Anaysis Of Spatiotemporal Variations Characters And The Cause Of Its Formation Of The Badain Jaran Desert Lake

The Badain Jaran Desert is famous for its unusual natural and humanities landscape, such as abrupt rare peaks, singing sand, lakes, magical springs and temples, which attracted domestic and foreign scholars’attention and research for a long time, especially how those lakes that in the desert were formed? But the issue had failed to resolve all the time. We thought that work in hydro chemical of the Badain Jaran Desert Lake was a basic task to know water quality of those lakes better. So perfect and added research on water quality in this area was help for solving the mechanism formation of the desert lakes.The paper mainly analysis spatiotemporal variations character of the Badain Jaran Desert lake, and the cause of its formation, then, make a qualitative explanation of its formation, which thanks to the scientific investigation of the Badain Jaran Desert, that sponsored by College of earth and environment science, Lanzhou University, united researchers of Gansu Desert control Research Institute and NingXia University, who collected plenty of first-hand data of the desert lakes form2009to2012. In this paper, firstly, we compared the water analysis result of September2009with1999and2010, also September2010, January, April, July2010, in order to understand the inter-annual changes of hydro chemical characters of Badain Jaran Desert Lake; Secondly, we made an overall research of spatial distribution features of those119lakes, that sampling in September2010; Thirdly, we chose an typical lake-Nuoertu, which sampling in April, July, October2011and January2012, for observation layered physical and chemical characteristic in seasons. The mainly research conclusions were as follows:(1)The inter-annual variability of ions in the Badain Jaran Desert lakes is stable, it means that there are no change on the recharge resource and ways. The seasonal change of lake ions is effected by the location of the lake, while we could find the high ion value appeared in autumn, and then in summer, the ion value is lower in winter and spring.(2) It shows "low edge high hinterland" of lake saltiness in Badain Jaran Desert. In September2010, there were119lakes in the desert totally, include65.5%salty lake,15.1%freshwater lake and15.1%weak saltwater. In another words, the edge of south of the desert had31lakes, which contains over half freshwater lake, one third weak saltwater lake; the edge of east and northwest of the desert laid8weak saltwater lake and saltwater lake; the inner desert had80lakes, which had salty lakes over90%.(3) The lake area expressed "big-north, small-south". Concretely speaking, lakes in the edge of south desert mostly were smaller than0.1Km2, while those that larger than Ikm2were all located in inner desert, it seems TDS was positively related with lake area, it was mostly related to rate and quality of supplies and discharge of groundwater.(4)The desert lake’s hydro chemical type present a pattern of "pieces-north, line-south". It means kind of Cl·SO4-Na freshwater lake or weak saltwater lake that lied in the edge of south desert just along a northeast to southwest line, several salty lake was Cl-Na. while lakes those lied in inner desert had a instability components of ion concentration. There were for types lake from east to west at least:SO4-Na, Cl·CO3-Na, CO3-Na, Cl-Na. Each type of lakes appeared intensively, just like four "piece" linked together. This huge difference between the two Lakes mostly affected by discharge of groundwater, and the geochemical process among ions in different evolution stage also can’t be neglected.(5) The Physical and chemical layered characters in April of Nuoertu in vertical was the most marked, the next is July, while October and January shows relatively homogeneous. The different characters of temperature and other water chemical in vertical lake water, is mainly caused by wind, temperature and discharge of groundwater or other factors.