Search

In this paper, we explored the trends of the atmospheric moisture budget, precipitation, and streamflow in summer during 1961 to 2005 and possible correlations between them by using the linear regression method in the Yangtze River basin, China. The results indicate that: (1) increasing tendencies can be detected in the atmospheric moisture budget, precipitation and streamflow in the Yangtze River basin; however, the significant increasing trends occur only in the atmospheric moisture budget and precipitation in the middle and lower Yangtze River basin; (2) both the ratio of summer moisture budget to annual moisture budget and the ratio of summer precipitation to annual precipitation exhibit a significant increasing trend in the Yangtze River basin. The ratio of summer streamflow to annual streamflow is in a significant increasing trend in Hankou station. Significant increasing summer precipitation can be taken as the major controlling factor responsible for the higher probability of flood hazard occurrences in the Yangtze River basin. The consecutively increasing summer precipitation is largely due to the consistently increasing moisture budget; (3) the zonal geopotential height anomaly between 1991 and 2005 and 1961 and 1990 is higher from the south to the north, which to a large degree, limits the northward propagation of the summer monsoon to north China. As a result, the summer moisture budget increases in the middle and lower Yangtze River basin, which leads to more summer precipitation. This paper sheds light on the changing properties of precipitation and streamflow and possible underlying causes, which will be greatly helpful for better understanding of the changes of precipitation and streamflow in the Yangtze River basin. [ABSTRACT FROM AUTHOR]

China is entering a critical and accelerating phase of urbanization. As one of the most urbanized regions in China, the Changjiang (Yangtze) River Delta has experienced dramatic urbanization and urban transformation. However, in the recent years, many changes have taken place in this region and there is limited attention to the regional urbanization path evolution, its problems and the way to solve these problems. Therefore, we should revisit the urbanization process in the Changjiang River Delta again. In this paper, we revisited urbanization paths of the Changjiang River Delta by data analysis, influence factors of urbanization by the Gray Relational Analysis, and major challenges to urbanization of the Changjiang River Delta by theoretical considerations. We found that the urbanization of the Changjiang River Delta had experienced several stages of large-scale spatial and urban system restructuring. Within the Changjiang River Delta, Shanghai, Zhejiang and Jiangshu had experienced different urbanization path with local characteristics. But with their development model gradually converging, their urbanization model is also converging. We also found that the major influence factors affecting the Changjiang River Delta urbanization were dynamic change and urbanization was driven by different key factors in different socio-economic development stages. Meanwhile, the Changjiang River Delta urbanization is facing many problems such as existing institutional arrangements, including the hukou (household registration) system and others which can not meet the needs of current socio-economic development and urbanization. Therefore, it is imperative to promote institutional innovation and adopt a new urbanization development strategy for the sake of the orderly and sustainable urbanization development in the Changjiang River Delta. [ABSTRACT FROM AUTHOR]

The paper reports the ground conditions in the Sanmashan area where people were relocated as a consequence of the impoundment of the Three Gorges Reservoir. Examination of the geology indicates the strong calcareous rocks were not only highly fractured to considerable depths but were also decalcified in the near surface layers. A combination of the highly fractured state and decalcified nature of the material resulted in significant changes in the bedrock parameters between the northern and southern parts of the study area; the southern area having been affected by the deep down-cutting of the Yangtze River, release of stress and the development of three large landslides. [ABSTRACT FROM AUTHOR]

The paper reports a study into the creep behavior of Yangtze River sand, which has implications for both the sustainability and serviceability of structures and the prediction of land subsidence in this area. Following sieve analysis, sand was compressed under pressures of 800, 1,600 and 3,200 kPa, with sieve analysis repeated after each test. This indicated particle crushing. Samples were also compressed by 800 kPa for 0.5, 1, 10, and 100 min, which indicated particle breakage is associated with creep. A new method is proposed to calculate the creep strain of Yangtze River sand, especially where laboratory test results are not available. Two case histories are presented which demonstrate the validity of this simple method for the prediction of post-construction settlement of a high-rise building on Yangtze River Sand and subsidence related to a pumped aquifer. [ABSTRACT FROM AUTHOR]

To identify problematic geological structures which would be encountered when driving tunnels in the high mountainous area of South West China, a joint geophysical and engineering geological study was made. The tunnels will form part of a project to divert water from the Yangtze to the Yellow Rivers. A controlled source audio-frequency magnetotelluric method (CSAMT) was carried out in 2004 between the Ma-ke and Jia-qu rivers in high, steep terrain. The paper discusses the method of data collection, processing, and analysis for the West route. The faults/fractures identified will need to be taken into account in the design and construction of the tunnel. [ABSTRACT FROM AUTHOR]

The occurrence of rice high-temperature damage (HTD) has increased with global warming. Cultivation of rice is seriously affected by the HTD in the middle and lower reaches of the Yangtze River, which directly affects food security in this region and in the whole of China. It is important to monitor and assess crop HTD using satellite remote sensing information. This paper reviews the recent development of monitoring rice HTD using optical remote sensing information. It includes the use of optical remote sensing information to obtain the regional spatial distribution of high temperatures, mixed-surface temperature retrieval for rice fields based on mixed decomposition information, the development of field and thermal infrared testing and modeling, and the satellite/ground-based remote sensing coupled method for monitoring rice HTD. Finally, the prospects for monitoring crop HTD based on remote sensing information are summarized. [ABSTRACT FROM AUTHOR]

Abstract  This paper presents a new kind of material for use in highway embankments in the soft soil of the Yangzi River delta. The experimental study was carried out first to evaluate the effectiveness of the proposed material, using different mixtures of river sand, cement and expanded polystyrene beads. This was confirmed by numerical modeling which indicated both its suitability as regards strength and a reduced settlement compared with the general lime stabilized soil embankments. The environmental advantage is that it utilized river sand which has to be removed to retain the profile of the river bed. [ABSTRACT FROM AUTHOR]

This paper reviews the land cover changes on the Tibetan Plateau during the last 50 years partly caused by natural climate change and, more importantly, influenced by human activities. Recent warming trends on the plateau directly influence the permafrost and snow melting and will impact on the local ecosystem greatly. Human activities increased rapidly on the plateau during the last half century and have significant impacts on land use. Significant land cover changes on the Tibetan Plateau include permafrost and grassland degradation, urbanization, deforestation and desertification. These changes not only impact on local climate and environment, but also have important hydrological implications for the rivers which originate from the plateau. The most noticeable disasters include the flooding at the upper reaches of Yangtze River and droughts along the middle and lower reaches of Yellow River. Future possible land cover changes under future global climate warming are important but hard to assess due to the deficits of global climate model in this topographically complex area. Integrated investigation of climate and ecosystems, including human-beings, are highly recommended for future studies. [ABSTRACT FROM AUTHOR]

On the basis of investigations on the composition and contents of heavy metals in the domestic refuse in the Three-Gorges region of the Yangtze River, in combination with the experimental results, this paper deals with the distribution rule of heavy metals in the various compartments of an incineration system: leachate pool, fly ash and residue. It is concluded that in the leachate pool heavy metals should not be neglectable since about 30% of Pb and 10% of Cr are leached here; in the incineration system, above 74% of Cr, As and Pb exists in residue; above 96% of Hg exists in fly ash and the contents of Cd in fly ash are close to those of residue. It is also concluded that the physical conditions of incineration have a significant influence on the distribution of heavy metals in the incineration system. [ABSTRACT FROM AUTHOR]

The ability to extract mitochondrial and nuclear DNA from ancient remains has enabled the study of ancient DNA, a legitimate field for over 20 years now. Recently, Y chromosome genotyping has begun to be applied to ancient DNA. The Y chromosome haplogroup in East Asia has since caught the attention of molecular anthropologists, as it is one of the most ethnic-related genetic markers of the region. In this paper, the Y chromosome haplogroup of DNA from ancient East Asians was examined, in order to genetically link them to modern populations. Fifty-six human remains were sampled from five archaeological sites, primarily along the Yangtze River. Strict criteria were followed to eliminate potential contamination. Five SNPs from the Y chromosome were successfully amplified from most of the samples, with at least 62.5% of the samples belonging to the O haplogroup, similar to the frequency for modern East Asian populations. A high frequency of O1 was found in Liangzhu Culture sites around the mouth of the Yangtze River, linking this culture to modern Austronesian and Daic populations. A rare haplogroup, O3d, was found at the Daxi site in the middle reaches of the Yangtze River, indicating that the Daxi people might be the ancestors of modern Hmong-Mien populations, which show only small traces of O3d today. Noticeable genetic segregation was observed among the prehistoric cultures, demonstrating the genetic foundation of the multiple origins of the Chinese Civilization. [ABSTRACT FROM AUTHOR]

This paper explores the demographic impacts of the implementation of the "Grand Development in West China" policies and environmental rehabilitation projects in the upper reaches of the Yangtze River. It analyses the interaction between the environmental reconstruction and environment-related migration in this region. The intertwined nature of environmental, ethnic, and poverty problems not only bears negatively upon the "alleviation of poverty conducing to the accruement of wealth" of the poverty-stricken population, but also hinders the rehabilitation of the environment. It brings forth some opinions regarding improving the capacity of regional sustainable development through environmental migration. [ABSTRACT FROM AUTHOR]