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排序方式: 共有389条查询结果,搜索用时 31 毫秒
1.
水文是水利工作乃至国民经济社会发展的基础性和公益性工作。环境的变化、社会的发展、新时期水利工作治水思路转变等均向水文工作提出了新的要求,也提出了许多新的水文科学技术问题。我们应该认真学习贯彻《中华人民共和国水文条例》,加强水文监测工作,加强水文资料的汇交、管理和共享.进一步推进水文现代化建设,推进水文事业的健康发展。 相似文献
2.
Soils and rocks are the predominant source of indoor radon (Rn) in southern Belgium. We have studied the correlations between geological features and indoor Rn concentrations using an indoor Rn data set of approx. 1700 short-term measurements. The sediments in the study region are divided into 11 geological series or 43 stages and 16 rock types. The results show a striking relation between indoor Rn concentration and the geological factors. 相似文献
3.
地震采集中检波器自然频率的试验分析 总被引:9,自引:1,他引:8
王增明 《石油地球物理勘探》2003,38(3):308-316
为了达到提高分辨率的目的,对不同自然频率的检波器进行了多次试验。通过试验分析认为,检波器在自然频率方面有所差别,在单炮记录上表现为对低、高频干扰压制情况有所不同,但是资料通过处理后,几种检波器的频谱和能量均无明显的差别。高分辨率勘探不等于高频勘探,而是一种宽频带的勘探,所以选择自然频率低的检波器有利于高分辨率勘探。 相似文献
4.
Preliminary results of ENVISAT RA-2-derived water levels validation over the Amazon basin 总被引:1,自引:0,他引:1
Frédéric Frappart Stéphane Calmant Frédérique Seyler 《Remote sensing of environment》2006,100(2):252-264
Since the launch of the ENVISAT satellite in 2002, the Radar Altimetry Mission provides systematic observations of the Earth topography. Among the different goals of the ENVISAT Mission, one directly concerns land hydrology: the monitoring of the water levels of lakes, wetlands, and rivers. The ENVISAT Geophysical Data Records products contain, over different type of surfaces, altimeter ranges derived from four specialized algorithms or retrackers. However, none of the retrackers are intended to the processing of the radar echoes over continental waters. A validation study is necessary to assess the performances of the different ENVISAT-derived water levels to monitor inland waters. We have selected four test-zones over the Amazon basin to achieve this validation study. We compare first the performances of these retracking algorithms to deliver reliable water levels for land hydrology. Comparisons with in-situ gauge stations showed that Ice-1 algorithm, based on the Offset Centre of Gravity technique, provides the more accurate water stages. Second, we examine the potentiality to combine water levels derived from different sensors (Topex/Poseidon, ERS-1 and -2, GFO). 相似文献
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针对临盘油区地质条件的复杂性和开发调整的困难度,本文阐述了复杂断块油藏开发治理技术的应用,如精细地质研究技术、剩余油研究技术以及改善水驱油效果的注采调整技术等。精细地质研究技术深化了对油藏的认识程度;剩余油研究技术深化认识不同类型油藏剩余油分布规律,明确了注采调整方向;针对不同类型油藏具有的不同潜力,创新注采调整思路,不断优化注采井网,改善了油藏的开发效果。 相似文献
7.
Selection of strategies that help reduce riverine inputs requires numerical models that accurately quantify hydrologic processes. While numerous models exist, information on how to evaluate and select the most robust models is limited. Toward this end, we developed a comprehensive approach that helps evaluate watershed models in their ability to simulate flow regimes critical to downstream ecosystem services. We demonstrated the method using the Soil and Water Assessment Tool (SWAT), the Hydrological Simulation Program–FORTRAN (HSPF) model, and Distributed Large Basin Runoff Model (DLBRM) applied to the Maumee River Basin (USA). The approach helped in identifying that each model simulated flows within acceptable ranges. However, each was limited in its ability to simulate flows triggered by extreme weather events, owing to algorithms not being optimized for such events and mismatched physiographic watershed conditions. Ultimately, we found HSPF to best predict river flow, whereas SWAT offered the most flexibility for evaluating agricultural management practices. 相似文献
8.
城市化引起的诸多水生态、水环境及洪灾问题均与天然水文条件的破坏紧密相关;水文控制指标是海绵城市建设中的关键控制指标。在调研国际城市雨洪管理的演变及目前城市水文控制指标发展趋势的基础上,提出海绵城市建设所必需的水文控制指标体系概念。该体系包括维持河湖湿地基流与地下水补给的入渗控制指标,减少雨洪面源污染的水质控制指标,防止河道侵蚀的水土侵蚀控制指标,以及避免小量级洪涝和减轻极端洪涝灾害的洪水控制指标。在此基础上,分析了我国在海绵城市建设中缺乏完整水文控制指标体系的现状,并提出了我国目前在建立城市雨洪管理水文控制指标工作中亟待开展的工作,为海绵城市建设中合理确定适合各地具体条件的水文控制指标体系提供研究思路与参考。 相似文献
9.
R. Bindlish T.J. Jackson B. Stankov M.H. Cosh C. Watts V. Lakshmi T. Keefer 《Remote sensing of environment》2008,112(2):375-390
An unresolved issue in global soil moisture retrieval using passive microwave sensors is the spatial integration of heterogeneous landscape features to the nominal 50 km footprint observed by most low frequency satellite systems. One of the objectives of the Soil Moisture Experiments 2004 (SMEX04) was to address some aspects of this problem, specifically variability introduced by vegetation, topography and convective precipitation. Other goals included supporting the development of soil moisture data sets that would contribute to understanding the role of the land surface in the concurrent North American Monsoon System. SMEX04 was conducted over two regions: Arizona — semi-arid climate with sparse vegetation and moderate topography, and Sonora (Mexico) — moderate vegetation with strong topographic gradients. The Polarimetric Scanning Radiometer (PSR/CX) was flown on a Naval Research Lab P-3B aircraft as part of SMEX04 (10 dates of coverage over Arizona and 11 over Sonora). Radio Frequency Interference (RFI) was observed in both PSR and satellite-based (AMSR-E) observations at 6.92 GHz over Arizona, but no detectable RFI was observed over the Sonora domain. The PSR estimated soil moisture was in agreement with the ground-based estimates of soil moisture over both domains. The estimated error over the Sonora domain (SEE = 0.021 cm3/cm3) was higher than over the Arizona domain (SEE = 0.014 cm3/cm3). These results show the possibility of estimating soil moisture in areas of moderate and heterogeneous vegetation and high topographic variability. 相似文献
10.
Eric S. Kasischke Laura L. Bourgeau-Chavez Kevin H. Wyatt Merritt R. Turetsky 《Remote sensing of environment》2009,113(9):1868-1873
We conducted a preliminary investigation of the response of ERS C-band SAR backscatter to variations in soil moisture and surface inundation in wetlands of interior Alaska. Data were collected from 5 wetlands over a three-week period in 2007. Results showed a positive correlation between backscatter and soil moisture in sites dominated by herbaceous vegetation cover (r = 0.74, p < 0.04). ERS SAR backscatter was negatively correlated to water depth in all open (non-forested) wetlands when water table levels were more than 6 cm above the wetland surface (r = − 0.82, p < 0.001). There was no relationship between backscatter and soil moisture in the forested (black spruce-dominated) wetland site. Our preliminary results show that ERS SAR data can be used to monitor variations in hydrologic conditions in high northern latitude wetlands (including peatlands), particularly sites with sparse tree cover. 相似文献