Remotely Sensed Imagery Analysis On The Sand Dunes Movement In Typical Area In Badan Jaran Desert, China

Bradain Jaran desert lies to the west of Alxa Plateau and is the second largest moving desert in the China. East of Bradain Jaran desert is Ulan Buh Desert and south of that is Tengger Desert. The three deserts are important sources of sandstorm of Alxa Plateau. The two deserts shake hand with Bradain Jaran desert and form three drift sand belt which is moving fast and sensitive to filed wind condition. Through the study of the area can provide insight in spatial dynamic pattern of Bradain Jaran desert as well as its regional distribution, and provide a basis to explore the potential application of remote sensing image.Among the various categories of landform evolution, sand dune is a kind which moves faster. Until now, it is still less report on this aspect while the dynamics mechanisms of sand dunes have been well studied. It's difficult to study the large area movement of sand dunes by using traditional method such as ground-based observations. Since Landsat satellite's launch in the 1970s, it provides long-period, large-scale images for the research of dunes movement. In this article, many temporary and scenes of Landsat Thematic Mapper imagery from 1989 to 2010 are used to analyze the movement of sand dunes in four typical areas of Badain Jaran desert. This article attempts to explore the potential of using sand dunes that interpreted from multi-temporal Landsat TM images, to study the Multi-annual moving trend of sand dunes in Bradain Jaran desert in terms of limitation of spatial resolution of Landsat TM. Sand dunes are distinguished by size in the four Sample areas that in North, East, Southeast, South, and the dynamic mechanism of sand dunes is discussed. The results are as follows:(1) Multi-annual movement of sand dunes in North is not distinct. The reason is described as follow:The images to be used for monitoring the movement of sand dunes have a short time interval of 20 years. Dunes in this area are very high so that they move very slowly. The moving distances of single points of dunes on the image are less than 30m, so that the movement of dunes can't be monitored.(2) Movement of Sand dunes of the three drift sand belts is distinct. The specific sand dunes movement is as follows:Sand dunes in eastern near Olji is mainly composed by crescent dunes, transverse dunes and the height of that are between 9 and 33m. Moving direction of sand dunes in the period of 1989 to 1999 and 1999 to 2010 is southeast that is consisting with the regional wind field. The mean moving distance of sand dunes is 39m between 1989 and 1999, while that is 39m between 1999 to 2010.A tendency of moving faster can be drawn from the above.Sand dunes in southeast near Menggen are mainly composed by crescent dunes, transverse dunes and the height of that are between 7 and 31m. Moving direction of sand dunes in the period of 1989 to 1999 and 1999 to 2010 is southeast that is consisting with the regional wind field. The mean moving distance of sand dunes is 51m between 1989 and 1999, while that is 55m between 1999 to 2010.A tendency of moving slower can be drawn.Sand dunes in eastern near Olji is mainly composed by transverse dunes and the height of that are between 9 and 33m. Sand dunes in these areas have reciprocation from Northwest to Southeast between 1989 and 2010, as a result of the instability of direction of the filed wind. Sand dunes move towards Northwest between 1989 and 1995, while that move towards Southeast between 2003 and 2010. Movement of dunes is not distinct between 1995 and 2003. The mean moving distance of sand dunes is 48m between 1989 and 1995, while that is 29m between 2003 to 2010.The moving velocity of sand dunes in this area decreased while their moving direction reverse.(3) Height of sand dunes can be calculated with ASTER DEM data. There is a negative correlation between speed of movement and height of sand dunes. The higher the dunes, the slower it move and vice versa.(4) Landsat TM image can be effectively used to the epochs of ten years' dynamic detection of sand dunes in the Bardain Jaran desert.