Influence of ENSO variability on sinking-particle fluxes in the northeastern equatorial Pacific     

Hyung Jeek Kim 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(8):865-874

A time-series sediment trap was operated from July 2003 to July 2008 at a station located in the 10°N thermocline ridge of the northeastern equatorial Pacific (10°30′N, 131°20′W), with the aim of understanding variations in natural background sinking-particle flux and the influence on such fluxes of ENSO (El Niño-Southern Oscillation). Each one of weak El Niño, moderate El Niño and moderate La Niña were observed during the monitoring period. During non-ENSO periods, total mass fluxes varied from 4.1 to 36.9 mg m⁻² d⁻¹, with a distinct seasonal variation, ranging from an average flux of 14.0 mg m⁻² d⁻¹ in the warm season (June-November) to 25.3 mg m⁻² d⁻¹ in the cold season (December-May). This seasonal fluctuation was characterized by a distinct difference in CaCO₃ flux between the two seasons. The enhanced particle fluxes during the cold season are attributed to the supply of nutrient-enriched subsurface water by wind-driven vertical mixing, supported by a simultaneous reduction in sea surface temperature and enhanced trade winds. The weak El Niño event occurred in the monitoring period had no recognizable effect on particle fluxes in the study area, but the moderate El Niño event was accompanied by a significant reduction in particle fluxes to 60% of the average background value in the warm season. In contrast, particle fluxes during the moderate La Niña increased to a maximum value of 129.9 mg m⁻² d⁻¹, almost three times the average background value. Organic carbon and biogenic silica fluxes were most sensitive to the El Niño and La Niña conditions. The observed variations of particle fluxes are synchronized with those of chlorophyll-a, suggesting primary productivity for the main cause of flux change. The present data indicate that marked seasonal variability in background fluxes commonly exceeds the variability associated with ENSO and post-ENSO signals, which should be taken into account when evaluating the influence of ENSO on sinking particle fluxes in the 10°N thermocline ridge area.  相似文献   

热带太平洋风应力距平场的主振荡型分析     

姜鹏  吴洪宝 《南京气象学院学报》2006,29(2):166-172

利用FSU（Florida State University）风应力逐月资料，运用POP方法，分析了热带太平洋地区风应力异常场结构与ENSO的联系。结果显示：纬向风应力有35、47和57月周期的传播型振荡；经向风应力有28和38月周期的传播型振荡。得到纬向、经向风应力传播型与ENSO振荡的耦合关系。同时指出，对El Nino／La Nina这样的大尺度海气相互作用现象的时空演变，应注重多种振荡混合的作用，而不应只分析单一模态的作用。风应力异常的局地振荡对El Nino／La Nina的影响也不应忽视。  相似文献   

非线性模糊识别及其在海温异常检测中的应用   总被引：5，自引：0，他引：5  

张韧  王继光  蒋国荣  周树道 《地球科学进展》2002,17(4):470-476

基于模糊推理和非线性模糊识别原理，讨论了从实际信号中检测识别主要影响因子，进而滤除干扰的方法，进行了相应的去噪试验。试验结果表明：由于模糊系统具有非线性、容错性和自适应学习等特性，因此，能够较为有效地辨识和检测出复杂非线性信号中的主要影响因子及其贡献大小。作为应用，研究了从观测资料中辩识El Niño/La Niña主要影响因子的诊断检测过程，并对 20世纪70年代以来出现的典型El Niño/La Niña事件中信风因子的影响作用进行了诊断检测和模糊识别，分析发现，70年代的几次ElNiño事件主要是由赤道西太平洋西风异常所触发，而80年代的几次El Niño事件（尤其是1982/1983年暖水事件）则主要是由赤道西太平洋与赤道东太平洋的信风活动异常共同所致，前者触发激励在先，后者巩固加强在后。  相似文献   

电感耦合等离子体发射光谱法同时测定钒钛磁铁矿中钒钛钴镍   总被引：1，自引：0，他引：1  

王立平  杨明灵  张丽  吴迪  赵海珍  尹剑飞 《岩矿测试》2012,31(3):450-455

钒钛磁铁矿样品经过氧化钠熔融,盐酸提取,溶液分取稀释后用电感耦合等离子体发射光谱法同时测定其中的V2O5、TiO2、Co、Ni。实验确定过氧化钠的用量为1.5 g,盐酸的用量为10 mL,选择干扰元素较少和背景干扰较小的V、Ti、Co、Ni分析谱线分别为292.4 nm、334.9 nm、230.7 nm、231.6 nm,在稀释因子为10(总稀释因子5000)的条件下进行分析,方法检出限为0.05～0.17μg/g。用国家一级钒钛磁铁矿标准物质GBW 07225(原矿)、钒钛磁铁矿标准物质GBW 07226a(精矿)、钒钛磁铁矿标准物质GBW 07227(尾矿)验证方法精密度和准确度,方法精密度(RSD,n=12)为0.41%～1.91%;除含量较低的Ni和Co外,相对误差(RE,n=4)均小于5%。通过安装氩气加湿器有效地解决了盐分较大带来的影响,在标准系列中加入等量空白溶液,保持基体与试样一致,消除了基体效应。方法分解样品彻底完全,分析流程简单,易于掌握,一次熔样可以同时测定多种元素,可适用于大批量样品分析。  相似文献   

苏北盆地高邮凹陷始新统戴南组一段稀土元素特征及其物源指示意义   总被引：1，自引：0，他引：1  

张妮  林春明  周健  陈顺勇  刘玉瑞  董桂玉 《地质论评》2012,58(2):369-378

稀土元素(REE)的物源对比表明,苏北盆地高邮凹陷戴南组一段沉积岩的物源以其西侧张八岭隆起的元古宙浅变质岩基底为主,并与大别和苏鲁造山带的浅变质岩基底存在亲缘关系,推断研究区的母岩类型为高钾I型花岗片麻岩。而张八岭隆起的新元古代细碧—石英角斑岩和绿片岩、中生代火成岩、大别山南部大范围的榴辉岩以及宁镇山脉的中生代中酸性侵入岩对研究区的物源影响很小。在高邮凹陷内部的物源方向分析中,轻重稀土元素分馏值[(La/Yb)N]与矿物成熟度指数(MMI)形成很好的吻合,(La/Yb)N值结合稀土元素总量(∑REE)及铕异常值(δEu)可对研究区内物源方向的精确判别具有指示意义。戴南组一段沉积时期,高邮凹陷的物源主要来自4个方向:西北部柘垛低凸起方向、东部吴堡低凸起方向、南部通扬隆起方向和西南部菱塘桥低凸起方向。高邮凹陷戴南组一段的沉积相类型与REE特征的相关性分析显示,重稀土元素分馏值[(Gd/Yb)N]与沉积相间存在较为规律的变化,表现在近岸水下扇相、扇三角洲相和三角洲相随其碎屑岩的成熟度升高,(Gd/Yb)N平均值呈逐渐升高的趋势,该趋势同样表现在相同沉积相的不同沉积亚相之间,说明(Gd/Yb)N平均值可较好地反映沉积相特征。  相似文献   

Reassessment of Prejanopterus curvirostris,a Basal Pterodactyloid Pterosaur from the Early Cretaceous of Spain     

Xabier PEREDA-SUBERBIOLA  Fabien KNOLL  José Ignacio RUIZ-OME?ACA  Julio COMPANY  Fidel TORCIDA FERNáNDEZ-BALDOR 《《地质学报》英文版》2012,86(6):1389-1401

Prejanopterus curvirostra, from the Early Cretaceous of La Rioja province, was the first pterosaur genus and species described from Spain. The material comprises disarticulated cranial and postcranial remains from several individuals. The fossil-bearing bed is assigned to the lacustrine Leza Formation (eastern Cameros Basin, NW margin of the Iberian Range). This unit is regarded as either Berriasian-Valanginian or Barremian-Aptian. Prejanopterus curvirostris (specific name emended) was originally diagnosed on the basis of several characters of which the most significant was a lateral curvature of the rostrum. Re-examination of the holotype (rostrum) and paratype (partial rostrum with teeth) indicates that there is no genuine sideways bend of the preserved premaxilla-maxilla segments, but a slight dorsal curvature. Prejanopterus is characterized by a unique combination of characters: an emended diagnosis is provided. In contrast with previous estimates, the wing span of Prejanopterus was probably not much (if ever) in excess of 2 m. A phylogenetic analysis suggests that Prejanopterus is a basal pterodactyloid positioned between Pterodactylus and Cycnorhamphus-Gallodactylus. Prejanopterus represents the first evidence of Pterodactylidae in the Early Cretaceous of the Iberian Peninsula.  相似文献   

Dechlorination of 3,3′,4,4′-tetrachlorobiphenyl (PCB77) in water,by nickel/iron nanoparticles immobilized on L-lysine/PAA/PVDF membrane     

《Physics and Chemistry of the Earth》2013

In this study, the dechlorination of chlorinated hydrocarbon 3,3′,4,4′-tetrachlorobiphenyl (PCB77) by bimetallic Ni/Fe nanoparticles immobilized on L-lysine/PAA/PVDF membrane was investigated at ambient conditions through the batch mode operation. The membrane support polyvinylidene fluoride (PVDF) was modified by in situ polymerization of acrylic acid in aqueous phase, then L-lysine was covalently bonded to the polymerized acrylic acid chains with the aid of a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). The modification procedure involved cationic ion exchange with Fe²⁺, reduction to Fe⁰ with NaBH₄ and finally deposition of Ni⁰. The scanning electron microscopic images showed that the Ni/Fe nanoparticles were successfully immobilized inside the membrane using the polyacrylic acid (PAA) as an inter-linkage between PVDF and L-lysine. A systematic characterization of the composite was performed using ATR-FTIR, HRSEM, EDX, HRTEM, XRD, and contact angle measurement studies and a relatively uniform distribution of Ni/Fe was found in L-lysine/PAA/PVDF membrane because of its hydrophilic nature. The obtained Ni/Fe nanoparticles consist of Fe⁰ core surrounded by the Ni⁰ shell. The diameter of Ni/Fe nanoparticles was predominantly within the range 20–30 nm. The immobilized Ni/Fe nanoparticles exhibited a good reactivity towards the dechlorination of the chlorinated hydrocarbon since the concentration of the PCB77 was decreased by catalytic dechlorination with Ni/Fe nanoparticles inside the L-lysine/PAA/PVDF membrane. Dechlorination efficiency of 98% was achieved within 9 h.  相似文献   

Analysis of Turkish precipitation data: homogeneity and the Southern Oscillation forcings on frequency distributions     

M. Çağatay Karabörk  Ercan Kahya  Ali Ümran Kömüşçü 《水文研究》2007,21(23):3203-3210

The homogeneity of newly compiled 212 precipitation records in Turkey for the period 1973‐2002 was checked by the Standard Normal Homogeneity Test (SNHT) and Pettitt Test. Stations were considered inhomogeneous if at least one of the tests rejects the homogeneity. As a result, 43 out of 212 stations were found to be inhomogeneous. In addition, the previously detected Southern Oscillation (SO)‐related precipitation anomalies by the authors were quantified at each station using the gamma distribution. The observed SO‐related shifts in the median precipitation amounts expressed as gamma percentiles may be considered as a typical SO response of that station. The results of this study confirm the wet responses of Turkish precipitations to El Nino events, whereas those for La Nina events seem to be masked by sampling variations within the study period. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

云南镍矿地质特征及找镍方向   总被引：1，自引：0，他引：1  

薛步高 《云南地质》2008,27(1):1-11

云南硫化镍矿以与铂钯矿的伴生镍为主（11．76万t）,其中：大理-弥渡（6．85万t）、金平（6．38万t）、元谋-永仁-牟定（5．12万t）。硅酸镍主要在墨江-元江（64．41万t）;蛇绿混杂岩型硫砷化物镍矿（1．73万t）,是云南-大特色。与成矿有关的岩体主要是华力西期,次为加里东期,产出与深大断裂有关。找矿方向应以富宁、金平及景东东山-红河底玛为主攻目标。  相似文献   

Synthesis and characteristics of Sr-dope LaNbO4 ultrafine powders     

TIAN Li-yu  YU De-li  LIU Shu-qin 《世界地质》2008,27(3)

  相似文献