SUSPENDED SEDIMENT TRANSPORT IN THE OFFSHORE NEAR YANGTZE ESTUARY

Based on the Estuarine, Coastal and Ocean Modeling System with Sediments (ECOMSED) model, a 3-D hydrodynamic-transport numerical model was established for the offshore area near the Yangtze Estuary in the East China Sea. The hydrodynamic module was driven by tide and wind. Sediment module included sediment resuspension, transport and deposition of cohesive and non-cohesive sediment. The settling of cohesive sediment in the water column was modeled as a function of aggregation (flocculation) and deposition. The numerical results were compared with observation data for August, 2006. It shows that the sediment concentration reduces gradually from the seashore to the offshore area. Numerical results of concentration time series in the observation stations show two peaks and two valleys, according with the observation data. It is mainly affected by tidal current. The suspended sediment concentration is related to the tidal current during a tidal cycle, and the maximum concentration appears 1 h-4 h after the current maximum velocity has reached.

东海陆架细颗粒沉积物组成分布特征及其物源指示

沉积物由源到汇的搬运过程是整个地球物质循环的一个重要环节；在这一过 程中，载有当时主要地质历史事件信息的沉积物汇入海洋；但因受到复杂的海洋 环境的改造以及人类活动的影响，这些信息的表现形式可能已经发生了改变。因 此，如何反演上述地质历史进程、预测其发展变化，成为海洋地质学研究的重要 内容。 本文通过对长江、黄河、钱塘江、瓯江和闽江等5 条中国东部入海河流沉积 物稀土元素（REE），以及东海陆架表层细颗粒沉积物中粘土矿物、元素组成等 的综合研究，借助数学统计，分析探讨了陆架区细颗粒沉积的物质来源、现代长 江入海沉积物在东海陆架区的影响范围，以及由源到汇输运过程中沉积物示踪标 记数值改变等问题。 长江口沉积物REE 在<2μm 和2-31μm 粒级中较富集，但全岩REE 总量 （ΣREE）在数值上受物质组成占优的2-31μm 粒级控制；因粉砂对水动力环境的 反映最为敏感，在输运过程中该粒级组成不稳定即可引起全岩REE 含量的变化。 全岩REE 含量在河口附近较高，在东海陆架区由岸向海有减小的趋势，轻重稀 土比值自28°N 向南有增大的趋势。在长江口和东海内陆架，水动力对沉积物的 作用可能对REE 含量空间分布模式的形成起着重要作用。 长江、黄河等五条河流沉积物的ΣREE、轻重稀土含量比值（L/HREE）等 参数在数值分布上有所不同。但陆架复杂的水动力环境可造成砂粒级沉积物中轻 重矿物分异、粉砂与粘土粒级间级配调整，并由此引起沉积物中REE 含量的数 值变化。此时，单由砂、粉砂等较大粒级区间内REE 含量的分布已经不能准确 判断沉积物物源的改变。在长期稳定的陆架沉积环境下，借助沉积物输运模型， 有可能解决因水动力因素造成的REE 分布变化的问题。 东海陆架区未能发现在数值上绝对不变的示踪标记物，而引起示踪指标变化 的决定性因素尚未明确。因此，本文采用前人研究中可以明显区分沉积物河流来 源的指标，借助统计学中聚类和判别分析方法定性地判断东海陆架区沉积物常、 微量元素和粘土矿物的可能物源。 根据四种主要粘土矿物相对含量与细颗粒沉积物微量元素的构成特征，推断 研究区表层类长江细颗粒物质主要为现代长江入海沉积物；它们主要分布在东海陆架中、西部区域，在中部可以跨越123°E 向东继续延伸，在北部可以达到外陆 架的东部边缘。研究区东侧、东海外陆架边缘表层细颗粒沉积物的微量元素构成 与现代长江沉积物存在较大差异，具有类黄河沉积物的性质，可能是在更新世冰 期干冷气候下形成的产物与现代河流入海细颗粒的混合物。

The combined effects of temperature and food supply on Calanus sinicus in the southern Yellow Sea in summer

The effects of temperature and food availability on the life history strategy of the planktonic copepod Calanus sinicus in the southern Yellow Sea in summer were studied in this paper. The fifth copepodite stage (CV) dominates the population in the central part of the southern Yellow Sea, where the Yellow Sea Cold Water Mass (YSCWM) occurs below the thermocline. Incubation experiments were conducted on CV C. sinicus caught from the YSCWM to examine the effects of temperature and food availability. Temperature at the surface (27degreesC) is lethal to CVs regardless of food availability. At the temperature in the middle of the thermocline (18degreesC), survival time of the specimens depends on food availability, being similar to20 days in treatments without extra food supply. At the temperature in the YSCWM (9degreesC), most animals survive at the end of 27 day incubation even in treatments without food supply. Developmental rate of CVs at 9degreesC without extra food supply is extremely low. The increase of either temperature or food supply promotes the developmental rate of CVs. According to these results, the surface layers with high temperature and low food abundance are detrimental for the survival and reproduction of C. sinicus. Low temperature and low food availability in the YSCWM help CV to maintain a much lower developmental rate and higher survival rate. The ecological trait of C. sinicus in the southern Yellow Sea in summer cannot be sufficiently explained solely by the effects of temperature.

Life history strategies of Calanus sinicus in the southern Yellow Sea in summer

Ecological and physiological features of the planktonic copepod Calanus sinicus in the southern Yellow Sea in summer were studied to reveal its life history strategy. From the coastal shallow waters to the central part of the southern Yellow Sea, a shift of the stage composition occurs from being dominated by the egg-nauplius stage to being dominated by the fifth copepodite (CV) stage. Most CVs reside in the Yellow Sea Cold Water Mass (YSCWM), where both temperature and food abundance are low. CVs in the YSCWM have longer body lengths, heavier body weights and higher carbon contents than those outside the YSCWM. Onboard incubations show that the development of CVs in the YSCWM is suspended. Energy conservation, development suspension and lack of diel vertical migration (DVM) behavior suggest a diapause status for the CVs in the YSCWM, although vertical distribution patterns indicate the CV individuals are not fully synchronous in physiology and development. This adaptive oversummering strategy would help C. sinicus to live through the warm and food-limited summer in the central part of the southern Yellow Sea; both low temperature and low food supply are necessary for CV to maintain the resting state in the YSCWM. Calanus sinicus exhibits different life history strategies in different regions of the southern Yellow Sea in summer.

Characteristics of nitrogen forms in the southern Huanghai Sea surface sediments

The distributions of different forms of nitrogen in the surface sediments of the southern Huanghai Sea are different and affected by various factors. The contents of IEF-N, SOEF-N and TN gradually decrease eastward, and those of SAEF-N northward, while those of WAEF-N westward. Around the seaport of the old Huanghe (Yellow) River, the contents of both SOEF-N and TN are the highest. Among all the factors, the content of fine sediment is the predominant factor to affect the distributions of different forms of nitrogen. The contents of IEF-N, SOEF-N, and TN have visibly positive correlation with the content of fine sediments, and the correlative coefficient is 0.68, 0.58 and 0.71 respectively, showing that the contents of the three forms of nitrogen increase with those of fine sediments. The content of WAEF-N is related to that of fine sediments to a certain extent, with a correlative coefficient of 0.35; while the content of SAEF-N is not related to that of fine sediments, showing that the content of SAEF-N is not controlled by fine grain-size fractions of sediments. In addition, the distributions of different forms of nitrogen are also interacted one another, and the contents of IEF-N and SOEF-N are obviously affected by TN, while those of inorganic nitrogen (WAEF-N, SAEF-N and IEF-N) are not affected by SOEF-N and TN obviously, although they are interacted each other.

东海陆架盆地西南部烟囱构造与油气运聚关系研究

In recent years, chimney structure has been proved one of important indicators and a useful guide to major petroleum fields exploration through their exploration history both at home and abroad. Chimney structure, which has been called "gas chimney" or "seismic chimney", is the special fluid-filled fracture swarm, which results from the boiling of active thermal fluid caused by abruptly decreasing of high pressure and high temperature in sedimentary layers of upper lithosphere. Chimney structure is well developed in continental shelf basin of East China Sea, which indicates the great perspectives of petroleum resources there. However, the chimney structure also complicated the petroleum accumulation. So the study of chimney structure on its formation, its effect on occurrence and distribution of petroleum fields is very important not only on theoretical, but also on its applied research. It is for the first time to make a clear definition of chimney structure in this paper, and the existence and practical meaning of chimney structure are illustrated. Firstly, on the viewpoint of exploration, this will amplify exploration area or field, not only in marine, but also on continent. Secondly, this is very important to step-by-step exploration and development of petroleum fields with overpressure. Thirdly, this will provide reference for the study on complex petroleum system with multi-sources, commingled sources and accumulation, multi-stage accumulations, and multi-suits petroleum system in the overlay basin. Fourthly, when the thermal fluid enters the oceanic shallow layer, it can help form gas hydrate under favorable low-temperature and high-pressure conditions. Meanwhile, the thermal fluid with its particular component and thermal content will affect the physical, chemical and ecological environments, which will help solving the problem of global resources and environment. Beginning from the regional tectonic evolution characteristics, this paper discussed the tectonic evolution history of the Taibei depression, then made an dynamical analysis of the tectonic-sedimentary evolution during the Mesozoic and Cenozoic for the East China Sea basin. A numerical model of the tectonic-thermal evolution of the basin via the Basin-Mod technique was carried out and the subsidence-buried history and thermal history of the Taibei depression were inverse calculated: it had undergone a early rapid rift and sag, then three times of uplift and erosion, and finally depressed and been buried. The Taibei depression contains a huge thick clastic sedimentary rock of marine facies, transitional facies and continental facies on the complex basement of ante-Jurassic. It is a part of the back-arc rifting basins occurred during the Mesozoic and Cenozoic. The author analyzed the diagenesis and thermal fluid evolution of this area via the observation of cathodoluminescence, scanning electron microscope and thin section, taking advantage of the evidences of magma activities, paleo-geothermics and structural movement, the author concluded that there were at least three tectonic-thermal events and three epochs of thermal-fluid activities; and the three epochs of thermal-fluid activities were directly relative to the first two tectonic-thermal events and were controlled by the generation and expulsion of hydrocarbon in the source rock simultaneously. Based on these, this paper established the corresponding model between the tectonic-thermal events and the thermal-fluid evolution of the Taibei Depression, which becomes the base for the study on the chimney structures. According to the analyses of the gas-isotope, LAM spectrum component of fluid inclusion, geneses of CO_2 components and geneses of hydrocarbon gases, the author preliminarily verified four sources of the thermal fluid in the Taibei Depression: ① dehydration of mud shale compaction, ② expulsion of hydrocarbon in the source rock; ③ CO_2 gas hydro-thermal decomposition of carbonatite; ④magma-derived thermal fluid including the mantle magma water and volatile components (such as H_2O, CO_2, H_2S, SO_2, N_2 and He etc.). On the basis of the vitrinite reflectance (Ro), homogenization temperature of fluid inclusion, interval transit time of major well-logging, mud density of the wells, measured pressure data and the results of previous studies, this paper analyzed the characteristics of the geothermal fields and geo-pressure fields for the various parts in this area, and discussed the transversal distribution of fluid pressure. The Taibei depression on the whole underwent a temperature-loss process from hot basin to cold basin; and locally high thermal anomalies occurred on the regional background of moderate thermal structure. The seal was primarily formed during the middle and late Paleocene. The overpressured system was formed during the middle and late Eocene. The formation of overpressured system in Lishui Sag underwent such an evolutionary process as "form-weaken-strengthen-weaken". Namely, it was formed during the middle and late Eocene, then was weakened in the Oligocene, even partly broken, then strengthened after the Miocene, and finally weakened. The existence of the thermal fluid rich in volatile gas is a physical foundation for the boiling of the fluid, and sharply pressure depletion was the major cause for the boiling of the fluid, which suggests that there exists the condition for thermal fluid to boil. According to the results of the photoelastic simulation and similarity physical experiments, the geological condition and the formation mechanism of chimnestructures are summarized: well compartment is the prerequisite for chimney formation; the boiling of active thermal fluid is the original physical condition for chimney formation; The local place with low stress by tension fault is easy for chimney formation; The way that thermal fluid migrates is one of the important factors which control the types of chimney structures. Based on where the thermal fluid come from and geometrical characteristics of the chimney structures, this paper classified the genetic types of chimney structures, and concluded that there existed three types and six subtypes chimney structures: organic chimney structures generated by the hydrocarbon-bearing thermal fluid in middle-shallow layers, inorganic and commingling-genetic chimney structures generated by thermal fluid in middle-deep layers. According to the seismic profiles interpretations, well logging response analysis and mineralogical and petrological characteristics in the study area, the author summarized the comprehensive identification marks for chimney structures. Especially the horizon velocity analysis method that is established in this paper and takes advantage of interval velocity anomaly is a semi-quantitative and reliable method of chimney structure s identification. It was pointed out in this paper that the occurrence of the chimney structures in the Taibei depression made the mechanism of accumulation complicated. The author provided proof of episodic accumulation of hydrocarbon in this area: The organic component in the boiling inclusion is the trail of petroleum migration, showing the causality between the boiling of thermal fluid and the chimney structures, meanwhile showing the paroxysmal accumulation is an important petroleum accumulation model. Based on the evolutionary characteristics of various types of chimney structures, this paper discussed their relationships with the migration-accumulation of petroleum respectively. At the same time, the author summarized the accumulating-dynamical models associated with chimney structures. The author analyzed such accumulation mechanisms as the facies state, direction, power of petroleum migration, the conditions of trap, the accumulation, leakage and reservation of petroleum, and the distribution rule of petroleum. The author also provides explanation for such practical problems the existence of a lot of mantle-derived CO_2, and its heterogeneous distribution on plane. By study on and recognition for chimney structure, the existence and distribution of much mantle-derived CO_2 found in this area are explained. Caused by tectonic thermal activities, the deep magma with much CO_2-bearing thermal fluid migrate upward along deep fault and chimney structures, which makes two wells within relatively short distance different gas composition, such as in well LF-1 and well LS36-1-1. Meanwhile, the author predicted the distribution of petroleum accumulation belt in middle-shallow layer for this area, pointed out the three favorable exploration areas in future, and provided the scientific and deciding references for future study on the commingling-genetic accumulation of petroleum in middle-deep layer and the new energy-gas hydrate.

中国东海陆架盆地构造-热演化研究

East China Sea Shelf Basin (ECSSB), as a basin with prospect of oil & gas resource and due to its special geological location on the west margin of the west Pacific, attracts a lot of attention from many geologists in the world.Based on systematic temperature measurements, bottom hole temperature (BHT) and the oil temperature data, the geothermal gradients in the ECS SB are calculated and vary from 25 to 43°C/km, with a mean of 32.7°C/km. The geothermal gradient in Fuzhou Sag has the higher value(40.6°C/km) in Taibei Depression than that in others. The lower value (27.2 °C/km) occurs in in Xihu Depression. The middle values occurs in Jiaojiang and Lishui sags in Taibei Depression with a mean value of 34.8 °C/km. Incorporated with the measured thermal conductivity, heat flow values show that the ECSSB is characterized by present-day heat flow around 70.6mW/m2, varying between 55 and 88 mW/m2. No significant difference in heat flow is observed between the Xihu and the Taibei Depressions. These heat flow data suggest that the ECSSB is geothermally not a modem back-arc basin.Applying the paleogeothermal gradient based method, thermal history is reconstructed using vitrinite reflectance (VR) and apatite fission track (AFT) data. The results suggest that the thermal history was different in the Taibei and the Xihu depressions. Paleo-heat flow values when the pre-Tertiary formations experienced their maximum temperature at the end of the Paleocene reached a mean of 81 mW/m2 in the Taibei Depression, much higher than the present-day value. The lower Tertiary sediments in the Xihu Depression experienced maximum temperatures at the end of Oligocene and reached a mean paleo-heat flow value of 83.4 mW/m2. The time, when the paleo-heat flow reached the maximum value, suggests that the ECSSB rifted eastward.Tectonic subsidence analysis shows that the timing of the major rifting episode was different across the ECSSB. The rifting occurred from the Late Cretaceous to the early Eocene in the Taibei Depression, followed by thermal subsidence from the late Eocene to the end of Miocene. In contrast, in the Xihu Depression the initial subsidence lasted until the early Miocene and thermal subsidence to the end of Miocene. From Pliocene to the present, an accelerated subsidence took place all along the West Pacific margin of the east Asia.The thermal lithosphere thickness is determined by temperature profile in the lithosphere, the mantle adiabat or the dry basalt solidus. It indicates that the thermal lithosphere reached the thinnest thickness at the end of Eocene in the Taibei Depression and the end of Oligocene in the Xihu Depression, respectively, corresponding with a value of 57-66km and 56-64km. In Taibei Depression, the lithosphere thickness decreased 16-22km from the end of Mesozoic to Paleocene. After Paleocene, the thickness increased 13-16km and reached 71-79 km at present-day. In Xihu Depression, From the end of Oligocene to present-day, the thickness increased 10-13km and reached 69-76km at present-day. The evolution of the lithosphere thickness is associated closely with the lithosphere stretching.Combining the reconstructed thermal history and the burial history, the maturation of the Jurassic oil-source rock shows that the main hydrocarbon generation phase was in the mid-Jurassic and a secondary hydrocarbon generation occurred at the end of Paleocene. The secondary generation was controlled mainly by the tectono-thermal background during the Paleocene.

Exceptional abundance of the snake pipefish (Entelurus aequoreus) in the north-eastern Atlantic Ocean

Pipefish (Syngnathidae) have occurred with unprecedented frequency in Continuous Plankton Recorder (CPR) samples to the west of the British Isles from 2003 to 2005. Identification by mtDNA sequencing established that they were snake pipefish, Entelurus aequoreus. The geographical range of the records were from the outer continental shelf of the Celtic Sea and north-west of Ireland to the mid-Atlantic Ridge between 40° and 57°N, with the greatest abundance near the shelf edge and adjacent oceanic waters south of Ireland and west of Brittany. There were records in every month from February to November but most were in late spring and summer. A proposed mechanism for the increase in abundance of the species is that recent climate change has had beneficial impacts on the reproduction of adults and the survival of larvae and juveniles.

Coccolithophore surface distributions in the North Atlantic and their modulation of the air-sea flux of CO2 from 10 years of satellite Earth observation data

Coccolithophores are the primary oceanic phytoplankton responsible for the production of calcium carbonate (CaCO3). These climatically important plankton play a key role in the oceanic carbon cycle as a major contributor of carbon to the open ocean carbonate pump (similar to 50 %) and their calcification can affect the atmosphere-to-ocean (air-sea) uptake of carbon dioxide (CO2) through increasing the seawater partial pressure of CO2 (pCO(2)). Here we document variations in the areal extent of surface blooms of the globally important coccolithophore, Emiliania huxleyi, in the North Atlantic over a 10-year period (1998-2007), using Earth observation data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). We calculate the annual mean sea surface areal coverage of E. huxleyi in the North Atlantic to be 474 000 +/- 104 000 km(2), which results in a net CaCO3 carbon (CaCO3-C) production of 0.14-1.71 Tg CaCO3-C per year. However, this surface coverage (and, thus, net production) can fluctuate inter-annually by -54/+81% about the mean value and is strongly correlated with the El Nino/Southern Oscillation (ENSO) climate oscillation index (r = 0.75, p < 0.02). Our analysis evaluates the spatial extent over which the E. huxleyi blooms in the North Atlantic can increase the pCO(2) and, thus, decrease the localised air-sea flux of atmospheric CO2. In regions where the blooms are prevalent, the average reduction in the monthly air-sea CO2 flux can reach 55%. The maximum reduction of the monthly air-sea CO2 flux in the time series is 155 %. This work suggests that the high variability, frequency and distribution of these calcifying plankton and their impact on pCO(2) should be considered if we are to fully understand the variability of the North Atlantic air-to-sea flux of CO2. We estimate that these blooms can reduce the annual N. Atlantic net sink atmospheric CO2 by between 3-28 %.

Factors governing the deep ventilation of the Red Sea

A variety of data based on hydrographic measurements, satellite observations, reanalysis databases, and meteorological observations are used to explore the interannual variability and factors governing the deep water formation in the northern Red Sea. Historical and recent hydrographic data consistently indicate that the ventilation of the near-bottom layer in the Red Sea is a robust feature of the thermohaline circulation. Dense water capable to reach the bottom layers of the Red Sea can be regularly produced mostly inside the Gulfs of Aqaba and Suez. Occasionally, during colder than usual winters, deep water formation may also take place over coastal areas in the northernmost end of the open Red Sea just outside the Gulfs of Aqaba and Suez. However, the origin as well as the amount of deep waters exhibit considerable interannual variability depending not only on atmospheric forcing but also on the water circulation over the northern Red Sea. Analysis of several recent winters shows that the strength of the cyclonic gyre prevailing in the northernmost part of the basin can effectively influence the sea surface temperature (SST) and intensify or moderate the winter surface cooling. Upwelling associated with periods of persistent gyre circulation lowers the SST over the northernmost part of the Red Sea and can produce colder than normal winter SST even without extreme heat loss by the sea surface. In addition, the occasional persistence of the cyclonic gyre feeds the surface layers of the northern Red Sea with nutrients, considerably increasing the phytoplankton biomass.

'In the Service of the Honourable East India Company': Politics and Identity in Dean Mahomet's Travels (1794)

The successful career of Dean Mahomet (1759-1851) as a migrant from India to Ireland (and later, England) has led to scholarly and popular interest in his work. His Travels through several parts of India in the Service of the Honourable East India Company (1794) published by subscription in Cork is reputedly the first English book by an Indian, and has been seen to counterbalance the many accounts of India by western travellers, and to assert, in autobiographical form, his identity as an Indian in 1790s Ireland. My paper analyses this text in relation to moral and economic criticisms of the East India Company in the eighteenth century, and in particular to legislation of 1793 which defined the role of the Company in Ireland’s trade with the east. These aspects of colonial politics involving Ireland and India as subject nations of Britain are shown to shape Mahomet’s discursive strategies and the complex identity produced in his text.

Nutrient Dynamics in the EEZ of the West Coast of India with Special Reference to the Oxygen Minimum Zone and Denitrification

The present work aims at deciphering the processes that control the nutrient distribution along the EEZ (Exclusive Economic Zone of India) of the west coast of India and to bring out its linkage with primary and secondary productivity. This work assume utmost importance as very few studies have hitherto focused entirely on the EEZ of the west coast of India to address the biochemical responses brought about by monsoons. The present study examines the seasonal variations in physicochemical parameters and associated primary biological responses along the west coast of India. This study targets to measure and understand the shelf ocean exchange in a typical coastal upwelling region of the southeast Arabian Sea, and the influence of convective mixing along the northern part of the west coast of India. The study focuses more directly on coastal upwelling along the southwest coast of India, within the EEZ. The effects of coastal upwelling, eddy formation and the offshore advection are apparent in the present investigation. This has consequences to fisheries and climate, in energy transfer to the food chain and the increased sequestering of carbon in the ocean. The study also focuses on the Oxygen Minimum Zone (OMZ) and dentrification observed along the EEZ of the west coast of India on a seasonal scale. In the study, an attempt is also made to demarcate the geographical boundaries of the denitrification zone in the EEZ of India and on the nature and magnitude of these variations, on a seasonal and inter annual scales

Use of digital camera to assess nitrogen status of winter wheat in the Northern China Plain

The most widely used methods to assess the nitrogen (N) status of winter wheat (Triticum aestivum L.) are the determination of plant total N by combustion, the testing of nitrate in the leaf tissue and the use of SPAD readings. However, due to their labor requirements or high costs these methods can hardly be applied to the huge wheat growing areas of the Northern China Plain. This study therefore examined an alternative method to measure the N status of wheat by using a digital camera to record the visible green light reflected from the plant canopy. The experiment was conducted near Beijing in a multi-factorial field trial with three levels of N. The intensity of green light reflected from the wheat canopy was compared to the total N concentration, to the nitrate concentration of the basal stem, and to the SPAD readings of leaves. The results show significant inverse relationships between greenness intensity, canopy total N, and SPAD readings at booting and flowering. At booting, sap nitrate <2000mgL^-1 was inversely related to greenness intensity and to sap nitrate concentration in the basal stem. At sap nitrate ~2000mgL^-1, the greenness intensity reached a plateau. At booting and flowering, significant inverse relationships between greenness intensity and shoot biomass were found. The results show the potential of the new method to assess the N status of winter wheat.

Las implicaciones de la expansión china en el sudeste asiático

El artículo presenta la génesis, proceso e implicaciones de la expansión estratégica de la República Popular China hacia el Sudeste asiático. En ese sentido, la hipótesis que se presenta es que Beijing aspira a un renacer pacífico en el Sur con objetivos en el campo económico, estratégico y político. En el plano de la economía lo que se pretende es la estabilidad en el vecindario, condición fundamental para el éxito de su modelo económico, financiero y comercial. En el ámbito estratégico se busca un acceso a fuentes de energía alternativas al carbón, y en lo político, China ha buscado reducir la influencia americana y disminuir el margen de maniobra de Taiwán. En una primera parte se presenta un análisis histórico para introducir al lector en las variables históricas más relevantes para la comprensión del tema en cuestión. En la segunda se estudia el litigio del Mar del Sur de China y la importancia que éste posee política y geoestratégicamente. Finalmente, se examina la influencia china en el Sudeste asiático en tres campos: el cultural, el económico del cual hace parte el financiero y comercial y por último en el geoestratégico.-----L’article illustre la genèse, le processus et les implications de l’expansion stratégique de la République Populaire Chine dans le Sud-est Asiatique. De ce fait, l’hypothèse qui nous présenterons demeure Sur l’idée que Pékin cherche une renaissance pacifique vers le Sud en vue des objectifs économiques, stratégiques et politiques. En ce qui concerne l’économie, la Chine veux la stabilité dans la région, car ceci est une condition essentielle pour la réussite du modèle économique, financer et commercial. Quant à la question stratégique, elle cherche l’accès aux sources alternatives d’énergie. Dans le domaine politique, Pékin aspire à réduire l’influence américaine et à isoler le Taiwan. Dans une première partie, nous introduirons les variables historiques les plus essentielles afin d’expliquer les racines de la problématique en question. Dans la deuxième, le contentieux pour la Mer du Sud de Chine sera analysé ainsi que son importance politique et geoestratégique. Finalement, nous étudierons le processus de l’influence chinoise dans le Sud-est Asiatique. Cela sera divisé en trois domaines, le culturel, l’économique dont le commercial et financière, et le geostratégique.-----This article illustrates the genesis, the process and the implications of the strategic expansion of the People’s Republic of China towards South East Asia. Therefore, the hypothesis that we present is that Beijing is pursuing a Pacific rise in the South aiming for economic, strategic and political goals. Regarding the subject of economy, China seeks stability in the region, due to the fact that it has become essential in the success of its economic, financial and commercial model. Regarding the strategic field China is looking for a way to access alternative energy sources. Politically speaking, Beijing has sought to reduce American influence in the region as well as the isolation of Taiwan. In the first part of the article the reader will find a historical introduction for a better understanding of the subject here treated. In the second part, the litigation of the South China Sea is analyzed due to its political and geostrategical importance. Finally, Chinese influence on South East Asia is examined in three fields: cultural, economic, including financial and commercial aspects as well as the geostrategic field.

The Namib Sand Sea digital database of aeolian dunes and key forcing variables

A new digital atlas of the geomorphology of the Namib Sand Sea in southern Africa has been developed. This atlas incorporates a number of databases including a digital elevation model (ASTER and SRTM) and other remote sensing databases that cover climate (ERA-40) and vegetation (PAL and GIMMS). A map of dune types in the Namib Sand Sea has been derived from Landsat and CNES/SPOT imagery. The atlas also includes a collation of geochronometric dates, largely derived from luminescence techniques, and a bibliographic survey of the research literature on the geomorphology of the Namib dune system. Together these databases provide valuable information that can be used as a starting point for tackling important questions about the development of the Namib and other sand seas in the past, present and future.