Quantifying ice storage in upper Indus river basin using ground-penetrating radar measurements and glacier bed topography model version 2

Ice reserve estimates is a fundamental prerequisite for water resources management. We selected the UIB (upper Indus river basin) as study area because it contains the most abundant mid-latitude glaciers outside the polar region, however, the ice reserve estimates remain unclear due to the harsh topography. In this study, we validated the parameters of the GlabTop2 model (Glacier Bed Topography version 2) using the ice thickness measured by GPR (ground-penetrating radar) and compared the “GPR-measured ice thickness and ice bed elevation” versus “the estimated results obtained from GlabTop2.” Integrated with IDW (inverse distance weighted) interpolated results of glaciers of various sizes, a reasonable parametric scheme (τ = 120 kPa and f = 0.8) of GlabTop2 was applied on vast amounts of glaciers in the UIB region. The GlabTop2 estimates indicated that the ice thickness of the UIB varied from 0 to 736.0 ± 110.0 m, with an average value of 74.5 ± 11.2 m. A significant spatial heterogeneity exists in the sub-basins. The Shyok, Shigar and Hunza that contain the most abundant ice reserve. Lesser quantities are stored in the Western Himalaya and Hindu Kush ranges, which account for 11.3 % and 6.7 % of the total ice reserve in the UIB, respectively. A total volume of 1162.4 ± 175.1 km³ of glacier can be converted to 1046.2 ± 157.6 Gt ice reserve; this is 13.6 times the annual average discharge obtained from the outlet of the Besham hydrological station. We aim to present estimates that can provide the baseline information for glaciology study of the Indus river.     

Numerical study on the mixed model in the GOCE polar gap problem

Gravity gradients acquired by the Gravity field and steady-state Ocean Circulation Explorer(GOCE) do not cover the entire earth because of its sun-synchronous orbit leaving data gaps with a radius of about 6.5° in the polar regions.Previous studies showed that the loss of data in the polar regions deteriorates the accuracy of the low order(or near zonal) coefficients of the earth gravity model,which is the so-called polar gap problem in geodesy.In order to find a stable solution for the earth gravity model from the GOCE gravity gradients,three models,i.e.the Gauss-Markov model,light constraint model and the mixed model,are compared and evaluated numerically with the gravity gradient simulated with the EGM2008.The comparison shows that the Best Linear Uniformly Unbiased Estimation(BLUUE) estimator of the mixed model can solve the polar gap problem as effectively as the light constraint model;furthermore,the mixed model is more rigorous in dealing with the supplementary information and leads to a better accuracy in determining the global geoid.     

黄淮海地区植被生长季变化及其气候变化响应

利用1982—2000年的NOAA/AVHRR逐旬数据,采用最大变化斜率法、曲线拟合法等方法分析黄淮海地区植被生长季开始及结束时间,选取典型样带,制作基于逐像元的I_NDV(归一化植被指数) 变化图,研究1982—2000年植被生长季的变化规律及其对气候变化的响应。结果表明:黄淮海地区生长季开始的平均时间为3月下旬,结束时间为11月上旬。20年来研究区植被四季平均I_NDV呈上升趋势,春季增长尤为显著,且随着年代的推移,植被生长季有延长的趋势,生长季提前是黄淮海地区植被活动对气候变化响应的主要方式。     

淮河流域水资源与水环境问题及对策研究

淮河流域是我国重要的粮食产区和工业基地.随着流域内经济社会的快速发展,水资源短缺和污染等问题所造成的影响日益严重.为实现淮河流域水资源的可持续利用,应完善水利工程设施,开发中水和雨水等新的水源;工农业生产采用节水技术;加强水环境保护,防止水质污染;综合规划水资源,构建水资源可持续利用体系.     

Numerical analysis of dislocations of the face slabs of the Zipingpu Concrete Faced Rockfill Dam during the Wenchuan earthquake

The Zipingpu Concrete Faced Rockfill Dam (CFRD) was obviously damaged during the Wenchuan earthquake in 2008. A wide range of dislocations occurred along the horizontal construction joints at EL. 845m, between the face slabs constructed in the second and third stages. The maximum displacement of the dislocations reached 17cm. In this study, the slab dislocations were investigated using finite element (FE) analysis. The method based on strain potential was applied to compute the permanent deformation of the Zipingpu Dam during the Wenchuan earthquake. The calculated magnitude of the slab dislocation showed good agreements with the field measurements. The dislocation mechanism was discussed. The results show that the dislocation of the concrete slab is a subsequent damage after the permanent deformation of the rockfill materials. The effects of the shear strength and the direction of the construction joints, the reservoir water level and the seismic waves were studied. The shear strength and the direction of the construction joints, reservoir water level and have a significant effect on the dislocation displacement. The dislocation can be effectively reduced by measures such as changing the direction of the construction joints or improving the shear strength at the horizontal joints.     

Numerical simulation of overflow at vertical weirs using a hybrid level set/VOF method

This paper presents the applications of a newly developed free surface flow model to the practical, while challenging overflow problems for weirs. Since the model takes advantage of the strengths of both the level set and volume of fluid methods and solves the Navier-Stokes equations on an unstructured mesh, it is capable of resolving the time evolution of very complex vortical motions, air entrainment and pressure variations due to violent deformations following overflow of the weir crest. In the present study, two different types of vertical weir, namely broad-crested and sharp-crested, are considered for validation purposes. The calculated overflow parameters such as pressure head distributions, velocity distributions, and water surface profiles are compared against experimental data as well as numerical results available in literature. A very good quantitative agreement has been obtained. The numerical model, thus, offers a good alternative to traditional experimental methods in the study of weir problems.     

北京市社会公众防震减灾科普认知、需求调查研究

为全面系统地评价防震减灾科普效果、准确分析公众的防震减灾科普需求,在2010年上半年开展了面向北京市公众的防震减灾科普现状及需求调查研究.结果表明,58.4%的公众接受过防震减灾科普知识宣传,不同人群接受程度不一;公众对地震预报仍抱有较大的期望,大学生和农民的防震减灾科普知识水平较低;电视、报纸杂志和网络是目前公众获取...     

湘东北幕阜山含绿帘石花岗闪长岩岩浆的上升速率：岩相学和矿物化学证据

出露于扬子地块东南缘的幕阜山复式岩体侵位年龄约为145Ma.该复式岩体的花岗闪长岩及其暗色微粒包体都含有独特的岩浆绿帘石.这些绿帘石呈自形晶,普遍发育熔蚀结构,部分具褐帘石核.微粒包体及花岗闪长岩中绿帘石的Ps值((100Fe3+/(Fe3++Al))均集中在26～28,TiO2含量小于0.2%,为典型的岩浆成因.岩相...     

全球油气勘探研究进展及对沉积储层研究的需求

近年来,全球油气勘探的重大发现和突破主要集中在被动大陆边缘深水区、岩性地层、海相碳酸盐岩、前陆盆地冲断带、成熟勘探地区、新勘探地区以及非常规油气等领域。勘探对象既包括常规构造、岩性地层、构造一岩性复合油气藏,也包括致密砂岩、页岩等非常规油气;勘探部位既包括被动大陆边缘、克拉通、前陆冲断带、前陆斜坡等常规油气藏分布区,又...