transport rate showed obvious seasonal variation characteristics, while the sand transport quantity of spring was significantly higher than other seasons. The research results provide a basis for the ecological environment assessment of the northeast edge of Ulan Buh Desert, and provide a theoretical basis for regional desertification prevention and control measures.