Numerical study on interaction between eddies and the Kuroshio Current east of Taiwan,China

We investigated the interaction between mesoscale eddies and the Kuroshio Current east of Taiwan,China,using a fine-resolution regional general circulation model.Mesoscale eddies are injected into a region east of Taiwan,China,according to the quasi-geostrophic theory of stratified fluids.Modeled eddies propagated westward at the velocity of the first baroclinic mode Rossby wave.When eddies collide with the Kuroshio Current east of Taiwan,China,the spatial structure and volume transport of the Kuroshio Current shows a significant variation.The upper 600 m of the anticyclonic eddy cannot cross the Kuroshio Current to reach the region west of the Kuroshio Current;rather,these waters flow northward along the eastern side of the Kuroshio Current.The upper water carried by the anticyclonic eddies cannot reach the shelf of the East China Sea(ECS).In contrast,the waters in the upper layer of the cyclonic eddy reach the western side of the Kuroshio Current and then flow northward.The dynamic mechanism analysis shows that the interaction between the Kuroshio Current and the cyclonic(anticyclonic) eddy decrease(increase)the horizontal potential vorticity(PV) gradient,or PV barrier,whereby the cyclonic(anticyclonic) eddy can(cannot) cross the Kuroshio Current.This study implies that the continental shelf could potentially be influenced by cyclonic eddies in the open ocean,which can transport heat and material from the upper open ocean acro s s the Kuroshio Current to the shelf waters.     

The effect of sloping bottom topography on the source-driven deep tropical circulation

ImODUCTIONInasedrinalseriesofPapersduringthelatel95osandl96()s,StonimlandANns(l958;l96()a,b)PresentedatheoreticalpictUreofthesoaree-drivendeepcirculaionintheoceanbasedongeOst-cd~cs.ItconsistsofaPole-wAninteriorflowresultingforavortexshetchingassociatedwithaslowuniformuPwellingthInllghouttheocean,andawestemboUndeqctirrentbalancingthemassbudget.Kawse(1987)formulatedalinear,tWo-layerbaxlinicmodeltostud}thedeeptroPicalcirculationdrivenbydeepwaterproduction.DistinctlydifferentfromtheStomm…     

Spatiotemporal variations of the surface Kuroshio east of Taiwan Island derived from satellite altimetry data

Spatiotemporal variation of the surface Kuroshio east of Taiwan Island is investigated by quantitatively analyzing 23-year(1993–2015)sea surface Absolute Dynamic Topography data.The annual mean state of the Kuroshio is shown,with a flow width ~136 km and surface transport ~7.75×10~4 m~2/s.The corresponding standard deviations of these are 28 km and 2.14×10~4 m~2/s.Results of power spectrum analysis indicate that the primary periods of Kuroshio surface transport east of Taiwan Island are 1 and 2.8 years,respectively.Spatially,the Kuroshio surface transport southeast of Taiwan Island has greater variability than that to its northeast.That transport showed strong seasonality,with a maximum 8.8×104 m~2/s in summer and minimum 7.5×10~4 m~2/s in winter,which was mainly caused by local monsoon winds.A linear long-term upward trend of Kuroshio surface transport during 1993–2015 was found,during which the mean,southeast,and northeast of the Kuroshio east of Taiwan Island increased by 0.30×10~4,0.22×10~4 and 0.36×104 m~2/s,respectively.Correlation and composite analysis show that the Philippines-Taiwan Oscillation(PTO)is important in the interannual variability of the Kuroshio.PTO-induced relative intensity of anticyclonic and cyclonic eddies is the dominant influence on the interannual variability of the Kuroshio east of Taiwan Island.     

Geomorphic characteristics of hillslope and channelized debris flows: A case study in the Shitou area of central Taiwan

The data on the hillslope and channelized debris flows in the Shitou area of central Taiwan occurred during Typhoons Toraji and Nali in 2001 were applied in this paper. The geomorphic parameters, including the flow length, gully gradient, drainage area and form factor of the debris flows were determined by spatial analysis using a Geographic Information System （GIS） based on the data derived from field investigation, aerial photographs, and topographical maps. According to such determined geomorphic parameters, the threshold conditions and empirical equations, such as the relationship between the gully gradient and drainage area and that between gully length and drainage area and topographic parameter, are presented and used to distinguish the geomorphic characteristics between the channelized and hillslope debris flows.     

Distribution of dissolved inorganic arsenic and its seasonal variations in the coastal area of the east China sea

Water samples were collected in the coastal area of the Changjiang Estuary on four cruises from August 2002 to May 2003. The seasonal variations of dissolved inorganic arsenic （DIAs） distributions were analyzed. The results showed that the distributions of DIAs were mainly influenced by Water （KSSW）. The concentration of the total dissolved the terrestrial input and the intrusion of the Kuroshio Subsurface inorganic arsenic （TDIAs） decreased consecutively from winter to summer, while it increased in autumn. The distributions of TDIAs showed some relationships with salinity and suspended particulate matter （SPM）. The relationships between DIAs speciation （including arsenite [ As（ Ⅲ ） ] and arsenate [ As（ Ⅴ ） ]）, biological activity and the availabilities of the phosphate were investigated in the study area for the cruise August 2002. The ratio of As （Ⅲ）/TDIAs increased with the decrease of phosphate concentrations. In the bottom water, the As（ Ⅲ ）/TDIAs ratio decreased with the increasing of N/P. The concentration of TDIAs decreased 28.7% approximately after the occurrence of harmful algal blooms （HAB） because of the uptake of arsenate by algae. Further study is needed about the arsenic source/sink relationships in their vertical or horizontal profiles and the uptake mechanism during the occurrence of harmful algal blooms.     

塔东古城地区奥陶系碳酸盐岩中钠长石的发现及其地质意义

综合应用岩石薄片显微镜鉴定、电子探针分析、阴极发光显微分析及流体包裹体温度测试等,研究塔东古城地区奥陶系碳酸盐岩的岩石矿物学特征.结果表明:塔里木盆地古城地区中下奥陶统灰岩中发育钠长石自生矿物,钠长石的发育和分布具有独特性,集中发育于鹰山组灰岩地层,以偶见、分散状和沿缝合线富集3种产状分布,主要交代灰岩微晶方解石沉积组分及海底胶结物方解石等早期成岩组分;钠长石的流体温度较高,温度在340~440℃之间,与沉积时或沉积期后不久的浅海岩浆热液喷流作用有关;钠长石被晚期热液鞍状白云石交代,被缝合线及构造裂缝切割改造,为古城地区第一期热液地质作用.该地区钠长石的发现丰富塔里木盆地热液地质作用的矿物学标志,为研究热液地质作用期次和热液演化史提供依据.     

Spatial-temporal variations of dominant drought/flood modes and the associated atmospheric circulation and ocean events in rainy season over the east of China

By using Season-reliant Empirical Orthogonal Function (S-EOF) analysis, three dominant modes of the spatial-temporal evolution of the drought/flood patterns in the rainy season over the east of China are revealed for the period of 1960-2004. The first two leading modes occur during the turnabout phase of El Nino-Southern Oscillation (ENSO) decaying year, but the drought/flood patterns in the rainy season over the east of China are different due to the role of the Indian Ocean (IO). The first leading mode appears closely correlated with the ENSO events. In the decaying year of El Nino, the associated western North Pacific (WNP) anticyclone located over the Philippine Sea persists from the previous winter to the next early summer, transports warm and moist air toward the southern Yangtze River in China, and leads to wet conditions over this entire region. Therefore, the precipitation anomaly in summer exhibits a ’Southern Flood and Northern Drought’ pattern over East China. On the other hand, the basin-wide Indian Ocean sea surface temperature anomaly (SSTA) plays a crucial role in prolonging the impact of ENSO on the second mode during the ENSO decaying summer. The Indian Ocean basin mode (IOBM) warming persists through summer and unleashes its influence, which forces a Matsuno-Gill pattern in the upper troposphere. Over the subtropical western North Pacific, an anomalous anticyclone forms in the lower troposphere. The southerlies on the northwest flank of this anticyclone increase the moisture transport onto central China, leading to abundant rainfall over the middle and lower reaches of the Yangtze River and Huaihe River valleys. The anomalous anticyclone causes dry conditions over South China and the South China Sea (SCS). The precipitation anomaly in summer exhibits a ’Northern Flood and Southern Drought’ pattern over East China. Therefore, besides the ENSO event the IOBM is an important factor to influence the drought/flood patterns in the rainy season over the east of China. The third mode is positively correlated with the tropical SSTA in the Indian Ocean from the spring of preceding year(-1) to the winter of following year(+1), but not related to the ENSO events. The positive SSTA in the South China Sea and the Philippine Sea persists from spring to autumn, leading to weak north-south and land-sea thermal contrasts, which may weaken the intensity of the East Asia summer monsoon. The weakened rainfall over the northern Indian monsoon region may link to the third spatial mode through the ’Silk Road’ teleconnection or a part of circumglobal teleconnection (CGT). The physical mechanisms that reveal these linkages remain elusive and invite further investigation.     

深层、超深层致密砂岩储层成岩相测井定量评价: 以库车坳陷博孜-大北地区为例

博孜-大北地区巴什基奇克组为深层、超深层致密砂岩储层, 岩性致密, 亟需揭示储层品质主控因素, 建立相配套的有利储层测井评价方法。为单井定量评价其成岩相, 充分利用岩心、常规薄片、铸体薄片、扫描电镜等资料, 对博孜-大北地区巴什基奇克组致密储层的岩石学、物性、成岩作用类型和强度、成岩矿物等特征进行了研究, 并在视压实率、视胶结率、溶蚀孔隙含量和成岩综合系数等参数定量计算的基础上, 根据成岩作用强度及其组合特征对储层成岩相分类命名, 划分出中等压实弱溶蚀相、碳酸盐胶结相及压实致密相等不同的成岩相类型。通过薄片等资料与测井资料拟合分析, 建立了成岩综合系数C_g的测井计算模型, 以及定量识别储层成岩相的方法。对X1、Y1等井的测井资料进行了处理, 并通过识别结果与物性分析、铸体薄片等的匹配关系, 验证了方法模型的可靠性。成岩相测井定量表征方法的建立可为有利储层预测提供指导。      

A study on the baroclinic structure of the abyssal circulation

In this paper, the linear continuously stratified ntxiel of the abyssal circulation proposed by Pedlosky (1992) was emended to include the second order term - (γθm) in the vertical turbulent mixing pararneterization of - (ω‘θ‘）x = kvθxx- θxxx, in which kv is a vertical diffusion coefficient,and γ is the second order coefficient of turbulent mixing (or simply called γ-term and γ＜0 is only allcmed). The influence of the γ-tema on the baroclinic structure of the abyssal circulation driven by up-welling out of the abyss was investigated, It was found that the γ-term has a noticeable influence on thebaroclinic structure of the upwelling driven abyssal circulation. For uniform upwelling, it favors the baroelinic layering of the abyssal circulation in the eastern part of the basin, but prevents the layering in thewest. In addition, this parameter was found to decrease the vertically averaging meridional velocity of theabyssal circulation frcrn the west to the east on the southern boundary. For upwelling localized near theeastern boundary, the γ - term favors baroclinic layering of the abyssal circulation in the whole basin.Especially, on the southern boundary the γ - term could strengthen the vertically averaging meridional ve-loeity in the west, but gready weaken it in the east. The ntntel presented here might be considered as anextension of the Pedlosky baroclinic ntntel of the abyssal circulation.     

A THREE-LAYER OCEAN CIRCULATION MODEL APPLICATION TO NUMERICAL STUDIES ON THE NORTH PACIFIC OCEAN CIRCULATION

The formulation and justification of a three-layer baroclinic ocean model developed to simulate thegeneral circulation of the ocean are described in this paper.Test of the model in simulating the annualmean circulation patterns in the North Pacific under the prescribed atmospheric forcing,which consists ofthe climatological surface wind stress and sea surface heat flux,and comparison of the results withobservations showed that the model basically simulated the large scale features of the annual meancirculation patterns in the North Pacific Ocean such as those of the intensified western boundary currentsand the North Equatorial Currents and Undercurrents.But due to the coarse resolution of the model,some details of these currents were poorly reproduced.The seasonal variations of the North Pacific Oceancirculation driven by the seasonal mean sea surface wind stress was calculated,the different aspects of theseresults were analyzed and the main current(the intensified western boundary currents)transports we     

A fisheries study on the sectional circulation in the East China Sea

Surveys since 1959 showed that the dynamic basis of the East China Sea sectional circulation is the nearshore seawater horizontal divergence caused by wind on the surface compensated by Kuroshio subsurface water convergence caused by meridional current in the lower layer. Fish always tend to migrate along certain routes or stay in certain areas favorable for development of eggs, survival of larvae and living of adults. The movement of water masses supplies a very important driving force for marine animals migrating long distance. The lower part of the sectional circulation formed by the subsurface water of Kuroshio is not suitable for the aggregation of fish because of its lack of oxygen, and has therefore a driving influence on demersal fishes. This study of the sectional circulation influence on the distributions of some commercially important species in the East China Sea reveals a close relationship between the circulation and the movement of fish schools. The principal factors influencing zonal vertical circulation are the meridional vector of the Kuroshio lower layer and atmospheric circulation, referning here mainly to the subtropical high pressure in the Asia-Pacific area that causes surface divergence and lifts subsurface water from the bottom to the surface at the nearshore area. Some simple methods for estimating the intensity of the sectional circulation are, introduced for fishery forecasts and operations.     

THREE-DIMENSIONAL BAROCLINIC NUMERICAL SIMULATION OF THE SOUTH CHINA SEA CIRCULATION＇S SEASONAL CHARACTERISTICS II. MIDDLE AND DEEP CIRCULATION

A three-dimensional baroclinic shelf sea model‘ s numerical simulation of the South China Sea (SCS) middle and deep layer circulation structure showed that: 1. In the SCS middle and deep layer, a seulhward boundary current exists along the east shore of the Indo-China Peninsula all year long.A cyclonic eddy (gyre) is formed by the current in the above sea areas except in the middle layer in spring, when an anticyclonic eddy exists on the eastern side of the current. In the deep layer, a larges-cale anticyclonic eddy often exists in the sea areas between the Zhongsha Islands and west shore of southern Luzon Island. 2. In the middle layer in snmmer and autumn, and in the deep layer in autumn and winter, there is an anticyclonic eddy (gyre) in the northeastern SCS, while in the middle layer in winter and spring, and in the deep layer in spring and snmmer, there is a cyclonic one. 3. In the middle layer,there is a weak northeastward current in the Nansha Trough in spring and snmmer, while in autumn and winter it evolves inl~ an anticyclonic eddy ( gyre), which then spreads westward l~ the whole western Nansha Islands sea areas.     

三峡重庆库区深部地球物理特征与断裂构造

为了深入研究三峡重庆库区岩石圈动力学特征及其对断裂构造活动的控制和影响．并为之提供基础资料，为三峡重庆库区地震、地质灾害的监测与防治提供基础依据，在已有地球物理资料的基础上，从综合地球物理研究角度出发，通过实测地震测线资料的再解释．采用新的处理技术方法，对本区的东西向主剖面和南北向支测线的地震测深资料进行二维射线追踪处理、Pg波成像；选用场分离技术、位移数字成像技术重新处理了重力和航磁资料，通过联合反演来建立深部二维构造剖面，对剖面所揭示的基底构造特征和地壳结构特征、主要断裂构造特征以及莫霍面的起伏特征进行了精细分析和细致研究．从地球物理平面场特征出发建立了岩石圈构造三维框架。研究结果表明，这样的研究思路准确、方法得当．结论可靠；沿该剖面，把可解译的断裂分为Ⅲ级：Ⅰ级为超岩石圈断裂；Ⅱ级为壳断裂；Ⅲ级为盖层断裂。依据地球物理特征，准确揭示了库区的断裂构造特征，达到了预期效果。     

Observed deformation characteristics of a deep excavation for the spring area in Jinan,China

The observed deflections and internal forces of pile-anchor retaining excavation were studied in spring area in Jinan city of China. Based on field measured data, the ground surface settlement, deflection of retaining piles and wall, internal force analysis of concrete piles, axial anchoring forces, groundwater table, and the deformation of surround building and pipelines were investigated. The results indicates that the combining application of concrete piles, jet grouting columns and anchors support system can effectively control excavation-induced surface ground settlements. The field maximum lateral wall deflections are between 0.02% and 0.19% of the excavation depth due to the competitive site conditions. The bending moment-depth relationship curve is S-type. Groundwater leakage results in the sharp drop in groundwater level, which is part of the reasons for the adjacent building settlement. The axial anchoring forces of the upper layer of anchors increase gradually during the excavation, but those of the lower layer of anchors slightly reduced firstly and then tend to be stable during the excavation procedure. In comparison with the histories of excavation cases, the small lateral wall deflection in this study results from the favorable site condition and the relative rigidity of the retaining structure system.     

A numerical study on seasonal variations of the Taiwan Warm Current

Princeton Ocean Model (POM) is employed to investigate the Taiwan Warm Current (TWC) and its seasonal variations. Results show that the TWC exhibits pronounced seasonal variations in its sources, strength and flow patterns. In summer, the TWC flows northeast in straight way and reaches around 32°N; it comes mainly from the Taiwan Strait, while its lower part is from the shelf-intrusion of the Kuroshio subsurface water (KSSW). In winter, coming mainly from the shelf-intrusion of the Kuroshio northeast of Taiwan, the TWC flows northward in a winding way and reaches up around 30°N. The Kuroshio intrusion also has distinct seasonal patterns. The shelf-intrusion of KSSW by upwelling is almost the same in four seasons with a little difference in strength; it is a persistent source of the TWC. However, Kuroshio surface water (KSW) can not intrude onto the shelf in summer, while in winter the intrusion of KSW always occurs. Additional experiments were conducted to examine effects of winds and transport through     

A NUMERICAL STUDY OF THE WINTERTIME CIRCULATION IN THE BOHAI AND HUANGHAI SEAS

The paper presents a numerical two-dimensional model (with a realistic sea basin and wind fields as exter nal forcing) to simulate the basic features of the wintertime circulation in the Bohai and Huanghai (Yellow) Seas (BHS) and to show how the circulation can be driven by wind. The main results can be summarized as follows (1) The basic features of the BHS wintertime circulation can be depicted by the wind-driven barotropi'c motion. (2) The traditionally named Huanghai Sea Warm Current (HSWC) is actually generated by the north wind field, at least in winter. (3) The southward coastal current off the Korean west coast plays a more significant role in the southern Huanghai Sea wintertime circulation than traditionally believed. (4) Though the coastal landform and bottom topography play important roles in the wintertime BHS circulation pattern, the wind is a primary forcing.     

A numerical study of the wintertime circulation in the Northern Huanghai Sea and the Bohai Sea part I: Basic characteristics of the circulation

A numerical model is developed to explain the response of the shelf sea to the abrupt imposition of a steady, secular mean windstream field and the basic characteristics of the wintertime circulation in the Northern Huanghai Sea (Yellow Sea) and the Bohai Sea by using equidistant, staggered grid points, an implicit finite difference scheme and our new “splitting computational method” of adjustment, development, and dissipation processes. So far as the major tendency of the circulation is concerned, the numerical result agrees with the observational data. The computational results show that the eastern anticyclonic and the western cyclonic circulations constitute the main body of the wintertime circulation in the Northern Huanghai Sea, and that the northern anticyclonic and the southern cyclonic circulations constitute the main body of the wintertime circulation in the Bohai Sea. Contribution No. 1508 from the Institute of Oceanology, Academia Sinica     

PERMAFROST DEGENERATION IN THE EAST OF QINGHAI-XIZANG PLATEAU

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Ore-controlling effect of structure and distribution of deep rock mass on Pb-Zn deposit in Qingchengzi ore concentration area,Liaoning

Qingchengzi ore concentration area in Liao-Ji rift is an important lead-zinc ore area of China,and the deep prospecting in this area has great prospects.Based on the spatial occurrence of ore bodies the Pb-Zn deposit can be divided into three types:layered,vein-shaped and pinnate.The deep geological conditions in this area are deduced by analyzing the tectonic evolution process and rock mass gravity inversion.The tectonic evolution of Liao-Ji rift can be divided into three stages:Paleoproterozoic extension period,Mesoproterozoic compression period and Mesozoic reactivation period.The magmatic activities in the Indosinian epoch led to the distribution pattern of the present deposits.According to the gravity inversion,Shuangdinggou-and Xinling rock masses on the north and south sides of the mining area are connected in the deep.The connected rock body might be distributed in the entire mining area.Xinling rock mass may be a branch extending from Shuangdinggou rock mass along the northeast trending fault,the connected rocks provide magmatic hydrothermal fluid for the final,folds and faults result in different types of ore body shapes.