共查询到20条相似文献，搜索用时 31 毫秒
1.
The dynamics of anthropogenic activity and anthropogenic sources of nutrients in the Republic of Bashkortostan have been analyzed. Statistical analysis of many-year data of hydrochemical monitoring have been used to establish the year-to-year and annual regularities in the variations of N compound concentrations in watercourses. Maps of the mean annual N concentration in its forms (ammonium, nitrites, and nitrates) have been constructed. The fitness of river water to different types of water use have been assessed. Probability distributions of the concentrations of hydrochemical components have been constructed for different phases of stream water regimes. The exceedance probabilities have been evaluated for MAC values of N compounds in watercourses. 相似文献
2.
3.
Lake Baikal: Extreme level as a rare hydrological event 总被引：1，自引：0，他引：1
M. V. Bolgov A. L. Buber E. A. Korobkina A. A. Lyubushin I. A. Filippova 《Water Resources》2017,44(3):522-536
The optimal boundaries of water level variation range in Lake Baikal have been determined under the conditions of runoff regulation at the Irkutsk HPP and the extremely low water abundance in lake basin in recent years. The properties of the time series of level regime and the characteristics of runoff from its drainage basin have been studied. The formation of long-term dry periods in the region has been studied, and the regularities in level regime variations in the lake have been estimated for both natural and runoff-regulation conditions, and the specifics of runoff regulation and level drawdown in dry years have been considered. 相似文献
4.
2009年2月福州乌鸦嘴泉水氡与该泉流量同时出现异常。为此观测人员进行了多次相关检查,在排除了观测人员、观测仪器以及该泉历史上曾经出现的干扰因素后,认为此次乌鸦嘴泉异常可能是受到位于该泉西南方向的鼓楼老年公寓内工地施工的影响,并对该异常的成因进行了分析。 相似文献
5.
《Continental Shelf Research》2006,26(17-18):2319-2334
Instrumented bottom tripods have provided important data on sediment transport processes on continental shelves and in estuaries for four decades. Since the initial deployment in a tidal channel in Puget Sound, WA, in 1965 numerous tripods have been constructed to investigate bottom boundary layer and sediment dynamics worldwide. Tripod data have led to new understanding of near-bottom wave and current flows in the coastal ocean, and have been crucial to the development of shelf circulation and sediment transport models. Calculations of bottom stress, bottom roughness, and sediment flux that resulted directly from tripod data have been compared to bottom boundary layer model results. Where these have differed, new or revised model components have been developed to improve the skill of the models. The many discoveries that have been made from tripod experiments include dense, near-bottom fluid mud layers that transport large quantities of suspended sediment offshore into deeper regions of the continental shelf. This process has been linked to the seaward progradation of subaqueous deltas and to the boundaries of mid-shelf mud deposits off rivers with high fine-sediment discharge. 相似文献
6.
井间地震资料分辨率很高,但是缺乏成熟的解释方法,本文针对井间地震资料的特点,借鉴地面地震解释技术对井间地震资料开展了精细解释方法研究.首先在深度域资料特点分析的基础上,利用区域速度和层析成像速度将深度域井间地震资料转换到时间域进行研究,并通过粗化降频建立起井间地震资料与地面地震资料之间的相似性联系,得到对井间地震低频反射特征的认识,结合井旁道合成地震记录标定建立起井间地震资料的反射特征,准确的解释了井间地震的反射层位.采用地震瞬时属性分析和时频属性分析得到了对沉积环境的认识,进一步通过波阻抗反演更好的认识井间储层特征.在实际应用中综合多种方法进行解释,并结合测井资料对比落实了井间砂体展布特征,得到对井间储层的精细描述结果,解决了两口井之间储层分布范围、横向连通性及厚度变化等问题,取得了较好的应用效果. 相似文献
7.
R. G. Dzhamalov N. L. Frolova G. N. Krichevets T. I. Safronova M. B. Kireeva M. I. Igonina 《Water Resources》2012,39(6):623-639
Variations in the characteristics of the annual, dry-season, and minimal monthly runoff in rivers of European Russia for the recent 35 years (1975?C2005) have been estimated and analyzed in comparison with a period of approximately the same duration (1935?C1969). The genesis of runoff for different river basins and the major causes of current changes in runoff characteristics have been studied. Regional regularities in the hydrological and geohydrological processes have been identified, and zoning of the territory has been performed with identification of specific features in the formation of river runoff in the European North and the basins of the Volga, Don, Ural, etc. The natural resources of surface and subsurface waters over 1970?C2005 have been re-estimated with the construction of appropriate maps. Water availability and load on water resources have been analyzed. 相似文献
8.
9.
滇西地震重点监视防御区中强地震潜在震源区的综合图像识别 总被引：2，自引：0，他引：2
本文利用滇西地区近些年来的地震地质、地球物理及地壳形变等方面的资料，经深入研究分析，最终选定了１２个较理想的特征参数，通过综合图像识别，在６４个研究对象中得到了２８个Ｄ类对象，占研究区总面积的４３％。其中有１６个对象历史上已有６级以上地震的记载；１２个为新判定的中强地震潜在震源区；１个为判定不稳定对象。最后给出了云南滇西地震重点监视防御区中强地震潜在震源区预测图。 相似文献
10.
E. B. Fefilova 《Water Resources》2011,38(5):637-649
The long-term dynamics of zooplankton in a northern river has been studied in the context of its pollution after an oil pipeline
break. Oil has been shown to have both negative and stimulating effect on planktonic communities and populations, and the
role of the drainage area in river system self-purification is studied. Artificial settling water bodies, which had been formed
by regulation of polluted flows in the river, have been found to have additional significance as biological regenerators of
aquatic ecosystems. 相似文献
11.
概述了太旧高速公路周缘地区（１９个县市）的地震灾害。在寻建筑物的类型进行划分的基础上,用地震安全性评定的综合概率法计算每个单元遭遇烈度的概率,得到了各类建筑物的易损性矩阵,最后计算得出１９个计算单元所有建筑物的破坏数量和预期经济损失,并对计算结果进行了分析和比较,最后提出防震减灾对策。 相似文献
12.
L. P. Babich A. Yu. Kudryavtsev M. L. Kudryavtseva I. M. Kutsyk 《Geomagnetism and Aeronomy》2008,48(3):378-391
Gigantic upward atmospheric discharges have been numerically simulated. The space-time distributions of the self-consistent electric field strength and charged particle densities have been obtained. The brightness, color, and evolution in the space and time of fluorescence above a thundercloud, which agree with the data of field observations of such high-altitude optical phenomena as blue jets and red sprites, have been calculated. It has been indicated that large duration of blue jets results from the emission of a decaying ion plasma of the air. The yields of hard gamma rays and neutrons, generated by upward discharges, have been calculated. 相似文献
13.
14.
PCBs in fish from the southern Baltic Sea: levels, bioaccumulation features, and temporal trends during the period from 1997 to 2006 总被引：1，自引：0，他引：1
Levels of seven marker polychlorinated biphenyls (PCBs) have been determined in five species of Baltic fish collected during 1997-2006. Downward time trends in the concentrations of heavier congeners of PCBs in different Baltic fish, with the exception of cod, have been observed between 1997 and 2001. In case of sprat and herring samples, the statistical significance of the time trends of the PCBs: 101, 118, 153, 138 and 180 concentrations has been proved. Species-specific bioaccumulation of PCBs has been indicated, and the lowest and highest levels of PCBs (expressed on the basis of lipid weight) have been observed in sprat and salmon samples, respectively. PCB profiles have been found to be similar in all the fish species tested. Sampling location has not been a crucial factor for the observed levels of various PCBs. In some fish species, PCB concentrations are negatively correlated with the fat content but have no relation with the fish length. 相似文献
15.
L. I. Miroshnichenko E. V. Vashenyuk J. A. Pérez-Peraza 《Geomagnetism and Aeronomy》2013,53(5):541-560
The main data have been summarized, and the results, achieved using data from the worldwide network during the entire period of ground-based observations of solar cosmic rays (SCRs) from February 28, 1942, when they were discovered, have been generalized. The methods and equipment for registering SCRs have been described. The physical, methodical, and applied aspects, related to the SCR generation, as well as the SCR interaction with the solar atmosphere, transport in the IMF, motion in the Earth’s magnetosphere, and the affect on the Earth’s atmosphere, have been discussed. It has been indicated that the fundamental results were achieved in this field of space physics during 70 years of studies. Special attention has been paid to up-to-date models and concepts of ground-level enhancement (GLE). The most promising tendencies in the development and application of this effective method of solar-terrestrial physics have been outlined. 相似文献
16.
SHRI R. S. CHUGH M.A. 《水文科学杂志》2013,58(2):10-17
Summary The Hooghly is a tidal river and Calcutta one of the most important ports of India is situated on it. The tidal effect stretches to over 175 miles length up to Nabadwip where two nonperennial rivers Bhagirathi and Jalangi, both taking off at different sites from the Gangesmeet and discharge their rain water (freshets) into the Hoogly all through the summer months. Other rivers join it also downstream. Annual tide tables are published for three places on the river viz Sagar, Diamond Harbour and Garden Reach. In this paper lunitidal intervals, durations of rise and fall, mean high water, mean low water, mean tide level and mean sea level planes and mean ranges have been shown to go through periodic seasonal changes. It has been shown that different tidal planes have changed differently in the intrior of the river indicating changes in tidal regimes and in the river bed. Whereas variations in yearly sea levels since 1882 have not been appreciable at Sagar, these at Garden Reach have changed considerable at indicating sometimes an improvement in the channel, other times worsening of the channel. Four 19 yearly cycles of mean sea-level at Garden Reach have been analysed to give phaselags different from Zero and large variations in amplitudes. To carry this study further one period of 19 years each for Sagar, Madras and Vishakhapatnam on East Coast and 4 periods each for Bombay and Aden in the Arabian Sea have also been analysed to see the possibility of nodal variations being constant in amplitude and phase over large areas of the ocean. 19-yearly cycles in the differences between MTL &; MSL have been examined for Bombay, Madras and Garden Reach. The effects of freshets on various planes have been analysed and the curves of annual freshets and MTLs at Garden Reach are found to run closely parallel. The variations in yearly high water and law water planes above MTLs of the corresponding years after corrections for the longitude of the moons' node have been found to be inappreciable. Theoretical extreme high water and low water planes have been found to be more extreme than actually recorded planes which are very near M.H.W.S. and M.L.W.S. planes indicating there are no predominant effects of winds and storms on the tides in the river. The mean ranges at Garden Reach have been found to be steadily increasing. Theoretical effects of increase in range and lowering of MSL on MHW and MLW plane has been found to agree with actual values. Monthly average temperatures and salinities show distinct annual cycles. High temperatures occur at the same times as low salinities and high mean sea levels. Vertical density structure may be responsible for a large part of annual variation in the sea level at Sagar which is a region of particular interest on account of opposite influences of seasonal monsoons, drainage of rivers and oceanic currents. Seasonal variations in average monthly pressure have been related to variations in mean sea levels and it is found that as the pressures decrease, the height of MSL increases. Tide in Hooghly has been found to be progressive type of wave. Rates of travel of tidal streams outside Sagar and rates of streams in the river have been given also, stating the effects of freshets on tidal streams. Bores in Hooghly have been examined. Shapes of tidal curves and profile of the bore at Garden Reach have been drawn. Rates of propagation of the bore from Doodsons' formulae have been compared with actual values and a remarkable agreement has been found. The rise of tide in 10 minutes and 30 minutes which is the time taken for the steep rise to disappear has been correlated with range of tide and a useful table has been included. Tides in Hooghly are predicted by applying harmonic shallow water corrections to open sea primary predictions at Sagar. As the freshets are unpredictable an approximate relationship has been worked out between the departures of actual freshets from num freshets of the years of analyses and departures of actual from predicted tides. From a knowledge of actual freshets the predictions can be corrected almost, daily. A large number of tables and only the essential graphs have been included to illustrate the contents. 相似文献
17.
Fractured carbonate or karst aquifers are highly susceptible to contamination. In Minnesota, the areas underlain by karst aquifers are often characterized by thin soil cover, poorly cased wells and/or collapse features. When coupled with improper land use decisions these aquifers have become extensively contaminated.
Evaluation of existing or potentially contaminated sites has required development of unique site evaluation techniques or combinations of techniques. Shallow geophysics have been used successfully to determine subsurface karst features, pinpoint locations for additional investigations and evaluate pump-test data. Soil texture, density and relative moisture content have been closely examined and criteria established to evaluate subsurface erosion susceptibility. Percent rock core recovery, mechanical response of drilling and drilling fluid loss have been used to characterize the secondary porosity and potential contamination susceptibility of the carbonate rock. Dye tracing via surface sinks and well injection have determined primary flow paths and have been useful in estimating flow times.
These techniques used solely or in conjunction have been very useful in evaluating contamination existing in the aquifers and as a predictive tool to evaluate the proposed land uses impacts. 相似文献
Evaluation of existing or potentially contaminated sites has required development of unique site evaluation techniques or combinations of techniques. Shallow geophysics have been used successfully to determine subsurface karst features, pinpoint locations for additional investigations and evaluate pump-test data. Soil texture, density and relative moisture content have been closely examined and criteria established to evaluate subsurface erosion susceptibility. Percent rock core recovery, mechanical response of drilling and drilling fluid loss have been used to characterize the secondary porosity and potential contamination susceptibility of the carbonate rock. Dye tracing via surface sinks and well injection have determined primary flow paths and have been useful in estimating flow times.
These techniques used solely or in conjunction have been very useful in evaluating contamination existing in the aquifers and as a predictive tool to evaluate the proposed land uses impacts. 相似文献
18.
Variation of fission track density with etching time has been analysed to standardize the etching conditions. The relations between the etching parameters (i.e., temperature, concentration and time) have been established. The differences in unheated samples and samples heated for different times at a constant temperature have been studied Graphs of thermal annealing vs. optimum etching time and of density reduction vs. length shrinkage have been constructed for applications in fission track geochronology. 相似文献
19.
N. I. Alekseevskii D. V. Magritskii P. K. Koltermann P. A. Toropov D. I. Shkol’nyi P. A. Belyakova 《Water Resources》2016,43(1):1-14
Inundatios on the Black Sea coast of Krasnodar krai between 1945 and 2013 have been analyzed. The main genetic types of inundations on the coast have been identified. The specific features and regularities of inundation wave transformation along the rivers and over time have been studied. Seasonal and maximal runoff of Black Sea rivers has been analyzed over a long-term period. Regularities in the variations of the number of inundatios and their characteristics over the coastal area have been revealed both at the annual and long-term scales. Quantitative estimates are given to the hazard and damage to the population and economic activity due to inundations in the valleys of Black Sea rivers. 相似文献
20.
A manual SPME method is presented for the analysis of organic compounds in industrial wastewater. 24 compounds commonly found in the wastewater of a chemical plant in northern Germany have been selected as reference compounds. Precision, linearity, and detection limits have been determined. Moreover, the effect of methanol content, pH value, salt content, and an excess of compounds on the extraction process have been studied. Several compounds have been investigated for their applicability as internal standards to quantify the compounds of interest. Since the method will later be transferred to a fully automated SPME-GC system, which will be operated directly on-site at an industrial wastewater purification plant, special attention has been paid to the analysis of real wastewater samples. In this context, the fibre stability has been studied by performing 53 extraction/desorption cycles from one wastewater sample. Neither a decrease in fibre performance nor in precision has been observed indicating that the proposed method is suitable for the analysis of real wastewater. 相似文献