嘉峪关台地震方位异常的初步探讨     

朱宗德  苏宏伟  萧淑娟 《高原地震》1999,(4)

对嘉峪关台 1 971～ 1 992年记录的不同方位的 3 0 0个地震进行了统计 ,分析后认为 :发生在嘉峪关台 SE方向的地震合成方位异常显著 ,特别是肃南地区的地震嘉峪关台记录存在明显的初动方位异常 ,异常夹角在 60°左右。认为这与祁连山北缘深大断裂以及河西走廊内部的活动断层有关  相似文献   

A remote sensing model of CO2 flux for wheat and studying of regional distribution     

Renhua Zhang  Xiaomin Sun  Zhilin Zhu  Hongbo Su  Gang Chen 《中国科学D辑(英文版)》1999,42(3):325-336

A model for calculating CO₂ flux in the wheat field and an algorithm for estimating CO₂ flux in the mejonal scale were presented using the remote sensing data and supplementary micpo-met~orological data. First of all a-longertenn measurement wae carried out during winter wheat growing period in Yucheng Experimental Station udng the spectmradiometer system, the thermal infrared radiometer system, the Bowen-ratio device as well as the eddy-correlation device. Two kinds of issues concerning remote sensing and CO₂ flux can be obtained. Based on the obeervations a remote sensing model was estabilished. Then when the NOAA-AVHRR passed over the experimental area simultaneous measurements were carried out with the satellites. A regional distribution image for CO₂ flux over wheat canopy in North China (500×500 km²) was made using the supplementary ground data and NOAA-AVHRR remote sensing data which was calibrated by the synchronous observation. The sources and sinks for CO₂ fluxes in the region can be seen obviously. Project supported by the National Natural Science Foundation of China (Grant Nos. 49671058, 49890330)  相似文献   

岩溶地区生态环境敏感度评价研究——以乌江流域为例   总被引：17，自引：6，他引：11  

苏维词 《中国岩溶》1997,16(1):57-65

岩溶地区作为一个独特的地域环境单元,具有环境承载量低、地表崎岖破碎、植被生长困难、生态系统脆弱、环境变化敏感的特点。本文以岩溶地貌极为发育的乌江流域为例,论述了岩溶地区生态环境敏感度评价的原则,探讨了敏感度评价的方法,通过分析人类活动与生态环境变化之间的关系,初步建立起了岩溶地区生态环境敏感度评价的指标体系。并在此基础上,利用层次分析法确定了不同影响因子（评价指标）对生态环境敏感度的权重,并据此计算出了流域内各县（市、区）的生态环境敏感度值,为流域的开发与治理提供依据   相似文献   

青藏高原东北缘地震断层的研究   总被引：4，自引：2，他引：2  

戴华光  贾云鸿  刘洪春  苏向洲  陈永明 《地质力学学报》1995,1(1):38-43

青藏高原东北缘新构造运动强烈,地震活动频繁。调查资料表明,伴随每次大地震的发生,都将产生规模不等的地震断层。本文研究了该区地震断层的分布规律、类型以及与先存断裂的关系等,同时对研究区不同地段的地壳稳定性进行了初步评价。   相似文献   

Impacts of headcut height on flow energy,sediment yield and surface landform during bank gully erosion processes in the Yuanmou Dry‐hot Valley region,southwest China          下载免费PDF全文

Baojun Zhang  Donghong Xiong  Guanghui Zhang  Su Zhang  Han Wu  Dan Yang  Liang Xiao  Yifan Dong  Zhengan Su  Xiaoning Lu 《地球表面变化过程与地形》2018,43(10):2271-2282

To quantify the changes in flow energy, sediment yield and surface landform impacted by headcut height during bank gully erosion, five experimental platforms were constructed with different headcut heights ranging from 25 to 125 cm within an in situ active bank gully head. A series of scouring experiments were conducted under concentrated flow and the changes in flow energy, sediment yield and surface landform were observed. The results showed that great energy consumption occurred at gully head compared to the upstream area and gully bed. The flow energy consumption at gully heads and their contribution rates increased significantly with headcut height. Gully headcuts also contributed more sediment yield than the upstream area. The mean sediment concentrations at the outlet of plots were 2.3 to 7.3 times greater than those at the end of upstream area. Soil loss volume at gully heads and their contribution rates also increased with headcut height significantly. Furthermore, as headcut height increased, the retreat distance of gully heads increased, which was 1.7 to 8.9 times and 1.1 to 3.2 times greater than the incision depth of upstream area and gully beds. Positive correlations were found between energy consumption and soil loss, indicating that energy consumption could be used to estimate soil loss of headcut erosion. Headcut height had a significant impact on flow energy consumption, and thus influenced the changes in sediment yield and landform during the process of gully headcut erosion. Headcut height was one of the important factors for gully erosion control in this region. Further studies are needed to identify the role of headcut height under a wide condition. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

Does hillslope trenching enhance groundwater recharge and baseflow in the Peruvian Andes?          下载免费PDF全文

Lauren D. Somers  Jeffrey M. McKenzie  Samuel C. Zipper  Bryan G. Mark  Pablo Lagos  Michel Baraer 《水文研究》2018,32(3):318-331

As Andean glaciers rapidly retreat due to climate change, the balance of groundwater and glacial meltwater contributions to stream discharge in tropical, proglacial watersheds will change, potentially increasing vulnerability of water resources. The Shullcas River Watershed, near Huancayo, Peru, is fed only partly by the rapidly receding Huaytapallana glaciers (<20% of dry season flow). To potentially increase recharge and therefore increase groundwater derived baseflow, the government and not‐for‐profit organizations have installed trenches along large swaths of hillslope in the Shullcas Watershed. Our study focuses on a nonglacierized subcatchment of the Shullcas River Watershed and has 2 objectives: (a) create a model of the Shullcas groundwater system and assess the controls on stream discharge and (b) investigate the impact of the infiltration trenches on recharge and baseflow. We first collected hydrologic data from the field including a year‐long hydrograph (2015–2016), meteorological data (2011–2016), and infiltration measurements. We use a recharge model to evaluate the impact of trenched hillslopes on infiltration and runoff processes. Finally, we use a 3‐dimensional groundwater model, calibrated to the measured dry season baseflow, to determine the impact of trenching on the catchment. Simulations show that trenched hillslopes receive approximately 3.5% more recharge, relative to precipitation, compared with unaltered hillslopes. The groundwater model indicates that because the groundwater flow system is fast and shallow, incorporating trenched hillslopes (~2% of study subcatchment area) only slightly increases baseflow in the dry season. Furthermore, the location of trenching is an important consideration: Trenching higher in the catchment (further from the river) and in flatter terrain provides more baseflow during the dry season. The results of this study may have important implications for Andean landscape management and water resources.  相似文献   

Model updating for real time dynamic substructures based on UKF algorithm     

Su Tingli  Tang Zhenyun  Peng Lingyun  Bai Yuting  Jin Xuebo  Kong Jianlei 《地震工程与工程振动(英文版)》2020,19(2):413-421

Combining the advantages of numerical simulation with experimental testing, real-time dynamic substructure (RTDS) testing provides a new experimental method for the investigation of engineered structures. However, not all unmodeled parts can be physically tested, as testing is often limited by the capacity of the test facility. Model updating is a good option to improve the modeling accuracy for numerical substructures in RTDS. In this study, a model updating method is introduced, which has great performance in describing this nonlinearity. In order to determine the optimal parameters in this model, an Unscented Kalman Filter (UKF)-based algorithm was applied to extract the knowledge contained in the sensors data. All the parameters that need to be identified are listed as the extended state variables, and the identification was achieved via the step-by-step state prediction and state update process. Effectiveness of the proposed method was verified through a group of experimental data, and results showed good agreement. Furthermore, the proposed method was compared with the Extended Kalman Filter (EKF)-based method, and better accuracy was easily found. The proposed parameter identification method has great applicability for structural objects with nonlinear behaviors and could be extended to research in other engineering fields.  相似文献   

基于经验参考场地的广义线性反演方法          下载免费PDF全文

傅磊  李小军  陈苏 《地震工程学报》2019,41(5):1290-1298

为了克服广义线性反演方法（GIT）中理想的参考场地难以找到的局限性,本文将四分之一波长法计算的平均场地放大系数和谱衰减法计算的高频衰减参数作为GIT方法的经验参考场地（ERS）。以2008年5月至8月间28个强震动台站记录的95个汶川8.0级地震余震的615组强震动记录为例,通过与其他方法的比较,验证了ERS-GIT的合理性,并讨论了各类方法之间差异的原因。结果显示,ERS-GIT方法、传统GIT方法和非参数化GIT方法计算得到的平均应力降依次为1.15 MPa,0.78 MPa和0.52 MPa;ERS-GIT方法和传统GIT方法得到的品质因子分别为Q（f）=75.02f^1.27和Q（f）=65.56f^1.22。以场地的卓越频率为分界,ERS-GIT方法得到的局部场地响应在长周期和高频部分分别与H/V谱比法和传统GIT方法更为接近。  相似文献   

基于FusionCompute的地震行业网私有云平台部署与实现     

苏日亚  安全  杨彦明  学峰 《地震地磁观测与研究》2019,40(3):182-186

针对传统地震数据机房存在业务扩展成本高且周期长、维护繁琐、无法保障重要业务系统的无故障连续运作等问题,采用虚拟化云计算技术,实现地震行业网的私有云服务。华为FusionCompute云服务系统将主机、存储等物理资源虚拟化,并整合为统一资源,供多个虚拟机使用,行业专网内运维人员通过用户接口远程访问云平台,在虚拟机上可快速、高效地按需搭建业务系统。地震私有云平台不仅减少业务扩展运营期间的设备采购、系统搭建、运行维护等人力和物力投入,且通过FusionCompute的迁移技术,实现业务系统的"零宕机"服务。  相似文献   

Observation of the Radio Radiation Flux of the Sun and Flares at a Wavelength of 5 cm     

Tlatov  A. G.  Bogod  V. M.  Pons  O.  Rodriges  M.  Estrada  R.  Pablo  S. 《Geomagnetism and Aeronomy》2020,60(8):1087-1092

Geomagnetism and Aeronomy - The results of long-term mesoscale observations in the microwave range are reviewed. The rationale for the resumption of observations at the Havana Radio Astronomy...  相似文献