天山北麓灌溉绿洲的形成和发展

17世纪以前，天山北麓是以牧为主地区，由“兵屯”建立的古代绿洲仅在交通要道呈星、点分布，且屡兴屡废。18－20世纪中叶，由清朝到民国，大力发展屯田，使社会发展进入半农半牧时期，这里形成的旧绿洲，呈断续岛状小片。1949年以后，由大规模农垦建立的新绿洲群，把分散小片旧绿洲联结在一起，形成与天山相平行绿洲带。本区绿洲形成特点是由屯垦和内地移民发展起来，起步虽晚，但发展很快；而且古绿洲、旧绿洲和新绿洲之间有延续性，不象塔里大盆地的很多古代绿洲已沦为沙漠、戈壁或风蚀地。     

中国中心城市铁路客运的空间联系及其结构图谱

基于全国286个地级城市交互式的"城市—车次—城市"铁路客运联系数据,运用基于O-D网络的GIS空间分析方法,从普快、快速、特快、动车和高铁等细分车次类型的角度全面解构全国铁路客运联系的空间格局与结构特征。研究认为,全国中心城市铁路空间联系分布格局体呈现向东倾斜的"开"字型结构,即由京沪—沪深线(沿海轴)、京广—京哈线两纵轴与陇海—兰新线、沪昆线两横轴相互交汇形成全国铁路客运的骨架。全国铁路客运联系服从类似城市体系的位序—规模分布特征,属于自然状态下集中型的空间最优分布。中国铁路客运联系总体上依托大的交通轴线以近域核心城市间的联系为主,动车组及高铁联系则集中表现为东部三大经济区间的联系。     

浅析环境地球化学的研究现状

环境地球化学是研究环境中化学物质迁移转化规律及其与环境质量和人类健康关系的学科.在其短短30年的发展历程中,历经了环境地球化学与健康、环境地球化学与污染及环境地球化学与全球环境变化3个阶段的研究.由于它是一个新兴的学科和研究对象的复杂性,目前还存在着学科交叉深度与广度的不够、化学物质动态监测不及时、与GIS的结合还不够等一些问题.但是,凭借其良好的发展势头,环境地球化学为改善人类生存与发展的生态环境和促进入类社会的可持续发展承担着艰巨的任务并发挥了巨大的作用.     

影响江南春雨年际变化的前期海洋信号及可能机理

利用1980—2017年华南地区303个国家级地面气象站逐小时降水数据、ERA-Interim再分析资料,分析华南前汛期（4—6月）降水统计特征,定义站点上短时（1—6 h）、中等时长（7—12 h）和长时（>12 h）降水事件,对比降水量、频次和强度在南海季风爆发前后的变化,以及所定义的西部内陆、东部内陆、沿海地区的异同。结果表明：（1）南海季风爆发后,研究区域平均而言,三类降水事件的降水量增多、小时降水强度增强,短时、长时降水事件发生频次增多,而中等时长降水事件发生频次有所减少。（2）从空间分布来看,南海季风爆发后,小时降水强度在整个华南地区均增强,西部内陆时长大于6 h的降水事件尤为明显;降水事件的发生频次在西部内陆和沿海地区升高,而东部内陆时长大于6 h的降水事件发生频次降低,因此,季风爆发后西部内陆和沿海地区的总降水量均显著增大,而东部内陆的总降水量变化不大。（3）西部内陆降水事件主要在夜间开始发生,持续时间越长的事件越早开始,且由西向东逐渐推迟;东部内陆短时降水事件主要在14时（北京时,下同）左右开始,季风爆发后更为明显,而时长大于6 h的降水事件的开始时间和峰值时间无明显的分布规律;沿海地区短时降水事件在季风爆发前主要于05—08时开始,季风爆发后,在海岸线约50 km以内仍然如此,而较远离海岸线的短时降水事件主要于14时开始,沿海地区长时降水事件在季风爆发前、后都倾向于在夜间开始,并在日间出现峰值。

     

The influence of rainfall and land use patterns on soil erosion in multi-scale watersheds: A case study in the hilly and gully area on the Loess Plateau,China

Soil erosion has become a major global environmental problem and is particularly acute on the Loess Plateau (LP), China. It is therefore highly important to control this process in order to improve ecosystems, protect ecological security, and maintain the harmonious relationship between humans and nature. We compared the effects of rainfall and land use (LU) patterns on soil erosion in different LP watersheds in this study in order to augment and improve soil erosion models. As most research on this theme has so far been focused on individual study areas, limited analyses of rainfall and LU patterns on soil erosion within different- scale watersheds has so far been performed, a discrepancy which might influence the simulation accuracies of soil erosion models. We therefore developed rainfall and LU pattern indices in this study using the soil erosion evaluation index as a reference and applied them to predict the extent of this process in different-scale watersheds, an approach which is likely to play a crucial role in enabling the comprehensive management of this phenomenon as well as the optimized design of LU patterns. The areas considered in this study included the Qingjian, Fenchuan, Yanhe, and Dali river watersheds. Results showed that the rainfall erosivity factor (R) tended to increase in these areas from 2006 to 2012, while the vegetation cover and management factor (C) tended to decrease. Results showed that as watershed area increased, the effect of rainfall pattern on soil erosion gradually decreased while patterns in LU trended in the opposite direction, as the relative proportion of woodland decreased and the different forms of steep slope vegetation cover became more homogenous. As watershed area increased, loose soil and craggy terrain properties led to additional gravitational erosion and enhanced the effects of both soil and topography.     

北江大堤植草护坡效应研究

北江大堤在航运的浪涛侵蚀以及洪水和雨水的冲蚀下，部分河段边坡已变得支离破碎，对广州和珠江三角洲地区的防洪安全构成了严重威胁。香根草和百喜草都能耐较长时间的水淹，并都有较强的抗逆性。结合土石方工程，并辅以三维网覆盖，将香根草和百喜种在北江两岸的边坡上。结果，这一护坡措施不仅有较地防止了洪流冲蚀和雨水侵蚀，较好地起到了固土护坡作用，而且绿化美化了河岸边坡，成功解决了河湖水库的河岸带难以植被覆盖的难题。     

中部六省R&D经费投入与结构分析

以中部六省为研究对象,对R&D经费投入总量及强度、R&D经费的支出结构与来源结构进行深入分析,并找出与先进地区或国家相比存在的差距。研究结果表明:中部六省之间,R&D经费投入与结构均存在较大差异。总体而言,中部六省R&D经费投入不足,强度偏低;对原始创新重视程度不够,R&D经费支出在科研机构与高校所占的比例以及在基础研究与应用研究所占的比例偏低;政府对R&D活动支持的力度有待进一步提升。     

Runoff and Soil Erosion on Slope Cropland: A Review

Soil erosion has become a serious environmental problem worldwide, and slope land is the main source of soil erosion. As a primary cover of slope land, crops have an important influence on the occurrence and development of runoff and soil erosion on slope land. This paper reviews the current understanding of runoff and soil erosion on slope cropland. Crops mainly impact splash detachment, slope runoff, and sediment yield. In this review paper, the effects of crop growth and rainfall on the splash detachment rate and the spatial distribution of splash detachment are summarized. Crop growth has a significant impact on runoff and sediment yield. Rainfall intensity and slope gradient can influence the level of erosive energy that causes soil erosion. Furthermore, other factors such as antecedent soil water content, soil properties, soil surface physical crust, and soil surface roughness can affect soil anti-erodibility. The varying effects of different crops and with different influence mechanisms on runoff and soil erosion, as well as changes in their ability to influence erosion under different external conditions should all remain focal points of future research. The effect of crop vegetation on runoff and soil erosion on slope land is a very important factor in understanding large-scale soil erosion systems, and in-depth study of this topic is highly significant for both theory and practice.     

1985-2005年环渤海地区土地利用变化时空格局

Based on TM image data and other survey materials, this paper analyzed the spatiotemporal patterns of land use change in the Bohai Rim during 1985–2005. The findings of this study are summarized as follows: (1) Land use pattern changed dramatically during 1985–2005. Industrial and residential land in urban and rural areas increased by 643,946 hm², of which urban construction land had the largest and fastest increase of 294,953 hm² at an annual rate of 3.72%. (2) The outward migration of rural population did not prevent the expansion of residential land in rural areas by 184,869 hm². This increase reveals that construction of rural residences makes seriously wasteful and inefficient use of land. (3) Arable land, woodland and grassland decreased at a rate of −0.02%, −0.12% and −1.32% annually, while unused land shrank by 157,444 hm² at an annual rate of −1.69%. (4) The change of land use types showed marked fluctuations over the two stages (1985–1995 and 1995–2005). In particular, arable land, woodland and unused land experienced an inversed trend of change. (5) There was a significant interaction between arable land and woodland. Industrial construction land in urban and rural areas showed a net trend of increase during the earlier period, but only adjustment to its internal structure during the second period. The loss of arable land to the construction of factories, mines and residences took place mainly in the fringe areas of large and medium-sized cities, along the routes of major roads, as well as in the economically developed coastal areas in the east. Such changes are closely related to the spatial differentiation of the level of urbanization and industrialization in the region.     

文化生态学视角下的南海诸岛地名文化

地名具有丰富的文化内涵,正日益受到学术界的高度关注。南海诸岛及其附近海域是中国政治敏感地带,多国为主权归属问题摩擦不断,研究其地名文化历史演变问题可为维护中国领土主权提供有力证据。基于南海诸岛地名命名、变更和演变等资料,采用文本分析方法,分析《更路簿》和不同时期公布的南海诸岛命名资料,并利用 GIS 将地名的演变情况进行地理可视化表达,同时对南海诸岛及其附近海域的开发者--渔民和老船长等进行深入访谈。研究发现：南海诸岛的土地名主要依据岛礁的自然地理环境特征而命名,地名的更替、消亡与社会文化环境紧密相关;1935 年公布的地名以音译英文地名为主,1947 年更名以去外国化、美化、纪念地名为主,1983 年对 1947 年所公布的标准地名更改很少,在这 118 个地名中,增加了前几次未公布地名 39 个,这些地名几乎都沿用渔民命名的土地名。