Abstract: Most of the mountain glaciers in the Northern Hemisphere are retreating recently because of the negative mass balance, reflecting the warm tendency of the climate change. The glacier mass balance in the mountains of the Northern Hemisphere has a significant regional features owing to the difference of the regional climate variations and the glacier responses to climate changing.
Abstract: Based on the results of correlation analysis, the possible processes about the influence of the Antarctic sea ice on the Northwest Pacific subtropical high are revea.led. The essence of these processes lies in adapting the intensity of meridional heat exchange to the fluctuation of Hl(total heat loss of atmosphere in the Antarctic region), so that the balance of the sea ice-ocean-atmosphere system can be kept. The meridional heat exchanges of lower atmosphere in the region north of 48°S in the southern hemisphere are also calculated to confirm above inference.
Abstract: Based on the flood exceeded series, a kind of flood frequency model-HSPPC model is developed by using the compound stochastic point process theory to be aimed at the shortcomings of flood risk HSPPB model. Combined with the measured flood data in hundred years and investigated flood data in thousand years in the middle and upper areas of the Yangtze River, the flood frequency of a large-scale water conservancy project is calculated and analyzed by using the HSPPC model. The result shows that HSPPC model is a kind of suitable one for flood frequency analysis, which is more flexible and more adaptable as compared with the traditional flood risk model.
Abstract: The real-time optimal operation model including long and short term operations of hydrothermal system is presented in this paper. The benifit from the model is remarkable because much characters about sequential decision of reservoir operation, power transmission loss, equipment maintenance and start-stopping of generating units are considered. Simulative operating in Jiangxi system in 1987 shows that the model can save more 6% of fuel.
Abstract: The water resources planning in the Jing-Jin-Tang (JJT)district is a multipurpose, large-scale and long-period complex problem which has profound effect on the development of the industry and the agriculture, and the people's life of the district. In this paper,a decision support system(DSS) prototype of JJT water resources plarming is established after analysing the problem in a system view. The DSS contains a user interface, a data base system, a model bank, a method bank, and a knowledge base system. In the model bank, there are system dynamic model and multi-purpose planning model, etc. In the method bank, there is a distance comparision method and a one-to-one comparision method, which is used for ranking the schemes. The knowledge base system contains some expert knowledge used for decision support. The logic and construction of the DSS of JJT water resources planning are emphatically stated in this paper.
Abstract: An optimal irrigation model of combining wells and canals is presented in Hetao irrigation district for conjunetive operation of surface water and groundwater. In the model the optimal planting plan and the operation policy are used in order to control the groundwater level and soil salinization and get steady and high harvest. The model is able to adjust the surface water, the water in the soil moisture belt and the aquifer cooperatively. The results are in agreement with that of the experiment area of 266.7hm2. Its effect is obvious in water-saving, harvest-increasing,groundwater levelcontrolling and soil-ameliorating. It has important significance for developing watersaving irrigation agriculture.
Abstract: A largescale system-mufti-objective decision model is presented in this paper, it can be used for optimization of successive building planning and operation of the reservoir for irrigation and comprehensive utilization. The mufti-objective dynamic programming model is solved by using a new algorithm of dynamic propramming, with changeable penalty term. The results of case study show that the mathematical model and solution tec hnique are available and the benefit obtained from optimizing operation is remarkable.
Abstract: The less efficient drainage system in Taihu lake basin was formed in the Ming and Qing Dynasties, with its source traced back to the South Song Dynasty, and is one of the factors causing the extraordinary flooding and waterloging calamity in 1991. Therefore, countermeasures for Taihu lake basin should be base dupon the principle of "flood drainage being the major means, while accompanied by augmenting storage capacity".
Abstract: Xinjiang, the western part of China, is landlocked and far from oceans, and has an arid climate. Evaporation properties in Xinjiang are in close relation with its unique natural and geographic conditions. As a result, the mountain areas are runoff forming areas where precipitation is greater than evaporation; the plains below the river mouths are runoff dissipating areas where actual evaporation is far greater than precipitation;and the broad desert areas are no-runoff areas where precipitation is completely consumed by evaporation. The experimental studies on evaporation and the available estimation methods for the evaporation from water surface, land and groundwater are presented.
Abstract: The runoff formation principle is an important aspect to develop methods of short-term flood forecasting. Some advances of the runoff yield mechanism, the watershed runoff yield, the flood routing, and the watershed concentration flood are systematically reviewed, meanwhile, their future developments are predicted.