城市水足迹计算与分析——以上海市为例

水足迹是基于消费基础的水资源利用情况的指示器.水足迹分析可定量反映城市人类活动对水资源系统产生的压力和程度,为城市水资源可持续规划与管理提供了新的思路和研究方向.本文以上海市为案例,计算了2005年上海市的水足迹,并分析了1999-2005年间上海水足迹动态变化过程.结果表明:2005年上海市总水足迹为243.04×108 m3,人均水足迹1 366 m3/cap/1,水匮乏度高达8.16;近7年间万元GDP水足迹逐年下降,但人均水足迹明显上升.这说明上海市水资源利用呈不可持续状态,今后需要注重提高水资源利用率,提倡节约型生产和消费模式以及实施虚拟水战略等来减少其水足迹,逐步实现城市水资源的可持续利用.     

Permian age of the Burpala alkaline pluton, Northern Transbaikalia: Geodynamic implications

This paper presents the U-Pb zircon age of pulaskite of the main phase (294 ± 1 Ma) and the rare metal syenite (283 ± 8 Ma) of the Burpala alkaline pluton. The geochronological data show that it was formed in the Early Permian. By age, it is comparable with the Synnyr pluton of the Synnyr rift zone, alkaline granitic rocks and bimodal volcanic associations of the Uda-Vitim rift zone, and carbonatites of the Saizhen rift zone of the Central Asian foldbelt. These intraplate igneous complexes were formed almost simultaneously with crustal granitic rocks of the Angara-Vitim batholite. All of this gives ground to suppose that the origination of their parental melts is a result of the influence of the mantle hot spot or mantle plume on the lithosphere that led to extensive crustal anatexis.     

格网DEM侵蚀学坡长并行计算方法

针对现有侵蚀学坡长串行算法在处理大区域海量数据时计算能力的不足,基于消息传递接口(MPI)并行化工具,提出了一种格网DEM的侵蚀学坡长并行计算方法,采用缓冲区更新计算策略,解决了并行计算过程中的数据依赖性问题。选取陕北黄土高原的两组不同分辨率的DEM数据对并行算法进行了测试,结果表明,提出的并行计算方法可以有效降低侵蚀学坡长的计算时间,并取得了较好的并行效率。     

广西防城港海域沉积物特征及输运趋势

通过对2010―2011年在广西防城港海域表层沉积物所取样品进行粒度实验,并利用二维沉积物粒径趋势分析模型进行了粒径输运趋势分析。结果表明,研究区海域底质沉积物类型主要为砂、粉砂质砂、砾石质砂、砂-粉砂-黏土、黏土质粉砂和砂质粉砂等6种。粒度参数在空间分布上,沿岸和西部海域中值粒径较粗,分选中等或较好,偏态呈正偏或极正偏,在海湾口处呈负偏或极负偏;东南部海域粒径较细,分选系数差,偏态呈负偏或近对称。根据沉积物输运趋势方向不同,将研究海域分为3个区：沿岸海域主要离岸输送,方向由北向南;东南部海域的沉积物输运趋势向中间汇聚,形成一个沉积中心;西南部海域,沉积物输运方向偏北。     

Continuous zircon growth during long-lived granulite facies metamorphism: a microtextural,U–Pb,Lu–Hf and trace element study of Caledonian rocks from the Arctic

Microtextural, U–Pb, trace element and Lu–Hf analyses of zircons from gneisses dredged from the Chukchi Borderland indicate a long-lived, Cambrian–Ordovician, granulite facies metamorphism. These results reveal a complete prograde, peak and cooling history of zircon growth during anatexis. Early increasing temperatures caused modification and Pb-loss of Precambrian zircons by recrystallization and dissolution/re-precipitation of existing grains. Small variations in initial ¹⁷⁶Hf/¹⁷⁷Hf results (0.282325–0.282042) and flat HREE patterns of these zircons indicate that they grew by dissolution/re-precipitation in the presence of garnet. Zircons subsequently crystallized from a partial melt during peak to post-peak metamorphism from 530 to 485 Ma. A broad range of initial ¹⁷⁶Hf/¹⁷⁷Hf ratios (0.282693–0.282050) and mineral inclusions within zircons suggest that this phase of growth incorporated Zr and Hf obtained from the breakdown of Zr-enriched phases. Microtextural evidence along with trace element and isotopic data suggests that final growth of metamorphic rims on zircon occurred during slow cooling and crystallization of residual partial melts during the early Ordovician (485–470 Ma). Younger, late Ordovician–Silurian (420–450 Ma) euhedral, oscillatory-zoned, trace element-enriched zircons crystallized within leucocratic veins that intrude the gneisses. Their age corresponds to granitoids dated from this same dredge. The intrusives and veins provide evidence that the Chukchi Borderland rifted from a position near Pearya and northwest Svalbard, which represent the northern continuation of the Caledonian orogen. Evidence for earlier Cambrian metamorphism has not been reported from this region. The age of granulite facies metamorphism reported here represents the earliest phase of deformation in the Arctic Caledonides.     

Anomalous increase in the foF2 critical frequency prior to the Spanish earthquake of May 11, 2011

A study of variations in the critical frequency of the F2 layer (foF2) prior to a shallow-focus eartquake with a magnitude M = 5.1 which occurred in Spain on May 11, 2011, is carried out. The obtained results show that a positive disturbance in the foF2 value was observed at the ionospheric Del’ebre station, which is the closest to the earthquake epicenter. At the same time, no disturbances in foF2 are revealed at ionospheric stations located at a greater distance from the epicenter. This fact makes it possible to conclude that the positive disturbance in the F2 layer observed at the Del’ebre station could have a sesmogenic nature.     

A study of three massive star-forming regions in CS lines

We have mapped three star-forming regions (G265.14+1.45, G269.16?1.14, G291.27?0.71) in the CS(3–2) and C³⁴S(2–1) lines using the 15 m SEST telescope (Chile), and analyzed the relative positions of methanol and H₂O masers, IRAS sources, and emission maxima in the CS lines. In most cases, the maser positions are close to those of the IRAS sources. We compared the radial velocities of the maser sources and high-density CS cores, and estimated the CS column densities assuming LTE. The sizes, densities, and masses of the dense core are estimated; the masses obtained in the LTE approximation agree with the virial masses.     

Quaternary sediments in the axial zone of the Brazil Basin

Lithological and micropaleontological studies of sediments were carried out along the meridional profile across the Brazil Basin. Based on nannoplankton and diatom assemblages, the sediments represented by oxidized miopelagic clays, differently reduced hemipelagic clays, and clayey-siliceous (Ethmodiscus) and calcareous (coccolith-foraminiferal) oozes are attributed to the Pleistocene-Holocene. Specific features of sedimentary material indicate its redeposition by Antarctic bottom waters, mudflows, slumps, and rockslides. It is shown that sedimentation in the Brazil Basin corresponds to the incomplete pelagic (miopelagic) type of oceanic lithogenesis transitional to the near-continental one.     

On the Attractive Force of an Elliptical Gaussian Ring

Solar System Research - A numerical-analytical method for analyzing the orbital evolution of a planetary satellite under the influence of a perturbing body moving in an elliptical orbit is...