Heavy-mineral variability in bottom sediments of the lower Chesapeake Bay,Virginia

Heavy minerals in bottom-sediment samples of the lower Chesapeake Bay show distribution patterns and interrelationships that denote characteristic mineral suites associated with defined geographic provinces. The Baymouth province has a garnet—hornblende—pyroxene suite, which is largely attributed to the influx of littoral and shelf sediments; the Eastern Shore province has a similar suite, derived largely from coastal erosion of the Eastern Shore peninsula. The Northern and Combined River provinces have a zircon—tourmaline—staurolite assemblage, which reflects derivation from an Appalachian Piedmont—Atlantic Coastal Plain sourceland. The Western Shore province is associated with a zircon—epidote—staurolite assemblage, apparently derived jointly from tributary influx and coastal erosion of the western shore. Factor analysis identified two major factors that account for 63% of the total variation in the relative amounts of the seven most common heavy minerals. The dominant factor (44%) is based on a zircon—hornblende—staurolite—pyroxene relationship, which indicates that mineral stability, as influenced by sediment maturity, is a major contributing factor. The second factor (19%) based on a tourmaline—epidote—staurolite—garnet relationship indicates that provenance is another major cause of heavy-mineral variability within the lower bay.     

New genera and species of benthic calanoid copepods from the New Zealand slope

Thirteen new species of benthic calanoid copepods are described from depths of 1,184–1,697 m off New Zealand. Seven species belong to previously described aetideid genera (Bradyidius—four spp., Comantenna—one sp., Pseudeuchaeta—two spp.) and the remainder represent new genera in three families: Aetideidae—three genera, four spp.; Arietellidae—one genus and sp.; Bathypontiidae—one genus and sp.     

Rises of the Amerasia Basin,Arctic Ocean,and Possible Equivalents in the Atlantic Ocean

Oceanology - Abstract—The main positive morphostructures of the Amerasia Basin — the Lomonosov Ridge, Alpha Ridge, Mendeleev Rise, Chukchi Plateau, and Northwind Ridge — are...     

The tectonics of the Okhotsk Sea

The northern and central parts of the Okhotsk Sea form an epiMesozoic platform. The hetero-aged acoustic basement is represented by deformed geosynclinal rocks from Cretaceous to Precambrian in age. The slightly deformed sedimentary cover levelled the uneven surface of the acoustic basement, and this Upper Paleogene—Neogene cover filled up the system of the structural basins. The general NW—SE and W—E extensions of the taphrogenic horsts and grabens of the acoustic basement were formed due to extension and subsidence of the earth's crust during the late Paleogene—Neogene.     

Possibilities of Using the Method of Median Gradients to Reveal Changes in Apparent Electrical Resistivity during the Nucleation of Earthquakes

Izvestiya, Atmospheric and Oceanic Physics - Changes in apparent electrical resistivity are calculated using one of the electrical survey methods—the median gradient—over the earthquake...     

Deformation of the Submerged Slope of the Anapa Bay-Bar From 2012 to 2018

Oceanology - Abstract—The article considers the long-term relief dynamics of the submerged slope of the Anapa bay-bar. The Anapa bay-bar consists of five morphological elements—Solenoe...     

Response-based estimation of sea state parameters — influence of filtering

Reliable estimation of the on-site sea state parameters is essential to decision support systems for safe navigation of ships. The wave spectrum can be estimated from procedures based on measured ship responses. The paper deals with two procedures—Bayesian Modelling and Parametric Modelling—which both use complex-valued frequency response functions (FRF) to estimate the wave spectrum. It is therefore interesting to investigate how the filtering aspect, introduced by FRF, affects the final outcome of the estimation procedures. In order to do this, extensive numerical simulations—with known wave parameters—are carried out for a large container vessel. The study shows that filtering has an influence on the estimations, since high-frequency components of the wave excitations are not estimated as accurately as lower frequency components.     

论IPCC-AR4模式对影响西北太平洋热带气旋的大气动力环境场的气候特征模拟性能

评估了23个IPCC-AR4模式在低纬地区1948—1999年7—9月大尺度环流场的模拟性能,重点关注西北太平洋区域的西太副高、季风槽以及台风活动海域的垂直风切变。结果显示,绝大多数模式的7—9月低纬地区500hPa平均高度场、850hPa风场空间分布与NCEP都具有很高的相似性,但大多模式500hPa高度场存在系统性偏低,而850hPa风场偏强。所有模式模拟的西北太平洋副高脊线与NCEP都有一致的西南-东北走向,但有些模式的脊线位置偏离NCEP的较远。有4个模式没有模拟出类似于NCEP的季风槽线。综合模式对夏季热带环流场、西北太平洋副热带高压、季风槽以及西北太平洋热带气旋活动关键区域垂直风切变气候特征的模拟性能,按性能优劣,排在前10的模式依次是mpi_echam5、cccma_t63、gfdl_cm2_1、cnrm_cm3、cccma_t47、ukmo_hadgem1、ingv_echam4、ncar_ccsm3_0、csiro_mk3_5、mri_cgcm2_3_2a;排在后6位的模式是inmcm3_0、iap_fgoals1_0_g、ipsl_cm4、miroc3_2_medres、giss_eh、giss_er。     

Short-term variability of the size spectra of suspended particles in a rapidly changing environment

Analysis of suspended matter collected in the lower St. Lawrence estuary indicated short-term variabilities in both the structure and dynamics of the particles. Variations with time and depth were ascribed to fluctuation of particle concentrations within the size ranges of the major peaks of concentration. A deterministic pattern was found for the temporal succession of the spectra when total particle concentrations were high. This was due to combinations of three factors that act in one of two ways, either (i) high current velocity—spring tide—stratified waters, or (ii) lower current velocity—neap tide—mixed waters. In the first case, the current effect prevailed, while the tide effect was dominant in the second one. A random pattern occurred in the succession of the spectra when lower particle concentrations and patches of smaller dimensions were present in well mixed water bodies. Successions of spectra were not always in phase at different depths within the water column.     

用钨酸钠分离法研究诏安湾甲藻休眠孢子

本文介绍了一种分离富集沉积物中甲藻休眠孢子的新方法－钨酸钠法，并用这种方法在诏安湾沉积物中分离到了12种甲藻休眠孢子。     

南黄海太阳沙西侧海域晚第四系地震层序和沉积环境演变

在南黄海太阳沙西侧潮流脊槽海域进行了密集网格的高分辨率浅地震勘探,测线间距主要为120 m和200 m。沉积物穿透厚度最大约80~90 m,划分为2个地震层序(SQ1和SQ2),细分为5个亚层(U1~U5)。位于下部的层序1(U1)为晚更新世陆相沉积,上部的层序2(U2~U5)以全新世海相沉积为主。根据地震相特征研究了各亚层的沉积环境,从晚更新世晚期以来,研究区经历了三角洲辫状河流—河流刻蚀—古河道充填—河口滨海—三角洲滨浅海—现代潮流脊槽的沉积环境演变过程。在早全新世中期,研究区发育了一条窄河口型潮流沙脊,并随海平面的快速上升而被掩埋。现代潮流沙脊形成于末次高海面后,与古潮流沙脊没有继承关系,与晚更新世古地形也没有关系,受控于潮流系统。     

北印度洋障碍层厚度气候态和季节变化特征及其成因初步分析

基于2004—2018年Argo (Array for Real-Time Geostrophic Oceanography)浮标观测的温度、盐度数据, 利用经验正交函数(EOF)分析和小波分析等方法对北印度洋(40°—105°E, 5°S—25°N)障碍层时空分布特征进行分析。结果显示: 北印度洋的东部常年存在障碍层, 而西部障碍层出现的概率相对较低; 较厚的障碍层出现在阿拉伯海东南部(67°—75°E, 3°—12°N)、孟加拉湾(82°—93°E, 11°—20°N)和赤道东印度洋(81°—102°E, 4°S—3°N)。阿拉伯海东南部和孟加拉湾障碍层厚度以年变化为主, 且呈同位相变化, 均为冬季最大, 夏季最小。赤道东印度洋区域则主要呈现半年周期变化, 在夏季和冬季各出现一次峰值。进一步分析表明, 孟加拉湾和赤道东印度洋障碍层厚度主要受等温层深度变化影响, 混合层深度变化对障碍层厚度变化的影响相对较小; 阿拉伯海障碍层厚度同时受等温层深度变化和混合层深度变化影响, 其中等温层深度变化对其影响更大。     

Attitudes toward offshore oil development: A summary of current evidence

Attitudes toward offshore petroleum have varied widely across both time and place. This paper summarizes the accumulated evidence from around the globe and then examines two regions that represent the polar extremes—both drawn from the same country and the same era—southern Louisiana and northern California, over the past two decades. The comparison illustrates that attitudes toward offshore oil development are best understood through a closer examination of the ways in which the offshore industry has interacted with a given region, over time, in terms of three sets of factors—the historical, biophysical, and social factors that shape the people and culture of a given place and time.     

Resonant interaction of waves of continuous and discrete spectra in the simplest model of a stratified shear flow

The equations of dynamics of eddy—wave disturbances of two-dimensional stratified flows in an ideal incompressible fluid that are written in a Hamiltonian form are used to study the resonant interaction of waves of discrete and continuous spectra. A gravity—shear wave generated at a jump of the density and vorticity of the undisturbed flow and a wave generated at a weak vorticity jump, which is similar to a wave of a continuous spectrum, participate in the interaction. The equations are written in terms of normal variables to obtain the system of evolution equations for the amplitudes of the interacting waves. The stability condition for eddy—wave disturbances is derived within the framework of the linear theory. It is shown that a cubic nonlinearity may lead to the stabilization of unstable disturbances if the coefficient of the nonlinear term is positive.     

Two Modes of Atmosphere–Ocean Interaction in the Atlantic Sector of the Arctic Basin

Oceanology - The paper examines the influence of the main mode of interannual variability of the North Atlantic climate system—the North Atlantic Oscillation (NAO)—on the hydrophysical...     

HPLC analyses of metal—organics in seawater — interference effects attributed to stationary-phase free silanols

Organic complexes of magnesium, iron, zinc and copper have been isolated from seawater by adsorption onto octadecylsilyl-modified silica (SEP-PAK cartridges). The compounds were fractionated by HPLC and metals were detected in the eluate by atomic fluorescence. The most polar fraction contained a significant proportion of the metal—organics but only a low percentage of the UV-absorbing (254 nm) material. Magnesium—organics of low polarity were found in deep (5000 m), water but the compounds do not seem to be derived from tetrapyrroles. There were large systematic variations in the chromatograms as the column aged and it is thought that free silanol groups were removing metals from the metal—organic complexes. The effect was most pronounced for magnesium. Inorganic metal ions can be adsorbed by columns containing capped or uncapped C18-bonded silica and the adsorption of metals is enhanced by treatment with methanol. The cation exchange capacities of chromatographic packings must be taken into account when metal—organic compounds are analysed by HPLC.     

南疆博斯腾湖近12.OkaB.P.以来古气候与古水文状况的变化

对南疆博斯腾湖湖相沉积物多手段的综合研究，揭示了近12.0kaB.P.以来古气候与古水文状况的变化过程与特征。结果表明，其气候的演化特征具有明显的西风型环境演变特征。研究还发现气候于12.0ka、10.0ka、4.0ka和1.5kaB.P.存在显著的阶梯式增暖变干特征，其中暖峰主要出现于11.5—11.0ka、9.4ka、7.5—7.0ka、6.5—6.0ka、3.0ka和2.0kaB.P.，气候特征以干暖为主，湖泊水文特征总体表现为盐度增加、水位下降、湖面缩小；而冷峰主要出现于11.0—10.0ka、8.8ka、5.0—4.5ka、3.3ka和1.5kaB.P.，此时湖泊膨胀淡化，湖面上升。在7.0—5.0kaB.P.期间出现的相对暖湿环境特征可能是全新世大暖期最盛期暖湿气候特征的反映，可能与此时西南夏季风势力增强有关，湖泊水文状况明显变好。     

Residence times of Manukau Harbour,New Zealand

Residence times of the three main channel systems of Manukau Harbour were calculated by methods based on the salinity measured in 10 tidal excursion segments: the freshwater replacement technique and a volume exchange model. The amount of freshwater present in the segments at high water was low (< 11% throughout the year), so salinities were high, with minimum values (winter) in each segment being in the range 30.1–34.0 (compared with a median value of 34.5 in the nearby coastal waters). The proportion of each segments’ volume which was exchanged with an adjacent segment during a tidal cycle varied markedly across the harbour, from ≤ 5 % in several shallow inner harbour segments to 65% in a deep segment adjacent to the entrance channel. For annual average conditions the freshwater replacement times of the channels were 11–18 days. Slightly longer residence times—12–26 days—were obtained from the volume exchange model. Calculated replacement times for two non‐conservative tracers— inorganic phosphorus and nitrogen—were approximately half those for freshwater, as 5–12% of these species disappeared from the water column each day.     

青藏高原地区近千年气候变化的时空特征

研究青藏高原地区过去千年气候变化的时空特征,对预测未来气候情景下该地区冰冻圈的变化及其水文-生态效应具有重要科学意义。基于15条反映青藏高原地区近千年气候变化的高分辨率重建序列,通过综合分析及经验正交函数(EOF)方法,进一步探讨了青藏高原地区过去千年气候变化的时空特征。综合重建序列显示:整体而言,青藏高原地区中世纪暖期(MWP)约持续到1450s,小冰期(LIA)约发生于1450—1870s,此后近百年来的温度在波动中逐渐升高;对比分析表明青藏高原地区MWP与20世纪前半叶的温暖幅度可比、也与其他北半球温度序列中同时期的气候特征相似,LIA较之我国中东部地区相对温暖。EOF分析结果揭示了过去千年典型气候特征(MWP、LIA及20世纪暖期等)在青藏高原的区域差异:对于MWP,其在高原东北部、中北部及西部地区约持续至1450s(其中约1250—1300s为冷波动),在喀喇昆仑及高原中东部地区约至13世纪初,高原南部诸多代用资料间接表明MWP约发生于11—15世纪(而在反映高原南部地区气候信息的第三主分量中MWP特征并不明显);对于LIA,高原东北部及西部地区的冷波动约为1450—1520s、1650—1750s、1780—1850s,喀喇昆仑地区的冷波动约为1450—1650s、1740—1780s、1820—1850s,高原南部、中东部及中北部地区的冷波动约为1580—1650s、1740—1780s(其中1670—1730s为相对暖期,并在喀喇昆仑地区也有所体现);对于近百年的全球显著升温过程,高原大部分地区均有记录,而南部与中东部地区的部分树轮年表则显示近几十年来夏季温度存在一定的下降趋势,这可能与全球变暖过程中不同季节(冬夏季节)温度变化的不一致性有关。