降雨径流系列的一致性分析

降雨径流关系是否发生变化，即不同时期降雨径流关系有无显著差异是一个生产中迫切需要解决的问题。本文以山西省榆社县云簇水库降雨径流系列为例，进行了降雨径流特性的分析，内容包括降雨径流双累积曲线的特性分析、年径流系数的变化过程分析、秩和检验、回归方程的差异分析等。得出云簇水库在１９７９年以前与以后，虽年径流深、年径流系数有差异，但降雨径流关系并无明显差异的结论。     

Laboratory tests to evaluate effectiveness of wicking geotextile in soil moisture reduction

A new type of woven geotextile, referred to as wicking geotextile, was developed and introduced to the market. Since this wicking geotextile consists of wicking fibers, they can wick water out from unsaturated soils in a pavement structure thus resulting in an increase of soil resilient modulus and enhance performance of roadways. In this study, a physical model test was developed to evaluate the effectiveness of the wicking geotextile in soil moisture reduction for roadway applications. A test box with a dimension of 1041 mm in length, 686 mm in width, and 584 mm in height was used in this study. Two HDPE plastic panels were used to separate the box into two sections, one containing a dehumidifier and the other backfilled with soil. The dehumidifier was adopted to collect the water, which was wicked out from the soil by the wicking geotextile and evaporated into air. Test results show that (1) the wicking geotextile wicked water out from the soil even at the moisture content close to the optimum moisture content and (2) the comparison of soil moisture contents before and after rainfall demonstrated that the wicking geotextile maintained the soil moisture contents after rainfall close to those before rainfall and had an effective distance for the soil moisture reduction.     

Infiltration Capacity Assessment of Urban Pavements Using the LCS Permeameter and the CP Infiltrometer

This paper presents the Cantabrian portable infiltrometer (CP infiltrometer), a specially designed device based on rainfall simulation for the assessment of the infiltration capacity of all types of urban pavements. Several pervious and impervious surfaces were tested with the LCS permeameter, an existing infiltration test based on the use of a column of water, and the CP Infiltrometer, simulating rain intensities with return periods of 10, 50, and 500 years and 5?min duration. The discussion of the results indicates that the CP infiltrometer could be used successfully to identify different levels of infiltration capacity and to assess the correct performance of pervious surfaces on which design, construction, and maintenance decisions are based.     

基于小波分析的滑坡变形规律研究

对于有多个GPS监测点的滑坡,通常只研究个别代表性较强的点的位移,以此近似反映滑坡整体变形情况,但这种以点代面的方法与实际相差较大。现利用三峡库区某滑坡长期地表位移监测资料,根据各监测点位移对滑坡整体位移的贡献率,求得综合位移曲线,再利用小波分析等数学方法推导综合位移方程,据此分析了外界因素(降雨、库水位)对滑坡变形影响机理及周期。结果表明:该滑坡现处于潜在不稳定状态,降雨和库水位对滑坡的影响周期约为12个月。应用滑坡总位移方程进行验证性预测后显示,其预测精度达到92%,因此该方程能更真实地反映滑坡稳定性现状和发展趋势,对同类滑坡的研究具有借鉴价值。     

豫西山区次降雨侵蚀力简化模型的建立

而降雨侵蚀力是定量监测评价一个地区土壤侵蚀状况的重要因子之一,找到适宜简便的计算方法十分重要。本文利用位于豫西山区鲁山县的两个水文站各三年共125次自记降雨过程资料,建立了该区域次降雨侵蚀力计算模型:R次=0.146×Pt×I30-1.189(r=0.992,n=105);并进行了预报效果检验,采取模型有效系数和相对偏差评价模型的的效果,结果表明二者分别为99%和8.8%。本文所创立的次降雨侵蚀力模型简便实用,不仅可以评价区域年R值分布,有效地分析R值的年内分布状况,更重要的是为水土流失定量监测从多年平均监测、年监测提高到次降雨流失量的监测提供了可能,从而实现区域定量监测的精度。     

长江九江段、鄱阳湖枯水期水位偏低原因分析与思考

本文通过3个不同时段描述了长江九江段、鄱阳湖枯水期水位下降趋势,并分析了其水位偏低的主要原因,提出避免和解决长江九江段、鄱阳湖枯水水位偏低的相应措施.     

15～23 GHz微波链路雨衰的敏感参量分析

为了提高微波链路雨衰特征的描述精度,拓展微波链路信号的可用参数,该文利用部署于江苏江阴地区的15 GHz,18 GHz和23 GHz微波链路和雨量计开展同步对比观测,拟合得到3种频段的微波链路雨衰关系.提取并分析了接收信号电平的平均值、中位数、25％分位数、75％分位数、标准差、极大值和极小值等13个特征量与晴雨时刻、...     

Rainfall-triggered debris flows following the Wenchuan earthquake

On 24 September 2008, 72 debris flows were triggered by heavy rainfall in the central part of the area affected by the Wenchuan Earthquake. This paper describes the process of debris-flow initiation and transport in the study areas and presents field observations on the roles of rainfall, lithology and the presence of faults. It is likely that following the ground shaking, the critical amount of accumulated precipitation and the hourly rainfall intensity necessary to initiate debris flow was reduced compared with values before the earthquake. A case study in the Xishanpo gully is presented; the debris flow from which caused a thick accumulation in the already devastated city of Beichuan. It is concluded that the whole of the area shaken by the Wenchuan Earthquake is now more susceptible to debris flows, which may be initiated by localized heavy rainfall. Care must be taken to properly assess this new type of geo-hazard.     

组合模型在降雨量预测中的应用

研究降雨量准确预测问题,降水量的变化既受大气环流、地形、气压、气候带等各种环境因子的影响,降水量的动态特征呈现复杂非线性和各种干扰因素,预测不可能准确。传统预测模型难以对其进行准确预测,预测精度低。为提高降雨量的预测精度,提出一种组合模型的降雨量预测模型。首先采用小波分析将降雨量数据进行分解成线性和非线性部分,然后分别采用ARIMA和RBF神经网络模型对其进行预测,最后采用小波重构线性和非线性预测结果,得到降雨量最终预测结果。仿真结果表明,相对于传统预测模型,组合模型提高了降雨量预测精度,预测结果可以帮助农业、水利部门提高防治旱涝灾害的科学依据。     

中国Ku波段广播通信卫星雨衰减分布

雨衰减对于１０ＧＨｚ以上无线电系统的影响是极为严重的。本文根据我国６５个站点的分钟降雨率数据，利用ＩＴＵ－Ｒ最新给出的雨衰减预报模式，计算出我国未来１２ＧＨｚ三个轨道