ENSO-independent contemporaneous variations of anomalous circulations in the Northern and Southern Hemispheres: The polar-tropical seesaw mode

Using the NCEP/NCAR reanalysis and the ENSO indices from the Climate Prediction Center over the period 1978–2014, we have investigated the contemporaneous circulation variations in the Northern and Southern Hemispheres by performing the singular value decomposition analysis of sea level pressure anomalies (SLPA) after the ENSO signal is regressed out. It is found that there exists a polar-tropical seesaw mode (PTSM) that characterizes with the out of phase fluctuations of SLPA between the polar and tropical regions in the Northern and Southern Hemispheres in boreal winter. This PTSM explains 47.74% of the total covariance of SLPA and is almost independent of ENSO. It demonstrates a long-term trend and oscillation cycles of 2–3 and 4–6 yr. The long-term trend in PTSM indicates that the sea level pressure gradually decreases in the tropics and increases in the polar region with time. This PTSM looks roughly symmetric about the equator besides the seesaw pattern of SLPA between the tropics and polar region in each hemisphere. The disturbances in the geopotential height field in association with the PTSM shows baroclinic features in the tropics whereas equivalent barotropic features in the mid and high latitudes in the troposphere. The anomalous thermal forcing in the tropical region is possibly one of the factors facilitating the formation of this PTSM. Significant global precipitation and temperature anomalies related to the PTSM are observed. In the positive PTSM phase, precipitation and temperature are higher than normal in southern Europe and the Mediterranean and surrounding areas, but lower than normal in northern Europe and Siberia. Precipitation is higher than normal while temperature is lower than normal in Northeast Asia. Significant temperature and precipitation anomalies possibly occur in the regions of western China, northern India, parts of North America, parts of subtropical Africa, Maritime Continent, and Antarctic. These results are helpful for better understanding of the circulation variations and the mechanisms behind the interactions between the Northern and Southern Hemispheres and the related winter climate anomalies over globe.     

地震台站雷电防护技术探讨

地震台站的仪器多采用集成电路、集成块等高精密电子元件,承受外部环境能力相对较弱,容易遭受雷电的侵害。在分析雷电如何危害地震台站仪器设备基础上,针对地震台站工作实际,探讨应用雷电防护技术,减轻雷电对地震观测技术系统仪器设备的损害,及对地震台站雷电防护的参考意义。     

中国板块构造与盐类矿产

中国大陆的华北、塔里木、准噶尔－兴安、华南及甘青藏等五大板块发展过程中于地块边缘活动带、陆间裂谷、陆内裂谷等场所生成的含盐盆地，沉积了各时期（Ｏ、Ｃ、Ｔ、Ｊ－Ｅ和Ｑ）盐类矿床。通过分析对比认为，甘青藏板块兰坪－思茅拗陷带（Ｊ２－Ｅ１、Ｑ），塔里木板块（Ｃ、Ｋ－Ｅ、Ｑ），华北板块（Ｏ２），华南板块（Ｔ１－２）为成钾有利地带，中国东部众多的Ｋ－Ｅ红层盆地中成钾条件较差     

ENSO循环与低纬度大气的正压和斜压运动

利用一个２层海洋模式和ＧＩＳＳＴ资料、ＮＣＥＰ再分析资料,对大气正压／斜压运动与ＥＳＮＯ循环之间的联系进行了研究。结果表明,在赤道中、东太平洋地区,大气斜压模在ＥＮＳＯ时间尺度上的变化位相略超前于正压模的变化,正压模的变化位相超前于ＳＳＴＡ变化,ＳＳＴＡ变化位相超前斜压模的变化位相。斜压纬向风异常与ＳＳＴＡ具有正相关关系（西太平洋西部相反）;正压模则与Ｎｉｎｏ３区海温异常有负相关关系（西太平洋西部     

土壤样品中稀土元素的高分辨电感耦合等离子质谱分析及其不确定度的评定探讨

在敞开体系中,用HF、HNO₃和HClO₄溶解电感耦合等离子体质谱法同时测定土壤样品中的15种稀土元素。在高分辨等离子体质谱仪(Element2)上建立了土壤样品中稀土元素含量的ICP-MS分析方法,经土壤国家一级标准物质分析验证,结果与标准值相符,测定的15种稀土元素的相对标准偏差均小于10%,加标回收率为96.5%~114.7%。实验表明,该方法不但操作简便快速,而且具有灵敏度高、检出限低,重现性好等优点,举例说明了测量不确定度的评定程序。     

Geochronology,Geochemistry and Petrogenesis of the Pungco Ophiolite,TibetEI北大核心CSCD

Although the middle section of the Bangong-Nujiang suture zone has been intensively investigated, its tectonic framework and evolution is still controversy. The Pungco ophiolite has a relative complete ophiolitic complex, which is an ideal specimen for studying this tricky problem. LA-ICP-MS U-Pb dating of zircons from the diabasic rock yielded an age of 159.0±2.1 Ma. This age suggests that the Pungco ophiolite was formed in the Late Jurassic, indicating the development of the Late Jurassic ophiolite in the third ophiolitic subzone. The whole-rock major and trace element compositions of diabasic and basaltic rocks exhibit mixed arc and N-MORB geochemical characteristics. Two diabasic samples have (87Sr/86Sr)i values of 0.7055 and 0.7063 and εNd(t) values of 11.28 and 11.84, respectively. The geochemical signatures and formation age of the Pungco ophiolite suggest that this ophiolite was probably produced in an active continental fore-arc setting. It originated from a N-MORB-like depleted mantle source with the involvement of subducted-slab fluids. Considering the regional geological background, the Pungco ophiolite was likely generated during the southward subduction of the Bangong-Nujiang Tethyan oceanic lithosphere beneath the Lhasa terrane, and belongs to a regional archipelagic arc-basin system together with the other Early Jurassic-Early Cretaceous ophiolites from the northern Tibet Lake district. © 2018, Science Press. All right reserved.     

GQL: Extending Xquery to query GML documents

GML is becoming the de facto standard for electronic data exchange among the applications of Web and distributed geographic information systems. However, the conventional query languages (e.g. SQL and its extended versions) are not suitable for direct querying and updating of GML documents. Even the effective approaches working well with XML could not guarantee good results when applied to GML documents. Although XQuery is a powerful standard query language for XML, it is not proposed for queryings spatial features, which constitute the most important components in GML documents. We proposes GQL, a query language specification to support spatial queries over GML documents by extending XQuery. The data model, algebra, and formal semantics as well as various spatial functions and operations of GQL are presented in detail.     

A Review of Study on Fe-C Interaction and Their Adsorption Properties to Soil Heavy Metal

Nowadays, the Fe-C coprecipitate mechanism is recognized by more and more scholars and becomes the hot topic in the environmental science. On the basis of discussing the interaction between iron oxide and organic matter, and the adsorption research progress of Fe-C complexes on heavy metals, the immobilization potential of Fe-C complexes on heavy metals in polluted soil were illustrated. The surface properties and physical characterizations of iron oxide are changed regularly with the interaction of organic matter, which lead to the higher adsorption capacity of Fe-C complexes in contrast to single iron oxide. Besides, the influences of pH values, organic matter types and surface properties of iron oxides on the adsorption capacity of Fe-C complexes on heavy metals were discussed. The excellent adsorption performance of Fe-C complexes in certain conditions will provide important theoretical basis for contaminated soil remediation.     

中国地震电磁现象的观测与研究

对近年来中国地震电磁现象(包括地面电磁场、大气电场、地磁脉冲和电离层扰动等)的观测研究进行了重点介绍。     

中国大陆西部强震前超低频磁场时空变化特征

对2015年至2019年期间中国大陆西部的磁通门磁力仪秒采样观测资料开展了5—100 s频段的地磁垂直强度极化分析,并运用一些数学方法对分析结果进行了处理.结果显示,极化高值在经向和纬向均无明显的形态和幅值变化,且极化高值与地磁外源场扰动无关.在此基础上筛选出18次极化高值异常事件,利用插值方法得到了极化高值异常的空间...