Groundwater system division and compilation of Groundwater Resources Map of Asia          下载免费PDF全文

CHENG Yan-pei  DONG Hua 《地下水科学与工程》2015,3(2):127-135

Based on landform, climate, river system, geological structure and hydrogeological structure and from the perspective of systematology, the groundwater system of Asia can be divided into 36 secondary groundwater systems under 11 primary ones by the intercontinental scale. A scientific evaluation of groundwater resources in Asia can be secured using water balance method and runoff modulus method through water circulating analysis and feature study of groundwater system on the basis of groundwater system division of Asia. With natural recharge(runoff) modulus(10~4m~3/km~2·a), the total amount of water resources and those available for exploitation of primary groundwater system can be evaluated-continuous aquifers in plains and basins contain 242.465× 10~9 m~3/a of water, 169.725× 10~9 m~3/a of which is recoverable; discrete aquifers contain 186.695× 10~9 m~3/a, 130.686× 10~9 m~3/a of which is available for exploitation; other scattered aquifers contain 38.614× 10~9 m~3/a, 27.029× 10~9 m~3/a of which could be exploited. In total, there is 467.774× 10~9 m~3/a of groundwater with 327.440× 10~9 m~3/a recoverable. The groundwater map of Asia is compiled according to groundwater system division, evaluation of the total amount and aquifer types to reflect the macro features of groundwater resources in Asia, laying a scientific foundation for exploitation and management of water resources here and for avoiding disputes over groundwater resources and environment among Asian countries.  相似文献   

南极冰下基岩热水驱动快速取心钻具研究   总被引：1，自引：1，他引：0       下载免费PDF全文

杨阳  范晓鹏  达拉拉伊  刘安  杨巍 《探矿工程》2017,44(7):48-51

南极大陆冰下基岩岩心对研究南极大陆地质构造及成因具有重要意义,目前尚没有任何一个国家在南极内陆成功钻取冰下基岩样品,研制可快速钻至冰岩界面并完成基岩采样的钻进设备迫在眉睫。针对极地冰下基岩取样技术难题,提出了一种可结合热水钻系统使用的采用热水驱动的冰下基岩取心钻具概念设计。该钻具系统采用常规热水钻完成南极大陆上覆冰层钻进,然后更换热水取心钻具穿过已有钻孔快速到达冰岩界面,完成冰下沉积物和基岩取心钻进,大大缩短基岩取心时间,提高钻进效率。结合中国自主研发的热水钻系统参数,对螺杆马达压力损失和输出扭矩进行理论计算,提出了螺杆马达选择依据。该技术有望在未来极地冰下基岩取心钻进中发挥重要作用。  相似文献   

Spatial and temporal variation of diverse inter‐tidal algal assemblages in Southwest O‘ahu          下载免费PDF全文

Traci Erin Cox  Heather L. Spalding  Michael S. Foster 《Marine Ecology》2017,38(3)

Spatial and temporal variation in tropical inter‐tidal communities is poorly known, making predictions about the effects of climate change and other anthropogenic disturbances difficult. Along Southwest O‘ahu, Hawai'i, local residents are concerned about the environmental effects of coastal development and the perceived loss of targeted algal species, which are collected for human consumption. To describe the coastal benthic community and better understand the processes that form and maintain it, the abundance and composition of macroalgae were sampled in the region's inter‐tidal zone from 2006 to 2015. Sixty‐six macroalgal species and two broad algal assemblages were identified that corresponded to substrate topography and sand influence at a similar tidal elevation. Along flat carbonate benches with a sand beach, Phaeophyceae and Rhodophytes occurred in almost equal proportions, while shores with slightly more topographic relief and angular substrate were dominated by Rhodophytes. Foliose or turf algal forms were most common. Surveys captured the local invasion of an alga, Avrainvillea sp. and significant declines in abundant macroalgae in 2015 after a period of unseasonably warm, calm water. Temporal changes in algal assemblages were related to maximum water temperature and wave height but not precipitation. Thus, algal assemblages appear to be structured by local beach morphology as they interact with sand and wave activity and episodically by unusual weather events. However, manipulation and continuous monitoring of the algal assemblages coupled to sensing of the localized environment is necessary to confirm factors related to assembly maintenance and recent species shifts.  相似文献   

基于经验模态分解削弱多波束残余误差的方法     

赵祥鸿  暴景阳  黄辰虎  黄贤源  陆秀平 《海洋通报》2017,36(6):662-667

针对多波束水深数据中存在的系统性残余误差,提出了基于经验模态分解方法来削弱残余误差的方法:首先利用经验模态分解方法对多波束测深数据作一维分解,将非线性、非平稳的多波束测深数据分解成准线性子波,然后构建水深数据趋势项与残余项,利用中央波束趋势项建立整体数据趋势项,最后加以水深数据残余项还原海底地形,削弱残余误差影响。通过实测多波束测深数据验证方法的有效性。  相似文献   

连云港赣榆港区水下地形地貌研究     

范彦斌  张晓飞  孙祝友 《江苏地质》2017,41(4):651-654

通过对连云港赣榆港区水下地形测量工作,结合以往采集数据分析,阐明了赣榆港区的水下地形变化趋势及周围地貌特征。研究区海底地形总体呈东—东南倾斜的趋势,地形变化较缓,以赣榆港航道为界,南部从柘汪河到龙王河口等深线较平直,由陆向海呈阶梯状分布,水深从0 m一直缓慢加深至-10 m,平均坡度＜1‰,近岸主要为沙泥滩,泥滩位于龙王河口以南,受河流及沿岸细粒物质大量补给和潮流作用为主的海洋动力控制,淤积作用显著。  相似文献   

Geospatial analysis of controls on subglacial bedform morphometry in the New York Drumlin Field – implications for Laurentide Ice Sheet dynamics     

Dale P. Hess  Jason P. Briner 《地球表面变化过程与地形》2009,34(8):1126-1135

The outline and trend of 6566 subglacial bedforms in the New York Drumlin Field have been digitized from digital elevation data. A spatial predictive model has been used to extend values of bedform elongation over an area measuring 200 km × 110 km. The resulting surface is used in conjunction with depth‐to‐bedrock data and an assumed duration of ice residence to test three proposed controls on bedform elongation. Upon comparison, the resulting display of morphometry is best explained by differences in ice velocity across the field of study. The existence of multiple zones of fast‐moving ice located along the southern margin of the Laurentide Ice Sheet is implied by the observed patterns of bedform elongation and orientation. We present two interpretations that are consistent with the observations. First, enhanced basal sliding caused by decreasing effective pressure near a calving margin is suggested as a possible mechanism by which localized fast ice flow is initiated and maintained. Second, topographically controlled ice streams likely occupied the fjord‐like troughs of the Appalachian Upland northern rim. Contrary to previous understanding of the Laurentide southern margin in New York State, the resulting palaeoglaciological reconstruction illustrates a dynamic mosaic of ice stream and/or outlet glacier activity. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Gravity and magnetic data inversion for 3D topography of the Moho discontinuity in the northern Red Sea area, Egypt   总被引：1，自引：0，他引：1  

Ilya Prutkin  Ahmed Saleh 《Journal of Geodynamics》2009,47(5):237-245

The main goal of our study is to investigate 3D topography of the Moho boundary for the area of the northern Red Sea including Gulf of Suez and Gulf of Aqaba. For potential field data inversion we apply a new method of local corrections. The method is efficient and does not require trial-and-error forward modeling. To separate sources of gravity and magnetic field in depth, a method is suggested, based on upward and downward continuation. Both new methods are applied to isolate the contribution of the Moho interface to the total field and to find its 3D topography. At the first stage, we separate near-surface and deeper sources. According to the obtained field of shallow sources a model of the horizontal layer above the depth of 7 km is suggested, which includes a density interface between light sediments and crystalline basement. Its depressions and uplifts correspond to known geological structures. At the next stage, we isolate the effect of very deep sources (below 100 km) and sources outside the area of investigation. After subtracting this field from the total effect of deeper sources, we obtain the contribution of the Moho interface. We make inversion separately for the area of rifts (Red Sea, Gulf of Suez and Gulf of Aqaba) and for the rest of the area. In the rift area we look for the upper boundary of low-density, heated anomalous upper mantle. In the rest of the area the field is satisfied by means of topography for the interface between lower crust and normal upper mantle. Both algorithms are applied also to the magnetic field. The magnetic model of the Moho boundary is in agreement with the gravitational one.  相似文献   

我国湿地景观研究现状、存在的问题与发展方向   总被引：11，自引：0，他引：11  

刘红玉  李玉凤  曹晓  郝敬峰  胡俊纳  郑囡 《地理学报》2009,64(11)

湿地景观研究是近十余年来新兴的热点领域,极大地推进了湿地学科发展.但是,由于湿地景观研究体现的是湿地与景观方法有机结合,其在发展过程中还存在许多问题.本文在对我国湿地景观研究现状系统分析基础上,重点阐明了湿地景观概念、分类、遥感信息提取精度、多源数据可比性、结构与格局研究方法、景观过程与功能研究内容与尺度等制约湿地景观研究的主要问题.并指出了未来发展方向:(1)重视湿地景观分类研究;(2)重视湿地景观破碎化研究;(3)重视发展基于过程和功能的景观格局研究方法;(4)重视多尺度湿地生物多样性研究;(5)重视湿地景观管理研究.  相似文献   

极地冰盖冰雷达探测技术的发展综述          下载免费PDF全文

崔祥斌  孙波  张向培  张栋  李鑫  唐学远  田钢 《极地研究》2009,21(4):322-335

分三个阶段,即早期冰雷达系统(20世纪60至80年代)、第二代冰雷达系统(20世纪8O年代至2000年)和新冰雷达系统(2ooo年之后),综述了极地冰盖冰雷达探测技术的发展。最后,展望了冰雷达探测技术未来的发展趋势。  相似文献   

Numerically quantifying the relative importance of topography and buoyancy in driving groundwater flow     

YANG JianWen    FENG ZuoHai  LUO XianRong & CHEN YuanRong Faculty of Earth Sciences  Guilin University of Technology  Guilin  China 《中国科学:地球科学(英文版)》2010,(1)

Both topography and buoyancy can drive groundwater flow;however,the interactions between them are still poorly understood.In this paper,the authors conduct numerical simulations of variable-density fluid flow and heat transport to quantify their relative importance.The finite element modeling experiments on a 2-D conceptual model reveal that the pattern of groundwater flow depends largely upon the relative magnitude of the flow rate due to topography alone and the flow rate due to buoyancy alone.When fluid ...  相似文献