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Based on graphical and quantitative methodology of landscape ecology and Geo-information Tupu, this paper studies the landscape spatial-temporal evolution characteristics of the Yellow River Delta (YRD), which was built up by periodic physical swings of the Yellow River (YR) rump channel during 1855-2000. According to the research on spatial-temporal evolution of YRD and YR rump channel, we conclude that the Qingshuigou channel has reached its limit and a new flow channel for YR should be built up sooner or later. It suggests that the shift of YR channel should abide by its natural rules of flowing through depressions among previous channels and could be carried out by artificial efforts. The paper discusses the problems and alternate ways out for treatment of the high content of silt in the YR flow at the estuary. [ABSTRACT FROM AUTHOR]

The main-channel of the lower Yellow River is the main path of water and sediment transportation. In this paper, we put forth a suggestion that the bank-full discharge of the main-channel in the lower Yellow River should be no less than 4000 m³/s, which is based on the demand from effective sediment transportation (or riverbed scouring), the demand of flood control on morphology of the cross section of the main-channel, and the possible riverbed-forming force of future flood. The forming of the main-channel is the process for the flood force to overcome the resistance from the riverbed. The forming of the main-channel configuration comes from the competition between riverbed-forming force of flood and resistance from the riverbed. Regarding the flood with medium or less sediment content and without floodplain inundated, the main-channel forming mechanism can be simplified as the relationship between the change of cross section area and WαQβ. For forming same main-channel, the needed flood force W0.32Q0.37 is definite, i.e., when the discharge is large, the flood volume can be smaller; if some flood is able to scour the main-channel, its force W0.32Q0.37 should be larger than 41. Not all floods that inundate floodplain have the function of silting in floodplain and scouring main-channel. Regarding flood with medium or less sediment content, only when the flood discharge is over 1.5 times of the relevant bankfull discharge, obvious scouring effect can occur in the main-channel. [ABSTRACT FROM AUTHOR]

Great achievements have been gained in assuring the safety of the lower Yellow River through arduous work in the past fifty years. But the disadvantages of boundary for river-flow are obvious, such as topography, tectonic movement and crustal stability. The main conflicts of less water and more sand, and the speeding up of sedimentation still exist, causing continuous river shrinkage. However, all the existing methods cannot completely avoid flood catastrophe, so a new control method needs to be explored. The method of changing-route based on geographical theory has always been a focus of debate over whether there are other feasible routes for the current Yellow River. From geoscientific point of view, this paper investigates whether there is a best feasible reservation route in Huang-Huai-Hai plain. Under the actual condition that the conflict between water and sand cannot be eradicated, the selection of the best reservation route should be the overlaying area of the optimum boundary conditions and the less social and economic loss. By detailed analysis of topography, tectonic movement, crustal stability and social-economic progress in the region of the lower Yellow River, the best reservation route is obtained by using the distance weighted function and the minimum cost function. The analysis result indicates that the reservation route can get rid of the influence of the elevation in central western Shandong Province, and the whole route flows through the Hal-Huang rift valley, which is good for channel stability. As to the basic parameters of water and sand movements, the gradient increases 36.2%, the length shortens 15.4% and the curvature reduces 12.2%. Using the reservation route can comparatively reduce the flood risk of the Yellow River, except that it will induce such problems as resettlement and relocation of towns, infrastructure reconstruction, water shortage in the abandoned area of the present route, as well as the resultant ecological and environmental degradation. But in contrast to the huge accumulative input to the harnessing of the Yellow River by the state, the absolute input of dealing with the above-mentioned problems is still acceptable. In the construction of corresponding infrastructures, using the reservation route will promote the region's socio-economic development and offer a rare chance of burgeoning. [ABSTRACT FROM AUTHOR]

The evaluation of crustal stability in the lower Yellow River region (LYR) is vital to the engineering project of the Yellow River embankment and construction of the Huang-Huai-Hai plain. From three aspects of tectonic stability, surface stability and medium stability, this paper analyzes in detail the factors such as tectonic activity, tectonic stress, exogenic geologic disasters and ground material composition which affect crustal stability in the study area and the spatial distributions of subordinate degree of the evaluation factors. It then constructs the crustal stability evaluation model of fuzzy mathematics based on GIS by using AHP to find out the interrelations among the various factors, comprehensive evaluation of fuzzy mathematics and the functions of spatial overlay and spatial database of ArcGIS. Based upon this the crustal stability evaluation is carried out, the results show that the areas of stable and instable regions are basically the same, being 48.72% and 51.28% respectively. The area of moderate stable region takes a dominant position, being about 70.58%. The crust instable region presents zonal distribution and under the control of tectonic faulted belt. But the region where the LYR runs across is mostly instable with a total length of the river being 568.345 km, or 78.93% of all. The river reach where the crustal stability is relatively poor along the LYR is concentrated in the Lankao-Dongping section. [ABSTRACT FROM AUTHOR]

Strong disturbances associated with auroral substorms originate from the ionosphere-magnetosphere owing to the effects of the solar wind, and the wind field in the ionosphere is related to such substorm activity. Here, we describe the analysis of four auroral substorm events, for which we employed an all-sky Fabry-Perot interferometer to observe the two-dimensional horizontal wind field and combined the results with data from an all-sky charge-coupled device imager, a fluxgate magnetometer installed at Yellow River Station, and the Super Dual Auroral Radar Network. The results demonstrate that, during auroral substorms, the vector wind field is related closely to variations in the ion drift and geomagnetic field. Moreover, we observed a changing wind field of approximately 300 m/s in response to variations in the electric and magnetic fields (likely caused by ion drag) and a disturbance of about 200 m/s that we attribute to the interaction of Joule heating and ion drag. [ABSTRACT FROM AUTHOR]

Based on the analysis of data on temperatures and moisture of soils in the active layer at four different permafrost sites in the source areas of the Yellow River (SAYR) in 2010-2012, the freeze-thaw processes of soils in the active layer were compared and contrasted for understanding the spatiotemporal variations. At the four studied sites, the thickness and mean annual temperature of permafrost are different. The temperatures at the top of permafrost (TTOP), i.e., the maximum depth(s) of seasonal frost and/or thaw penetration, are −1.9 °C at the Chalaping site (CLP), −0.9 °C at the site on the southern bank of the Zhaling Lake (ZLH), −0.4 °C at the Maduo Town site (MDX), and 1.1 °C at the site on the northern bank of the Eling Lake (ELH). Differences in the mean annual ground temperature of permafrost and TTOPs may be responsible for the differentiations in the freeze-thaw processes of soils in the active layer. With rising TTOPs, the ground thawing started earlier: CLP in early June, ZLH in late May, MDX in early May, and ELH in mid-April, while the freezing began later: CLP in early October, ZLH in early to mid-October, MDX in mid-October, and ELH in the mid- to late October. With increasing TTOPs, the freeze-up periods for permafrost sites were shortened: 202 days at CLP, 130 days at ZLH, 100 days at MDX, and the period of complete thaw was 89 days at ELH. At the CLP and ZLH sites, the two-directional ground freezing (downwards from ground surfaces and upwards from the permafrost table) and thawing finished in the same year, but the ground freezing at the MDX continued to the end of the next January, with very slow freezing rates in the end. At the ELH site, ground freezing kept on until early May when thawing began on the surface, and upward and downward thawing became increasingly stable in late June to early July. At each site, with rising TTOPs, the downward freezing accelerated in comparison with the upward freezing, and with an increasing proportion of downward frozen depth, and with the larger ratios of freezing to thawing duration. In summary, the patterns of thawing and freezing processes in the active layer in the SAYR differ from those in other parts of the Qinghai-Tibet Plateau to a noticeable extent. [ABSTRACT FROM AUTHOR]

Through intensive studies, we have established an index system for evaluating the loss and impact caused by large-scale flood disasters, and constructed a methodological system for pre-assessing the loss and impact caused by large-scale flood disasters. Through numerical simulation, submerged characteristics of large-scale flood can be determined. According to the characteristics of spatial corresponding distribution between land-use types and types of disaster-affecting subjects, we have realized spatialization for social and economic statistic data, and have completed spatialization evaluation on the loss and social impact caused by large-scale flood disasters using the spatial analytical function of GIS software. It is possible that large-scale flood can occur in the lower Yellow River. Flood management requires pre-assessment on the loss and impact caused by flood disasters. Nevertheless, there is no appropriate pre-assessment method for the lower Yellow River at present. By imitating the flood happened in Yuanyang, the north bank of the lower reach of Yellow River in 1958, we did pre-assessment on the loss and social impact caused by the overflow flood. We found that this method can be used to predict the types, quantity and spatial distribution of economic loss caused by large-scale flood disasters. This method can determine population affected by disasters and degree and spatial distribution of disasters. Indirect loss can be predicted as well using this method. In general, this method can meet the needs of regions affected by flood for planning and making decisions in fighting floods and reducing loss. [ABSTRACT FROM AUTHOR]