黄河源区水文模拟中地形和融雪影响

为分析地形和融雪对水文模拟影响,利用SWAT模型在黄河源区进行1960—1990年水文模拟。二者的影响分别通过对子流域划分高程带和运用融雪模块来体现。研究表明,单独考虑融雪影响或考虑融雪、地形的共同影响下,模拟结果均能达到合格;单独考虑地形的影响下能达到良好。相比融雪影响,地形对流域水量平衡的模拟起主要作用。划分高程带对子流域的气温影响较大,对降水影响小。子流域气温的降低使得蒸散发减小,从而增加产水量,其中地下水增加最多,其次是地表径流和壤中流。地形和融雪的影响使地下水的补给来源改变,调整地下水参数后,最终模拟结果达到优秀。地形和融雪在黄河源区水文模拟中的影响可以为其他高山地区水文研究提供参考。     

我国西南地区秋季降水年际变化的空间差异及其成因

使用1980～2010年全国站点降水资料、ERA-Interim再分析环流资料、哈德莱海表温度资料,运用聚类分析和旋转经验正交函数分解,对西南地区的秋季降水按照其年际变化规律进行分区,进而分析影响各区域降水变化的物理过程和机理。结果表明:西南地区被分为东、西两个区域。西南东、西区域秋季降水的年际变化、显著周期、旱涝异常年份、相关的环流系统都有明显差异。西南东部秋季降水主要与热带海温异常有关,受低纬度环流影响。当赤道东太平洋为暖海温异常,热带印度洋为西正东负的偶极子型海温异常时,分别激发出西北太平洋反气旋和孟加拉反气旋,共同向西南东部输送水汽,造成西南东部降水偏多。西南西部降水在秋季三个月份与不同的环流形势对应:9月降水由中南半岛反气旋输送的暖湿气流决定;10月降水受高原以东反气旋环流和孟加拉湾低槽共同影响;11月降水主要受中高纬环流异常的影响,与斯堪的纳维亚遥相关存在显著负相关。     

对斯特恩新报告的要点评述和解读

 2006年10月,英国推出的由著名经济学家斯特恩爵士领导编写的《斯特恩回顾：气候变化经济学》,从经济学的角度着重论述了全球应对气候变化的紧迫性,强调只有尽快大幅度减少温室气体排放,才能避免全球升温超过2℃可能造成的巨大经济损失,且减排成本并不高。2008年4月,斯特恩爵士再次推出一份报告,提出为实现上述目标构建2012年后国际气候制度的基本要素,这对后续国际谈判可能会产生一定的影响。通过比较分析两份报告的关系和不同特点,对新报告中国际气候制度设计和评价的基本原则,全球减排的长期目标和减排义务的分担,通过资金、技术、市场、适应等国际政策措施吸引发展中国家参与,减少毁林排放,以及政策执行和制度建设等问题进行了评述和解读,其中内涵对深入开展国际气候制度的研究和我国参与国际气候谈判有重要启发。     

晚中生代—新生代构造体制转换与鄂尔多斯盆地改造

鄂尔多斯盆地是叠加在华北古生代克拉通台地之上的中生代大型陆内盆地。晚中生代—新生代是鄂尔多斯盆地重要的改造阶段,区域构造体制经历了重大转换,在盆地周缘形成不同方向和不同样式的构造带。其中发生在中、晚侏罗世时期的燕山运动主幕,对鄂尔多斯盆地的定型和发展具有划时代意义,这期构造变动导致鄂尔多斯盆地周缘挤压逆冲构造带的形成。早白垩世时期,对区域构造应力体制转换的响应,鄂尔多斯盆地处于弱引张构造环境,引张构造变形主要集中在盆地西南缘地带,六盘山古地堑发育。新生代时期,构造变形主要发生在鄂尔多斯盆地周缘,形成一系列地堑盆地。晚中新世或上新世以来的新构造运动时期,受到青藏高原快速隆升和向东构造挤出作用的影响,鄂尔多斯盆地西南缘六盘山褶皱带快速崛起,而在盆地的其他周边地带则发生引张变形和地块差异性升降。最后,笔者论述了不同构造应力体制下盆地的改造作用,讨论了鄂尔多斯盆地研究中的一些基础地质构造问题。     

Impacts of global warming on hydrological cycles in the Asian monsoon region

The hydrologic changes and the impact of these changes constitute a fundamental global-warmingrelated concern. Faced with threats to human life and natural ecosystems, such as droughts, floods, and soil erosion, water resource planners must increasingly make future risk assessments. Though hydrological predictions associated with the global climate change are already being performed, mainly through the use of GCMs, coarse spatial resolutions and uncertain physical processes limit the representation of terrestrial water/energy interactions and the variability in such systems as the Asian monsoon. Despite numerous studies, the regional responses of hydrologic changes resulting from climate change remains inconclusive. In this paper, an attempt at dynamical downsealing of future hydrologic projection under global climate change in Asia is addressed. The authors conducted present and future Asian regional climate simulations which were nested in the results of Atmospheric General Circulation Model （AGCM） experiments. The regional climate model could capture the general simulated features of the AGCM. Also, some regional phenomena such as orographic precipitation, which did not appear in the outcome of the AGCM simulation, were successfully produced. Under global warming, the increase of water vapor associated with the warmed air temperature was projected. It was projected to bring more abundant water vapor to the southern portions of India and the Bay of Bengal, and to enhance precipitation especially over the mountainous regions, the western part of India and the southern edge of the Tibetan Plateau. As a result of the changes in the synoptic flow patterns and precipitation under global warming, the increases of annual mean precipitation and surface runoff were projected in many regions of Asia. However, both the positive and negative changes of seasonal surface runoff were projected in some regions which will increase the flood risk and cause a mismatch between water demand and water availability in the agricul     

“堑秋湖”围堤改变鄱阳湖洲滩湿地土壤碳循环过程

水文节律是影响湖泊湿地土壤碳循环的重要因素."堑秋湖"是鄱阳湖传统的渔业生产方式,对鄱阳湖碟形湖水文节律具有显著影响.因此,本文研究了"堑秋湖"对鄱阳湖洲滩土壤碳循环的影响.结果表明,"堑秋湖"围堤内外洲滩土壤总有机碳含量无显著差异,但围堤内土壤轻组有机碳含量比围堤外低35.03%.围堤内土壤有机碳(SOC)矿化速率明显高于围堤外.围堤内SOC矿化的平均Q10为2.72,比围堤外低4.83%,但两者SOC矿化的水分敏感性没有显著差异.围堤内外SOC矿化速率分别与土壤可溶性有机碳和土壤轻组氮含量相关关系最为显著.综上所述,"堑秋湖"围堤已经改变了鄱阳湖洲滩的土壤碳循环过程.模拟湖泊湿地土壤碳循环时需要充分考虑当地渔业生产的影响.     

枝角类亚化石揭示的湖北太白湖过去百余年环境演变

近百年来长江中下游地区的浅水湖泊经历了气候变化及日益增强的人类扰动,造成了普遍的湖泊富营养化、水动力条件和水生生态系统的状态转变,水体的生态服务功能明显退化.枝角类作为一种重要的水生生物,敏感地响应于湖泊及其流域的环境变化,但目前对亚热带湖泊中的枝角类亚化石的环境指示意义,与其它古生态指标如硅藻、摇蚊等对环境变化的响应差异尚未明确.因此,本文以浅水湖泊太白湖为研究对象,结合流域历史资料和监测数据,基于沉积岩芯中枝角类群落过去百年来的期演化序列,重建了近百年来太白湖的历史环境演变过程及机制.对比硅藻及摇蚊的群落演化特征,探讨了多门类古生态指标对环境变化的响应差异.本文重点讨论了枝角类对湖泊鱼类产量指示意义及利用枝角类亚化石来重建历史环境的应用前景及不足.     

气候变化对水文水资源影响的研究进展

气候变化成为21 世纪世界最重大的环境问题之一,愈来愈引起国际社会和各国政府的重视和关注。研究 气候变化对水文水资源的影响,对于理解和解决可能引起的与工业、农业、城市发展等经济领域密切相关的水文水 资源系统的规划管理、开发利用、运行管理、环境保护、生态平衡等问题具有重要的理论意义和现实意义。本文主要 从研究方法、气候变化情景的生成技术、与水文模型接口技术和水文模拟技术等几个方面综合概述了气候变化对 水文水资源的影响,同时提出存在的问题与展望。     

Integrated hydrologic modeling in the inland Heihe River Basin, Northwest China

As a typical inland river basin in arid Northwest China, having distinct hydrological characteristics and severe and representative water problems, the Heihe River Basin (HRB) has attracted considerable research interest worldwide and in 2007 became a pilot basin of the G-WADI network of UNESCO/IHP. Many research programs have been conducted in the HRB since the 1980s, producing rich knowledge and data about the basin, which will be very helpful to further studies. This paper reviews research efforts related to hydrologic modeling and ongoing model integration studies performed in the HRB in recent years. Recently, an observation network covering the whole area and a Web-based data-sharing system have been established which can greatly improve data acquisition. This paper tabulates modeling activities in past years, including model applications, model modifications and enhancements, and model coupling efforts. Also described is a preliminary modeling integration tool designed to quickly build new models, which has been developed for hydrologic modeling purposes. Challenges and issues confronted in current studies are discussed, pointing toward key research directions in the future.     

Continuous prediction of clay‐bed stream erosion in response to climate model output for a small urban watershed

The response of the semi‐alluvial clay‐bed Watts Creek is assessed subject to climate change. Climate impacts are expected to have regional variability, and few studies have assessed the impacts of future climate in a small urban watershed. The 21‐km² watershed located in Ottawa, Ontario, Canada, is highly urbanized (68%) and agricultural (20%) with limited forest cover (12%). Continuous simulations were performed using the SWMHYMO lumped hydrologic modelling platform for the open water year, excluding spring freshet (April 1 to October 31). A shear stress exceedance and stream power erosion routine was added to the platform to calculate erosion potential. To account for uncertainty in the collected data, 9 different field datasets were used to calibrate the model, each leading to a distinct set of calibrated parameter values. The difference between the datasets lies in the choice of the rating curves and calibration period. The 2041–2080 precipitation outputs of the 4th version of the Canadian Regional Climate Model (CanRCM4) ran under representative concentration pathways (RCPs) 4.5 and 8.5 at the MacDonald Cartier International Airport were downscaled using quantile matching and then used as input to the continuous hydrologic model. For each set of calibrated parameters, a cumulative effective work index based on the reach‐averaged shear stress was calculated for Watts Creek using both the historic (1967–2007) and projected future (2041–2080) flows, using a bed material critical shear stress for entrainment of 3.7 Pa. These results suggest an increase of 75% (respectively 139%) under RCP4.5 (respectively RCP8.5) in cumulative effective work index compared with historic conditions for the average measured bed strength. The work index increase is driven by an increased occurrence of above‐threshold events and, more importantly, by the increased frequency of large events. The predicted flow regime under climate change would significantly alter the erosion potential and stability of Watts Creek.