中国夏季降水异常分布的非线性特征

运用基于前馈型人工神经网络的非线性主成分分析方法(NLPCA),对中国近50 a夏季降水异常分布的非线性特征进行了分析。结果表明,中国夏季降水的异常分布具有一定的非线性特征,当夏季降水距平的一维NLPCA近似在非线性主成分取极端相反位相时,对应的空间分布型表现出明显的不对称性;一维NLPCA对夏季原始降水距平场的近似,比传统一维PCA的近似更为逼真。     

云南麻栗坡新寨锡矿物化探异常特征

新寨锡矿是物化探扫面发现的大型锡石硫化物矽卡岩型矿床，高磁，高激电率，低电阻率异常，原生晕Sn,W,Cu,Zn,As,B,Ag,Cd,Be,Bi,In,F(Mo,Ge,Co)等元素异常，次生晕Sn,Cu,Zn,As,B等异常，总结地球物理化学特征，对滇东南寻找同类矿床具有重要指导意义。     

Geochemical Characteristics and Genetic Significance of Datangpo‐Type Manganese Ore Deposits during the Cryogenian Period

The Datangpo‐type manganese ore deposits, which formed during the Nanhuan (Cryogenian) period and are located in northeastern Guizhou and adjacent areas, are one of the most important manganese resources in China, showing good prospecting potential. Many middle‐to‐large deposits, and even super‐large mineral deposits, have been discovered. However, the genesis of manganese ore deposits is still controversial and remains a long‐standing source of debate; there are several viewpoints including biogenesis, hydrothermal sedimentation, gravity flows, cold‐spring carbonates, etc. Geochemical data from several manganese ore deposits show that there are positive correlations between Al₂O₃ and TiO₂, SiO₂, K₂O, and Na₂O, and strong negative correlations between Al₂O₃ and CaO, MgO, and MnO in black shales and manganese ores. U, Mo, and V show distinct enrichment in black shales and inconspicuous enrichment in Mn ores. Ba and Rb show strong positive correlations with K₂O in manganese ores. Cu, Ni, and Zn show clear correlations with total iron in both manganese ores and black shales. ∑REE of manganese ores has a large range with evident positive Ce anomalies and positive Eu anomalies. The Post Archean Australian Shale (PAAS) normalized rare earth element (REE) distribution patterns of manganese ores present pronounced middle rare earth element (MREE) enrichment, producing “hat‐shaped” REE plots. ∑REE of black shales is more variable compared with PAAS, and the PAAS‐normalized REE distribution patterns appear as “flat‐shaped” REE plots, lacking evident anomaly characteristics. δ¹³C values of carbonate in both manganese ores and the black shales show observable negative excursions. The comprehensive analysis suggests that the black shales formed in a reducing and quiet water column, while the manganese ores formed in oxic muddy seawater, which resulted from periodic transgressions. There was an oxidation–reduction cycle of manganese between the top water body and the bottom water body caused by the transgressions during the early Datangpo, which resulted in the dissolution of manganese. Through the exchange of the euphotic zone water and the bottom water, and episodic inflow of oxygenated water, the manganese in the bottom water was oxidized to Mn‐oxyhydroxides and rapidly buried along with algae. In the early diagenetic stage, Mn‐oxyhydroxides were reduced and dissolved in the anoxic pore water and then transformed into Mn‐carbonates by reacting with HCO₃^? from the degradation of organic matter or from seawater. In the intervals between transgressions, continuous supplies of terrigenous clastics and the high productive rates of organic matter in the euphotic zone resulted in the deposition of the black shales enriched in organic matter.     

PAN graphs An aid to GIS analysis

Abstract

Many data structures are possible for the storage of topological information for computer-based maps. The PAN graph is here suggested as an aid in the selection of a strategy appropriate to the application. Examples are given for the mapping of triangular networks and Thiessen polygons. Application of the technique is appropriate to both education in, and design of, spatial data structures for automated cartography and geographical information systems     

http://www.sciencedirect.com/science/article/pii/S1674987111000764

The Jinding Zn-Pb deposit has been generally considered to have formed from circulating basinal fluids in a relatively passive way,with fluid flow being controlled by structures and sedimentary facies,similar to many other sediments-hosted base metal deposits.However,several recent studies have revealed the presence of sand injection structures,intrusive breccias,and hydraulic fractures in the open pit of the Jinding deposit and suggested that the deposit was formed from explosive release of overpres-sured fluids.This study reports new observations of fluid overpressure-related structures from underground workings(Paomaping and Fengzishan).which show clearer crosscutting relationships than in the open pit.The observed structures include:I) sand(±rock fragment) dikes injecting into fractures in solidified rocks:2) sand(±rock fragment) bodies intruding into unconsolidated or semi-consolidated sediments;3) disintegrated semi-consolidated sand bodies;and 4) veins and breccias formed from hydraulic fracturing of solidified rocks followed by cementation of hydrothermal minerals.The development of ore minerals(sphalerite) in the cement of the various clastic injection and hydraulic fractures indicate that these structures were formed at the same time as mineralization.The development of hydraulic fractures and breccias with random orientation indicates small differential stress during mineralization,which is different from the stress field with strong horizontal shortening prior to mineralization. Fluid flow velocity may have been up to more than 11 m/s based on calculations from the size of the fragments in the clastic dikes.The clastic injection and hydraulic fracturing structures are interpreted to have formed from explosive release of overpressured fluids,which may have been related to either magmatic intrusions at depth or seismic activities that episodically tapped an overpressured fluid reservoir.Because the clastic injection and hydraulic structures are genetically linked with the mineralizing fluid source,they can be used as a guide for mineral exploration.     

Numerical boundary conditions for solar magnetohydrodynamic flows using the method of characteristics

We discuss the self-consistent time-dependent numerical boundary conditions on the basis of theory of characteristics for magnetohydrodynamics (MHD) simulations of solar plasma flows. The importance of using self-consistent boundary conditions is demonstrated by using an example of modeling coronal dynamic structures. This example demonstrates that the self-consistent boundary conditions assure the correctness of the numerical solutions. Otherwise, erroneous numerical solutions will appear.     

Hydraulic and salinity regime of two affected sites in the Yizre'el valley,Israel

Causes of recent salinization of numerous plots in the Yizre'el Valley of Israel were examined through a detailed field study of two severely affected sites. in particular, the theory of artesian influence on salt build-up in the upper cultivated soil layer was investigated. Two piezometer nests and 12 wells were installed to study the subsurface hydraulic regime. Water samples and soil extracts were taken to characterize the chemical composition down to 10m. No significant head differences were measured at the lower site, while at the upper site 96 per cent of the head that existed at the deep (7.5 m) artesian layer was dissipated within the overlying thick clay layer. Slight head differences were noted in the shallow layers. the deep-lying, coarse-textured aquifer differs markedly from the upper confining layers and constitutes an independent water body that has little relevance to surface processes. Chemical and hydrological analyses indicate that applied low-quality irrigation waters May, be the primary cause of downward-moving salinity and alkalinity which, in turn, affect soil permeability and site productivity.     

国家自主决定贡献的特征研究

国家自主贡献（NDC）机制于2015年巴黎气候变化大会确立,要求各缔约方参考各国国情以“自下而上”的方式提出应对气候变化目标。汇总梳理了作为国家自主贡献前身的国家自主决定贡献（INDC）164份,总结提出了各国文件的共性框架,重点对减缓和适应目标、实施条件和公平性等4类特征进行了统计分析。研究发现,各缔约方国家自主决定贡献文本差异显著,虽然具有共性框架,但是在具体目标阐述方式、覆盖经济行业及温室气体范围、实施条件和公平性阐述等方面选择迥异,此外,气候变化谈判立场对缔约方国家自主决定贡献承诺内容和形式的选择具有较大影响。     

GRAPES区域集合预报模式的初值扰动增长特征

基于GRAPES-REPS（Global and Regional Assimilation and Prediction Enhanced System-Regional Ensemble Prediction System）区域集合预报模式和集合变换卡尔曼滤波（Ensemble Transform Kalman Filter,ETKF）初值扰动方法,对2015年6月1~15日10 km与15 km水平分辨率分别进行集合预报试验,通过分析ETKF初值扰动分量、初值扰动方差准确率、动能谱、扰动能量演变、日变化及集合离散度、均方根误差等特征,揭示GRAPES-REPS区域集合预报ETKF初值扰动结构及增长特征。结果表明:（1）ETKF初值扰动方案产生的扰动能够保持所有正交、不相关方向的误差方差,且ETKF分量α参数值及放大因子具有较好的稳定性。（2）ETKF初值扰动方法生成的扰动场以大尺度扰动为主,扰动结构及能量具有随流型依赖特征,低层以内能扰动为主,高层以动能扰动为主,且集合扰动可以有效捕捉预报误差的结构。（3）GRAPES区域集合预报初值扰动总能量和集合离散度随预报时效的延长均呈发展趋势,但离散度增长率小于均方根误差增长率,即集合预报总体存在集合离散度不足的问题。（4）水平分辨率提高可以增加中高层大尺度扰动波谱能量,明显改进等压面及近地面风场及温度场的集合预报效果。值得指出的是,GRAPES-REPS区域集合预报低层内能扰动能量存在明显的日变化特征,特别是青藏高原地区更加显著,需要进一步研究青藏高原初值扰动结构的合理性。     

1981－2020年沂沭河流域极端降水事件特征及环流背景

利用1981—2020年沂沭河流域内12个气象台站逐日降水观测资料,西太平洋副热带高压（西太副高）指数、太平洋年代际振荡指数（PDO）等资料以及NCEP/NCAR逐日再分析资料,采用线性趋势分析、累积距平法联合滑动t检验、morlet小波分析、相关性分析、合成分析等方法,研究近40 a沂沭河流域极端降水事件的时空变化特征,并进一步研究极端降水指数与气候因子之间的相关性以及极端降水事件的异常环流背景。结果表明：沂沭河流域极端降水事件具有整体上增多且强度增强的特征,且近年来在频次和年极端降水量上波动峰间值增大,分别为6.2 d/a、538.2 mm/a,极端降水事件日趋严重。空间分布上南多北少,中部、北部较南部增速更明显。极端降水频次和年极端降水量均在1989年和2002年左右突增;极端降水强度在1989年突增,2000年左右突减。极端降水的频次、强度和年极端降水量分别以22 a、10 a和22 a的周期波动为主。西太副高的脊线位置跟频次和年极端降水量具有正相关性,PDO与频次和年极端降水量具有负相关性。东亚夏季风强度和西太副高的位置是影响沂沭河流域极端降水事件多寡的重要因子,在预测该流域的极端降水情况时可做参考依据。