5—6月东北冷涡持续活动及强度特征

利用1960—2012年5—6月NCEP/NCAR逐日再分析资料,基于冷涡经典定义,采取客观识别方法检索东北冷涡活动过程,根据东北冷涡活动时空变化特征给出东北冷涡持续活动过程标准, 通过冷涡强度指数进行定量化分析,该指数对冷涡持续活动过程具有较好表征意义。冷涡活动强对应5月乌拉尔山阻塞高压、贝加尔湖阻塞高压和6月鄂霍次克海阻塞高压活动频繁。通过强弱指数年合成,得到6月强指数年冷涡系统较深厚,集中于对流层中高层,冷心结构明显,具有一定大气斜压特征; 高层存在冷中心,低层有冷空气活动,中高层西风带呈明显的上游分流和下游汇合特征,分汇流之间呈东北高、西南低的偶极子阻塞形势;弱指数年冷涡系统较浅薄,主要集中在对流层中低层,冷心结构不明显,不存在阻塞形势。     

大兴安岭Cu- Mo- Ag多金属成矿带主要地质成矿特征及潜力分析

大兴安岭成矿带是2008年确定的首批16个重要成矿带之一,随着新的找矿进展和预测成果不断涌现,需要对其开展新一轮研究总结。本文以新的研究成果和找矿突破为基础,通过综合分析,重新厘定大兴安岭成矿带的边界并将其命名为"大兴安岭Cu-Mo-Ag多金属成矿带"。结合区域成矿地质背景的综合研究,在区内划分了5个III级成矿带,初步建立了Cu-Mo-Ag多金属成矿带成矿谱系,并将其主要成矿期归纳为两期:海西期和燕山期;在典型矿床成矿地质特征及潜力评价综合分析的基础上,总结了研究区主要成矿类型为热液型银铅锌矿、斑岩型铜钼矿和接触交代型铁锡多金属矿。结合区域找矿进展和潜力评价最新成果,认为本区Cu、Mo、Ag、Sn、Pb、Zn潜力巨大,为下一步勘查部署的主攻矿种,同时在本区划分了16个远景区,其中10个为重点远景区,6个为远景调查区,对研究区下一步矿产勘查部署工作有一定指导意义。     

Fractionation characteristics of rare earth elements (REEs) linked with secondary Fe,Mn, and Al minerals in soils

Soil secondary minerals are important scavengers of rare earth elements (REEs) in soils and thus affect geochemical behavior and occurrence of REEs. The fractionation of REEs is a common geochemical phenomenon in soils but has received little attention, especially fractionation induced by secondary minerals. In this study, REEs (La to Lu and Y) associated with soil-abundant secondary minerals Fe-, Al-, and Mn-oxides in 196 soil samples were investigated to explore the fractionation and anomalies of REEs related to the minerals. The results show right-inclined chondrite-normalized REE patterns for La–Lu in soils subjected to total soil digestion and partial soil extraction. Light REEs (LREEs) enrichment features were negatively correlated with a Eu anomaly and positively correlated with a Ce anomaly. The fractionation between LREEs and heavy REEs (HREEs) was attributed to the high adsorption affinity of LREEs to secondary minerals and the preferred activation/leaching of HREEs. The substantial fractions of REEs in soils extracted by oxalate and Dithionite-Citrate-Bicarbonate buffer solutions were labile (10 %–30 %), which were similar to the mass fraction of Fe (10 %–20 %). Furthermore, Eu was found to be more mobile than the other REEs in the soils, whereas Ce was less mobile. These results add to our understanding of the distribution and geochemical behavior of REEs in soils, and also help to deduce the conditions of soil formation from REE fractionation.     

Change Analysis of Three Major Antarctic Ice Shelves Based on Multi-source Remote Sensing Data

In recent years, melting and calving happen in the Antarctic ice shelves. In this paper, seven periods of coastlines were applied to provide an analysis of the ice front changes of Ross, Filchner-Ronne and Amery ice shelves with the inclusion of 1997 and 2000 Radarsat products, 2003/2004 and 2008/2009 MODIS products and 2006, 2012, 2015 coastline which were extracted from MODIS images. Change area, SCE (Shoreline Change Envelope) and NSM (Net Shoreline Movement) were applied to analyze the variation of the ice shelf front. The results shows that, the ice front of Amery ice shelf has advanced since 1997 and the total outward extension distance of the ice front was about 20 to 25 km while the advance area reached 3.03×10³ km². Ross ice shelf and Filchner-Ronne ice shelf continued to advance after ice calving events under the driver action of glacier. However, the advance area was less than the retreat area and the net change area is respectively -9.39×10³ km² and -5.86×10³ km². The retreat distance of the collapse area were up to 53 km and 39 km in the two biggest ice shelves.     

Iron Reduction Along an Inundation Gradient in a Tidal Sedge (<Emphasis Type="Italic">Cyperus malaccensis</Emphasis>) Marsh: the Rates,Pathways, and Contributions to Anaerobic Organic Matter Mineralization

Incubation experiments were adopted to characterize the rates and pathways of iron reduction and the contributions to anaerobic organic matter mineralization in the upper 0–5 cm of sediments along a landscape-scale inundation gradient in tidal marsh sediments in the Min River Estuary, Southeast China. Similar sediment characteristics, single-species vegetation, varied biomass and bioturbation, distinct porewater pH, redox potential, and electrical conductivity values have resulted in a unique ecogeochemical zonation along the inundation gradient. Decreases in solid-phase Fe(III) and increases in nonsulfidic Fe(II) and iron sulfide were observed in a seaward direction. Porewater Fe²⁺ was only detected in the upland area. High rates of iron reduction were observed in incubation jars, with significant accumulations of nonsulfidic Fe(II), moderate accumulations of iron sulfides, and negligible accumulations of porewater Fe²⁺. Most of the iron reduction was microbially mediated rather than coupled to reduced sulfides. Microbial iron reduction accounted for 20–89 % of the anaerobic organic matter mineralization along the inundation gradient. The rate and dominance of microbial iron reduction generally decreased in a seaward direction. The contributions of microbial iron reduction to anaerobic organic matter mineralization depended on the concentrations of bioavailable Fe(III), the spatial distribution of which was significantly related to tidal inundation. Our results clearly showed that microbial iron reduction in the upper sediments along the gradient is highly dependent on spatial scales controlled primarily by tidal inundation.     

皂角沱崩塌形成机制数值模拟

以位于"5·12"汶川大地震震中区的皂角沱崩塌为研究对象,通过对崩塌所处的自然地理、工程地质环境进行野外调查,分析崩塌的发育特征;采用不连续变形分析软件DDA,对坡体失稳崩塌的全过程进行模拟研究。结果表明,斜坡地形放大效应在震中区是客观存在的,具倾向坡外的陡倾控制性结构面的高陡突出地形对地震波具有明显的放大作用。该坡体崩塌失稳模式为:峰值加速度放大→增加的振幅迫使岩体沿陡倾坡外的控制性结构面迅速拉裂→沿滑动面发生崩滑→高速脱离滑源区→巨大的势能和动能驱动块体做长距离运动。通过数值模拟可知,随着斜坡坡高的增大,地震加速度和速度无论是在水平向,还是在竖直向均存在放大效应,但是水平向的放大效应较竖直向更明显;结构面监测点的加速度和速度放大系数相比稳定的坡体要大得多,地震袭来,当遇到陡倾坡外的不连续结构面时,斜坡动力响应强烈,最终危岩体沿控制性结构面发生崩滑破坏。     

Curvedness feature constrained map matching for low-frequency probe vehicle data

Map matching method is a fundamental preprocessing technique for massive probe vehicle data. Various transportation applications need map matching methods to provide highly accurate and stable results. However, most current map matching approaches employ elementary geometric or topological measures, which may not be sufficient to encode the characteristic of realistic driving paths, leading to inefficiency and inaccuracy, especially in complex road networks. To address these issues, this article presents a novel map matching method, based on the measure of curvedness of Global Positioning System (GPS) trajectories. The curvature integral, which measures the curvedness feature of GPS trajectories, is considered to be one of the major matching characteristics that constrain pairwise matching between the two adjacent GPS track points. In this article, we propose the definition of the curvature integral in the context of map matching, and develop a novel accurate map matching algorithm based on the curvedness feature. Using real-world probe vehicles data, we show that the curvedness feature (CURF) constrained map matching method outperforms two classical methods for accuracy and stability under complicated road environments.     

Size distributions and source function of sea spray aerosol over the South China Sea

The number concentrations in the radius range of 0.06 – 5 μm of aerosol particles and meteorological parameters were measured on board during a cruise in the South China Sea from August 25 to October 12, 2012. Effective fluxes in the reference height of 10 m were estimated by steady state dry deposition method based on the observed data, and the influences of different air masses on flux were discussed in this paper. The number size distribution was characterized by a bimodal mode, with the average total number concentration of(1.50 ± 0.76)×10~3 cm~(-3). The two mode radii were 0.099 μm and 0.886 μm, both of which were within the scope of accumulation mode. A typical daily average size distribution was compared with that measured in the Bay of Bengal. In the whole radius range, the number concentrations were in agreement with each other; the modes were more distinct in this study than that abtained in the Bay of Bengal. The size distribution of the fluxes was fitted with the sum of log-normal and power-law distribution. The impact of different air masses was mainly on flux magnitude, rather than the shape of spectral distribution. A semiempirical source function that is applicable in the radius range of 0.06 μmr_(80)0.3 μm with the wind speed varying from 1.00 m s~(-1) to 10.00 m s~(-1) was derived.     

省市级基础地理信息框架数据联动更新探究

基于潍坊市寿光基础地理信息数据库建设更新工程与省地理信息公共服务平台框架数据更新工程,探索了省市基础地理信息框架数据联动更新的工作模式,提出了通过建立多比例尺基础框架数据的方式,建立省市基础框架数据库的联系,通过增量更新的模式完成省市两级基础框架数据库联动更新的方法。