2015年12月乌鲁木齐极端暴雪成因分析

利用常规观测资料、NCEP FNL（1o×1o）再分析资料以及卫星、雷达资料,对乌鲁木齐2015年12月10日-12日的极端暴雪天气过程的环流演变及暴雪产生和维持的机制进行了初步分析。结果表明：此次暴雪过程是欧洲脊发展推动乌拉尔山地区长波槽东移南压,同时配合低层风场的辐合切变、地面冷锋及地形强迫抬升等共同作用造成此次过程。500hPa偏南气流,700hPa、850hPa的偏北气流在乌鲁木齐的交汇有利于加强冷暖空气的汇合和水汽的聚集,为乌鲁木齐强降雪提供了有利的动力条件。各物理量场的配合及地形作用使得此次乌鲁木齐大暴雪持续时间长,降雪强度大;降雪前期乌鲁木齐逆温使不稳定能量集中释放;散度辐合中心最强时段及上升运动均与降雪时段对应,乌鲁木齐地形引起的强迫抬升为暴雪提供有利的垂直环流;水汽的主要来源为阿拉伯海及孟加拉湾,且水汽在中低层的辐合上升明显,水汽通量散度辐合中心的出现时间对本次乌鲁木齐大暴雪的最强降水时段有很好的指示意义。     

一个海洋资料的客观分析方法和分析场的置信水平

这项工作提出了用于海洋资料的一个客观分析方法。这个方法是根据ＧａｕｓＭａｒｋｏｖ原理建立的。当给出一个待分析场中有限个资料点上的观测值时，使用这个方法可以得到相应物理量（如速度，流函数和温度等）的最小平方误差的线性估计场。在建立这个方法的过程中，也给出了计算ＲＭＳ误差的公式。使用这个方法还可以设计出有效的空间取样阵列。本文使用这个方法对海冰速度，海面风速和流函数等分别进行了分析，试验结果表明，这个方法简单、方便，得到了满意的结果     

基于语义的多细节层次3维房产模型

针对2维房产管理中的产权重叠、表达不完全和建筑物室内外一体化管理难题,在综合分析3维房产数据的对象类型及其应用特性的基础上,从概念层次提出了一种基于语义的多细节层次3维房产模型。该模型通过空间与产权的语义描述,对3维房产管理对象间的多细节层次关系进行一体化表达,特别是实现了对建筑物内部的房产空间关系表达,有利于明晰内部空间(户)的产权划分及各房产对象间的产权关联,为建立产权明晰与室内外综合管理的真3维房产应用提供了理论依据。     

The Yudomian of Siberia,Vendian and Ediacaran systems of the International stratigraphic scale

In Russia, the terminal Neoproterozoic formally includes the Vendian of western part of the East European platform and the concurrent Yudoma Group of Siberia. As is shown in this work, the designated subdivisions correspond in the stratotypes only to the upper, Yudomian Series of the Vendian. In the Siberian platform, the Ust-Yudoma and Aim horizons of the Yudomian are tightly interrelated. The lower of them, bearing remains of Ediacaran Fauna, represents the Ediacarian Stage, whereas the upper one containing small-shelled fossils (SSF) corresponds to the Nemakit-Daldynian Stage divided into the trisulcatus and antiqua superregional zones. In more complete sections of the platform periphery, sediments of these subdivisions conformably rest on siliciclastic succession that should be ranked as basal subdivision of the Yudomian. The succession is concurrent to the Laplandian Stage of the East European platform. According to geochronological dates obtained recently, the Yudomian Series spans interval of 600–540 Ma. In the East European platform, the Upper Vendian (Yudomian) begins with the Laplandian basal tillites of synonymous stage. In the west of the platform, tillites are dated at 600 Ma like the Upper Vendian base in Siberia. The next Ediacarian Stage of the East European platform is stratigraphic equivalent of the Redkino Horizon, while summary range of the Kotlin and Rovno horizons is concurrent to that of the Nemakit-Daldynian Stage. The Vendian of Russia is conformably overlain by the Tommotian Stage of the Lower Cambrian. Intense pre-Vendian events constrained distribution areas of the Lower Vendian sediments in Russia. The Lower Vendian deposits of the East European platform are most representative and well studied in the central Urals, where they are attributed to the Serebryanka Group. In Siberia, separate subdivisions representing the Lower Vendian are the Maastakh Formation of the Olenek Uplift, two lower members of the Ushakovka Formation in the Baikal region, and the Taseeva Group of the Yenisei Range. Chronological interval of the Lower Vendian corresponds to 650–600 Ma. The Marinoan Glaciation dated in Australia at 650–635 Ma is concurrent to basal part of the pre-Yudomian interval of the Vendian in Russia, whereas the Laplandian Tillite and Gaskiers Glaciation (600–580 Ma) correspond to onset of the Yudomian Epoch. The new Ediacaran System (Knoll et al., 2004) legalized in the International Neoproterozoic scale is close in range to the entire Vendian (635–544 Ma), although without basal beds (Marinoan Tillite) it deprives the terminal Neoproterozoic of its original sense. Inferiority of the system consists also in its indivisibility into stages. Hence, it is clear that the Vendian System subdivided in detail in Russia should be retained in the rank of terminal system of the Precambrian, one of the basic in general scale of the Neoproterozoic.     

Determining the condition of groundwater in evaluating the need for corrective measures: a case for the national groundwater-monitoring network in South Korea

Groundwater data (water level, electrical conductivity (EC) and temperature) have been collected since 1995 from the national groundwater-monitoring stations in South Korea. Recently, substantial groundwater-level decline and deterioration of groundwater quality were reported at several stations. Relevant authorities undertook to investigate the groundwater hazards and to devise mitigation measures for selected monitoring stations. However, there were no criteria to determine the status of the groundwater level and EC, compared with historic data. A methodology is presented, which defines the groundwater condition. Using the suggested criteria, water level and EC data are classified into normal, watch and warning levels, leading to different administrative measures and technical investigations. The primary criterion compares the observed values for the evaluation year (e.g. 2003) and the historic values of normal years preceding the evaluation year (e.g. 1996–2002), using box plots. The secondary criterion uses variation trends of the values with the aid of parametric and non-parametric trend tests. Final decisions are dependent on scores assigned to each test. According to the criteria suggested, detailed investigations and mitigation measures for water level decline are required for seven stations and those for water quality are needed for 18 stations because they reside within the warning classification.     

Numerical Study of Storm Surge Inundation in the Southwestern Hangzhou Bay Region During Typhoon Chan-Hom in 2015

Storm surge inundation is a major concern in marine hazard risk assessment during extreme weather conditions.In this study,a high-resolution coupled model(the ADVanced CIRCulation model+the Simulating WAves Nearshore model)was used to investigate the storm surge inundation in the southwestern Hangzhou Bay region during Typhoon Chan-hom in 2015.The simulated hydrodynamic processes(sea surface wave and storm tide)were validated with measured data from wave buoys and tide gauges,indicating that the overall performance of the model was satisfactory.The storm surge inundation in the coastal area was simulated for several idealized control experiments,including different wave effects(wave-enhanced wind stress,wave-enhanced bottom stress,and wave radiation stress).Dike overflowing cases with different dike heights and dike breaking cases with different dike breach lengths were considered in the simulation.The results highlight the necessity of incorporating wave effects in the accurate simulation of storm surge inundation.Dike height significantly influences the magnitude and phase of the maximum inundation area in the dike overflowing cases,and dike breach length is an important factor impacting the magnitude of the maximum inundation area in the dike breaking cases.This study may serve as a useful reference for accurate coastal inundation simulation and risk assessment.     

Identification of groundwater drought prone zones in Pedda vagu and Ookachetti vagu watersheds,tributaries of the Krishna River,India

The Pedda vagu and Ookachetti vagu watersheds located in the semi-arid regions of Mahabubnagar district are highly dependent on groundwater for irrigation owing to unreliable rainfall and over extraction of groundwater. The present study has been conducted to identify spatio-temporal groundwater droughts and drought-prone zones. Temporal groundwater droughts have been determined using a standardized water-level index along with spatial groundwater droughts using spline interpolation in Geographic Information Systems. The study shows that the groundwater droughts varied among the stations during the observation period, i.e. 1998–2011. However, the spatial assessment shows that the region as such experienced more mild groundwater droughts except during severe meteorological drought years (1998, 2002, 2004 and 2008); this indicates that the region has good scope for groundwater exploitation during dry spells and initial stages of droughts. Therefore, it is critical to have plans for the development of groundwater to cope with drought.     

Reed litter Si content affects microbial community structure and the lipid composition of an invertebrate shredder during aquatic decomposition

The decomposition of plant litter is an important mechanism in regard to energy and nutrient dynamics of ecosystems. Silicon concentration of plant tissue can affect these processes by changing litter quality, i.e. nutrient stoichiometry and cellulose and phenols content. To determine which group of microbial decomposers benefits from high Si content in plants and how this impacts on animal decomposers, a batch experiment was conducted with reed leaf litter (Phragmites australis) differing in Si content in the presence/absence of invertebrate shredders (Gammarus pulex). Lipid concentration of G. pulex, in reed litter and fine particulate matter (FPOM) were examined. High Si concentration in reed resulted in a decline of gram positive bacteria in the heterotrophic biofilm and of gram negative bacteria in FPOM. The lipid composition in the next trophic level, the decomposer G. pulex, changed too, indicating a diet shift in favor of bacteria and algae with increasing litter Si concentration. Thus, basal decomposers were affected by the Si availability in plant resources, and these effects likely persist along the food chain, as FPOM is a dominant food supply for other groups, e.g. collectors. This impact of Si content on plant substrate quality for decomposer food webs may have global relevance, due to related modifications in carbon and nutrient cycling during litter decomposition.     

Water table and transpiration dynamics in a seasonally inundated Melaleuca quinquenervia forest,north Queensland,Australia

Water table fluctuations and transpiration were monitored in a seasonally inundated Melaleuca quinquenervia floodplain forest at Cowley Beach, north Queensland, Australia. Techniques were developed to reconstruct inundation duration and seasonal and inter‐annual variability at this site using long‐term stream flow data. It was estimated that the median duration of inundation in any year was 75 days with maximum and minimum durations of 167 days and 8 days, respectively. Measurements of individual tree transpiration using heat‐pulse techniques showed a strong relationship between tree size and tree water use, which was used for scaling to stand transpiration. Stand transpiration rates were found to be closely tied to atmospheric drivers of evaporation, and transpiration of M. quinquenervia was found to be unaffected by inundation. This ability to transpire during inundation may be due to physiological adaptations of this species. These adaptations are believed to include dynamic root systems that can quickly respond to rising and falling water tables and dense networks of fine apogeotropic roots, which grow on and within the papery bark. Rates of stand transpiration remained low throughout the study (0·46 mm d^?1, 164 mm y^?1) despite the fact that transpiration was not limited by solar energy inputs or soil moisture deficit. Low stand transpiration was attributed to the low density, stunted nature and small sapwood area of trees at this site. Copyright © 2007 John Wiley & Sons, Ltd.     

论地理学面临的挑战与发展

地理科学研究地球表层系统特定时空层次下的系统有序度和变化。其发展正面临着几大挑战:①地球表层系统的复杂性难以精确定量描述;②人地关系变化速度超过人类认识与预警能力;③地球表层系统的模糊性与科学价值精确性存在矛盾;④地理学与其它学科的竞争剧烈;21世纪地理学研究主要趋势:①地理学研究人文化;②界面研究将成为自然地理研究热点;③全球研究是地理学重大题材;④地理学研究生态化;⑤山地研究将成为地理学重大领域;为着地理学的顺利发展,建议:①造就地理学思想家和战略家;②进行地理学方法论的集成和创新;③寻找适合各时代认识水平的定量化方法;④重点突出与人类命运攸关的重大课题,创立有震撼性、权威性的理论和成果。