A cellular automata model of surface water flow

Previous cellular automata models of surface water flow have been constructed to reflect steady, gradually‐varied flow conditions. While these models are extremely important in showing the near‐equilibrium forms that result from the interactions of water and boundary material, highly dynamic forms and processes require models that represent unsteady flow conditions. In order to simulate unsteady flow in a cellular model of surface water flow, the conservation of mass and the Manning's equations are coupled with an algorithm to delay the movement of water from one pixel to the next until the correct timing is reached. This approach yields highly realistic flood wave hydrographs when compared with flood observations in the Walnut Gulch Experiment Watershed. Coupling this unsteady flow model with simple laws of sediment erosion, transport, and deposition should allow event‐based simulations of watershed and river channel geomorphologic change. Copyright © 2007 John Wiley & Sons, Ltd.     

Evaluation of Electro-Oxidation of Textile Effluent Using Response Surface Methods

In the present investigation, treatment of textile effluent using an electrochemical technique was designed and analyzed using the Box-Behnken method. The influence of individual parameters on electro-oxidation of textile effluent has been critically examined using the response surface method (RSM), and a quadratic model for chemical oxygen demand (COD) reduction has been developed. It has been observed from the present analysis that the predicted values are in good agreement with experimental data with a correlation coefficient of 0.945.     

边坡稳定性优势面分析与专家系统推理策略

文章对边坡稳定性优势面分析与评价的专家系统及其推理策略和实现过程进行了阐述;并对在实现过程及实际应用中的技术问题进行了探讨。     

Arc／Info—Grid模块及其水文模型应用

利用地理信息系统可以建立流域的数字高程模型,并与grid模块的水文表面分析工具结合,形成直观的流域环境三维显示,再通过计算、统计与分析,即可获取精确的水文因子数据,为进一步水文定量研究及应用提出了一种高效的方法。     

元素地球化学场及其地学意义

有关岩浆花岗岩成因的原地重熔说,揭示了各种化学元素在内生过程中的迁移规律。据此并结合元素在周期表中的位置,得出了元素地球化学场的概念,元素地球化学场不但总结了元素在原地重熔过程中的聚散趋势,而且揭示了元素自身组构与其空间分布规律的关系,展示出三个不同层次的地质断面,即花岗岩体上部和顶部盖层断面,大陆地壳断面及地球球体断面。     

初冬季节青藏高原清水河地区甲烷排放率变化(英)

As the globally largest area covered by high altitudinal permafrost, the Qinghai-Tibet Plateau may contribute substantially to atmospheric CH4 budget when global warming. Preliminary observations on CH4 emission at Qingshuihe from November 5 to 14, 1995 show that alpine grassland may be a small source for atmospheric CH4 during early winter. The emission rates of CH4 from moist grassland surface varied from-16. 1 to 23. 9 μg. m-2h-1, with an average of 1. 82 μg. m-2h-1. Emission rates of CH4 from water surface of Qingshuihe River were from -21. 0 to 37. 1 μg. m-2h-1, with an average of 1. 56 μg. m-2h-1. The emission rates of CH at 30 to 200 cm in depth ranged from-69. 0 to 36. 0 μg. m-2h-1, with the average rate at these depths varying from -2. 15 to 2. 04 μg' m-2h-1. The mean emission rates of CH4 in the active layer and permafrost indicate the lower part of active layer tends to release CH4, CH4 is absorbed at low rates in the middle section and in the vicinity of permafrost table, and net fluxes of CH4 is emitted from the soils in the upper part. During the observation periods, the methane concentrations in static chambers and emission rates of grassland and water surface displayed noticeable diurnal variations. The water/ice content may play important role in the spatial variations of methane emission rates. The emission rates of methane is weakly correlated with the ground temperatures at sampling depths and air temperatures. The observed emission rates of methane from the comparatively dry and sandy grassland soils are quite low compared with that observed in the permafrost regions in the high latitudes.     

Evaluation of vegetative criteria for near-surface groundwater detection using multispectral mapping and GIS techniques in semi-arid Botswana

The critical need to consider all options in the search for groundwater in semi-arid areas has promoted work on the possible association of near-surface groundwater and vegetation characteristics using a combination of remote-sensing data and geographic information systems (GIS) techniques. Two vegetative criteria (dense woody cover and abundance of deep-rooting species) are identified as being indicative of near-surface groundwater, and their spatial distribution is tested against the location of aquifers in southeast Botswana. Vegetative criteria classes were combined in a GIS environment with the distribution of geomorphic units and bedrock geology to determine the degree of coincidence with assumed or known aquifers. Results indicate that the distribution of dense woody vegetation as mapped from Thematic Mapper imagery has some potential in identifying especially surficial but also bedrock near-surface groundwater sources in mostly naturally vegetated semi-arid areas. Dense woody cover classes tend to select aquifers in topographically higher areas while classes comprising some deep-rooting species tend to select low-lying aquifers such as those occurring in fossil valleys. Deep-rooting species, however, are less successful as a vegetative criterion. Although various technical refinements are suggested, this work shows that vegetative criteria mapping can however be used in conjunction with conventional geological/geophysical techniques to enhance the prospects for groundwater location in relatively undisturbed semi-arid areas.     

Modern diatom, cladocera, chironomid, and chrysophyte cyst assemblages as quantitative indicators for the reconstruction of past environmental conditions in the Alps. II. Nutrients

Surface sediments from 68 small lakes in the Alps and 9 well-dated sediment core samples that cover a gradient of total phosphorus (TP) concentrations of 6 to 520 g TP l^-1 were studied for diatom, chrysophyte cyst, cladocera, and chironomid assemblages. Inference models for mean circulation log₁₀ TP were developed for diatoms, chironomids, and benthic cladocera using weighted-averaging partial least squares. After screening for outliers, the final transfer functions have coefficients of determination (r², as assessed by cross-validation, of 0.79 (diatoms), 0.68 (chironomids), and 0.49 (benthic cladocera). Planktonic cladocera and chrysophytes show very weak relationships to TP and no TP inference models were developed for these biota. Diatoms showed the best relationship with TP, whereas the other biota all have large secondary gradients, suggesting that variables other than TP have a strong influence on their composition and abundance. Comparison with other diatom – TP inference models shows that our model has high predictive power and a low root mean squared error of prediction, as assessed by cross-validation.