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81.
本文通过总结前辈们的研究成果,综合概括我国同位素水文地质学近20余年取得的发展和成就。指出我们的不足与面临的挑战。  相似文献   
82.
四川盆地及周边地区TRMM 3B42数据精度检验   总被引:2,自引:1,他引:1  
多源信息融合的流域水文模拟及预报技术,是目前水文预报发展的一个重要方向。以易发生长江流域特大洪水的四川盆地及周边地区为研究区域,从单个站点及子流域降水量相关性、降雨空间分布和相对误差等方面对TRMM卫星3B42产品探测精度进行了检验分析。结果表明:研究区TRMM 3B42数据与地面观测数据在日、月尺度上具有较高的相关性(R >0.5),3 h尺度相关性较差(R<0.5),且3 h和日尺度在降水量峰值拟合上存在较为明显的数值偏差和时间上的提前或延迟;不同时间尺度下两组数据的空间分布特征总体具有较好的一致性;两组数据2008—2010年降水量序列均值相对偏差在±10%的概率密度百分数为32.26%。总体上研究区TRMM 3B42数据呈现高估(四川盆地大部分区域),局部出现低估(四川盆东南及地周边地区);研究区3 h尺度TRMM 3B42数据探测精度明显低于日尺度,高程变化对TRMM 3B42数据的探测精度具有一定影响。因此,针对该区域TRMM 3B42数据3 h和日尺度数据序列精度相对较差的问题,应用该卫星数据进行3 h尺度流域水文模拟及预报研究时,就需要对该区域卫星数据和地面观测数据进行融合,充分发挥两种数据的优势。  相似文献   
83.
植被气孔阻抗对区域气候影响的数值试验   总被引:1,自引:0,他引:1  
应用区域气候模式RegCM3,单向嵌套NASA/NCAR全球环流模式CAM30的输出结果,模拟1992—1997年不同气候背景下,植被气孔阻抗变化对鄱阳湖流域地表水循环过程和地面热量平衡的影响。结果表明,在现代气候条件下,气孔阻抗加倍导致年平均温度增加了033 ℃(193%),降水减少了023 mm/d(24%);在CO2加倍的未来情景下(1)气孔阻抗不变时,平均温度增加了169 ℃(996%),降水增加了083 mm/d(86%),(2)气孔阻抗加倍时,年平均温度增加了202 ℃(119%),降水增加了068 mm/d(71%)。总的看来,气孔阻抗加倍的放大了CO2浓度增加(即温室效应)带来的影响。  相似文献   
84.
Despite a long history of synergy, current techniques for integrating Geographic Information System (GIS) software with hydrologic simulation models do not fully utilize the potential of GIS for modeling hydrologic systems. Part of the reason for this is a lack of GIS data models appropriate for representing fluid flow in space and time. Here we address this challenge by proposing a spatiotemporal data model designed specifically for large‐scale river basin systems. The data model builds from core concepts in geographic information science and extends these concepts to accommodate mathematical representations of fluid flow at a regional scale. Space–time is abstracted into three basic objects relevant to hydrologic systems: a control volume, a flux and a flux coupler. A control volume is capable of storing mass, energy or momentum through time, a flux represents the movement of these quantities within space–time and a flux coupler insures conservation of the quantities within an overall system. To demonstrate the data model, a simple case study is presented to show how the data model could be applied to digitally represent a river basin system.  相似文献   
85.
The influence of hydrological dynamics on vegetation distribution and the structuring of wetland environments is of growing interest as wetlands are modified by human action and the increasing threat from climate change. Hydrological properties have long been considered a driving force in structuring wetland communities. We link hydrological dynamics with vegetation distribution across Everglades National Park (ENP) using two publicly available datasets to study the probability structure of the frequency, duration, and depth of inundation events along with their relationship to vegetation distribution. This study is among the first to show hydrologic structuring of vegetation communities at wide spatial and temporal scales, as results indicate that the percentage of time a location is inundated and its mean depth are the principal structuring variables to which individual communities respond. For example, sawgrass, the most abundant vegetation type within the ENP, is found across a wide range of time inundated percentages and mean depths. Meanwhile, other communities like pine savanna or red mangrove scrub are more restricted in their distribution and found disproportionately at particular depths and inundations. These results, along with the probabilistic structure of hydropatterns, potentially allow for the evaluation of climate change impacts on wetland vegetation community structure and distribution.  相似文献   
86.
87.
A 3-D finite element model (Feflow) has been used for regional groundwater flow modelling of Upper Chaj Doab in Indus Basin, Pakistan. The thematic layers of soils, landuse, hydrology, infrastructure and climate were developed using Geographic Information System (GIS). The numerical groundwater flow model is developed to configure the groundwater equipotential surface, hydraulic head gradient and estimation of the groundwater budget of the aquifer. Integration of GIS with groundwater modelling and satellite remote sensing capabilities has provided an efficient way of analysing and monitoring groundwater status and its associated land conditions. The Arcview GIS software is used as additive tool to develop supportive data for numerical groundwater modelling, integration and presentation of image processing and modelling results.
The groundwater behaviour of the regional model shows a gradual decline in watertable from year 1999 onward. The persistent dry condition and high withdrawal rates play an influential role in lowering down the groundwater levels. Different scenarios were developed to study the impact of extreme climatic conditions (drought/flood) and variable groundwater abstraction on the regional groundwater system. The results of the study provide useful information regarding the behaviour of aquifer in order to organize management schemes on local and regional basis to monitor future groundwater development in the area.  相似文献   
88.
In this paper, a recently introduced artificial intelligence technique known as Gene Expression Programming (GEP) has been employed to perform symbolic regression for developing a parametric scheme of flow duration curve (FDC) regionalization, to relate selected FDC characteristics to catchment characteristics. Stream flow records of selected catchments located in the Auckland Region of New Zealand were used. FDCs of the selected catchments were normalised by dividing the ordinates by their median value. Input for the symbolic regression analysis using GEP was (a) selected characteristics of normalised FDCs; and (b) 26 catchment characteristics related to climate, morphology, soil properties and land cover properties obtained using the observed data and GIS analysis. Our study showed that application of this artificial intelligence technique expedites the selection of a set of the most relevant independent variables out of a large set, because these are automatically selected through the GEP process. Values of the FDC characteristics obtained from the developed relationships have high correlations with the observed values.  相似文献   
89.
The plains materials that form the martian northern lowlands suggest large-scale sedimentation in this part of the planet. The general view is that these sedimentary materials were transported from zones of highland erosion via outflow channels and other fluvial systems. The study region, the northern circum-polar plains south of Gemini Scopuli on Planum Boreum, comprises the only extensive zone in the martian northern lowlands that does not include sub-basin floors nor is downstream from outflow channel systems. Therefore, within this zone, the ponding of fluids and fluidized sediments associated with outflow channel discharges is less likely to have taken place relative to sub-basin areas that form the other northern circum-polar plains surrounding Planum Boreum. Our findings indicate that during the Late Hesperian sedimentary deposits produced by the erosion of an ancient cratered landscape, as well as via sedimentary volcanism, were regionally emplaced to form extensive plains materials within the study region. The distribution and magnitude of surface degradation suggest that groundwater emergence from an aquifer that extended from the Arabia Terra cratered highlands to the northern lowlands took place non-catastrophically and regionally within the study region through faulted upper crustal materials. In our model the margin of the Utopia basin adjacent to the study region may have acted as a boundary to this aquifer. Partial destruction and dehydration of these Late Hesperian plains, perhaps induced by high thermal anomalies resulting from the low thermal conductivity of these materials, led to the formation of extensive knobby fields and pedestal craters. During the Early Amazonian, the rates of regional resurfacing within the study region decreased significantly; perhaps because the knobby ridges forming the eroded impact crater rims and contractional ridges consisted of thermally conductive indurated materials, thereby inducing freezing of the tectonically controlled waterways associated with these features. This hypothesis would explain why these features were not completely destroyed. During the Late Amazonian, high-obliquity conditions may have led to the removal of large volumes of volatiles and sediments being eroded from Planum Boreum, which then may have been re-deposited as thick, circum-polar plains. Transition into low obliquity ∼5 myr ago may have led to progressive destabilization of these materials leading to collapse and pedestal crater formation. Our model does not contraindicate possible large-scale ponding of fluids in the northern lowlands, such as for example the formation of water and/or mud oceans. In fact, it provides a complementary mechanism involving large-scale groundwater discharges within the northern lowlands for the emplacement of fluids and sediments, which could have potentially contributed to the formation of these bodies. Nevertheless, our model would spatially restrict to surrounding parts of the northern plain either the distribution of the oceans or the zones within these where significant sedimentary accumulation would have taken place.  相似文献   
90.
在回顾国内外雷达网建设和在水文水资源学中发挥重要作用的基础上,着重对国内外的雷达降水的估测算法、雷达临近降水预报和雷达测雨信息在水文模型中的应用研究进行了探讨和分析,并就未来雷达技术应用于水文水资源学的研究进行了展望。  相似文献   
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