Estimating the geostrophic velocity obtained by HF radar observations in the upstream area of the Kuroshio

A method to extract geostrophic current in the daily mean HF radar data in the Kuroshio upstream region is established by comparison with geostrophic velocity determined from the along-track altimetry data. The estimated Ekman current in the HF velocity is 1.2% (1.5%) and 48° (38°)-clockwise rotated with respect to the daily mean wind in (outside) the Kuroshio. Furthermore, additional temporal smoothing is found necessary to remove residual ageostrophic currents such as the inertial oscillation. After removal of the ageostrophic components, the HF geostrophic velocity agrees well with that from the altimetry data with rms difference 0.14 (0.12) m/s in (outside) the Kuroshio.     

Hydrodynamic forces on partly buried tandem, twin pipelines in current

This study extends the investigations of the forces on a cylinder, laid on, or partly buried in the bed with a parallel twin dummy cylinder nearby and without it, and were determined by measuring the pressure distribution on the cylinder in the case of a steady current. The pressure distribution around the cylinder was measured by using pressure transducers. The forces on the cylinder were calculated by the integration of the measured pressures on the surface of the cylinder. Force coefficients were obtained for the ranges of Re=0.8×10⁴–1.5×10⁴ for the burial depth to diameter RATIO=0:0.7. The distance between axis of the measurement and dummy cylinders to diameter ratio (x/D) was 2, 1.5 and 1. The dummy cylinder was replaced downstream and upstream of the measurement cylinder.     

潮流沙脊的水力学问题探讨

借用河流水力学顺直河道中有两个次生横向环流的假说来解释潮流沙脊的成因，水槽实验和实际观察也支持了这一观点．正是这一次生的纵轴横向环流（即螺旋流）将泥沙从沟槽带向脊顶，建造了大致与潮流方向平行的潮流沙脊．根据底质粒度成份和分布特点．可分为粗底质沙脊和细底质沙脊两类．前者组成物质偏粗，底质分布为脊细槽粗，后者组成物质偏细，底质分布为脊粗槽细．这是因为影响颗粒起动流速的主导因素不同，前者以重力为主，后者以颗粒间粘结力为主．它们都反映沟槽中流速大于脊顶处流速．     

河西走廊疏勒河流域地质灾害危险性现状评估方法的应用——以甘肃省河西走廊(疏勒河)农业灌溉暨移民安置综合开发建设项目8个移民社区及配套工程建设为例

依据“建设用地地质灾害危险性评估技术要求”、利用野外踏勘及相关资料,对“甘肃省河西走廊（疏勒河）农业灌溉暨移民安置综合开发建设项目8个移民社区及配套工程”进行地质灾害危险性现状评估。结果认为：评估区发育和分布的地质灾害类型有土壤盐渍化、风蚀沙埋和洪水冲蚀。现状评估结果：土壤盐渍化和洪水冲蚀危险性均小;风蚀沙埋有1处危险性中等,其它危险性小。     

太湖入湖河道沉积物中生物利用磷和营养水平分析

为了解太湖入湖河道的营养状况,研究了太湖西部河流沉积物生物利用磷的组成与分布。研究结果显示,北部沉积物中营养元素较高,南部较低;沉积物中生物利用磷的含量次序为藻类可利用磷(AAP)>NaHCO3提取磷(OLP)>水溶性磷(WSP)>易解吸磷(RDP),其中AAP是重要的生物利用磷,AAP的比例越高,富营养化程度越高。AAP与营养元素的相关性在不同区域河道有所不同,北部河道与总氮(TN)、总磷(TP)相关性较好,中部和南部河道与沉积物有机质总量(TOM)相关性较好。沉积物的生物利用磷受不同污染源影响较大。对比河道沉积物与湖泊沉积物的特征,发现湖泊沉积物中生物利用磷(BAP)/总磷(TP)、藻类可利用磷(AAP)/总磷(TP)都高于河道沉积物,表明湖泊沉积物中的磷更容易被植物吸收。     

Lake bank filtration at Nainital,India: water-quality evaluation

There are different water-supply schemes in Uttarakhand, India to tap the water from streams, rivers and lakes. At Nainital, seven tube-wells (depths 22.6–36.7 m), located at a distance of <100 m from the lake, are being used to abstract (1) lake water after passage through the soil and (2) subsurface water/groundwater flowing towards the lake. Water samples from the lake and tube-wells were analyzed in monsoon and non-monsoon periods from 1997 to 2006. Total dissolved solids, EC, alkalinity and hardness were found to be marginally greater in tube-well waters. The difference in hydrochemistry of tube-well water was mainly due to variation in flow regimes during monsoon and non-monsoon periods. Results clearly indicate that lake water as such is not potable as it contains unacceptable levels of organic matter in terms of COD (~44 mg/L), coliforms (~15.6 × 10⁴ MPN/100 mL) and nutrients. Coliform bacteria and COD have not been detected in any of the tube-well water samples over the years. Lake water, treated by sand filters did not conform to drinking water standards. These investigations have led to the closure of the treatment facility and installation of two tube-wells in addition to the existing five tube-wells.

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Résumé  Il existe divers projets d’alimentation en eau dans l’état d’Uttarakhand, Inde, afin de capter l’eau de ruisseaux, de rivières et de lacs. A Nainital, sept puits tubés (profondeur de 22.6–36.7 m), situés à une distance < à 100 m du lac, sont utilisés pour prélever (1) de l’eau du lac après transit à travers le sol et (2) de l’eau de sub-surface/eau souterraine s’écoulant vers le lac. Des échantillons d’eau du lac et des puits tubés ont été analysés en périodes de mousson et de celles sans mousson 1997 à 2006. Résidu sec, C.E., alcalinité et dureté ont été trouvés marginalement supérieurs dans l’eau des puits tubés. La différence d’hydrochimie de l’eau des puits tubés était surtout due à la variation des régimes d’écoulement pendant les périodes de mousson et de celles sans mousson. Les résultats indiquent clairement que l’eau du lac en tant que telle n’est pas potable car elle contient des teneurs inacceptables de matière organique en termes de COD (~44 mg/L), de coliformes (~15.6 × 10⁴ MPN/100 mL) et d’éléments nutritifs. Des bactéries coliformes et du COD n’ont été détectés dans aucun des échantillons d’eau de puits tubés au fil des années. L’eau du lac traitée par des filtres à sable ne se conformait pas aux normes de l’eau potable. Ces recherches ont conduit à la fermeture de l’installation de traitement et à l’implantation de deux puits tubés en plus des cinq puits existants.

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Resumen  En el estado de Uttarakhand, India, existen diferentes esquemas de abastecimiento de agua que explotan agua de arroyos, ríos y lagos. En Nainital, siete pozos (profundidades entre 22.6–36.7 m), ubicados a una distancia de <100 m del lago, se usan para extraer (1) agua del lago luego de su pasaje a través del suelo y (2) agua superficial y subterránea que fluye hacia el lago. En períodos de monzón y de no monzón de 1997 a 2006 se han analizado muestras de agua del lago y de las captaciones. Se halló que el agua de los pozos es ligeramente mayor en términos del total de sólidos disueltos, la conductividad eléctrica, la alcalinidad y la dureza. La diferencia en la hidroquímica del agua de las perforaciones se debe principalmente a la variación de los regímenes de flujo durante los períodos de monzón y de no monzón. Los resultados claramente indican que el agua del lago no es potable por su contenido inaceptable de materia orgánica medida como demanda de carbono orgánico/oxígeno –DCO- (~44 mg/L), coliformes (~15.6 × 10⁴ NMP/100 mL) y nutrientes. En el período, no se han detectado bacterias coliformes ni DCO en las muestras de agua de las captaciones. El agua del lago, tratada con filtros de arena, no conformó los estándares de agua para bebida. Estas investigaciones han demostrado la necesidad de clausurar las instalaciones de tratamiento y la adición de dos captaciones a las cinco ya existentes.

     

Holocene climate reconstructions of Ulungur Lake (Xinjiang,China) inferred from ostracod species assemblages and stable isotopes

In this paper, the data on the paleoclimatic and paleoenvironmental changes during the Holocene are presented and a discussion is made on a 225-cm-long sediment core from Ulungur Lake, located in Northwest China. The chronology is constructed from six AMS radiocarbon dates on the bulk organic matter. On the basis of the analysis of ostracod assemblages and the shell stable isotopes, the core is divided into three paleoclimatic and paleoenvironmental evolution stages: 9 985–5 250 cal.aB.P. stage is the wettest phase of the core section. The climate changed from moderate-dry to cool-wet, and then to warm-wet in turn, and the lake level rose accordingly, showing the characteristic of a high lake level. 5 250–1 255 cal.aB.P. stage was the driest phase of the core sediment. The climate turned from the early warm-dry to the late warm-wet and the lake level fell and rose again. Finally, the 1 255 cal.aB.P. stage was the medium stage of the section. The temperature was low and then increased after the 1920s and the climate was dry. The whole climatic and environmental evolution records of Lake Ulungur were not only in agreement with the sporopollen record of the same core but also in agreement with the record of environmental changes of adjacent areas. It responded to regional environmental changes and global abrupt climate events, following the westerly climate change mode on 100-year-scale, primarily with cold-wet and warmdry characteristics. __________ Translated from Quaternary Sciences, 2007, 27(3):382–391 [译自:第四纪研究]     

Influence of submerged aquatic vegetation on size class distribution of perch (Perca fluviatilis) and roach (Rutilus rutilus) in the littoral zone of Lake Geneva (Switzerland)

The abundance of different size classes of perch and roach in the littoral zone of Lake Geneva was compared between submerged aquatic vegetation and unvegetated zones. Samples were taken with gillnets during four periods between June and October 1993. During the vegetation period (June to September), perch 9 cm and roach 10 cm were more abundant in vegetation whereas roach > 20 cm were more abundant in open water. Perch larger than 18 cm and medium roach were equally distributed in both habitats whatever the period, whereas medium perch distribution fluctuated according to the period. In October, after the decline of the vegetation, no more differences in fish distribution were observed except for small roach, which were always more abundant in the vegetated sites.     

Pesticide residues in birds at Lake Nakuru,Kenya

Specimens of three species of birds were collected from Lake Nakuru, Kenya, between September and October 1990. Samples of liver, kidney, muscle, fat and brain tissue were removed and analyzed for organochlorine pesticide residues. Fat was extracted and the content of three lindane (BHC/HCH) isomers (, and ), aldrin, heptachlor, heptachlorepoxide, endrin, dieldrin, DDD, DDE and DDT was determined. The samples contained varying residue levels of 12 organochlorine pesticides. No residues of 0, p'-DDD were detected. The most prevalent compounds were DDE and -BHC, found in 95.5 per cent and 66.4 per cent of the samples, respectively. The highest median residue concentration was 207 mg kg^–1×10^–3 of DDE in pelican fat tissue. White pelicanPelecanus onocrotalus, and the white-necked cormorant,Phalacrocorax carbo, showed greater concentrations of organochlorine residues than the lesser flamingo,Phoenicopterus minor. The mean DDE concentrations in pelican liver samples in 1970 and 1990 were 64 mg kg^–1×10^–3 and 274 mg kg^–1×10^–3, respectively. In cormorant liver samples the mean DDE concentration was 15 mg kg^–1×10^–3 in 1970 and 52 mg kg^–1×10^–3 in 1990. The mean DDE concentration in flamingo liver remained more or less similar at 2 mg kg^–1×10^–3 in 1970 and 1990.     

Intrinsic sample methods for mineral exploration and resource assessment

We report on an objective methodology, referred to as intrinsic sample methodology, for the delineation of exploration target areas or resource areas for assessment. Important features of the methodology include (1) identification of recognition criteria for critical genetic factors, (2) synthesis of new variables from enhanced geodata, (3) estimation of logit probability models, and (4) cutting of estimated logit probabilities to delineate exploration targets or resource areas. The methodology is demonstrated on the Walker Lake quadrangle of Nevada and California.