The characteristics of land cover and macroscopical ecology changes in the source region of three rivers in Qinghai-Tibet plateau during last 30 years

We obtained four phases of land cover spatial data sets by interpreting MSS images of middle and late 1970s and three phases of TM images of late 1980s, 2004 and 2008 based on field investigation in Three Rivers' Source Region. We analyzed the temporal and spatial characteristics of land cover and macro ecological changes in Three Rivers' Source Region in Qinghai-Tibet plateau since middle and late 1970s. Indicated by land cover condition index change rate and land cover change index, land cover and macroscopical ecological condition degenerated (7090 period Zc -0.63, LCCI -0.58)-obviously degenerated (9004 period, Zc -0.94, LCCI -1.76)-slightly meliorated (0408 period, Zc 0.06, LCCI 0.33). This course was jointly driven by climate change, grassland stocking pressure and implement of ecological construction project.

Effects of La3+ on lipid fluidity land structural transitions in human erythrocyte membranes

The effects of La3+ on the structure and function of human erythrocyte membranes were investigated by fluorescence polarization, spin-labeled electron spin resonance (ESR) and differential scanning calorimetry (DSC). The results showed that increasing concentrations of La3+ inhibited (Na++K+)-ATPase and Mg2+-ATPase activities. La3+ lowered the lipid fluidity of erythrocyte membranes and induced structural transitions in erythrocyte membranes.

EAWM-related air-sea-land interaction and the Asian summer monsoon circulation

Based on the data analysis, this study further explores the characteristics of East Asian winter monsoon (hereafter, EAWM, for brevity) as well as the related air-sea-land system, and illustrates how and to what degree anomalous signals of the subsequent Asian summer monsoon are rooted in the preceding EAWM activity. We identified an important air-sea coupled mode, i.e., the EAWM mode illustrated in Section 3. In cold seasons, strong EAWM-related air-sea two-way interaction is responsible for the development and persistence of the SSTA pattern of EAWM mode. As a consequence, the key regions, i.e., the western Pacific and South China Sea (hereafter, SCS, for brevity), are dominated by such an SSTA pattern from the winter to the following summer. In the strong EAWM years, the deficient snow cover dominates eastern Tibetan Plateau in winter, and in spring, this anomaly pattern is further strengthened and extended to the northwestern side of Tibetan Plateau. Thus, the combined effect of strong EAWM-related SSTA and Tibetan snow cover constitutes an important factor in modulating the Asian monsoon circulation. The active role of the EAWM activity as well as the related air-sea-land interaction would, in the subsequent seasons, lead to: 1) the enhancement of SCS monsoon and related stronger rainfall; 2) the northward displacement of subtropical high during Meiyu period and the related deficient rainfall over Meiyu rainband; 3) above-normal precipitation over the regions from northern Japan to northeastern China in summer; 4) more rainfall over the Arabian Sea and Northeast India, while less rainfall over southwest India and the Bay of Bengal. The strong EAWM-related air-sea interaction shows, to some degree, precursory signals to the following Asian summer monsoon. However, the mechanism for the variability of Indian summer monsoon subsequent to the strong EAWM years remains uncertain.

Analysis on suspended sediment deposition rate for muddy coast of reclaimed land

A new expression for calculating suspended fine-sediment deposition rate is developed based on theoretic analysis and experiments. The resulting equation is applied to simulation of fine sediment deposition in the reclaimed land in the Hangzhou Bay, China. The hydrodynamic environment in this area is solved by use of a long wave model, which gives the 2D-velocity field and considers bathymetric changes due to fine sediment deposition. The expression is proved convenient to use in engineering practice, and the predicted deposition rate agrees with the annual data available from field measurements from the first year to the third year after the construction of the long groin as a reclaiming method.

The effect of land management on plant community composition, species diversity, and productivity of alpine Kobersia steppe meadow

Grassland degradation is widespread and severe on the Tibet Plateau. To explore management approaches for sustainable development of degraded and restored ecosystems, we studied the effect of land degradation on species composition, species diversity, and vegetation productivity, and examined the relative influence of various rehabilitation practices (two seeding treatments and a non-seeded natural recovery treatment) on community structure and vegetation productivity in early secondary succession. The results showed: (1) All sedge and grass species of the natural steppe meadow had disappeared from the severely degraded land. The above-ground and root biomass of severely degraded land were only 38 and 14.7%, respectively, of those of the control. So, the original ecosystem has been dramatically altered by land degradation on alpine steppe meadow. (2) Seeding measures may promote above-ground biomass, particularly grass biomass, and ground cover. Except for the grasses seeded, however, other grass and sedge species did not occur after seeding treatments in the sixth year of seeding. Establishment of grasses during natural recovery treatment progressed slowly compared with during seeding treatments. Many annual forbs invaded and established during the 6 years of natural recovery. In addition, there was greater diversity after natural recovery treatment than after seeding treatments. (3) The above-ground biomass after seeding treatment and natural recovery treatment were 114 and 55%, respectively, of that of the control. No significant differences in root biomass occurred among the natural recovery and seeded treatments. Root biomass after rehabilitation treatment was 23-31% that of the control.

The effect of land management on carbon and nitrogen status in plants and soils of alpine meadows on the Tibetan plateau

Large-scale grassland rehabilitation has been carried out on the severely degraded lands of the Tibetan plateau. The grasslands created provide a useful model for evaluating the recovery of ecosystem properties. The purposes of this research were: (1) to examine the relative influence of various rehabilitation practices on carbon and nitrogen in plants and soils in early secondary succession; and (2) to evaluate the degree to which severely degraded grassland altered plant and soil properties relative to the non-disturbed native community. The results showed: (1) The aboveground tissue C and N content in the control were 105-97 g m(-2) and 3.356gm(-2), respectively. The aboveground tissue C content in the mixed seed treatment, the single seed treatment, the natural recovery treatment and the severely degraded treatment was 137 per cent, 98 per cent, 49 per cent and 38 per cent, respectively, of that in the control. The corresponding aboveground tissue N content was 109 per cent, 84 per cent, 60 per cent and 47 per cent, respectively, of that in the control. (2) Root C and N content in 0-20 cm depths of the control had an 2 2 average 1606 gm(-2) and 30-36 gm(-2) respectively. Root C and N content in the rehabilitation treatments were in the range of 26-36 per cent and 35-53 per cent, while those in the severely degraded treatment were only 17 per cent and 26 per cent of that in the control. (3) In the control the average soil C and N content at 0-20 cm was 11307 gm(-2) and 846 gm(-2), respectively. Soil C content in the uppermost 20 cm in the seeded treatments, the natural recovery treatment and the severely degraded treatment was 67 per cent, 73 per cent and 57 per cent, respectively, while soil N content in the uppermost 20cm was 72 per cent, 82 per cent and 79 per cent, respectively, of that in the control. The severely degraded land was a major C source. Restoring the severely degraded lands to perennial vegetation was an alternative approach to sequestering C in former degraded systems. N was a limiting factor in seeding grassland. It is necessary for sustainable utilization of seeding grassland to supply extra N fertilizer to the soil or to add legume species into the seed mix. Copyright (c) 2005 John Wiley & Sons, Ltd.

港西油田现代油藏管理研究与实践

Through years of practice, reservoir management has already become the basic mode of foreign oil companies to realize the high-efficient development of the oil field. From the view of reservoir development and technological economy, reservoir management regards the study of the reservoir engineering, designs of reservoir projects and the dynamic analysis of the reservoir's performance as a system. In the fields of reservoir description, the establishment of the geological models and development models, the dynamic simulations of reservoir exploitation and the design of the oil engineering, reservoir management emphasizes the cooperation of the geology and the engineering, the combination of the engineering technology and the economic evaluation. In order to provide the means and basis for the reservoir geology study, reservoir evaluation, reserves calculation, numerical simulation, development plan and risk analysis, it adopts the reservoir management activities(team work) to make and implement the optimized oil field development management strategies so that secientific and democratic decision making can be achieved. Under the planned economic system for a long time, the purpose of Chinese reservoir development has been to fulfill the" mandatory" production task. With the deepening of the reform, the management organization of Chinese petroleum enterprises has been gradually going through the transition and reforms to the operational entity and the establishment of the mode of oil companies under the socialist market economy system. This research aims at introducing the advanced reservoir management technique from foreign countries to further improve the reservoir development results and wholly raise the economic benefits of Chinese mature land facieses sandstone reservoirs in the later stage of the water flooding. We are going to set up a set of modern reservoir management modes according to the reservoir features, current situation and existing problems of GangXi oil field of DaGang oil company. Through the study and implementation of the reservoir description and numerical simulation technology effectively, we plan to work out integrated adjustment projects, to study the related technology of oil recovery; to set up the effective confirmable data procedure and data management system of the reservoir management, to establish the coordinated model and workbench related to geology, engineering and economy in order to realize the real time supervision and evaluation on the process of reservoir development. We hope to stipulate modernization management tools for GangXi oil fields to rationally utilize various kinds of existing technological methods and to realize the economic exploitation and achieve the maximum benefits from the reservoir. The project of the modem reservoir management will be carried out on the GangXi oil field of DaGang oil company for this oil field is typical and has integrated foundamental materials and perfect networks. Besides, it is located in the good geographical position enjoying very convenient traffic. Implementing modern reservoir management will raise the recovery ratio, reduce the production cost and improve the working efficiency. Moreover, the popularization of modern reservoir management will improve the comprehensive benefits of DaGang oil company and even the whole Petro China. Through the reserch of this project, the following technical indicators can be reached: Establishing the concept of modern reservoir management. Establishing a set of integrated data information management system adapt to the features of GangXi reservoir. 3. Forming technical research modes of modern reservoir management suitable for mature reservoirs in the later developing stage. 4. Advancing projects of GangXi reservoir which are maxium optimized in engineering technique and economic benefits of oil exploitation. Besides, this set of technology, research principle and method can guide the mature reservoir of DaGang oil field and even the whole PetroChina to develop the further research of reservoir adjustment and improve the reservoir recovery factor and developing level constantly.