三种综合气象干旱指数在洞庭湖流域的适用性分析

结合洞庭湖流域水文气象特点,从不合理跳跃点、统计特征、区域干旱以及空间分布等方面综合分析了3种气象干旱指数在该流域的适用性及可靠性。评价结果表明：（1）NCC2CI与CInew指数均可较好解决传统CI指数评估中出现的不合理震荡、旱情加剧等不足,且该指数对长历时干旱表现较为敏感,对短历时干旱存在漏测的可能性;（2）对具有较大烈度特征的干旱事件,NCC2CI指数虽然能较好地监测出等级较高的干旱强度,但对极端干旱强度的特征表征有所不足;（3）干旱NCC2CI指数较好地延续了传统CI指数的统计特性以及空间分布特性,反映出的某时段较大降水对日后的影响时段为20~40 d,指数表征更加符合干旱发生的过程。而CInew指数反映的影响时段为45~70 d,且在空间分布上变化较大,应用可靠性相对较差。综合比较分析表明,NCC2CI指数在洞庭湖流域更具实用性,研究结果对其它类似流域干旱评估具有一定参考作用     

Bankfull Regional Curves for the Alleghany Plateau/Valley and Ridge,Piedmont, and Coastal Plain Regions of Maryland

Regional curves are empirical relationships that can help identify the bankfull stage in ungaged watersheds and aid in designing the riffle dimension in stream restoration projects. Bankfull regional curves were developed from gage stations with drainage areas less than 102 mi² (264.2 km²) for the Alleghany Plateau/Valley and Ridge (AP/VR), Piedmont, and Coastal Plain regions of Maryland. The AP/VR regions were combined into one region for this project. These curves relate bankfull discharge, cross‐sectional area, width, and mean depth to drainage area within the same hydro‐physiographic region (region with similar rainfall/runoff relationship). The bankfull discharge curve for the Coastal Plain region was further subdivided into the Western Coastal Plain (WCP) and Eastern Coastal Plain (ECP) region due to differences in topography and runoff. Results show that the Maryland Piedmont yields the highest bankfull discharge rate per unit drainage area, followed by the AP/VR, WCP, and ECP. Likewise, the Coastal Plain and AP/VR streams have less bankfull cross‐sectional area per unit drainage area than the Piedmont. The average bankfull discharge return interval across the three hydro‐physiographic regions was 1.4 years. The Maryland regional curves were compared to other curves in the eastern United States. The average bankfull discharge return interval for the other studies ranged from 1.1 to 1.8 years.     

泾河流域1644-2003年洪涝灾害和洪水沉积特征研究

通过对泾河流域1644-2003年洪涝灾害历史文献资料的搜集、整理和分析,对该时期泾河流域洪涝灾害等级、洪涝灾害时空变化特征及其成因进行研究。同时结合泾河下游洪水沉积剖面,对该时期洪水特征进行分析。研究表明:泾河流域1644-2003年发生洪涝灾害总计165次,平均每2.18年发生一次。主要以中度涝灾为主,其次为大涝灾,轻度涝灾和特大涝灾发生次数较少。1644-2003年,泾河流域的洪涝灾害总体呈现不断增加的特点,泾河流域洪涝灾害发生频次最高的是在1894-1953年,发生频次最低的是在1644-1723年。泾河流域发生的165次洪涝灾害中,上游发生的洪涝灾害最多,其次为下游,中游最少,上、中、下游同时发生的洪涝灾害为4级特大涝灾。不同阶段气候的冷暖干湿变化和人类活动对泾河流域植被的破坏是泾河流域发生洪涝灾害的主要原因。1644-2003年的洪涝灾害在泾河下游形成了2.56 m厚的河漫滩洪水沉积剖面,该剖面沉积层主要由特大涝灾、部分大涝灾和中度涝灾形成,剖面记录的洪水频次比历史文献记录的洪水频次要明显少。     

Participatory research and sustainable development in the Sahelo-Sudanian region

SUMMARY

A participatory research programme was conducted in the groundnut basin of Senegal, where there was a need to intensify the local farming systems. The research yielded a set of technical references and profitable innovations, which were introduced through specific development actions. The technology transfer aims at the establishment of sustainable farming systems and takes into account the climatic risks and innovation costs. Identification of research themes and implementation of results was based on various analyses: climatic analysis at regional level (establishment of climatic zones) and identification of constraints at farm level. Farmers' interests and the research results were combined to define suitable interventions for each surveyed farm, with the aim of increasing farm income and restoring soil fertility. The research also yielded elements for formulating an appropriate and realistic agricultural policy for the region. Clearly, the development of livestock farming activities is essential in bringing new economic life into the region and increasing the sustainability of farming systems in erratic climatic conditions.     

生态系统服务价值与人类活动强度关联性分析及权衡——以淇河流域为例

以淇河流域为研究对象，利用2000~2015年土地利用/覆被数据，结合当量因子法修正中国陆地不同生态系统服务价值当量表，采用双变量相关分析法和生态系统服务权衡模型分析生态系统服务权衡协同关系，引入人类活动强度指数评估模型分析人类活动影响空间特征，运用空间自相关探讨人类活动影响与生态系统服务价值的空间关联性及LISA聚类分析.结果表明：（1）2000~2015年淇河流域生态系统服务价值呈下降趋势，2010年生态系统服务最低（19.29亿元），废物处理平均价值最大（3.68亿元），娱乐文化平均价值最小（0.81亿元）；（2）从生态系统权衡协同关系来看，两种相关性分析均表明研究区生态系统服务以协同关系为主，由线性关系发现供给服务、调节服务与支持服务呈现为互为增益的协同关系，文化服务与支持服务、供给服务、调节服务分别表现为此消彼长的权衡关系，生态系统服务权衡协同度表明土壤保持和原材料及土壤保持和生物多样性协同度最高（4.4），权衡度最高（-5.2）为水源涵养和原材料、水源涵养和生物多样性；（3）淇河流域人类活动强度空间分异显著，流域下游人类活动影响强度明显高于上游地区，人类活动强度与生态系统服务价值空间相关性由正相关转向负相关.     

Fuzzy modelling to identify key drivers of ecological water quality to support decision and policy making

Water quality modelling is an effective tool to investigate, describe and predict the ecological state of an aquatic ecosystem. Various environmental variables may simultaneously affect water quality. Appropriate selection of a limited number of key-variables facilitates cost-effective management of water resources. This paper aims to determine (and analyse the effect of) the major environmental variables predicting ecological water quality through the application of fuzzy models. In this study, a fuzzy logic methodology, previously applied to predict species distributions, was extended to model environmental effects on a whole community. In a second step, the developed models were applied in a more general water management context to support decision and policy making. A hill-climbing optimisation algorithm was applied to relate ecological water quality and environmental variables to the community indicator. The optimal model was selected based on the predictive performance (Cohen’s Kappa), ecological relevance and model’s interpretability. Moreover, a sensitivity analysis was performed as an extra element to analyse and evaluate the optimal model. The optimal model included the variables land use, chlorophyll and flow velocity. The variable selection method and sensitivity analysis indicated that land use influences ecological water quality the most and that it affects the effect of other variables on water quality to a high extent. The model outcome can support spatial planning related to land use in river basins and policy making related to flows and water quality standards. Fuzzy models are transparent to a wide range of users and therefore may stimulate communication between modellers, river managers, policy makers and stakeholders.     

枯季乌江河流“呼吸”作用及其性质探讨

发源于云贵高原上的乌江是长江流域的重要支流之一。乌江流域喀斯特地貌广泛发育，是中国南方典型的喀斯特河流。以枯水季节乌江流域水体中的实测温度、溶解氧、碱度和pH值等理化参数为依据，探讨了乌江流域河道水体的CO2分压(〖WTBX〗P〖WTBZ〗CO2)与河流“呼吸”通量的变化规律。乌江流域枯水季节河道水体〖WTBX〗P〖WTBZ〗CO2介于2913~1 530 μatm之间，平均值为9493 μatm，约为大气的3倍，各支流样点的平均值为9924 μatm，大于干流平均值9026 μatm，由此推断乌江流域干支流河道在枯季是大气CO2的“源”。受各游段流域特征以及人类活动的影响，干支流河道水体〖WTBX〗P〖WTBZ〗CO2表现出明显的空间差异。水体〖WTBX〗P〖WTBZ〗CO2与溶解氧的相关关系不显著，说明河道内有机质的异养呼吸不是喀斯特乌江流域枯季水体中溶解无机碳的主要来源，其河道水体中高〖WTBX〗P〖WTBZ〗CO2成因复杂。〖WTBX〗P〖WTBZ〗CO2的上述分布规律是流域支流汇入、地下水以及河道水体有机质氧化分解等共同作用的结果。     

黄河下游历史泥沙灾害的宏观特征及其与流域因素及人类活动的关系(Ⅰ)──历史气候及植被因素的影响

以历史上黄河下游的决溢频率为泥沙灾害的代用指标；研究了黄河下游历史泥沙灾害的宏观特征．研 究表明，气候因素对黄河下游决溢频率有深远的影响．隋唐以前，天然植被尚未遭到显著破坏，当湿润指标 增大时，有利于植被的生长，故黄河下游决溢频率减小．１０世纪以后，二者的关系与此相反，当湿润指标增 大时，决溢频率也增大，反之亦然．每世纪大旱年颁次与每世纪决溢频次之间呈明显正相关，说明目前受到 各方面广泛关注的黄河下游“小水大灾”现象，在历史上已经存在．干旱时期中，河槽萎缩，一旦大水来 临，很容易发生决溢．以华山松树木年轮指数为气温的代用指标，研究了气温变化与决溢频率变化的关系， 结果表明，在５０ａ的尺度上，当气温降低时，决溢频率增大，反之亦然．人类活动是影响黄河下游泥沙灾害 的重要因素．     

拉伸型渭河盆地地震孕育发生的构造模型

依据拉伸型渭河盆地块体周边断裂活动特征和块体运动特征,建立了盆地地震孕育发生的构造模型,旨在探索地震孕育发生的机制,为研究类似盆地地震孕育、发生及其分布规律和地震监测预报、震灾防御等各项防震减灾工作部署提供科学依据。     

REGIONAL RUNOFF SIMULATION FOR SOUTHEAST MICHIGAN1

ABSTRACT: The feasibility of simulating monthly runoff for southeast Michigan, which comprises four major river basins, was evaluated with the Streamflow Synthesis and Reservoir Regulation watershed model. The evaluation covered a 13-year period (1961–73), which encompassed a complete runoff cycle. Results indicate it is feasible to simulate monthly runoff volumes on a regional scale with a single equivalent watershed by using daily precipitation and temperature data. Simulation of regional flows appears particularly attractive for the Great Lakes basin, since the basin consists of many relatively small watersheds. This method also appears promising for development of monthly runoff forecasts by employing average monthly meteorological data distributed on a daily basis. Tests of six-month runoff forecasts show relatively small deterioration with time and offer considerable improvement over climatology.