水文重力效应改正中一维地下水模拟算法的对比

基于一维地下水渗透方程详细推导其有限差分解算过程,引入不同于显式差分的隐式差分和中心差分格式,对比分析不同差分格式对地下水模拟结果及其相应地下水重力效应的影响,并对其中的层间参数取值和非线性方程的线性化问题进行探讨。结果表明,在日本Isawa扇形地区超导台站,不同层间参数加权公式能够引起最大约0.15 μGal的重力效应差异,影响在1.9%以内;不同差分格式和线性化方法组合形式能够引起最大约0.12 μGal的重力效应差异,影响在1.5%以内。     

无锡站年际降雨趋势、特征与预报分析

针对近年极端灾害性气候频发的现状,对暖冬影响下无锡站降雨年际变化趋势、历史演变特征和近几年水文预报情况进行了分析。结果表明:在暖冬影响下,无锡站降雨年际间呈现出干旱—湿润周期性变化的特征,具有水文旋回的性质,在太湖地区有代表性,可作为该时段的降雨预报模型;该模型打破了年际降雨无规律的传统思维定式,与历史演变法相结合,能提高预报效率与精度;水文旋回的发现和降雨预报模型的建立,可推动水文气象长期预报与气候展望研究。     

Benthic foraminifers in upper Quaternary sediments of the southern Bering Sea: Distribution and paleoceanographic interpretations

Composition and distribution of benthic foraminifers, being coupled with isotopic-geochemical data on Upper Pleistocene and Holocene sediments from the southern Bering Sea (Core GC-11; 53°31′ N, 178°51′E, water depth 3060 m), demonstrate variations in bottom water properties during the last 54 kyr. Their abundance increased to some extent during short periods corresponding to warm Dansgaard-Oeshger interstadials 14, 12, 8, and 2 of marine isotopic stages (MIS) 3 and 2. The first and second deglaciation phases separated by the Younger Dryas cooling episode are marked by significant abundance peaks of benthic foraminifers (an order magnitude higher than in the glacial period), although their share in community of benthic and planktonic foraminifers taken together decreases. Species typical of stable high-productivity areas gain the dominant position. A significant proportion of agglutinated species in the Holocene sediments is indicative of Ca ions deficiency that accelerates dissolution of carbonate tests up to their disappearance approximately 2.5–3 ka ago.     

广义极值分布及其在水文中的应用

广义极值分布,包括Ｉ型、Ⅱ型和Ⅲ型,是一套完整的统计分布。以往,由于研究不足,常常只能采用极值Ｉ型分布,使应用受到了限制。本文中,详细地探讨了广义极值分布的统计特性,首次研制了该分布的离均系数表,并给出了水文频率计算中的示例。分析表明,应用广义极值分布,也能得到较好的适线结果。特别是有了离均系数表,对水文频率分析和各类统计计算是十分方便的。     

长江中下游地区洪涝灾害风险性评估

以湖北省香溪河古洞口水库为例,首先,结合1997—2016年近20 a降水资料,计算分析不同时间尺度(3、6、12、24 h)强降水分布特征; 然后, 选取新安江水文模型,通过40场洪水的模拟率定水文模型的参数; 最后,结合古洞口水库防洪能力,利用水文模型模拟计算该水库不同基准水位和时间尺度条件下的致汛临界面雨量(到达汛限水位所需的面雨量)。模拟试验表明:利用水文模型计算中小流域临界面雨量能模拟计算并直观给出水库不同基准水位和时间尺度条件下的洪水人库过程曲线、水位变化过程曲线与流域致汛临界面雨量,其意义明确,技术方法可行; 在初始条件(基准水位)相同时,时间尺度越小,临界面雨量越小。

     

昆明盐矿三维建模及溶通性分析

针对地下盐矿在开采过程中,随时可能会因为溶通状况的改变而发生坍塌地质灾害,本文利用矿山数字管理软件Quanty Mine,确定昆明盐矿的三维模型,以期监控盐矿开采不同阶段溶通的变化规律,为避免盐矿过度开采导致地质灾害的发生。     

基于GIS/RS的流域水文过程分布式模拟——Ⅰ模型的原理与结构

面向流域水资源管理,提出了一个基于GIS/RS的流域分布式水文模型,模型主要包括单元水文模型与河网汇流模型两大部分。单元水文模型涉及到冠层截留、融雪、蒸散发、坡面流、非饱和土壤水运动和地下水出流等水文物理过程。产流计算考虑到地形坡度的影响采用基于地形指数的计算方法。汇流演算基于河网结构采用分段马斯京根方法。模型的大部分参数与输入信息可以利用GIS和RS技术获取,能够对气候变化和人类活动对下垫面的改变,做出快速的模拟与响应。     

Process identification at a slow‐moving landslide in the Vorarlberg Alps

A fine‐grained slope that exhibits slow movement rates was investigated to understand how geohydrological processes contribute to a consecutive development of mass movements in the Vorarlberg Alps, Austria. For that purpose intensive hydrometeorological, hydrogeological and geotechnical observations as well as surveying of surface movement rates were conducted during 1998–2001. Subsurface water dynamics at the creeping slope turned out to be dominated by a three‐dimensional pressure system. The pressure reaction is triggered by fast infiltration of surface water and subsequent lateral water flow in the south‐western part of the hillslope. The related pressure signal was shown to propagate further downhill, causing fast reactions of the piezometric head at 5·5 m depth on a daily time scale. The observed pressure reactions might belong to a temporary hillslope water body that extends further downhill. The related buoyancy forces could be one of the driving forces for the mass movement. A physically based hydrological model was adopted to model simultaneously surface and subsurface water dynamics including evapotranspiration and runoff production. It was possible to reproduce surface runoff and observed pressure reactions in principle. However, as soil hydraulic functions were only estimated on pedotransfer functions, a quantitative comparison between observed and simulated subsurface dynamics is not feasible. Nevertheless, the results suggest that it is possible to reconstruct important spatial structures based on sparse observations in the field which allow reasonable simulations with a physically based hydrological model. Copyright © 2004 John Wiley & Sons, Ltd.