2000年北半球大气环流特征及其对中国气候的影响   总被引：2，自引：0，他引：2       下载免费PDF全文

王永光 《气象》2001,27(4):12-15

2000年受La Nina结束后冷水事件的影响，北半球大气环充的要主特征表现为：500hPa东亚中纬度呈经，纬向环流交替分布，西太平洋副热带高压偏弱，偏北，偏东，热带对流活动冬季偏强，夏季偏弱，赤道辐合带偏弱，在上述大气环流的影响下，台风偏少，夏季主要多雨带位于黄河与长江之间，黄河以北地区干旱严重。  相似文献   

Origin of Dissolved Groundwater Sulphate in Coastal Plain Sediments of the Rio de la Plata, Eastern Argentina     

Williams S. Logan  Ronald V. Nicholson 《Aquatic Geochemistry》1997,3(4):305-328

Groundwater of the coastal plain of the Rio de La Plata, Argentina,contains up to 17 g L^-1 SO₄ and 37 gL^-1 TDS. Some of this SO₄ is from paleo-seawater intrusion; however, SO₄ : Cl ratios can be>2 : 1, and most of the SO₄ must, therefore, have another source. Three possible sources were investigated: gypsum, organic matter,and iron sulphides. Dissolved SO₄ showed δ³⁴S valuesfrom -7 to 0‰, typical values for S from iron sulphides or organicmatter, but distinct from that of seawater (+22‰). To test whetherthe SO₄ was derived from oxidation of reduced S, four 4-mcores were taken from marine sediments of the coastal plain. Two were takenfrom higher, drier areas where the highest dissolved SO₄values were encountered, and two were taken from lower, wetter areas thathad much lower SO₄ concentrations. Pore waterSO₄, Cl and alkalinity were determined; solids were analyzedfor SO₄, sulphide-S and organic-S. Sulphide-S was the dominant form of reduced S, averaging about0.5% S in the lower interval (2.5–4 m) of the cores. Sulphidewas absent in the upper 2.5 m in both topographically higher and lowerareas. Sulphate was present in the entire unit in the higher, drier areas,but almost absent in lower areas. Organic-S was insignificant. Our model for the origin of dissolved SO₄ is: fine-grainedpyrite was oxidized during hotter or drier periods. Some resulting dissolvedSO₄ was precipitated as gypsum. Iron from the pyriteprecipitated as FeOOH. Lower, wetter areas formed over time where recharginggroundwater dissolved most of the gypsum. In higher areas with low hydraulicgradients and high net evapotranspiration, SO₄ remained asgypsum and in the dissolved phase. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Approaches to equilibrium in the distribution of trace elements among the principal minerals in a high-grade metamorphic terrane   总被引：2，自引：0，他引：2  

Kretz  Campbell  Hoffman  Hartree  & Teesdale 《Journal of Metamorphic Geology》1999,17(1):41-59

X-ray fluorescence, instrumental neutron activation, and particle-induced X-ray emission methods were used to determine the distribution of numerous trace elements among garnet (Grt), Ca-pyroxene (Cpx), hornblende (Hbl), biotite (Bt), plagioclase (Pl) and K-feldspar (Kf) in a high-grade metamorphic terrane within the Grenville Province of the Canadian Shield. Results are presented as distribution formulae, e.g. Sr: Kf 1.1 Pl 16 Hbl 2.2 Cpx 1.0 Bt 1.2 Grt Sc: Hbl 1.1 Cpx 1.0 Grt 7.8 Bt 22 Pl 2.6 Kf V: Hbl 1.15 Bt 2.07 Cpx 6.0 Grt (1.4% CaO)>1 (Pl, Kf) Zn: Bt 1.6 Hbl 1.62 Cpx 2.9 Grt 10 Pl Ga: Bt 1.2 Hbl 1.2 Pl 2.5 Cpx 1.3 Grt where numbers are distribution ratios, e.g. ppm Sr in Hbl/ppm Sr in Cpx=2.2. Examples of inter-element similarities and differences are (a) both Rb and Cs are concentrated in biotite relative to K-feldspar, but for Rb the ratio is 2.3 and for Cs it is 16, (b) the distribution formulae for seven lanthanides are similar except for the position of garnet, e.g. Ce: Hbl 2.7 Cpx 2.8 Pl 1.1 Bt 11 Kf 16 Grt Yb: Grt 2.8 Hbl 2.7 Cpx 9 Pl 1.0 Bt 7 Kf and (c) all of Sr, eight lanthanides, Zr, V and Cr are concentrated in hornblende relative to Ca-pyroxene by a factor that lies in the narrow range of 2.2–3.1. There is a larger variation (departure from the mean) in some distribution ratios than in others. Thus the mean ratios (Hbl/Cpx) for each of six elements and in parentheses the percentage relative standard deviation are Zn 1.62 (8.6), V 2.38 (12), Cr 2.42 (18), Sr 2.7 (28), Ba 2.9 (36) and Ni 1.66 (38). We suggest that variation of this kind is the result of differences from place to place in the magnitude of deformation and recrystallization (which facilitated the rearrangement of atoms), combined with rates of lattice and crystal-boundary diffusion that are unique for the various elements, thus permitting some trace elements to approach equilibrium more closely than others.  相似文献   

超稳定Y型沸石为载体的新型Ni-Mo环境催化剂     

李迪恩  彭明生 《矿物岩石地球化学通报》1999,(4)

在经济高速发展的今天,必须注意保护和改善我们赖以生存的地球环境：既要尽量减少污染,又需加强对已有污染物的处理。能源（煤、石油、天然气）的利用是工业革命的强大推动力,但也是污染地球环境的主要来源。因此,我们必须提高能源的利用效率,减少其中污染物的含量,从而减少能源的利用对环境的污染,同时加强治理能源工业和利用所产生的污染物,例如石油残渣。在石油和液化煤的提炼过程,所利用的主要是催化的氢化和氢气裂解反应。工业上最常用的催化剂是以γＡｌ２Ｏ３为载体,Ｃｏ或Ｎｉ为促进剂的Ｍｏ或Ｗ的硫化物。但是,由于北…  相似文献   

青海拉脊山东段水系沉积物地球化学异常特征     

罗开欢 《矿产与地质》1993,7(4):307-310

青海拉脊山东段水系沉积物地球化学测量,发现金源、喇嘛庙、七里寺峡Au、As、Ag、Bi、Sb、Hg等元素的水系沉积物组合异常.Au、Ag、As相对高浓度带发育形态、分布范围、异常浓集中心吻合,与区内已知尼旦沟金矿床地球化学异常特征可以类比,发现有金、铜矿体和金矿化,显示铜金成矿的有望远景地段.  相似文献   

Acidification and metal contamination in Whitepine Lake (Sudbury,Canada): a paleolimnological perspective     

Aruna S. Dixit  Sushil S. Dixit  John P. Smol 《Journal of Paleolimnology》1993,9(2):141-146

Diatom and chrysophyte assemblages from a sediment core from Whitepine Lake were examined to infer changes in lakewater pH, nickel and aluminum concentrations since pre-industrial times, and to help determine the cause of the virtual extirpation of the lake trout population from the lake during the 1960s and 1970s. Our study indicates that acidification started in the 1920s, and that the maximum inferred pH decline (from 6.2 to 5.8) occurred between 1960 and 1970, coincident with the peak in metal mining and smelting activity in the Sudbury basin. Lakewater [Al] and [Ni], as inferred from our diatom transfer functions, increased. It appears that in addition to the pH decline, elevated [Al] may have played an important role in the decline of lake trout from Whitepine Lake in the 1960s and 1970s. Diatom-inferred lakewater pH and [Ni] have recovered slightly in the recent sediments, which coincides with reductions in emissions that have occurred since the mid-1970s.  相似文献   

5-Br-PADAP-TritonX-100析相光度多波长K系数法测定微量铁、钴、镍、铜     

周发连  高艳明  邹晓红 《华东地质学院学报》1992,(2)

本文研究了Fe(Ⅲ),Co(Ⅱ),Ni(Ⅱ.),Cu(Ⅱ)在5-Br-PADAP-TritonX-100体系中的析相显色反应。利用该体系具有一定选择性和富集、分离的特点,采用多波长K系数法,根据公式ΔA=A-sum from i=1 to n K_iA_i=KC,在一个测定波长和与干扰组分个数相等的参比波长下,测定混合多组分体系的吸光度。求得相应K值后,再计算各待测组分含量。本法用于测定人发中微量铁、钴、镍、铜取得了满意结果。  相似文献   

Polarographische Bestimmung von Nickel und Chrom in Klärschlämmen Polarographic Determination of Nickel and Chromium in Sewage Sludge     

M. Kolb  J. Mann  J. Schfer  F. Müller  G. Bogenschütz  C. Dengler 《洁净——土壤、空气、水》1994,22(6):261-264

The contents of Ni and Cr in sewage sludge with high and low amounts of heavy metals were investigated by polarography. The DIN-digestion (aqua regia) was used, and the resulting solution was treated with H₂O₂/UV (90 °C, 60 min) for further destroying of the organic material. Besides, the solution of the DIN-digestion was examined with AAS (flame) and ICP-OES. With the determination of Ni it was shown that after digestion with aqua regia no further treatment with H₂O₂/UV is necessary. Contrariwise it was found that for the determination of Cr a H₂O₂/UV photolysis is necessary followed by further steps to get good agreement with AAS and ICP results as well as with the certified values of a sludge of the Community Bureau of Standards.  相似文献   

金川硫化铜镍矿床成矿岩浆性质和源区特征讨论   总被引：12，自引：0，他引：12  

杨合群  汤中立 《甘肃地质》1997,6(1):44-52

通过对造岩矿物、岩石化学和铂族元素等信息的综合分析，认为金川岩体的母岩浆属拉斑玄武质苦橄岩浆，是地幔橄榄岩经３３％部分熔融的产物；硫、钕、锶、氧等同位素资料说明岩浆源区可能在上地幔低速层底部，属富集型地幔  相似文献   

2011年1月贵州冻雨天气成因分析     

李丽丽  肖天贵  黄金全  冷宇 《气象科技》2013,41(6):1116-1121

利用2011年1月NCEP1°×1°6 h再分析资料和贵州省气象局提供的84个地面气象站1970—2011年冬季（12月至次年2月）资料对贵州省2011年1月持续的低温冻雨天气进行了气候统计和诊断分析。此次冻雨天气范围广,强度大,34个站气温达到40年来历史同期最低值。此次过程中的亚欧大陆环流异常的主要表现是乌拉尔山阻塞高压阶段性活跃,在里海槽前西南气流的持续补充下两次崩溃三次重建,在脊前形成深厚低压中心,导致频繁有冷空气南下影响贵州地区。  相似文献