A Mesocyclone over the Northern Sea of Japan in February 2013

Oceanology - The article considers a particular event in the influence of a mesoscale cyclone (MC) on the northern Sea of Japan on February 10–11, 2013. The passage of the MC was accompanied...     

黄土区人类活动影响下的 产汇流模拟研究

日益频繁的人类活动改变了流域下垫面条件,对流域产汇流产生很大的影响。本文以黄河中游典型支流岔巴沟为研究区域,提出利用基于DEM的分布式水文模拟技术,探讨流域人类活动过程中的产汇流模拟,避免了经验公式的概化和由此引起的局限。模拟的结果证实了该方法的可行性。采用网格滞蓄的方法可以在子网格上体现人类活动引起的下垫面的变化及其对产汇流的影响,反映各个时期的产汇流条件,对降雨做出合理响应。     

The Structure of the Bazhenov Horizon in the Northeast Part of West Siberia

A new variant of the structural-facies zonation of the Bazhenov horizon (Tithonian–Lower Berriasian) in the northeastern part of West Siberia was considered using lithofacies and structural analysis. The low content of terrigenous sedimentary material in the high-carbon facies of the Bazhenov Formation is explained by the capturing of the material by the relatively deep Pur–Taz Paleobasin, where the fan of the Yenisei–Khatanga strait was formed. The Pur–Taz Paleobasin was filled by the sediments of the Yanovstanov Formation. In the northeast the basin borders the vast and relatively shallow Ob Paleobasin, where the black shales of the oil-source Bazhenov Formation were accumulated.     

Dating of mine waste in lacustrine sediments using cesium-137

For over a century Medicine Lake in northern Idaho has received heavy-metal-laden tailings from the Coeur d'Alene mining district. Establishing the depositional chronology of the lake bottom sediments provides information on the source and rate of deposition of the tailings. Cesium-137, an isotope produced in the atmosphere by nuclear bomb tests, was virtually absent in the environment prior to 1951, but reached its apex in 1964. Our analysis of cesium-137 in the sediments of Medicine Lake revealed that 14 cm of fine-grained tailings were deposited in the lake from 1951 to 1964 and tailing deposition downstream was greatly reduced by the installation of tailings dams in the district in 1968. Cesium-137 analysis is accomplished by a fairly simple gamma-ray counting technique and should be a valuable tool for analyzing sedimentation in any lacustrine environment that was active during the 1950s and 1960s.     

Micromammals and paleoenvironmental interpretation in southern Africa

Micromammalian remains from archaeological sites in southern Africa provide paleoenvironmental evidence at a number of levels of precision. At the lowest level, broad vegetation categories can be identified. At the second level, proportional representation of vegetation categories and general climatic conditions are indicated. the possible overlying effects of agriculture and sea-level changes can also be identified. At the third level, there is clear but as yet largely unrealized potential for quantifying climatic variation and specifying environmental factors. In order to improve potential for interpretation, greater rigor is necessary in sample collection and in the establishment of the widest possible comparative data base, with the latter being in particular need of attention. Detailed paleoenvironmental information can also provide an independent data base for assessment of ecological approaches to archaeology.     

The effects of heating on low-temperature susceptibility and hysteresis properties of basalts

The variation of the low-field susceptibility of basalts down to liquid-nitrogen temperature always falls into one of three types that depend on the composition and grain size of the titanomagnetite grains present. Group 1 basalts contain predominantly unoxidised, multidomain homogeneous titanomagnetites having x 0.3. Group 2 basalts contain predominantly titanomagnetite grains with many exsolved ilmenite lamallae that subdivide the grains so that they act similarly to single domains. Group 3 basalts contain predominantly multidomain magnetite or magnetite-rich titanomagnetite having x 0.15. After repeated heating to 615°C, the group 1 basalts gradually oxidise above 300°C to produce the characteristics of group 2 basalts, owing to the exsolution of ilmenite. On the other hand, both group 2 and 3 basalts are stable to oxidation until at least 500°C. They are therefore the most useful material for palaeointensity studies.     

Fluids in the lithosphere, 2. Experimental constraints on CO2 transport in dunite and quartzite at elevated P-T conditions with implications for mantle and crustal decarbonation processes

In a series of experiments at 0.5–1.3 GPa and 1050–1200°C we have monitored the transport, via crack propagation, of CO₂ into well-annealed olivine and quartz aggregates. The objectives were to determine (1) the extent and rate of fluid penetration; (2) the effect of varying both P-T conditions and microstructure; and (3) the fluid penetration pathways. Experiments on CO₂ penetration into dunite annealed in the absence of MgO indicate rapid and pervasive fluid transport on a grain-dimension scale, but a limited penetration distance ( 1 mm). Additional experiments on dunite annealed in the presence of MgO (either dispersed or present at both ends), however, resulted in CO₂ penetration that was both pervasive on the scale of individual grains and almost always completely through the 5 mm long samples. The abundance of fine (10 μm) grains in the MgO-free dunite, in contrast to the much larger grain sizes of the samples annealed with MgO present, suggests the difference in fluid penetration behavior may arise because the strength variation in dunite scales with the grain size. Effects arising from changes in olivine point defect chemistry, however, are an additional possibility. The response of synthetic quartzite to CO₂ overpressure is distinct from that of dunite: Quartzite experiences rapid and complete penetration of CO₂, via a macroscopically visible system of transgranular fractures, over the range of P-T conditions investigated.The small amount of porosity ( 2–3%) present in most rock samples fabricated for this study, lacks three-dimensional connectivity, thus precluding any enhanced fluid penetration via porous flow. Pores could possibly enhance fluid penetration as the result of a small reduction in resistance to fracture, but the probable abundance of strength-controlling flaws in natural rocks is likely to produce similar behavior.The results of our experiments on olivine and olivine + MgO suggest that the transport of pressurized CO₂ in very olivine-rich mantle environments will be pervasive on the scale of individual grains and its extent may be dependent on rock microstructure and/or crystal chemical effects. Such pervasive fluid transport, perhaps associated with magma decarbonation, may have interesting implications for both magma transport and local LREE enrichment of adjacent mantle wall-rock. The ease with which quartzite is penetrated by CO₂ at the conditions of our experiments underscores the possible role of decarbonation reactions in crustal permeability-enhancement processes.     

文安5.1级地震的一些异常特征

对文安5.1级地震的一些异常进行了分析和总结,认为地震逆时针方向迁移可能是地震空间活动的一个基本特征,其可作为背景异常。震前,地磁交汇法出现的异常,再次显示出该方法对地点预测的最大优势,交汇点附近即是未来震中区。这些异常特征对我们认识地震和预测地震都具有一定意义。     

An investigation of the controls on Irish precipitation δ18O values on monthly and event timescales

This two-year study investigates the relative influence of meteorological variables (precipitation amount and temperature), atmospheric circulation, air mass history, and moisture source region on Irish precipitation oxygen isotopes (δ¹⁸O_p) on event and monthly timescales. Single predictor correlations reveal that on the event scale, 20% of δ¹⁸O_p variability is attributable to the amount effect and 7% to the temperature effect while on the monthly timescale the North Atlantic Oscillation accounts for up to 20% of δ¹⁸O_p variability and the amount and temperature effects are not significant. In comparison, multivariate linear regression reveals that the interaction of temperature and precipitation amount explains up to 40% of δ¹⁸O_p variance at event and monthly timescales. Five-day kinematic back trajectories suggest that the amount-weighted mean δ¹⁸O_p value of southerly- and northerly-derived events are lower by 2‰ relative to events derived from the west. Because air mass history and atmospheric circulation appear to influence δ¹⁸O_p in Ireland, Irish paleo-δ¹⁸O_p proxy records are best interpreted as reflecting a combination of parameters, not just paleotemperature or paleorainfall.     

国务院气象数据服务系统的升级改造

为了更好地保障国务院办公厅接收中国气象局提供的各类气象数据,解决旧有系统存在的问题,对现有国务院气象数据服务系统进行升级改造。全新开发的数据收集发送功能,解决了现有系统无法进行非法文件过滤和配置灵活性问题;升级现有的监视系统,使新系统满足业务需要的检索、报警、时效计算等功能;扩充的补调下载功能更加贴近操作员的使用习惯。改造后的系统通过数据传输与时效监视功能的分离和程序的改进,增强了传输可靠性和时效性,同时能够为未来业务应用扩展提供支持。经过实际业务测试,系统运行稳定,并为2011年国务院汛期服务提供了有效支撑。