Chloride as tracer of solute transport in the aquifer–aquitard system in the Pearl River Delta,China

A 1D numerical model is constructed to investigate the impact of sedimentation and sea level changes on transport of Cl^? in the aquifer–aquitard system in the Pearl River Delta (PRD), China. The model simulates the evolution of the vertical Cl^? concentration profiles during the Holocene. Sedimentation is modeled as a moving boundary problem. Chloride concentration profiles are reconstructed for nine boreholes, covering a wide area of the PRD, from northwest to southeast. Satisfactory agreement is obtained between simulated and measured Cl^? concentration profiles. Diffusion solely is adequate to reproduce the vertical Cl^? concentration profiles, which indicates that diffusion is the regionally dominant vertical transport mechanism across the aquitards in the PRD. The estimated effective diffusion coefficients of the aquitards range from 2.0?×?10^–11 to 2.0?×?10^–10 m²/s. The effective diffusion coefficients of the aquifers range from 3.0?×?10^–11 to 4.0?×?10^–10 m²/s. Advective transport tends to underestimate Cl^? concentrations in the aquitard and overestimate Cl^? concentrations in the basal aquifer. The results of this study will help understand the mechanisms of solute transport in the PRD and other deltas with similar geological and hydrogeological characteristics.     

Numerical simulation of elasto-plastic electro-osmosis consolidation at large strain

In this paper, a numerical solution for the electro-osmosis consolidation of clay in multi-dimensional domains at large strains is presented, with the coupling of the soil mechanical behaviour, pore water transport and electrical fields being considered. In particular, the Modified Cam Clay model is employed to describe the elasto-plastic behaviour of clay, and some empirical expressions are used to consider the nonlinear variation of the hydraulic and electrical conductivities of the soil mass during the consolidation processes. The implementation of the theoretical model in a finite element code allows for analysis of the evolution of the transient response of the clay subjected to electro-osmosis treatment. The proposed model is verified via comparison with data from a large strain electro-osmosis laboratory test, to demonstrate its accuracy and effectiveness. Various numerical examples are also investigated to study the deformation characteristics and time-dependent evolution of the excess pore pressure. Finally, a well-documented field application of electro-osmosis is simulated to provide further verification. The results show that the numerical solution is effective in predicting the nonlinear behaviour of clay during electro-osmosis consolidation.     

Migration and transformation of manganese during the artificial recharging of a deep confined aquifer

Field tests and laboratory experiments were performed, using an artificial groundwater recharging site in Southeast China as an example, to investigate the migration and transformation of manganese during the artificial recharging of a deep confined aquifer. The migration and transformation of total manganese and divalent manganese (Mn(II)) were influenced by mixing, oxidation reactions, and the dissolution of minerals containing manganese, and increasing the dissolved oxygen (DO) concentration was found to promote the dissolution of minerals containing manganese. The laboratory experiments showed that the retardation factors were higher upstream than downstream of the recharging hole. The amount of dissolution that occurred decreased, and the amount of mixing that occurred increased as the distance from the recharging hole increased. The DO concentration decreased as the amount of dissolution of minerals containing manganese that occurred decreased. A high temperature, a high DO concentration, and the presence of microorganisms were found to promote the dissolution of minerals containing manganese, which caused the total manganese and Mn(II) concentrations to increase.     

Mapping the vegetation distribution of the permafrost zone on the Qinghai-Tibet Plateau

In this paper,an updated vegetation map of the permafrost zone in the Qinghai-Tibet Plateau(QTP) was delineated.The vegetation map model was extracted from vegetation sampling with remote sensing(RS) datasets by decision tree method.The spatial resolution of the map is 1 km×1 km,and in it the alpine swamp meadow is firstly distinguished in the high-altitude areas.The results showed that the total vegetated area in the permafrost zone of the QTP is 1,201,751 km~2.In the vegetated region,50,260 km~2 is the areas of alpine swamp meadow,583,909 km~2 for alpine meadow,332,754 km~2 for alpine steppe,and 234,828 km~2 for alpine desert.This updated vegetation map in permafrost zone of QTP could provide more details about the distribution of alpine vegetation types for studying the vegetation mechanisms in the land surface processes of highaltitude areas.     

河南省基本公共服务质量空间格局与空间效应研究

构建基本公共服务质量评价指标体系,对河南省基本公共服务水平和空间格局特征进行了分析,最后采用空间杜宾模型研究了基本公共服务的空间溢出效应与影响因素。研究发现：① 2005~2014年河南省各市基本公共服务水平呈不同程度的上升趋势,但整体水平不高;空间格局上呈自西北向东南衰减的半环带圈层结构。② 基本公共服务在市际尺度上具有显著的全局与局部自相关特征,随时间呈现集聚-分散-集聚的演变模式;高高集聚与低低集聚的空间俱乐部趋同特征明显。③ 空间杜宾模型检验表明基本公共服务空间上存在溢出效应;城镇化水平、地方政府财政支出能力、地方经济发展活力对基本公共服务具有正向促进作用。     

2011/2012年夏季南极半岛北端周边海域的水团与水交换

通过分析中国第28次南极考察队于2011年12月至2012年1月在南极半岛北端周边海域获得的5条断面CTD观测温盐剖面数据, 进一步认识了该海域的水团组成和水交换情况。观测区域南部的鲍威尔海盆及周边深海区, 可以观测到保持了较显著高温核心的威德尔深层水、密度大于28.27 kg·m^-3的威德尔海深层水以及温度低于－0.7 ℃的威德尔海底层水。周边陆坡上的威德尔海深层水则表现出因与周围水体发生混合而核心性质减弱的特征。在菲利普海岭、埃斯佩里兹海槽等复杂地形处, 观测到的对应于威德尔海深层水深度的混合与热盐入侵过程更为显著。威德尔海深层水能够到达南设得兰群岛以北的象岛东北面海域, 但是高盐核心加深至1 500 db, 并上覆温度基本不变但盐度随深度显著增大的较暖水体, 表明威德尔海深层水经历了不同的路径和变性过程。布兰斯菲尔德海峡中没有绕极深层水大规模侵入的迹象, 但是乔治王岛周边陆架上可能存在涡旋等中尺度过程, 会影响德雷克海峡与布兰斯菲尔德海峡之间的水交换。     

Characterizing the winter concurrent variation patterns of the subtropical and polar-front jets over East Asia

In this study, the concurrent variation relationships between the East Asian subtropical jet (EASJ) and polar-front jet (PFJ) over the East Asian land mass in the winter season on different timescales are identified and the impacts of the jet concurrent variation patterns on the atmospheric circulation in mid–high latitude regions and climate anomalies in China are examined, using NCEP–NCAR reanalysis data and observational data. The major variability modes of the winter upper-level wind field on interannual timescales are characterized by the meridional shift of the PFJ and out-of-phase variation in the intensity of the subtropical jet and PFJ. On subseasonal and synoptic timescales, the concurrent variation relationships can be categorized into four configuration patterns: a strong (weak) subtropical jet accompanied by a weak (strong) PFJ, or a strong (weak) subtropical jet with a strong (weak) PFJ. The out-ofphase variation [i.e., a stronger (weaker) EASJ and weaker (stronger) PFJ] is found to be more common than the inphase variation [i.e., a stronger (weaker) EASJ and stronger (weaker) PFJ]. These concurrent variation relationships represent the integral structure and variation features of the atmospheric general circulation over East Asia, and have significant impacts on the weather and climate. The strong subtropical jet/weak PFJ (weak subtropical jet/strong PFJ) pattern leads to anomalous negative (positive) geopotential height in midlatitude regions and favors cold (warm) conditions, and positive (negative) rainfall anomalies in southern China. For both strong jet configurations, the geopotential height anomaly in the mid–high latitudes shows a northwest–southeast tilted dipole pattern, resulting in northern warm–southern cold temperature anomalies, and positive rainfall anomalies in southern China. For both weak jet situations, positive geopotential height anomalies dominate the East Asian area, and warm conditions occur over most areas in China, corresponding to less negative rainfall anomalies in southern China. The complicated rainfall and temperature anomaly patterns in China can be explained by the concurrent variation relationships between the two jets. A close relationship may exist between the synoptic-scale transient eddy activity (STEA) and the intensity of jet streams, especially for the PFJ. Significantly reduced (strengthened) STEA over the polar-front area is intimately associated with a decreased (increased) intensity of the PFJ.     

河南省能源消费碳排放动态变化及空间分异

在分析河南省1978—2015年能源消费碳排放总量和结构变化的基础上,利用Im PACT等式对河南省碳排放驱动因素进行了研究和对未来碳排放量进行了情景预测,并运用空间自相关分析法探讨了空间分异特征。结果表明:(1)1978—2015年,河南省碳排放量总体上呈现增加的趋势,年均增长5.11%,由煤炭和石油消费导致的碳排放比重一直稳定在95%以上。(2)弹性分析表明人均真实GDP增加1%将导致人均能源消费量增加0.48%,利用强度下降0.52%,而环境影响增加0.53%。(3)保持经济增长的同时,与2011—2015年相比,1978—2015年效率年均增长率提高5.25倍,是河南省实现循环经济建设的一种可行方案。(4)河南省2015年碳排放全局Moran’s I值为0.047,呈微弱空间正相关,各地市碳排放具有明显的二元结构特征,空间集聚特征不明显。     

基于水下摄像的渔山列岛厚壳贻贝资源评估与分析

厚壳贻贝是我国东部沿海重要的经济贝类之一,自然环境中栖息范围不甚明确。本文于2014年7月间利用水下摄像的手段,调查和分析了渔山列岛不同断面上厚壳贻贝的自然分布特征。结果表明:渔山列岛潮下带5条断面的生态类型差异显著,不同断面栖息的优势种也不相同;断面间厚壳贻贝的栖息密度均值为37.04~185.80 ind/m2,其中断面A的栖息密度最低,断面E的栖息密度最高,断面C和断面D的栖息密度相差不大,但是不同调查样方内厚壳贻贝的栖息密度从0~388.89 ind/m2不等;厚壳贻贝主要分布在水深3~9 m的水层中,其中以水深5~8 m的水层中最为密集,约占总栖息密度的90%以上;在水深8 m的区带上,厚壳贻贝的栖息密度为160.19 ind/m2,当水深小于1 m和大于11 m时,厚壳贻贝分布极少;经双因素方差分析表明,厚壳贻贝栖息密度在不同断面(F=57.011,P<0.01)和不同水层(F=66.495,P<0.01)中的差异均极显著,断面和水层的交互作用(F=10.483,P<0.01)对厚壳贻贝的自然分布也有极显著差异;经检验,厚壳贻贝栖息密度(A)的自然分布与水深(D)呈正态分布,可以用高斯方程拟合,R2的取值范围为0.8753~0.9997;利用聚类分析发现,调查样方被明显的分为3组,体现了水深在厚壳贻贝自然分布中的显著作用。