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Recent advances in hydrology studies under changing permafrost on the Qinghai-Xizang Plateau
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作者 Lu Zhou YuZhong Yang +1 位作者 DanDan Zhang HeLin Yao 《Research in Cold and Arid Regions》 CSCD 2024年第4期159-169,共11页
Due to the great influences of both climate warming and human activities,permafrost on the Qinghai-Xizang Plateau(QXP) has been undergoing considerable degradation.Continuous degradation of plateau permafrost dramatic... Due to the great influences of both climate warming and human activities,permafrost on the Qinghai-Xizang Plateau(QXP) has been undergoing considerable degradation.Continuous degradation of plateau permafrost dramatically modifies the regional water cycle and hydrological processes,affecting the hydrogeological conditions,and ground hydrothermal status in cold regions.Permafrost thawing impacts the ecological environment,engineering facilities,and carbon storage functions,releasing some major greenhouse gases and exacerbating climate change.Despite the utilization of advanced research methodologies to investigate the changing hydrological processes and the corresponding influencing factors in permafrost regions,there still exist knowledge gaps in multivariate data,quantitative analysis of permafrost degradation's impact on various water bodies,and systematic hydrological modeling on the QXP.This review summarizes the main research methods in permafrost hydrology and elaborates on the impacts of permafrost degradation on regional precipitation distribution patterns,changes in surface runoff,expansion of thermokarst lakes/ponds,and groundwater dynamics on the QXP.Then,we discuss the current inadequacies and future research priorities,including multiple methods,observation data,and spatial and temporal scales,to provide a reference for a comprehensive analysis of the hydrological and environmental effects of permafrost degradation on the QXP under a warming climate. 展开更多
关键词 Qinghai-Xizang Plateau Permafrost degradation hydrological processes
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基于Hydrology的山区1:1万DEM水系提取研究 被引量:5
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作者 安祺 杨霏 +2 位作者 陈丹 杨霜霜 任苏敏 《重庆工商大学学报(自然科学版)》 2012年第11期87-92,共6页
利用重庆市万州区4幅比例尺为1∶1万,地面分辨率为5 m的DEM数据,根据地表径流模型原理,通过ArcGIS中的HydrologyTools模块进行D8算法提取流域水系,计算汇流累积量,并最终生成河网。结果表明:对1∶1万DEM进行水系提取,最小水道集水面积... 利用重庆市万州区4幅比例尺为1∶1万,地面分辨率为5 m的DEM数据,根据地表径流模型原理,通过ArcGIS中的HydrologyTools模块进行D8算法提取流域水系,计算汇流累积量,并最终生成河网。结果表明:对1∶1万DEM进行水系提取,最小水道集水面积阈值设定为50 000个栅格较合理;对于山地地形,基于1∶1万DEM数据,利用ArcGIS Hydrology模块提取河网的方法,从提取的效率和结果的精度两方面看来都是切实可行的。 展开更多
关键词 数字高程模型 水系提取 hydrology 万州区
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基于MCR模型与Hydrology扩展模块的建设用地适宜扩张路径研究 被引量:3
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作者 杨俊 易洁 +1 位作者 李争 李万钰 《国土资源科技管理》 2020年第4期24-36,共13页
随着城市化进程的不断加快,建设用地扩张迅速,不合理的城市扩展模式会干扰区域经济与生态之间的协调发展,引发资源利用不合理、生态环境恶化等负面效应。利用移动窗口法、MCR模型、Hydrology扩展模块相结合,得到武汉市适宜扩张路径、生... 随着城市化进程的不断加快,建设用地扩张迅速,不合理的城市扩展模式会干扰区域经济与生态之间的协调发展,引发资源利用不合理、生态环境恶化等负面效应。利用移动窗口法、MCR模型、Hydrology扩展模块相结合,得到武汉市适宜扩张路径、生态安全路径,为未来城市规划提供了借鉴。结果表明:(1)适宜建设区(适宜扩张区、优化建设区)所占比例达60.59%,说明目前城市发展格局较为合理;(2)不同的适宜性分区对于建设活动的要求不同,适宜建设区域可引导进行建设开发活动,禁止建设区、生态恢复区应设立相关政策,严禁开发;(3)“山谷线”作为建设用地的适宜扩展路径,“山脊线”作为生态安全路径,可避免建设用地盲目扩张,为城市建设指明了方向;(4)生态关键点对于维护城市的生态安全至关重要,应制定相关措施,进行有效管理。 展开更多
关键词 MCR模型 hydrology扩展模块 适宜扩张路径 武汉市
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Primary Research on WSeveral Theorems,Laws and Corollaries of Hydrology 被引量:2
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作者 龚云 《Agricultural Science & Technology》 CAS 2009年第4期1-3,54,共4页
The conceptions of theorems, laws and corollaries of hydrology were put forward. Combining with hydrology practice, several theo- rems, laws as well as corollaries of hydrology were summarized. The study provided some... The conceptions of theorems, laws and corollaries of hydrology were put forward. Combining with hydrology practice, several theo- rems, laws as well as corollaries of hydrology were summarized. The study provided some references for accelerating the development of hydrology theory in these aspects and promoting the improvement of its production technology. 展开更多
关键词 hydrology THEOREM LAW Corollary
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Present and future of hydrology 被引量:9
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作者 Xiao-fang RUI Ning-ning LIU +1 位作者 Qiao-ling LI Xiao LIANG 《Water Science and Engineering》 EI CAS CSCD 2013年第3期241-249,共9页
The complexities of hydrological phenomena, the causes that lead to these complexities, and the essences and defects of reductionism are analyzed. The driving forces for the development of hydrology and the formation ... The complexities of hydrological phenomena, the causes that lead to these complexities, and the essences and defects of reductionism are analyzed. The driving forces for the development of hydrology and the formation of branch subjects of hydrology are discussed. The theoretical basis and limitations of existing hydrology are summarized. Existing misunderstandings in the development of the watershed hydrological model are put forward. Finally, the necessity of the expansion of hydrology from linear to nonlinear is discussed. 展开更多
关键词 hydrological phenomenon hydrological theory hydrological method hydrologicalmodel REDUCTIONISM nonlinear
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Hydrology and water resources variation and its response to regional climate change in Xinjiang 被引量:18
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作者 XU Changchun CHEN Yaning +2 位作者 YANG Yuhui HAO Xingming SHEN Yongping 《Journal of Geographical Sciences》 SCIE CSCD 2010年第4期599-612,共14页
Based on the surface runoff, temperature and precipitation data over the last 50 years from eight representative rivers in Xinjiang, using Mann-Kendall trend and jump detection method, the paper investigated the long-... Based on the surface runoff, temperature and precipitation data over the last 50 years from eight representative rivers in Xinjiang, using Mann-Kendall trend and jump detection method, the paper investigated the long-term trend and jump point of time series, the surface runoff, mean annual temperature and annual precipitation. Meanwhile, the paper analyzed the relationship between runoff and temperature and precipitation, and the flood frequency and peak flow. Results showed that climate of all parts of Xinjiang conformably has experienced an increase in temperature and precipitation since the mid-1980s. Northern Xinjiang was the area that changed most significantly followed by southern and eastern Xinjiang. Affected by temperature and precipitation variation, river runoff had changed both inter-annually and intra-annually. The surface runoff of most rivers has increased significantly since the early 1990s, and some of them have even witnessed the earlier spring floods, later summer floods and increasing flood peaks. The variation characteristics were closely related with the replenishment types of rivers. Flood frequency and peak flow increased all over Xinjiang. Climate warming has had an effect on the regional hydrological cycle. 展开更多
关键词 hydrology and water resources climate change XINJIANG
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IMPORTANCE OF HYDROLOGY, SOIL AND VEGETATIONIN WETLAND RESEARCH 被引量:4
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作者 Elizabeth J.Johnson Peter L.M.Veneman XING Baos-han 《湿地科学》 CSCD 2003年第2期128-135,共8页
Wetlands, one of the most productive systems in the biosphere are a unique ecosystem. They occur in landscapes that favor the ponding or slow runoff of surface water, discharge of ground water, or both. Wetlands are n... Wetlands, one of the most productive systems in the biosphere are a unique ecosystem. They occur in landscapes that favor the ponding or slow runoff of surface water, discharge of ground water, or both. Wetlands are not only important for maintaining plant and animal diversity, but also for balancing global carbon budget via sequestrating or releasing CO2 from/into atmosphere depending on their management. Therefore, it is imperative to understand how wetlands form and function, then we can better manage, utilize, and protect these unique ecosystems. Hydrie soils,hydrophytic vegetation, and wetland hydrology are the three main parameters of wetlands. These parameters are interrelated with each other which jointly influence the development and functions of wetland ecosystems. The objective of this paper was to report the current understanding of wetlands and provide future research directions. The paper will first focus on aspects of hydrology research in wetlands, and then shift to soil hydrosequence and wetland vegetation to better understand processes, structure, and function of wetlands, and conclude with some possible future research directions. 展开更多
关键词 hydric soils VEGETATION hydrology WETLANDS future research
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Important progress on the use of isotope techniques and methods in catchment hydrology 被引量:4
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作者 JinKui Wu 1,2, YongJian Ding 1, BaiSheng Ye 1, QiYue Yang 3, Zhi Wei 1 1. Key Laboratory of Ecological Hydrology and Basin Sciences in Cold and Arid Regions Environmental and Engineering Re-search Institute, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China. 2. Institute for Landscape Ecology and Resources Management, Justus-Liebig-University Giessen, Giessen 35392, Germany. 3. College of Earth and Environmental Science, Lanzhou University, Lanzhou, Gansu 730000, China. 《Research in Cold and Arid Regions》 2009年第3期207-214,共8页
The use of isotope techniques and methods in catchment hydrology in the last 50 years has generated two major types of progress: (1) Assessment of the temporal variations of the major stocks and flows of water in catc... The use of isotope techniques and methods in catchment hydrology in the last 50 years has generated two major types of progress: (1) Assessment of the temporal variations of the major stocks and flows of water in catchments, from which the estimation of wa-ter residence times is introduced in this paper. (2) Assessment of catchment hydrologic processes, in which the interactions be-tween different waters, hydrographical separation, and bio-geochemical process are described by using isotopes tracers. Future progress on isotope techniques and methods in hydrology is toward the understanding of the hydrological process in large river basins. Much potential also waits realization in terms of how isotope information may be used to calibrate and test distributed rainfall-runoff models and regarding aid in the quantification of sustainable water resources management. 展开更多
关键词 ISOTOPE hydrological process CATCHMENT PROGRESS
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Land Surface Hydrology Parameterization over Heterogeneous Surface for the Study of Regional Mean Runoff Ratio with Its Simulations 被引量:3
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作者 刘晶淼 丁裕国 +1 位作者 周秀骥 王纪军 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2002年第1期89-102,共14页
An analytical expression for subgrid–scale inhomogeneous runoff ratios generated by heterogeneous soil moisture content and climatic precipitation forcing is presented based on physical mechanisms for land surface hy... An analytical expression for subgrid–scale inhomogeneous runoff ratios generated by heterogeneous soil moisture content and climatic precipitation forcing is presented based on physical mechanisms for land surface hydrology and theory of statistical probability distribution. Thereby the commonly used mosaic parameterization of subgrid runoff ratio was integrated into a statistical–dynamic scheme with the bulk heterogeneity of a grid area included. Furthermore, a series of numerical experiments evaluating the reliability of the parameterization were conducted using the data generated by the emulated simulation method. All the experimental results demonstrate that the proposed scheme is feasible and practical. 展开更多
关键词 Land surface process hydrology Subgrid scale Heterogeneous distribution Probability distribution density
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Karst caves and hydrology between geodesy and archeology:Field trip notes 被引量:2
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作者 Carla Braitenberg Tommaso Pivetta +2 位作者 Giuliana Rossi Paola Ventura Ambra Betic 《Geodesy and Geodynamics》 2018年第3期262-269,共8页
The Geodynamics-Earth-Tides-meeting-2016 was held in the Karst, the origin of geologic karst- formation. Surface-rivers are absent, and water flows in channels over distances of 30 km, forming subsurface caves. Geodet... The Geodynamics-Earth-Tides-meeting-2016 was held in the Karst, the origin of geologic karst- formation. Surface-rivers are absent, and water flows in channels over distances of 30 km, forming subsurface caves. Geodetic observations allow detecting caves and sense hydrologic flow. The Karst water had been recognized before Romans as provision for man and livestock. Proto-historic remains near the mouth of the underground river suggest the water outpouring from the Karst was associated with deities to be worshiped. Here the geodetic and cultural aspects of the Karst are summarized, illustrating the field trip that had been offered to the participants. 展开更多
关键词 Karst springs ARCHEOLOGY hydrology TILTMETER
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Coupled modeling of land hydrology-regional climate including human carbon emission and water exploitation 被引量:4
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作者 XIE Zheng-Hui ZENG Yu-Jin +4 位作者 XIA Jun QIN Pei-Hua JIA Bing-Hao ZOU Jing LIU Shuang 《Advances in Climate Change Research》 SCIE CSCD 2017年第2期68-79,共12页
Carbon emissions and water use are two major kinds of human activities. To reveal whether these two activities can modify the hydrological cycle and climate system in China, we conducted two sets of numerical experime... Carbon emissions and water use are two major kinds of human activities. To reveal whether these two activities can modify the hydrological cycle and climate system in China, we conducted two sets of numerical experiments using regional climate model RegCM4. In the first experiment used to study the climatic responses to human carbon emissions, the model were configured over entire China because the impacts of carbon emissions can be detected across the whole country. Results from the first experiment revealed that near-surface air temperature may significantly increase from 2007 to 2059 at a rate exceeding 0.1 ~C per decade in most areas across the country; southwestern and southeastern China also showed increasing trends in summer precipitation, with rates exceeding 10 mm per decade over the same period. In summer, only northern China showed an increasing trend of evapotranspiration, with increase rates ranging from 1 to 5 mm per decade; in winter, increase rates ranging from 1 to 5 mm per decade were observed in most regions. These effects are believed to be caused by global warming from human carbon emissions. In the second experiment used to study the effects of human water use, the model were configured over a limited region-- Haihe River Basin in the northern China, because compared with the human carbon emissions, the effects of human water use are much more local and regional, and the Haihe River Basin is the most typical region in China that suffers from both intensive human groundwater exploitation and surface water diversion. We incorporated a scheme of human water regulation into RegCM4 and conducted the second experiment. Model outputs showed that the groundwater table severely declined by -10 m in 1971-2000 through human groundwater over- exploitation in the basin; in fact, current conditions are so extreme that even reducing the pumping rate by half cannot eliminate the ground- water depletion cones observed in the area. Other hydrological and climatic elements, such as soil moisture, runoff generation, air humidity, precipitation, wind field, and soil and air temperature, were also significantly affected by anthropogenic water withdrawal and consumption, although these effects could be mitigated by reducing the amount of water drawn for extraction and application. 展开更多
关键词 China hydrological cycle Climate change Anthropogenic activities Land--atmosphere coupling modeling
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Aspects of forest restoration and hydrology:the hydrological function of litter 被引量:5
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作者 Luara Castilho Pereira Leonardo Balbinot +2 位作者 Marcelle Teodoro Lima Julieta Bramorski Kelly Cristina Tonello 《Journal of Forestry Research》 SCIE CAS CSCD 2022年第2期543-552,共10页
Although forests play important roles in the hydrological cycle,there is little information that relates the water retention capacity of litter in areas under passive restoration,especially in Cerrado savannas.This st... Although forests play important roles in the hydrological cycle,there is little information that relates the water retention capacity of litter in areas under passive restoration,especially in Cerrado savannas.This study relates litter levels to water holding capacity and effective water retention among forest fragments under different passive restoration stages:46,11,and 8 years to better understand litter hydrological functions in the Cerrado.Water retention capacity and effective water retention capacity of litters(unstructured materials,branches and leaves)in the field were monitored on a monthly basis.Total litter accumulation at 46 years was significantly higher than that of the other succession stages.Unstructured litter mass was significantly higher than that of leaves and branches.The 46-year stage had the highest water holding capacity in the leaf fraction,followed by unstructured material and branches.Although the water holding capacity was lower in the oldest resto-ration,this site showed the highest efficiency under field conditions.The process was quickly reestablished,as the 11-year restoration showed results closer to that for the 46-year stage in comparison to the area at 8 years.Thus,passive restoration plays a key role in soil water mainte-nance due to the influence of litter in Cerrado savannas.Deforestation and the imminent need of restoring degraded sites,highlight the need for further studies focused on bet-ter understanding of the process of forest restoration and its temporal effect on soil water recovery dynamics. 展开更多
关键词 Forest hydrology Litter interception STEMFLOW CERRADO Águas Perenes Forest Water holding capacity
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Effects of fire disturbance on forest hydrology 被引量:2
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作者 姚树仁 《Journal of Forestry Research》 SCIE CAS CSCD 2003年第4期331-334,共4页
Fire is quite a common natural phenomenon closely related to forest hydrology in forest ecosystem. The influence of fire on water is indirectly manifested in that the post fire changes of vegetation, ground cover, soi... Fire is quite a common natural phenomenon closely related to forest hydrology in forest ecosystem. The influence of fire on water is indirectly manifested in that the post fire changes of vegetation, ground cover, soil and environment affect water cycle, water quality and aquatic lives. The effect varies depending upon fire severity and frequency. Light wildland fires or prescribed burnings do not affect hydrology regime significantly but frequent burnings or intense fires can cause changes in hydrology regime similar to that caused clear cutting. 展开更多
关键词 Forest fire Forest hydrology Water cycle FLOW Water quality
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Assessing the Hydrology of a Data-Scarce Tropical Watershed Using the Soil and Water Assessment Tool: Case of the Little Ruaha River Watershed in Iringa, Tanzania 被引量:1
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作者 Winfred B. Mbungu Japhet J. Kashaigili 《Open Journal of Modern Hydrology》 2017年第2期65-89,共25页
The hydrology of the Little Ruaha River which is a major catchment of the Ihemi Cluster in the Southern Agricultural Growth Corridor of Tanzania (SA-GCOT) has been studied. The study focused on the hydrological assess... The hydrology of the Little Ruaha River which is a major catchment of the Ihemi Cluster in the Southern Agricultural Growth Corridor of Tanzania (SA-GCOT) has been studied. The study focused on the hydrological assessment through analysis of the available data and developing a model that could be used for assessing impacts of environmental change. Pressures on land and water resources in the watershed are increasing mainly as a result of human activities, and understanding the hydrological regime is deemed necessary. In this study, modeling was conducted using the Soil and Water Assessment Tool (SWAT) in which meteorological and streamflow data were used in the simulation, calibration and evaluation. Calibration and evaluation was done at three gauging stations and the results were deemed plausible with NSE ranging between 0.64 and 0.80 for the two stages. The simulated flows were used for gap filling the missing data and generation of complete daily time series of streamflow at three gauging stations of Makalala, Ihimbu and Mawande. Results of statistical trends and flow duration curves, revealed decline in magnitudes of seasonal and annual flows indicating that streamflows are changing with time and may have implications on envisioned development and the water dependent ecosystems. 展开更多
关键词 hydrology LITTLE Ruaha ANTHROPOGENIC Activities SWAT-CUP
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Variation Trends of Hydrology and Water Resources in Yangtze River Delta Region,China and Its Responses to Climate Change 被引量:3
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作者 XU Nai-zheng LIU Hong-ying WEI Feng 《Meteorological and Environmental Research》 2012年第6期13-16,共4页
Global warming has become one of important environmental issues, and will alter the spatial distribution of hydrology and water re- sources through accelerating atmospheric and hydrological cycles. Yangtze River Delta... Global warming has become one of important environmental issues, and will alter the spatial distribution of hydrology and water re- sources through accelerating atmospheric and hydrological cycles. Yangtze River Delta region, an economic center in China, has experienced a re- gional temperature increase since the 1960s, forming a heat island, and the warming rate has improved since the 1990s. The characteristics of hy- drology and water resources changed under regional climate warming. Here, the impacts of climate change on hydrology and water resources were discussed from the aspects of precipitation change, sea level rise, seawater invasion and water pollution in Yangtze River Delta region, China. 展开更多
关键词 Climate change hydrology and water resources Yangtze River Delta region China China
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Seagull Lake,Western Eyre Peninsula,South Australia:A Saline Lake to Benefit from Climate Change? Ⅱ. Hydrology and Plants
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作者 Peri COLEMAN 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期66-67,共2页
Seagull Lake is an unusual saline lake,having a marine spring connected to a large continental ecosystem.With climate change the balance between marine,meteoric and groundwater inputs to,and evaporitic and groundwater
关键词 conceptual hydrological model aquatic and palustrine plants Tecticornia flabelliformis predicted changes.
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Impacts of Climate Change on the Hydrology of a Small Brazilian Headwater Catchment Using the Distributed Hydrology-Soil-Vegetation Model
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作者 Lívia Alves Alvarenga Carlos Rogério de Mello +3 位作者 Alberto Colombo Sin Chan Chou Luz Adriana Cuartas Marcelo Ribeiro Viola 《American Journal of Climate Change》 2018年第2期355-366,共12页
Climate change is one of the greatest issues for human society. The objective of this study is to assess the impacts of future climate change on seasonal average discharge and monthly water budget in a small headwater... Climate change is one of the greatest issues for human society. The objective of this study is to assess the impacts of future climate change on seasonal average discharge and monthly water budget in a small headwater catchment, located on the Grande River basin, in Minas Gerais, Brazil. The assessment is carried out using the hydrology model, DHSVM. The atmospheric forcing to drive the Distributed Hydrology-Soil-Vegetation Model (DHSVM) is derived from the downscaling of the HadGEM2-ES projections by the Eta Regional Climate Model, at 5-km high resolution. The projections assume the RCP4.5 and RCP8.5 IPCC AR5 emission scenarios. Baseline period was taken between 1961 and 1990. The projections are assessed in three time slices (2011-2040, 2041-2070 and 2071-2099). The climate change is assessed in time slices of 30 years and in comparison against the baseline period to evaluate the hydrological changes in the catchment. The results showed differences in the hydrological behavior between the emission scenarios and though time slices. Reductions in the magnitude of the seasonal average discharge and monthly water budget may alter the water availability. Under the RCP4.5 scenario, results show greater reductions in the water availability in the first time slice, whereas under RCP8.5 scenario greater reductions are indicated in the third time slice. 展开更多
关键词 CLIMATE Changes RCP4.5 and RCP8.5 Scenarios hydrologICAL Model DISCHARGE
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Modeling Urban Hydrology: A Comparison of New Urbanist and Traditional Neighborhood Design Surface Runoff
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作者 Christopher Andrew Day Keith Allen Bremer 《International Journal of Geosciences》 2013年第5期891-897,共7页
Urban development generally leads to an increase in impervious cover resulting in a greater volume of surface runoff following storm activity. However, the type of urban development in place strongly controls the degr... Urban development generally leads to an increase in impervious cover resulting in a greater volume of surface runoff following storm activity. However, the type of urban development in place strongly controls the degree of impervious cover generated. Traditional neighborhood designs focus on a medium-to-low urban density spread over larger areas, while new urbanist neighborhood designs incorporate more diversity by increasing urban density across smaller areas. The purpose of this study is to model and compare the potential surface runoff for two urban neighborhoods in Austin, Texas-Circle C Ranch, a traditional neighborhood design, and Mueller, a new urbanist development for a 10-year 24-hour storm scenario. Potential surface runoff was calculated by layering various geospatial datasets representing the physical characteristics of both study sites within the Watershed Modeling System (WMS) to configure the HEC-HMS runoff model. Results initially imply that the higher density new urbanist neighborhood significantly increases total and peak storm runoff compared to the traditional neighborhood. However, a greater number of residential units are available at Mueller over the same area as Circle C Ranch. When taking this into account the increased potential surface runoff is negated at the new urbanist site. Although new urbanist neighborhoods will usually contain more residential units than traditional developments when compared at the same scale, the higher urban density associated with these neighborhoods demand the development of more effective stormwater retention systems to cope with a potential increase in surface runoff. 展开更多
关键词 Urban hydrology NEW URBANISM RUNOFF MODELING Land Use
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A Technical Note: Orientation of Cracks and Hydrology in a Shrink-Swell Soil
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作者 Takele M. Dinka Robert J. Lascano 《Open Journal of Soil Science》 2012年第2期91-94,共4页
Crack orientations are an important soil physical property that affects water flow, particularly in vertic soils. However, the spatial and temporal variability of crack orientations across different land uses and gilg... Crack orientations are an important soil physical property that affects water flow, particularly in vertic soils. However, the spatial and temporal variability of crack orientations across different land uses and gilgai features is not well-documented and addressed in hydrology models. Thus;there is a need to quantify crack orientations for different land uses and to incorporate their spatial and temporal dynamics into hydrological models. Our objectives were to document the spatial variability of cracks orientations across two land uses and to demonstrate the potential importance of crack orientation related to the hydrology of Vertisols. The exploratory field measurements of the spatial distribution of crack orientations across two Vertisol catenae of two land uses and gilgai features are presented. The field survey showed the complexity of crack geometry in a field, the potential impact of crack orientation on Vertisol hydrology and the challenges associated with measurement of crack orientations. 展开更多
关键词 CRACK ORIENTATION hydrology
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Influence of Civil Authority on Rural Grass-roots Democracy and Social Autonomy in Northwest Minority Regions
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作者 Junlin DU 《Asian Agricultural Research》 2014年第1期75-79,83,共6页
System of villagers autonomy is one of the basic political systems in China and one of those systems ensuring that the people are the masters of the country. Northwest minorities generally live in the remote northwest... System of villagers autonomy is one of the basic political systems in China and one of those systems ensuring that the people are the masters of the country. Northwest minorities generally live in the remote northwestern China where economy and education are relatively underdeveloped compared with those in central and eastern China and civil authority has great influence on rural grass-roots democracy as well as social autonomy there,which causes difficulties to the development of rural democracy and social autonomy. Assisting northwest minority regions in overcoming the difficulties of developing grass-roots democracy and social autonomy,carrying out effective measures to properly guide the development and influence of civil authority and finally achieving the construction of new socialist countryside have great significance in ensuring that people there are the masters of their country. 展开更多
关键词 NORTHWEST MINORITY CIVIL AUTHORITY grass-roots dem
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