巴尔喀什湖水量平衡研究   总被引：8，自引：3，他引：5  

龙爱华  邓铭江  谢蕾  王姣妍  李湘权 《冰川冻土》2011,33(6):1341-1352

巴尔喀什-阿拉湖流域是中亚地区重要和独特的景观生态系统,巴尔喀什湖是该区域的核心,其水位变化作为巴尔喀什湖流域生态系统及其保护的主要指标,向来备受世人关注.研究巴尔喀什湖水量平衡,对合理确定巴尔喀什湖生态系统保护目标及保护措施,具有十分重要的理论与现实意义.在明晰巴尔喀什湖水系、水位影响因素的基础上,构建了巴尔喀什湖水...  相似文献   

地表能量变化对多年冻土活动层融化过程的影响   总被引：11，自引：10，他引：1  

李韧  赵林  丁永建  王银学  杜二计  刘广岳  肖瑶  孙琳婵  刘杨  石伟 《冰川冻土》2011,33(6):1235-1242

利用青藏高原北部唐古拉综合观测场2006-2008年辐射平衡及活动层温度观测资料,分析了高原北部地表能量变化对活动层融化过程的影响.结果显示：该地地表能量具有明显的季节变化特征,总辐射、净辐射、土壤热通量及地面热源强度6-7月最大,11-12月最小;研究时段土壤热通量年平均值0.12MJ.m-2.d-1,活动层土壤以吸...  相似文献   

天山乌鲁木齐河源1号冰川径流对气候变化的响应分析   总被引：10，自引：6，他引：4  

焦克勤  叶柏生  韩添丁  井哲帆  杨惠安 《冰川冻土》2011,33(3):606-611

利用天山乌鲁木齐河源1号冰川1959-2006年的气象、冰川物质平衡和1980-2006年的水文资料,分析了其冰川径流的变化.结果表明:由于1996年以来的显著升温,导致了1号冰川水文点径流主要受夏季气温变化的控制,冰川物质损失对径流的补给作用已超过了降水的作用.1996-2006年与1980-1995年相比,夏季气温...  相似文献   

太湖水量平衡影响因素分析及误差控制措施研究   总被引：2，自引：1，他引：1  

申金玉  石亚东  高怡  莫李娟  陈润 《水文》2011,31(3):60-63

本文在搜集2001~2008年太湖水量平衡中各个计算要素的基础上,分析计算太湖水量平衡的绝对误差及相对误差。究其原因,误差产生的影响因素主要有测验手段、风浪、巡测线内的产流、农业用水等。根据对影响因素分析,本文有针对性地提出了误差控制措施,重点是要加强测验手段及频次,从而减小水量平衡误差,为太湖水量分配方案提供更加精准的数据基础和依据。  相似文献   

基于土壤植被不同参数化方法的流域蒸散发模拟     

邵薇薇  徐翔宇  杨大文 《水文》2011,31(5):6-14

植被和土壤是水循环中的重要载体,模拟流域水循环时植被和土壤的参数化也显得尤为重要。通过对比流域蒸散发模拟中分布式模型和集总式概念模型的土壤植被参数化方法,计算了潘家口水库流域不同时间尺度上的流域蒸散发,分析了不同时间尺度下流域蒸散发的影响因素。通过分析得出:(1)分布式水文模型中的植被参数化方法包括对植被时空分布与变化的描述,以及与之相关的土壤-植被-大气中水分和能量的传输过程的描述。(2)从GBHM模型与流域水热耦合平衡模型的对比分析可知,在流域尺度上,年实际蒸散发与潜在蒸散发之间呈互补的高度非线性关系;但在山坡和小时时间尺度上,实际蒸散发与潜在蒸散发之间呈正比关系,并可近似为线性正比关系。(3)基于流域水热耦合平衡模型在不同时间尺度的参数化分析可知,考虑植被土壤水分和植被覆盖度能改善对流域蒸散发的年际和季节变化的模拟精度;土壤水分和植被的影响随着时间尺度变小表现得越来越显著。  相似文献   

Bi‐directional coupled tuned mass dampers for the seismic response control of two‐way asymmetric‐plan buildings     

Keh‐Chyuan Tsai  Yi‐Jer Yu 《地震工程与结构动力学》2011,40(6):675-690

This paper proposes bi‐directional coupled tuned mass dampers (BiCTMDs) for the seismic response control of two‐way asymmetric‐plan buildings subjected to bi‐directional ground motions. The proposed BiCTMD was developed from the three‐degree‐of‐freedom modal system, which represents the vibration mode of a two‐way asymmetric‐plan building. The performance of the proposed BiCTMD for the seismic response control of elastic two‐way asymmetric‐plan buildings was verified by investigating the reductions of the amplitudes of the associated frequency response functions. In addition, the investigation showed that the proposed BiCTMD is effective in reducing the seismic damage of inelastic asymmetric‐plan buildings. Therefore, the BiCTMD is an effective approach for the seismic response control of both elastic and inelastic two‐way asymmetric‐plan buildings. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Theoretical constraints to gully erosion research: time for a re‐evaluation of concepts and assumptions?     

Rafaello V. Bergonse  Eusébio J. Reis 《地球表面变化过程与地形》2011,36(11):1554-1557

Gullies are conceptualized in the literature as essentially fluvial forms with dimensional boundaries arbitrarily defined between rills and river channels. This notion is incompatible with the existing variability of form and process, as mass movements frequently exert a fundamental control on gully initiation and expansion, to the point of features outgrowing their original contributing area. The inability of a conceptual framework to incorporate existing observations inevitably constrains methodologies and research results. In this commentary, several examples of published results are contrasted with the prevailing assumption of an essentially fluvial nature, with the purpose of encouraging discussion on the need for a revised conceptual framework in gully erosion research. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Linear and angular momentum conservation in hydraulic jump in diverging channels     

Alessandro Valiani Valerio Caleffi 《Advances in water resources》2011,34(2):227-242

This paper addresses the integral conservation of linear and angular momentum in the steady hydraulic jump in a linearly diverging channel.The flow is considered to be divided into a mainstream that conveys the total liquid discharge, and a roller where no average mass transport occurs. It is assumed that no macroscopic rheological relationship holds, so mass, momentum and angular momentum integral balances are independent relationships. Normal stresses are assumed to be hydrostatic on vertical, cylindrical surfaces. Viscous stresses are assumed to be negligible with respect to turbulent stresses. Assuming that the horizontal velocity distribution in the mainstream is uniform and that the horizontal momentum and angular momentum in the roller are negligible with respect to their mainstream counterparts, an analytical solution is obtained for the free surface profile of the flow. This solution is fundamental for finding the sequent depths and their positions. Consequently, it permits solving for the length of the jump, which is assumed to be equal to the length of the roller. Mainstream and roller thicknesses can also be derived from the present solution. This model may also be theoretically used to derive the average shear stresses exerted by the roller on the mainstream and the power losses per unit weight. This second relationship, which returns the well-known classical expression for total power loss in the jump, demonstrates that the strongly idealized mechanical model proposed here is internally consistent.  相似文献   

高层隔震结构扭转分析   总被引：2，自引：0，他引：2  

祁皑  商昊江  范宏伟 《世界地震工程》2011,27(1)

为研究高层隔震结构在地震作用下的扭转效应,用Etabs软件建立1个高层抗震结构和4个具有不同扭转特性的高层隔震结构的空间模型进行地震响应分析,以验证此原则上部结构质量中心与隔震层刚度中心的重合与否对结构扭转效应的影响程度,而后考察偏心高层隔震结构在偶然偏心地震作用下结构的扭转效应。结果表明:由于地震作用的减小,扭转效应要远小于原抗震结构,且隔震本身对于结构扭转效应的抑制效果要好于上述原则;扭转效应的减震率大于平动效应的减震率。布置在隔震层平面外围的铅芯橡胶隔震支座对隔震层的扭转有一定的控制作用。  相似文献   

Nontectonic signals in reprocessed continuous GPS position time series of CMONOC     

Tian  Yunfeng 《地球空间信息科学学报》2011,14(3):207-215

The nearly nine-year continuous GPS data collected since 1 March 1999 from the Crustal Motion Observation Network of China(CMONOC) were consistently analyzed.Most of the nonlinear movements in the cumulative position time series pro-duced by CMONOC data center disappeared;and more accurate vertical terms and tectonic signals were extracted.Displacements caused by atmospheric pressure loading,nontidal ocean loading,soil moisture mass loading,and snow cover mass loading using the National Centers for Environmental Prediction(NCEP) Reanalysis I/II models and Estimation of the Circulation and Climate of the Ocean(ECCO) data can explain most of the vertical annual terms at many stations,while only parts can be explained at Lhasa and southern coastal sites,indicating that there are some deformation mechanisms that are still unknown or not modeled accurately.The remarkable differences in vertical position time series for short-baseline sites reveal that GPS stations can be greatly affected by lo-cal factors;and attention should be paid when explaining observed GPS velocity vectors.  相似文献