The Impact of Urbanization on Groundwater Quantity,Quality,Hydrothermal Changes and Its Countermeasures     

Wanbin Huang  Chunhua Yan  Xiaonan Zhang  Guoyu Qiu 《地球科学进展》2020,35(5):497-512

Groundwater, as a drinking water source for nearly one third of the world’s urban population, plays a strategic role in the development of urbanization. The object of this study is urban areas with the largest demand for water resources, the heaviest load of groundwater pollution and the most intense development of underground projects. This study sorted out the eco-hydrological problems such as the variation of the groundwater hydrological process, the groundwater pollution, and the urban heat island of groundwater in urban areas under the background of urbanization. Furthermore, the mechanism of changes in the quantity, quality and heat of groundwater was also systematically analyzed, and the intrinsic interaction among these three factors was revealed. The study showed that changes in land use and land cover caused by the urbanization are the main reasons for the variation of groundwater hydrological process. The pollution load of urbanization construction and domestic production waste has aggravated the deterioration of groundwater quality. The increase in vertical heat flux caused by urbanization gives rise to the warming of groundwater. By summarizing the eco-hydrological problems and causes of groundwater in urbanized areas, several suggestions were proposed: \mathrm{①} Establishing the evaluation method and system of urban groundwater resources; \mathrm{②} Speeding up the technological breakthroughs of groundwater pollution control; \mathrm{③} Improving the regional control strategies for groundwater pollution; \mathrm{④} Optimizing the allocation of groundwater resources. This study will provide the theoretical basis and technical support for ensuring urban water safety, building ecological civilized cities and further promoting the sustainable development of economy and society.  相似文献   

气举反循环钻进井壁稳定及适用性探讨          下载免费PDF全文

郑伯乐  郑秀华  段晨阳  叶宏宇 《探矿工程》2020,47(6):13-18

气举反循环工艺具有钻进效率高、携带岩屑能力强、防漏效果好以及钻头寿命长等优点，同时还可以提高流体矿产的产能。但是一般认为气举反循环钻进抽吸作用会产生负压，不利于井壁稳定，不宜在松散地层应用。本文通过计算气举反循环钻进环空水力参数，并从环空压力以及冲洗液流态、流速等方面探讨研究气举反循环钻进中井壁稳定及其适用性，指出通过选取合适的钻具组合以及调节冲洗液性能，可使气举反循环工艺对不同地层的适应性更广。  相似文献   

延迟交联凝胶研制及其在广西某铀矿堵漏应用          下载免费PDF全文

熊正强  陶士先  刘俊辉  李晓东  薛倩冰 《探矿工程》2020,47(4):140-144

针对地质钻探小井眼条件下失返性漏失堵漏技术难题，开展了适用于地质钻探堵漏要求的聚合物交联凝胶研究。采用单因素优选法，优选了交联凝胶体系用各种处理剂，并以环保型植物胶GJ为成胶剂，加入交联控制剂N1及交联剂1号等组分，研制了一种延迟交联凝胶。该凝胶在广西某铀矿勘查ZK6-37-1孔堵漏成功应用，解决了2个孔段失返性漏失问题。研究结果表明，该凝胶具有交联时间可控(交联时间10～75 min)以及较高的凝胶强度（承压≥6 MPa），在解决失返性漏失方面具有广阔的应用前景。  相似文献   

Late Holocene changes in vegetation and atmospheric circulation at Lake Uddelermeer (The Netherlands) reconstructed using lipid biomarkers and compound‐specific δD analysis          下载免费PDF全文

《第四纪科学杂志》2018,33(1):100-111

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一个基于MOM的全球海洋数值同化预报系统     

刘娜  王辉  凌铁军  祖子清  秦英豪 《海洋通报》2018,(2):139-148

随着国家战略利益的拓展,国家对全球海洋环境预报保障的需求日益凸显。近年来,国家海洋环境预报中心研发并建立我国首个涵盖全球大洋的"全球海洋数值预报系统",该预报系统由MOM4全球海洋环流模式及三维变分同化系统组成。该系统的建立,实现了全球范围海洋环流预报业务全覆盖,为我国探索深海大洋环境的迫切需求提供有力保障,明显提升了我国海洋环境预报能力,体现了我国海洋数值预报技术的发展和进步。该系统的历史回报试验和业务化试运行结果表明其对全球海洋环境要素具有较好的预报能力,其预测结果已经在实际业务中得到了应用,在"雪龙号"极地遇险脱困、马航MH370失联飞机搜救等重大事件的预报保障任务中发挥了重要作用,为我国实施海洋强国战略,推进实施"21世纪海上丝绸之路"的战略构想,应对海上突发事件、维护国家海洋权益等各个方面提供有力的科技支撑和保障,并成为我国全球海洋预报业务的重要参考依据。  相似文献   

极地低压对费拉姆海峡大西洋入流水天气尺度变化的影响     

孙瑞立  高郭平 《海洋学报(英文版)》2018,37(3):42-50

The Atlantic inflow in the Fram Strait(78°50′N) has synoptic scale variability based on an array of moorings over the period of 1998–2010. The synoptic scale variability of Atlantic inflow, whose significant cycle is 3–16 d, occurs mainly in winter and spring(from January to April) and is related with polar lows in the Barents Sea. On the synoptic scale, the enhancement(weakening) of Atlantic inflow in the Fram Strait is accompanied by less(more)polar lows in the Barents Sea. Wind stress curl induced by polar lows in the Barents Sea causes Ekman-transport,leads to decrease of sea surface height in the Barents Sea, due to geostrophic adjustment, further induces a cyclonic circulation anomaly around the Barents Sea, and causes the weakening of the Atlantic inflow in the Fram Strait. Our results highlight the importance of polar lows in forcing the Atlantic inflow in the Fram Strait and can help us to further understand the effect of Atlantic warm water on the change of the Arctic Ocean.  相似文献   

湖南省武陵山片区人口城镇化与流通产业发展协同演化及其减贫效应研究   总被引：1，自引：0，他引：1  

杨水根  王露 《地理科学》2020,40(11):1909-1920

运用协同度模型、空间ESDA、趋势面分析和面板计量回归模型，分析湖南省武陵山片区2001—2017年人口城镇化与流通产业发展协同的时空演化特征及其减贫效应。研究发现：湖南省武陵山片区人口城镇化与流通产业协同发展整体呈上升趋势但水平偏低，不同板块间协同水平差异显著且有扩大倾向；具有“集聚–分散–集聚”空间循环过程，局部空间极化效应明显，形成邵阳板块的显著热点区和湘西自治州板块的显著冷点区；协同发展“东高西低”空间分布格局更趋明显，“北高南低”分布态势减弱；两者协同发展对农民收入提升、贫困减缓具有显著正向促进作用，进一步空间效应分解发现协同减贫的空间正外溢性显著；实施人口城镇化与流通产业发展“双轮”协同驱动战略是实现乡村振兴的现实需要，也是落实高质量脱贫方略的重要支撑。  相似文献   

大城市近郊农地流转的时空特征及影响因素     

许红梅  郭炎  李志刚  林赛南  李娈琼 《地理科学》2020,40(12):2055-2063

以武汉市蔡甸区为例，结合多源、多时段的村级农地流转数据，采用探索性空间分析和多元线性回归分析方法，揭示大城市近郊农地流转的时空特征及影响因素。研究发现：① 流转规模呈跨越式增长，经历快速增长和短期减速增长两个阶段，流转速度受土地政策影响较大；农地流转的空间分布由随机转向集聚，高高集聚区由主干道沿线转移至以农业为主的平原街镇，低低集聚区由不显著到集中于城镇化水平较高的街镇；② 控制自然、区位、社会经济等因素后，发现流转主体、流转用途对农地流转具有显著影响。建议清楚把握农地流转时空演化特征，合理选择流转主体和流转用途，以优化大城市近郊的人地关系，促进城乡统筹和乡村振兴。  相似文献   

农户的非农就业如何影响中国的土地流转?   总被引：1，自引：0，他引：1  

王佳月  辛良杰  王亚辉 《地理学报(英文版)》2020,30(3):378-400

To clarify the impact of non-agricultural employment on rural land circulation in China,we built logit models using the Chinese Household Income Project 2013 dataset,which includes 18,948 household samples over 15 provinces,126 cities and 234 counties of China in 2013.We use the proportion of non-agricultural income,the proportion of non-agricultural laborers and non-agricultural fixed operating assets to reflect the degree of the households’dependence on agriculture,the degree of the households’laborers committed to non-agricultural employment and the stability of non-agricultural employment,respectively.The results show that the stability of non-agricultural employment is an important reason for farmers to transfer out their land,and an increase in non-agricultural income is the fundamental reason.The proportion of non-agricultural assets has the greatest impact on the decision to transfer land,followed by the proportion of non-agricultural income.Per unit increase in the non-agricultural income ratio has a stronger effect on the transfer-out decision than it does on the transfer-in decision,which is a 0.09 increase of the probability of transfer-out the land and a 0.07 decrease of the probability of transfer-in the land.In terms of regional differences,when considering the impact of non-agricultural employment on the land transfer-out decision,the impacts of non-agricultural income and labor force are the greatest in the Central region.The impact of non-agricultural assets is the greatest in the Eastern region.For the Eastern region,the decision to transfer out land is mainly affected by non-agricultural assets and the non-agricultural labor force,and the decision to transfer in land is mainly affected by non-agricultural assets.In the Central and Western regions,the decision to transfer out land is mainly affected by non-agricultural assets,non-agricultural income and the non-agricultural labor force,in that order.The decision to transfer in land in the Central region is not significantly affected by non-agricultural employment.The decision to transfer in land in the Western region is mainly affected by non-agricultural assets,non-agricultural labor force and non-agricultural income,in that order.We note that non-agricultural assets have a prominent impact on land transfer,which shows that the stability of non-agricultural employment has an important impact on land transfer decision-making.Vocational training for rural labor forces may be an effective means to promote stable non-agricultural employment and simultaneously facilitate rural land circulation,especially in Central and Western China.  相似文献   

气候变化对东北大西洋渔获物组成、多样性和营养级的影响     

陈爽  陈新军 《海洋学报》2020,42(10):100-109

东北大西洋是世界上重要的捕捞海域，气候变化对该海域捕捞产生了重要的影响。本文基于联合国粮农组织所提供的1982?2016年东北大西洋渔获产量数据，对该海域渔获物组成、多样性、平均营养级及主成分变化特征进行时间序列上的分析，并结合东北大西洋海域气候、环境因子，应用广义可加模型探究渔获物组成与气候变化之间的关系。结果显示:渔获物多样性的变化总体上呈下降趋势，2002?2010年间处于较低水平；平均营养级在2002年之前呈平缓下降的趋势，2002年之后开始波动上升，相关性分析表明这两个指标与海域环境因子的变化较为相关。对渔获物组成进行主成分分析显示，第一主成份变化的方差解释率达到35.3%，且与海域气候、环境因素有较高的相关性，第一主成分变化能够较好地表征气候影响下渔获物组成变化的情况。广义可加模型分析结果显示，渔获物组成变化的影响因素按解释率由高到低分别为:海表温度、海平面高度、盐度、海冰和北大西洋涛动指数。该研究有助于认识气候变化对海洋渔业资源及其结构组成的影响。  相似文献