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The sandy land in the southern region of the Tengger Desert is adjacent to cities and towns, and land desertification poses a threat to the livelihood and production of local residents. To determine dynamic changes in local desertification, five periods (1973, 1987, 1992, 2001, and 2009) of remote sensing data are studied by remote sensing (RS) and geographic information system (GIS). The desert contraction area is primarily centered around three units (Wuwei, Gulang, and Jingtai) and nearby regions of Zhongwei City. The primary desert expansion areas include the west side of Helan Mountain (WSHM), the Central Mountainous Area (CMA), and the eastern and western Zhongwei units far from towns. From 1973 to 2009, the degree of change in the contracting part of the primary desert expansion unit showed an increasing trend; in brief, most of the desert (especially after 2001) has been developing in a direction in which desertification has been gradually controlled. The primary desert expansion areas are less affected by human activity, but they are primarily controlled by natural factors (especially wind and terrain). The desert contraction areas occur around the towns and nearby regions with frequent human activity; desertification is primarily controlled by human factors. With rapid economic development (especially after 2000), the scale of the cultivated area, town, and ecological protection engineering has gradually expanded, and the latter two are primarily built on a previous desert, which is the root cause of the reduction in the desert areas around the towns and the shrinkage toward north of border. Therefore, reasonable and effective human activity in the southern region of the Tengger Desert is playing a crucial role in preventing desertification. [ABSTRACT FROM AUTHOR]

Based on dust storm records and meteorological data from six stations in the area surrounding the Tengger Desert over the period 1960-2007, the diurnal, monthly and interannual variation of dust storms and severe dust storms, as well as their relation to wind speed, precipitation and temperature, are analyzed and discussed. Statistical analyses demonstrate that such storms occur more frequently from 9:00 to 21:00 local standard time and much more frequently between March and May, especially April. Dust storm frequency (DSF) and severe dust storm frequency (SDSF) show a significant linear decreasing trend from 1960 to 2007. For monthly variability, winds (especially strong ones with speeds 10-20 m/s) are the main factor controlling both dust storm types. Precipitation and temperature have an indirect effect on DSF and SDSF by controlling vegetation growth. For interannual variability, strong wind is still the main control, with precipitation a relatively important cofactor. Temperature has an irregular but somewhat negative relationship with dust storms. Precipitation and especially temperature have likely been important in the increase of DSF since 2000. [ABSTRACT FROM AUTHOR]

It is very important to strengthen the research about the heavy metal pollution of soil in vulnerable ecological regions of the south-central arid area of Northwest China for regulating and guiding local industrial and municipal activities and for protecting the environment. In this study, 48 surface soil samples were collected in the desert-loess transitional zone in the south of the Tengger Desert. The distributions of elements (heavy metal based) and the differences between urban and natural soils were analyzed. We observed that As, Pb, Cu, Zn and S were clearly enriched in the Baiyin area, and Ni and Cr were mainly enriched in the Zhongwei area. V, Mn, Ti, Bi, Co and W were enriched in the southeast margin of the Tengger Desert, where there is relatively little human activity. Over the entire study area, Ce, La and Nd were widely distributed across regions whether with strong or weak human activity. Based on the distributions of elements, we suggest that in the desert-loess transitional zone in the south of the Tengger Desert, the distribution and abundances of element As, Pb, Cu, Zn, S, Ni and Cr are strongly related to the human activities in the area, but the elements V, Mn, Ti, Bi, Co, W, Ce, La and Nd are derived mainly from natural sources. [ABSTRACT FROM AUTHOR]

The Shagou section contains rich information about the formation and evolution of sand storms in the windward side of of the Tengger Desert (southern Tengger Desert, east of the Hexi Corridor). By investigating the grain size classes and the standard deviation of three sample groups in the Shagou section we discover that every group has four sensitive grain size components, and each sensitive grain size component has a tendency to be finest for the palaeosol stratum, coarsest for the sand stratum, and the loess intermediate between the two. The three sample groups have differences in their grain size distributions. Both S1 (average) and L1 (average) have two peaks. L1 (sand stratum) has three peaks and an additional coarse peak (275.4-550 µm) which is consistent with the grain size distribution pattern of the modern sand storm samples in the Tengger Desert. Moreover the additional peak of the palaeo-sand stratum correspondingly the interval of the grain size is exactly consistent with one of the four sensitive grain size components. Because the sand stratum in L1 of the Shagou section was the direct result of sand storm process of the Tengger Desert, the sand group percent of 275.4-550 µm in the Shagou section could be used as a sensitive indicator of sand storm in the south of the Tengger Desert (east of Hexi Corridor). [ABSTRACT FROM AUTHOR]

Abstract: In northern China, high spatial and temporal instability exists in the southern desert border. Since the region is very sensitive to the changes of global climate and the migration of the southern desert border threatens the survival of surrounding inhabitants, it is very important to strengthen the research about the migration of the southern desert border of northern China. The dust in the downwind of the desert contains relevant information of the desert evolutionary history. In order to investigate the relationship between dustfall grain size and the southern border of northern China desert, we collected 56 eolian surface soil samples from the south of the Tengger Desert, selected two near north–south transects from these samples and used the grain size class-standard deviation method. We finally obtained three sensitive grain size components (ranking by degree of sensitivity from high to low): 61.8–185.4μm, 18.2–61.8μm and 2.3–18.2μm. The values of the three sensitive grain size components from the 56 eolian surface soil samples and the three commonly used grain-size indicators, which are the median grain size, >20μm and >63μm particle content, have been converted to the grain-size contour figures. In the six grain-size contour figures, the contour of the 61.8–185.4μm particle content component has the highest degree of similarity with the southern border of the Tengger Desert, followed by the >63μm particle content component, and then the components of the median grain size, 18.2–61.8μm particle content, >20μm and 2.3–18.2μm particle content in turn. Relative to the >20μm and >63μm particle content indicators, the indicator of 61.8–185.4μm particle content is not only the most sensitive one in theory, but also has the highest degree of similarity between its contour and the southern desert border in practical terms. Moreover, this indicator is further defined as the upper limit of coarse grain size. Since the coarse grains in the eolian deposits are mainly from the near-source desert, the component of 61.8–185.4μm particle content within the loess to the south of the Tengger Desert could be regarded as the indicator of the migration of the southern desert border, which could be used to quantitatively reconstruct the desert palaeo-border in the future. [Copyright &y& Elsevier]