Wind regime and sand transport in the corridor between the Badain Jaran and Tengger deserts, central Alxa Plateau, China

The Alxa Plateau in north China is characterized by frequent sand dust storm activity, desertification, various blown sand hazards and extensive sand dunes. Three of China’s major sand deserts, the Badain Jaran (BJ), Tengger and Ulan Buh (UB), are distributed in this region. The BJ desert lies to the northwest and is separated from the other two deserts by mountains Yabrai and Alateng. However, the dominant northwest wind could transport sand from the BJ to the other two deserts through several corridors. Locating the sand source for these deserts is fundamental in understanding the formation and evolution of the aeolian landforms. It has been proposed that the sand in the Tengger desert is from the BJ desert. However, evidence supporting the hypothesis is still limited. To estimate the sand contribution of the BJ to the Tengger desert, we measured wind speeds at a 2 m height above the ground for the period from November 2010 to December 2011. We then calculated the amount of sand transport and observed the speed of dune migration in the junction part of the two deserts. Sand-transporting winds (⩾6.0 m s−1) occurred mostly in spring and winter, and accounted for 16.4% of the total of the year. The prevailing wind directions were NW, WNW and NNW, and were occupied 61.9% of the total frequency of sand-transporting winds. The frequencies of winds decreased with increasing wind speed, and strong wind frequencies (⩾17.0 m s−1) were 5.3% of the sand-transporting winds. In comparison to adjacent areas, the drift potential in the corridor was several times higher, indicating an obvious effect of narrowing. During the period of observation, 752 sand-transporting events occurred with durations from 10 to 1940 min (32 h). In the corridor, the sand transport flux was 372 tons m−1 yr−1, an order of magnitude larger than previous estimation, and the annual total amount of sand transported through the corridor was over 5 million tons, indicating a substantial sand supply from the BJ to the Tengger desert. Sand transport in spring and winter accounted for 99.8% of annual total. The amount of sand transported by a single sand-transporting event varied greatly, up to five orders of magnitude.