大兴安岭地区的一次暴雪天气诊断分析

利用常规观测资料、FY-2气象卫星水汽云图、多普勒雷达资料、NCEP(1°×1°)逐6h再分析资料对2016年11月13—14日东北冷涡背景下的大兴安岭地区暴雪天气过程进行分析。结果表明:高空冷涡后部横槽南摆,使干冷空气南下以及冷涡前部西南低空急流北上且辐合急剧加强为暴雪天气提供了非常有利的环流背景;≥20m·s-1的西南低空急流作为水汽输送带,为暴雪区提供了充足的水汽来源;垂直上升运动中心和散度辐合辐散中心基本耦合且加强,为暴雪提供了强有利的动力抬升条件,有利于上升运动的增强发展;暴雪是发生在条件对称不稳定的(湿位涡MPV2<0)的背景下,暴雪中心位于MPV2等值线密集带以及MPV2绝对值得到较大增长的区域。水汽图像上有表征干侵入特征的干缝、斧形暗区等;雷达回波显示低层东南风急流非常显著,低层强烈发展的东南暖湿气流与东北—西南走向的大兴安岭山脉相垂直时,地形强迫抬升不仅使迎风坡的垂直上升运动迅速加强,而且使低层水汽辐合得到加强和维持为暴雪提供了充足的水汽,这也是暴雪主要集中在大兴安岭东麓的重要因素。     

Abundant Fe–Ti oxide inclusions in olivine from the Panzhihua and Hongge layered intrusions, SW China: evidence for early saturation of Fe–Ti oxides in ferrobasaltic magma

Abundant Fe–Ti oxide inclusions in cumulus olivine (Fo_77–81) from the Panzhihua and Hongge intrusions, Emeishan large igneous province, SW China, document the first evidence for early crystallization of Fe–Ti oxides in ferrobasaltic systems in nature. The intrusions also contain significant stratiform Fe–Ti–V oxide ores. The oxide inclusions are sub-rounded or irregular, range from ∼5 to 50 μm in diameter, and are dominated by either titanomagnetite or ilmenite. The fact that the inclusions are either titanomagnetite- or ilmenite-dominant suggests that they are trapped crystals, instead of immiscible oxide melt, formed during growth of the host olivine. The absence of other silicate phases in the inclusion-bearing olivine is difficult to reconcile with a possible xenocrystic origin of the oxide inclusions. These oxide inclusions are thus interpreted to be cumulus minerals crystallized together and trapped in olivine from the same parental magma. In addition to Fe–Ti oxides, some inclusions contain amphibole + biotite ± fluorapatite that might have formed by reaction of trapped hydrous liquid with the host olivine. Numerical modeling of high-Ti Emeishan basalts using the MELTS program successfully simulates early crystallization of olivine (∼Fo₈₁) and Fe–Ti spinel in the presence of a moderate amount of H₂O (∼1.5 wt%) under pressure and fO₂ conditions generally pertinent to the Panzhihua and Hongge intrusions. The modal mineralogy of the oxide inclusions is in good agreement with the bulk compositions of the ore, as inferred from whole-rock data, in a given intrusion. This is consistent with the interpretation that the stratiform oxide ores in the intrusions formed by accumulation of Fe–Ti oxide crystals that appeared on the liquidus with olivine and clinopyroxene.     

Synchronous syntectonic granite emplacement in the south palmer river region,Hodgkinson Province,Australia

Deformation partitioning in pluton wall‐rocks during granite intrusion that is synchronous with regional tectonism potentially creates structures suggesting different timing of emplacement. This is due to variations in style and intensity of fabric development, particularly porphyroblast‐matrix microstructures. In the South Palmer River region, detailed mapping plus microstructural examination of matrix and porphyroblast‐matrix relationships assist correlation of deformation elements across variations in deformation style and intensity. The results indicate that the emplacement of each granite body occurred during the compressional Permian D₄ event. The fabrics that developed regionally and in the pluton/wall‐rock systems during D₄ show differing degrees of intensity and style, which are spatially related to the intensity of D₄ fabric development in the adjacent country rock. Granite isotopic ages support non‐diachronous formation of D₄ structures across the region.     

江西武功山热穹隆变质--岩浆作用及演化

处于扬子与华夏古板块加里东期拼贴带的武功山热穹隆,以造山期变形花岗岩为中心,南华一寒武系遭受绿片岩相一低角闪岩相变质并形成变质矿物分带,环绕岩体分布,与中生代以来伸展形成的脆性断裂系统构成外环,共同组合形成屹立于晚古生代地层分布区的穹隆状构造。在区域递增变质带基础上,造山早期,深部初始重熔岩浆与深埋的变质岩发生交代形成原地型英云闪长质“混染岩浆”,岩浆上浸过程中,活动组分不断作用于围岩,致使围岩的成分、结构构造产生重新调整,形成岩体边缘混合岩。同时,由于硅铝质围岩组分加入,酸度增加,而渐变过渡为花岗闪长质岩浆。造山晚期,进一步演化为岩浆型正常花岗岩,并呈套叠状侵入于早期岩体之中。从早到晚构成同源岩浆演化系列,并发育明显构造应力变形。热穹隆区加里东期形成递进渐增变质一岩体边缘混合一变形花岗岩“三位一体”分布格局。中生代伸展一岩浆作用的复合叠加,进一步强化了热穹隆的构造背景。大致在旱白垩世末基本定型。     

Marine and human activity influences on the groundwater quality of southern Korinthos area (Greece)

In this paper the groundwater quality of the southern part of Korinthos region (north‐east Peloponnese) is discussed. The geology is characterized by a thick sequence of Neogene marls alternating with sandstones, overlain by superficial Quaternary deposits. The latter consist of a mixture of loose materials such as conglomerates, marly sandstones, sands and clay to silty sands. The area is crossed by a fault system parallel to the coastline, and the Quaternary sediments have formed extended Tyrrhenian marine terraces. Two aquifers have been identified in the area. The first is unconfined and occurs within the Quaternary sediments whereas the other is a deep confined aquifer occurring within the underlying Neogene marl series. Analysis of hydrochemical evolution over the past 30 years has indicated significant deterioration of quality owing to seawater intrusion and nitrate pollution. The various sources of pollution have rendered, to a large extent, shallow groundwater unsuitable not only for potable water supply but also for irrigation purposes. However, this is not the case for the deeper confined aquifer. Statistical analysis was used to explore the evolution of salinization during the years 1968 and 1998. In view of the alarming conditions caused by the documented groundwater quality deterioration, the need for integrated water resources management is stressed to maintain the socio‐economic growth of the region studied. Copyright © 2003 John Wiley & Sons, Ltd.     

Stack unit mapping of coastal aquifer to predict and control sea water intrusion using remote sensing and a geographical information system

Aquifers are inherently susceptible to contamination and coastal aquifers in specific are highly vulnerable to sea water intrusion. For efficient planning and management of coastal aquifers in Kayalpattu and Tiruchopuram villages, which extend over 4·05 km², it is essential to delineate and predict the extent of intrusion into the shallow aquifer. Management of ground water in coastal aquifers is composed of major elements that should be properly evaluated, and special attention is given to the sea water intrusion problem. Different data, like hydro‐geomorphological and depth‐wise iso‐apparent resistivity, are integrated spatially using a geographical information system. The stack‐unit mapping approach is used to delineate the zones with iso‐apparent resistivity of less than 10 Ω m have been found to be increasing in areal extent with reference to depth. Copyright © 2003 John Wiley & Sons, Ltd.     

关联规则和序列模式算法在入侵检测系统中的应用

将关联规则算法与序列模式算法应用于入侵检测系统中,介绍了将扩展的关联规则Apriori算法与序列模式GSP算法相结合,挖掘原始审计数据中频繁模式的过程,并实现了这两种算法在入侵检测中的应用.     

湖北省气象局网络安全系统设计

通过介绍湖北省气象局网络安全需求，分析了现有网络系统存在的安全弱点，利用目前主要的网络安全防御技术，设计了一个整体的网络安全系统，为湖北省气象局网络安全系统的后续建设和实施提供了具体的思路。     

Isotopic and geochemical identifications of groundwater salinisation processes in Salalah coastal plain,Sultanate of Oman

A detail investigation was carried out to improve the current knowledge of groundwater salinisation processes in coastal aquifers using hydrochemical and isotopic parameters. Data of major ions for 40 wells located in the Salalah plain aquifer, Sultanate of Oman, were collected during pre-monsoon 2004 and analysed. The groundwater changes along the general flow path towards the coast from fresh (EC < 1500 μS/cm), brackish (EC: 1500–3000 μS/cm) and saline (EC > 3000 μS/cm). Results of inverse modeling simulations using PHREEQC show that dissolution of halite may be the main source of Cl and Na in the study area. Ionic delta calculation indicates that the depletion of Na and K and enrichment of Ca and Mg in groundwater were probably attributed to reverse ion exchange reactions. During a sampling campaign conducted in October 2015, 11 groundwater samples were collected for Cl, Br and isotopic analysis (²H/¹⁸O). Molar Cl/Br ratios in fresh groundwater were higher than those of seawater, indicating the impact of halite dissolution on the groundwater quality. For saline groundwater, these ratios were less than those of seawater, showing the influence of anthropogenic input from agriculture on the same. Relatively depleted isotopic signature of all groundwater samples show that the monsoon precipitation is the main source of groundwater recharge in the study area.     

Groundwater recharge and salinization in the arid coastal plain aquifer of the Wadi Watir delta,Sinai, Egypt

The Quaternary coastal plain aquifer down gradient of the Wadi Watir catchment is the main source of potable groundwater in the arid region of south Sinai, Egypt. The scarcity of rainfall over the last decade, combined with high groundwater pumping rates, have resulted in water-quality degradation in the main well field and in wells along the coast. Understanding the sources of groundwater salinization and amount of average annual recharge is critical for developing sustainable groundwater management strategies for the long-term prevention of groundwater quality deterioration. A combination of geochemistry, conservative ions (Cl and Br), and isotopic tracers (^87/86Sr, δ⁸¹Br, δ³⁷Cl), in conjunction with groundwater modeling, is an effective method to assess and manage groundwater resources in the Wadi Watir delta aquifers. High groundwater salinity, including high Cl and Br concentrations, is recorded inland in the deep drilled wells located in the main well field and in wells along the coast. The range of Cl/Br ratios for shallow and deep groundwaters in the delta (∼50–97) fall between the end member values of the recharge water that comes from the up gradient watershed, and evaporated seawater of marine origin, which is significantly different than the ratio in modern seawater (228). The ^87/86Sr and δ⁸¹Br isotopic values were higher in the recharge water (0.70,723 < ^87/86Sr < 0.70,894, +0.94 < δ⁸¹Br < +1.28‰), and lower in the deep groundwater (0.70,698 < ^87/86Sr < 0.70,705, +0.22‰ < δ⁸¹Br < +0.41‰). The δ³⁷Cl isotopic values were lower in the recharge water (−0.48 < δ³⁷Cl < −0.06‰) and higher in the deep groundwater (−0.01 < δ³⁷Cl < +0.22‰). The isotopic values of strontium, chloride, and bromide in groundwater from the Wadi Watir delta aquifers indicate that the main groundwater recharge source comes from the up gradient catchment along the main stream channel entering the delta. The solute-weighted mass balance mixing models show that groundwater in the main well field contains 4–10% deep saline groundwater, and groundwater in some wells along the coast contain 2–6% seawater and 18–29% deep saline groundwater.A three-dimensional, variable-density, flow-and-transport SEAWAT model was developed using groundwater isotopes (⁸⁷Sr/⁸⁶Sr, δ³⁷Cl and δ⁸¹Br) and calibrated using historical records of groundwater level and salinity. δ¹⁸O was used to normalize the evaporative effect on shallow groundwater salinity for model calibration. The model shows how groundwater salinity and hydrologic data can be used in SEAWAT to understand recharge mechanisms, estimate groundwater recharge rates, and simulate the upwelling of deep saline groundwater and seawater intrusion. The model indicates that most of the groundwater recharge occurs near the outlet of the main channel. Average annual recharge to delta alluvial aquifers for 1982 to 2009 is estimated to be 2.16 × 10⁶ m³/yr. The main factors that control groundwater salinity are overpumping and recharge availability.