Sediment dynamics and temporal variation of runoff in the Yom River,Thailand

The Yom River is one of the four major sediment sources to the Chao Phraya River in Thailand.Human activities and changes in climate over the past six decades may have affected the discharge and sediment load to some extent.In the current study,the river discharge and sediment characteristics in the mainstream of the Yom River were investigated using the field observation data from 2011 to 2013 and the historical river flow and sediment data from 1954 to 2014 at six hydrological stations operated by the Royal Irrigation Department of Thailand(RID).The non-parametric Mann-Kendall test and double mass curve were used to analyze the sediment dynamics and temporal changes in the discharge of the Yom River.The results revealed that the sediment was mainly transported in suspension,and the bed-tosuspended sediment loads ratio varied between 0 and 0.05.The daily suspended sediment load(SSL)in the upper and middle basins had a strong correlation with the daily discharge and could be represented by power equations with coefficients of determination higher than 0.8.The daily suspended sediment load in the lower basin did not directly depend on the corresponding discharge because of the reduction in river slope and water diversion by irrigation projects.It also appeared that the river discharges and sediment loads were mainly influenced by climate variation(floods and droughts).Moreover,the average sediment transport of the upper,middle,and lower reaches were 0.57,0.71,and 0.35 million t/y,respectively.The sediment load in the lower basin decreased more than 50%as a result of changes in the river gradient(from mountainous to floodplain areas).The results from sediment analysis also indicated that the construction of the Mae Yom Barrage,the longest diversion dam in Thailand,and land-use changes did not significantly affect the sediment load along the Yom River.     

我国东部季风区不同自然带年径流特征及人类活动影响的比较研究*

本文在分析我国东部季风区不同自然带年径流与气侯因子关系的基础上,揭示了径流深随纬度和经度变化的规律,并对不同自然带中人类活动对河川径流的干预强度进行了比较,指出半干旱区是人类活动对径流影响最严重的地区,在这里应加强水资源的保护并大力推行各种节水措施。     

Palaeoenvironmental Reconstructions Based on Geochemical Parameters from Annually Laminated Sediments of Sacrower See (northeastern Germany) Since the 17th Century

The history of hardwater lake Sacrower See (Brandenburg, northeastern Germany) was reconstructed back to the 17th century based on a multi-proxy study of five short sediment cores dated by varve chronology, ²¹⁰Pb and ¹³⁷Cs isotopes. We were able to distinguish three main phases: The lake was mesotrophic prior to the 1830s with an oxic hypolimnion. From the early 19th century on, δ¹³C of organic matter indicates that primary productivity starts to increase slowly. Between the 1830s and 1872, the lake went through a transition towards eutrophy. Low calcite contents in the homogeneous sediment are caused by dissolution connected to increasing primary productivity and growing importance of decomposition processes. After 1873, and accelerated since 1963, Sacrower See is characterised by growing nutrient input, and thus further increasing primary productivity. The lake is eutrophic, and decomposition of organic matter causes high oxygen consumption in the hypolimnion, which becomes regularly anoxic during thermal summer stratification. Biogenic varves are preserved in the sediment, characterised by layers of autochthonous, biochemically precipitated calcite crystals. In this study, we were able to demonstrate that Sacrower See is an example of exceptional slow increase of anthropogenically enhanced nutrient input, and of the imprint which these processes have on sediments of a hardwater lake.     

丹霞地貌与岩溶地貌旅游景观之比较研究

对丹霞地貌与岩溶地貌的旅游景观进行系统比较,揭示两者在发育条件及分布特点、自然及人文旅游景观方面的相似性与差异性.在发育条件上,两者的岩性、构造环境和主要外营力均存在显著差异;另一方面,两者的发育又都依赖于一定的水热条件和密集的节理裂隙.在空间分布上,两者发育最典型的地区均在我国南方亚热带、热带湿润区;其中,东南地区尤以丹霞景观见长,西南地区更以岩溶景观取胜.自然景观方面,丹霞景观与岩溶景观在类型、外形、组合上有较多相似之处;两相比较,岩溶风景胜在山奇洞奥,而丹霞风景则胜在赤壁丹崖.人文景观方面,丹霞地貌     

Encyclopaedic vision: Speculating on The Dictionary of Human Geography

Since the turn of the millennium, human geography has witnessed the publishing of an increasing number encyclopaedias and dictionaries as well as books under the headings of “handbooks”, “readers” and “companions” to different fields within the discipline. In the present paper, I take as a point of departure this encyclopaedic “frenzy” in order to speculate on the works and values of a long-standing and authoritative geographical companion, The Dictionary of Human Geography (DHG) [Johnston, R.J., Gregory, D., Haggett, P., Smith, D.M., Stoddart, D.R. (Eds.), 1981. The Dictionary of Human Geography. Blackwell, Oxford; Johnston, R.J., Gregory, D., Smith, D.M. (Eds.), 1986a. The Dictionary of Human Geography, second ed. Blackwell, Oxford; Johnston, R.J., Gregory, D., Smith, D.M. (Eds.), 1994. The Dictionary of Human Geography, third ed. Blackwell, Oxford; Johnston, R.J., Gregory, D., Pratt, G., Watts, M. (Eds.), 2000a. The Dictionary of Human Geography, fourth ed. Blackwell, Oxford]. Apart from being subject to regular book reviews, the DHG has escaped attention from geographers critically engaged in debating the works of the discipline. It is argued here that this is due to the fact that the DHG appears to have established itself as an apparently objective recording of human geographers’ myriad of interests. The DHG is, however, a product of complex webs of subjective, situated concerns and thus a version of the discipline deserving of debate.     

新农村建设与乡村发展研究——唐山、秦皇岛乡村个案分析

新农村建设与乡村发展是目前学术界讨论的热点领域。以唐山、秦皇岛10个村庄为案例,从农业经济、社会结构、社会服务与人居环境、基层组织与个人精英、城乡联系五个方面分析了案例地区乡村发展的主要特征与存在问题。最后,结合当前中国新农村建设,从国家政策与乡村内生发展、基于城乡合作的多样化乡村经济、"空心村"改造与人居环境整治、村庄规划编制与实施四个方面对未来中国的乡村发展进行了探讨。     

中国历史地理研究的新进展

以往五年间中国历史地理研究几乎在各个分支都取得了坚实的进步。《中国历史地图集》等图集的完成显示了历史地图编绘的成就。政区地理研究和地名考释论著丰富,但对其意义的认识尚显不足。人文地理研究处于起步阶段,必将成为最有希望、最繁荣的分支。自然地理研究较集中在气候、地貌、水文方面,深入挖掘文献资料与新手段的运用是必然的发展趋势。     

海洋工程人因可靠性研究进展

海洋结构物在其生命周期的设计、建筑和工作等阶段中发生的灾害性事故（船舶和海洋平台的碰撞、搁浅、腐蚀病劳破坏、沉船、火灾、爆炸等）大多与人为错误和组织错误（ＨＯＥ有关,据统计,大约６０％～９０％的事故意 由ＨＯＥ引起,因此海洋工程中进行人因可靠性分析研究很有必要,在全面回顾近年来各国在这一领域的研究现状,分析和总结人因可靠性评估（ＨＲＡ）研究方法的基础上,重点介绍了失效模式及影响分析（ＦＭＥＡ）,事     

Quantification of biogeomorphic interactions between small-scale sediment transport and primary vegetation succession on proglacial slopes of the Gepatschferner,Austria

Proglacial slopes provide suitable conditions for observing the co-development of abiotic and biotic systems. The frequency and magnitude of geomorphic processes and plant composition govern this interplay, which is described in the model of biogeomorphic succession. In high mountain environments, this model has only been tested in a limited number of studies. The study aimed to quantify small-scale sediment transport via erosion plots along a plant cover gradient and to investigate the influence of sediment transport on plant communities. We aimed to generate quantitative data to test existing biogeomorphic models. Small-scale biogeomorphic interactions were investigated on 30 test plots of 2 × 3 m size on proglacial slopes of the Gepatschferner (Kaunertal) in the Austrian Alps during the snow-free summer months over three consecutive years. The experimental plots were established on slopes along a plant cover gradient. A detailed vegetation survey was carried out to capture biotic conditions, and specific sediment yield was measured at each plot. Species abundance and composition at each site reflected successional stages. Additional environmental parameters, such as terrain age, geomorphometry, grain size distribution, soil nutrients, and precipitation, were also included in the analyses. We observed two pronounced declines in geomorphic activity on plots with both above 30% and above 75% plant cover. Nonmetric multidimensional scaling showed distinct clusters of vegetation composition that mainly followed a successional gradient. Sites that were affected by high-magnitude geomorphic events showed different environmental conditions and species communities. Quantified process rates and observed species composition support the concept of biogeomorphic succession. The findings help to narrow down a biogeomorphic feedback window.