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1.
刘天仇 《中国地理科学(英文版)》1995,5(4):344-354
ＳＴＵＤＩＥＳＯＮＷＡＴＥＲＳＴＡＧＥＦＬＵＣＴＵＡＴＩＯＮＯＦＹＡＭＺＨＯＬＡＫＥＩＮＸＩＺＡＮＧＬｉｕＴｉａｎｃｈｏｕ（刘天仇）（ＴｉｂｅｔａｎＢｕｒｅａｕｏｆＷａｔｅｒＲｅｓｏｕｒｃｅａｎｄＨｙｄｒｏｌｏｇｉｃａｌＳｕｒｖｅｙ，Ｌｈａｓａ３５０... 相似文献
2.
In order to reach the designated final water level of 175 m, there were three impoundment stages in the Three Gorges Reservoir, with water levels of 135 m, 156 m and 175 m. Baishuihe landslide in the Reservoir was chosen to analyze its displacement characteristics and displacement variability at the different stages. Based on monitoring data, the landslide displacement was mainly influenced by rainfall and drawdown of the reservoir water level. However, the magnitude of the rise and drawdown of the water level after the reservoir water level reached 175 m did not accelerate landslide displacement. The prediction of landslide displacement for active landslides is very important for landslide risk management. The time series of cumulative displacement was divided into a trend term and a periodic term using the Hodrick-Prescott(HP) filter method. The polynomial model was used to predict the trend term. The extreme learning machine(ELM) and least squares support vector machine(LS-SVM) were chosen to predict theperiodic term. In the prediction model for the periodic term, input variables based on the effects of rainfall and reservoir water level in landslide displacement were selected using grey relational analysis. Based on the results, the prediction precision of ELM is better than that of LS-SVM for predicting landslide displacement. The method for predicting landslide displacement could be applied by relevant authorities in making landslide emergency plans in the future. 相似文献
3.
Moiwo Juana Paul 《中国地理科学(英文版)》2006,16(3):229-235
The impact of land-use on distributed groundwater recharge and discharge in the western Jilin (WJ) was analyzed in this study.
WJ is a transitional, semi-arid zone with a fragile, hydrological closed ecosystem in the Songhua River Basin (SRB). The research
tool includes a seamlessly linked MODFLOW, WetSpass, the Seepage packages, and ArcGIS. The model calibration showed good agreement
between simulated water table elevation and measured water table depths, while predicted groundwater discharge zones showed
strong correlations with field occurrences of drainage systems and wetlands. Simulated averages for distributed recharge,
water table elevation and groundwater drawdown were 377.42mm/yr, 194.43m, and 0.18m respectively. Forest vegetation showed
the highest recharge, followed by agricultural farmlands, while open-water and other drainage systems constituted groundwater
exit zones. When present land-use conditions were compared with the hypothetical natural pre-development scenario, an overall
loss of groundwater recharge (24.09mm/yr) was observed, which for the project area is 18.05 × 108m3. Groundwater abstraction seemed to be the cause of water table drawdown, especially in the immediate vicinities of the supply
wells. An important issue of the findings was the ability of the hypothetical forest vegetation to protect, and hence sustain
aquifer reserves and dependent ecosystems. The profound data capture capability of ArcGIS makes it particularly useful in
spatio-temporal hydroecological modeling.
Biography: Moiwo Juana PAUL (1967–), male, a native of Sierra Leone of West Africa, Ph.D. candidate, specialized in wetland
ecology. 相似文献
4.
5.
《山地科学学报》2020,17(1):191-202
Many landslides in reservoir areas continuously deform under cyclic water level fluctuations due to reservoir operations. In this paper,a landslide model, developed for a typical colluvial landslide in the Three Gorges Reservoir area, is used to study the effect of cyclic water level fluctuations on the landslide. Five cyclic water level fluctuations were implemented in the test, and the fluctuation rate in the last two fluctuations doubled over the first three fluctuations. The pore water pressure and lateral landslide profiles were obtained during the test. A measurement of the landslide soil loss was proposed to quantitatively evaluate the influence of water level fluctuations. The test results show that the first water level rising is most negative to the landslide among the five cycles. The fourth drawdown with a higher drawdown rate caused further large landslide deformation. An increase of the water level drawdown rate is much more unfavorable to the landslide than an increase of the water level rising rate. In addition, the landslide was found to have an adaptive ability to resist subsequent water level fluctuations after undergoing large deformation during a water level fluctuation. The landslide deformation and observations in the field were found to support the test results well. 相似文献
6.
Sub-tidal barotropic current variations coupled with residual sea level fluctuation in the Bohai and Yellow Seas during wintertime are addressed in this study.The temporal evolution and spatial distribution of current fluctuation are investigated using moored acoustic Doppler current profiler data in a three-dimensional numerical model.It is found that a southward current followed by a northward current occurred in the northern Yellow Sea during the fluctuation,concurrent with a significant outflow followed by inflow through the Bohai Strait.The process is consistent from surface to bottom and is coupled with remarkable residual sea level fluctuation.This quasi three-day fluctuation with amplitude 0.2-0.3 m/s leads to 1 m/1.2 m drawdown in the northern Yellow and Bohai Seas,respectively,strongly influencing water exchange between those seas.Because this a prominent feature in the seas,it is necessary to evaluate its effect on fluctuation during winter in future studies,in particular,the northward current during the recovery phase of sea level in the Bohai and Yellow Seas regarding seasonal variation. 相似文献
7.
A model study is conducted to examine the role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007. The model generally agrees with the observations in showing considerable seasonal and interannual variability of the Pacific water inflow at Bering Strait in response to changes in atmospheric circulation. During summer 2007 anomalously strong southerly winds over the PaCific sector of the Arctic Ocean strengthen the ocean circulation and bring more Pacific water into the Arctic than the recent （2000-2006） average. The simulated summer （3 months ） 2007 mean Pacific water inflow at Bering Strait is 1.2 Sv, which is the highest in the past three decades of the simulation and is 20% higher than the recent average. Particularly, the Pacific water inflow in September 2007 is about 0.5 Sv or 50% above the 2000-2006 average. The strengthened warm Pacific water inflow carries an additional 1.0 x 1020 Joules of heat into the Arctic, enough to melt an additional 0.5 m of ice over the whole Chukchi Sea. In the model the extra summer oceanic heat brought in by the Pacific water mainly stays in the Chukchi and Beaufort region, contributing to the warming of surface waters in that region. The heat is in constant contact with the ice cover in the region in July through September. Thus the Pacific water plays a role in ice melting in the Chukchi and Beaufort region all summer long in 2007, likely contributing to up to O. 5 m per month additional ice melting in some area of that region. 相似文献
8.
Thethreatagainstthecoastallowlandcausedbysea-levelriseisoneofthefocusesoftheworid'sat-tention.Thebestestimatevalueofglobaltheoreticalsea-levelriseinthe2lstcenturyisO.66m(SCOR,l99l)byworldwideauthoritativeorganizationsuchasIPCC(IntergovernmentPanelofClimateChange)etal.ThecrustofChangiiangDeltaissubsiding.Theaveragesubsidencerateinthelast2OOOaisl.2mm/a(PANetal.,l985).TheislandsoftheChangiiangRivermouthareaccumulatinglowlandislandsandtheirnat-uralelevationisbelowthehightidallevelofsprin… 相似文献
9.
基于GRACE及GRACE-FO重力卫星数据,通过滑动T检验确定海河流域陆地水储量突变的特征时间点,分析其时空演变特征;结合多变量趋势分析和贡献率量化法探究陆地水储量变化成因,讨论南水北调工程的贡献。结果表明,在南水北调前(2004-01~2015-01)后(2015-01~2020-10),海河流域陆地水储量的衰减趋势分别为-17.19 mm/a和-13.49 mm/a,缓解约24%,缓解趋势由南到北逐渐增大;人类活动与气候变化对流域陆地水储量变化的贡献率比为7∶3,人为耗水是海河流域陆地水储量常年处于亏损状态的主要原因;调水量的贡献率和趋势呈现年际增大和升高态势,预示南水北调工程在改善区域陆地水储量方面具有巨大潜力。 相似文献
10.
1 IntroductionForthepast 1 5years,muchattentionofoceanographershasbeenfocusedontheroleofironinlimiting phytoplankton productivityinthehigh nutrient ,low chlorophyll(HNLC)regions.OnboardshipironenrichmentincubationshavebeencarriedoutinthethreewellknownHNLCregions :notablyequatorialPacificOcean ,subarcticPacificO ceanandSouthernOcean (seereferencesinTable 1 ) .Theinsituironenrichmentexper imentshavebeenaccomplishedintheequatorialPacific (IronEx1in 1 993 (Wells 1 994)andIronEx2in 1 996(… 相似文献
11.
Influence of the Convection over the South China Sea on the Summer Precipitation of Shandong Province 总被引：2，自引：0，他引：2
1 Introduction ShandongProvince ,whichislocatedintheeastofChina ,consistspartlyofpeninsulaandpartlyofinlandwithatotalareaofabout 1 5 0 0 0 0km2 .Lyingfrom34°2 0′Nto 38°2 0′Nandfrom 1 1 4°4 0′Eto 1 2 2°4 0′E ,alltheareabelongstothemoderateregionandtothetypicalAsianmonsoonclimate .SoShandong’ssum merprecipitationaccountsforover 6 0 %oftheannualrainfall,andaccordinglyflood droughtdisastersmain lyoccurinsummer.Moreover,becauseitisgeographi callylocatedinthetransitionalareabetweenthe… 相似文献
12.
湖泊水位是评估湖泊水量变化的重要指标。本文以洪泽湖、高邮湖及洞庭湖为研究对象,利用集中度的概率密度函数方法(CPDF)来提高Jason-2测高数据精度,分析了降水量与各个湖泊水位变化的相关性,并基于实测水位数据对比评价了Jason-2测高卫星原始GDR数据和CPDF方法处理后的卫星数据的精度。结果表明:①Jason-2原始GDR数据点的分布存在疏密之分,大部分数据分布相对集中,且有一定的周期变化,但评价结果显示精度较差,故原始GDR数据不能直接用于湖泊水位监测;②CPDF方法可以极大提高测高卫星的水位数据精度,洪泽湖与高邮湖的均方根误差分别由1.92 m与1.74 m减少到了0.32 m和0.36 m,相关系数由0.28和0.04提高到了0.85和0.72。对于南北宽度较窄且日水位变化较大的湖泊(如洞庭湖),CPDF方法提高原始GDR结果的精度有限;③洞庭湖降水与水位相关性最强,高邮湖次之,而洪泽湖降水与水位成不显著的负相关,是洪泽湖水利工程对于水位的调节导致了这一结果。本研究对于利用测高卫星获得湖泊水位值,进而对湖泊进行动态监控,特别是在填补资料匮乏地区湖泊水位数据方面具有重要意义。 相似文献
13.
郑州五龙电厂锅炉用水以开采地下水为主 ,开采量 4 0 0 0m3/d。由于区内地下水位持续下降 ,农业开采井涌水量减少 ,当地农民认为是由电厂开采引起的 ,双方矛盾激化 ,严重影响了电厂的生产、生活秩序。通过水文地质调查认为 ,电厂开采量基本合理 ,且由于电厂开采井与农用井开采层位不一 ,二者之间有一厚约 30m的致密坚硬粘土层 ,有一定的隔水能力。因此 ,电厂的合理开采对周边农用井不会有大的影响 ,区内地下水位持续下降 ,主要是下游上街至荥阳一带形成的复合降落漏斗引起的。区域上的地下水超采引起全县范围内水位下降。 相似文献
14.
利用2002-08～2016-12 GRACE数据扣除泄漏影响得到的长江流域陆地水储量（TWS）变化，分析其时空变化特征和趋势。结果表明，在此期间长江流域TWS增速为0.13±0.12 cm/a；TWS变化大的区域，如泄漏改正后三峡库区TWS变化由约10 mm/a变为15~20 mm/a，并呈现更大的空间异质性。利用多种气象数据，从气候变化和人类活动角度深入研究长江流域水循环变化。结果表明，降水量与TWS变化在时间和空间上都具有较高的相关性，TWS变化延迟1~2个月；上游源头处温度是影响TWS变化的主导因素，温度升高加速了上游高山冰川融化，使TWS具有增长趋势；三峡工程的蓄水也导致TWS变化；ENSO是长江流域TWS变化的主要影响因素。 相似文献
15.
在库水位波动和降雨作用的共同影响下，库岸滑坡的变形规律往往更为复杂。以三峡库区麻柳林滑坡为例，基于野外调查、钻探编录、深部位移监测以及数值模拟等手段，分析了库水位波动和降雨作用下滑坡变形特征及演化规律。结果表明:麻柳林滑坡在粉质黏土层和块石层交界处发育一个次级滑带，目前该滑坡主要沿次级滑带运动，导致次级滑动的原因与坡体物质的差异性有关；Si(Sf)指标分析法揭示滑坡的滑带还未完全破坏，滑坡仍处于蠕变状态；根据三峡水库水位调度规律，将一个完整水文年划分为6个阶段，数值模拟结果表明滑坡在库水位缓慢下降阶段变形速率较小、在快速下降阶段和低水位阶段变形速率持续增大、在快速上升阶段和缓慢上升阶段以及高水位阶段变形速率则保持平稳。其中，降雨的直接影响和降雨导致库水位波动进而对滑坡变形造成的间接影响，使得麻柳林滑坡在低水位阶段的变形显著增加、稳定性最差，应加强该时段内滑坡的监测和预警。 相似文献
16.
CHEN Meixiang) ZUO Juncheng) LI Peiliang) DU Ling) and LI Lei)) Oceanography Department Ocean University of China Qingdao P. R. China ) Key Laboratory of Coastal Disaster Defence Ministry of Education Hohai University Nanjing P. R. China 《中国海洋大学学报(英文版)》2007,6(2):117-124
Based on a ship survey during January 1998, the characteristics of the flow, the thermohaline properties and the volume transport of the Arabian Sea are discussed. A strong westward flow exists between 10.5?N and 11?N, part of which turns to the south as the Somali current near the coast at about 10?N and the rest turns north. At the passage between the African continent and the So- cotra Island, the northern branch separates into two flows: the left one enters the passage and the right one flows eastward along the southern slope of the island. Off the island the flow separates once more, most of it meandering northeast and a small fraction flow- ing southeast. Volume transport calculation suggests that the tidal transport is one or two orders of magnitude smaller than the total transport in this region and it becomes more important near the coast. The average velocity of the flow in the upper layer (0-150 m) is about 20 cm s-1, with a maximum of 53 cm s-1 appearing east of the Socotra Island, and the subsurface layer (200-800 m) has an aver- age velocity of 8.6 cm s-1; the velocity becomes smaller at greater depths. The depth of the seasonal thermocline is about 100 m, above which there is a layer with well mixed temperature and dissolved oxygen. High-salinity and oxygen-rich water appears near the surface of the northern Arabian Sea; a salinity maximum and oxygen minimum at 100 m depth along 8?N testifies the subduction of surface water from the northern Arabian Sea. Waters from the Red Sea and the Persian Gulf also influence the salinity of the area. 相似文献
17.
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18.
Reservoir-landslide hazard assessment based on GIS: A case study in Wanzhou section of the Three Gorges Reservoir 总被引：2，自引：1，他引：1
Reservoir-landslide is mainly caused by changes in hydrodynamic conditions of slope interior at the time of water storage or discharge. The current study mainly focuses on the typical reservoir landslide, but the sudden occurrence of some unknown landslides brought a lot of difficulties for hazards prevention. Therefore, we proposed a method to evaluate the regional scale reservoir-landslide hazard. We took Wanzhou section of Three Gorges Reservoir （China） as the study area and systemically and synthetically carried out the reservoir-landslide hazard evaluation under the condition of water level regulation. Firstly, we made reservoir-landslide susceptibility assessment by using the methods of spatial analysis and statistics based on geological and geomorphological materials and field survey data, and then, analyzed the regional-scale slope stability based on the infinite slope model used to analyze the bank slope stability change under the condition of water fluctuation, finally, developed a reservoir-landslide hazard evaluation model based on the results of susceptibility and stability. The hazard evaluation model was used to predict and evaluate the hazard change under the role of water level regulation. The results showed that the landslide hazard of the whole region decreased during water storage, landslide hazards increased during water discharge. The faster the regulation speed, the greater the slope hazard. The results can provide the basis for hazard management and regional land-use planning. 相似文献
19.
Air temperature and snow cover variability are sensitive indicators of climate change. This study was undertaken to forecast and quantify the potential streamflow response to climate change in the Jhelum River basin. The implications of air temperature trends (+0.11°C/decade) reported for the entire north-west Himalaya for past century and the regional warming (+0.7°C/decade) trends of three observatories analyzed between last two decades were used for future projection of snow cover depletion and stream flow. The streamflow was simulated and validated for the year 2007-2008 using snowmelt runoff model (SRM) based on in-situ temperature and precipitation with remotely sensed snow cover area. The simulation was repeated using higher values of temperature and modified snow cover depletion curves according to the assumed future climate. Early snow cover depletion was observed in the basin in response to warmer climate. The results show that with the increase in air temperature, streamflow pattern of Jhelum will be severely affected. Significant redistribution of streamflow was observed in both the scenarios. Higher discharge was observed during spring-summer months due to early snowmelt contribution with water deficit during monsoon months. Discharge increased by 5% 40% during the months of March to May in 2030 and 2050. The magnitude of impact of air temperature is higher in the scenario-2 based on regional warming. The inferences pertaining to change in future streamflow pattern can facilitate long term decisions and planning concerning hydro-power potential, waterresource management and flood hazard mapping in the region. 相似文献
20.
Asam Farid Perviez Khalid Klian Zaib Jadoon Muhammad Asim Iqbal Muhammad Shafique 《山地科学学报》2017,14(1):158-174
This paper studies electrical resistivity dataset acquired for a groundwater study in the Domail Plain in the northwestern Himalayan section of Pakistan. Through a combination of geostatistical analysis, geophysical inversion and visualization techniques, it is possible to re-model and visualize the single dimension resistivity data into 2D and 3D space. The variogram models are utilized to extend the interpretation of the data and to distinguish individual lithologic units and the occurrence of saline water within the subsurface. The resistivity data has been calibrated with the lithological logs taken from the available boreholes. As such the alluvial system of the Domail Plain has formed during episodes of local tectonic activity with fluvial erosion and deposition yielding coarse sediments with high electrical resistivities near to the mountain ranges and finer sediments with medium to low electrical resistivities which tend to settle in the basin center. Thus a change is depositional setting happened from basin lacustrine environment to flash flooding during the Himalayan orogeny. The occurrence of rock salt in the northern mountains has imparted a great influence on the groundwater quality of the study area. The salt is dissolved by water which infiltrates into the subsurface through the water channels. Variogram aided gridding of resistivity data helps to identify the occurrence and distribution of saline water in the subsurface. 相似文献